http://www.eoearth.org/ Wed, 31 Dec 1969 19:00:00 GMT 15 en-us cutler@bu.edu http://www.eoearth.org/e/i/header_logo.gif http://www.eoearth.org/ http://www.eoearth.org/article/Lesser_Long-nosed_Bat <a href='/article/Lesser_Long-nosed_Bat'><img border='0' src='/upload/thumb/6/61/Lesser_long-nosed_bat1_USFS_MerlinDTuttle.jpg/200px-Lesser_long-nosed_bat1_USFS_MerlinDTuttle.jpg' width='100'/></a> <p><em><strong>This article was prepared for the U.S. Forest Service by Kim Winter of the <a href="http://www.coevolution.org/people.html" class='external text' title="http://www.coevolution.org/people.html">Coevolution Institute</a>. The images were made by Merlin D. Tuttle of <a href="http://www.batcon.org/home/default.asp" class='external text' title="http://www.batcon.org/home/default.asp">Bat Conservation International</a>.</strong></em></p> <p>During late spring in the <a href="/article/Sonoran_desert">Sonoran Desert</a>, the white flowers of Saguaro (<em>Carnegiea gigantea</em>) cacti bloom for just one evening to attract Lesser Long-nosed Bats (<em>Leptonycteris curasoae yerbabuena</em>) and Mexican Long-tongued Bats (<em>Choeronycteris mexicana</em>) for <a href="/article/Pollination">pollination</a>. The bats use their elongated muzzles to reach deep into Saguaro blossoms for nectar, covering their hairy heads with copious amounts of pollen that drop onto other flowers as the bats fly from cactus to cactus throughout the night. The blossoms close by the following afternoon, allowing daytime visitors such as wasps, bees, butterflies, and birds to pick up any remaining nectar or pollen left behind.</p> <p>Lesser long-nosed bats are perfectly adapted to feed and pollinate Saguaros and other large Southwestern and Mexican succulents such as Organ-pipe Cactus (<em>Stenocereus thurberi</em>), agaves (<em>Agave </em>spp.) and Cardón (<em>Pachycereus pringlei</em>). Their narrow snouts easily detect the strong melon scent of the night-blooming flowers, and their brush-tipped tongues extend deeply into flowers to extract rich quantities of nectar and pollen produced by the cacti to ensure that pollinators will find them during their brief period of bloom.</p> <p>Bat pollination of cacti and agaves helps maintain healthy <a href="/article/Desert_biome">desert</a> <a href="/article/Ecosystem">ecosystems</a>. Saguaros, the state flower of Arizona, are <a href="/article/Keystone_species">keystone species</a> in the Sonoran Desert and grow up to 50 feet in height, providing important perching and nesting sites for Red-tailed Hawks (<em>Buteo jamaicensis</em>); and nesting cavities for Gilded Flickers (<em>Colaptes chrysoides</em>) and Gila Woodpeckers (<em>Melanerpes uropygialis</em>), Elf Owls (<em>Micrathene whitneyi</em>), Purple Martins (<em>Progne subis</em>), and other birds. Once the Saguaro fruit ripens in June, Lesser Long-nosed Bats, White-winged Doves (<em>Zenaida asiatica</em>), Gila Woodpeckers, and other birds consume the fleshy red pulp and thereby disperse the seeds, which pass through their guts intact. Agaves provide an important food resource to the Lesser Long-nosed Bat during its annual migration from <a href="/article/Mexico">Mexico</a> to the Sonoran Desert.</p> <p>The Lesser Long-nosed Bat is federally listed as endangered species by the <a href="/article/United_States_Fish_and_Wildlife_Service">U.S. Fish and Wildlife Service</a> under the <a href="/article/Endangered_Species_Act%2C_United_States">Endangered Species Act of 1973</a>. The survival of both bats and their desert food plants are threatened by loss of habitat due to development, <a href="/article/Invasive_species">invasive</a> annual <a href="/article/Grasses">grasses</a>, and changes in <a href="/article/Fire_ecology_fact_sheet">fire</a> regimes. With nature in the balance, ensuring the future of the southwestern desert will depend on appreciating and protecting the roles played by both pollinator and plant in these fragile ecosystems.</p> <p><big><strong>Further Reading</strong></big></p> <ul><li>Celebrating Wildflowers: <a href="http://www.fs.fed.us/wildflowers/pollinators/bats.shtml" class='external text' title="http://www.fs.fed.us/wildflowers/pollinators/bats.shtml">Bat Pollination</a></li><li><a href="http://www.batcon.org/" class='external text' title="http://www.batcon.org/">Bat Conservation International</a></li><li><a href="http://www.desertmuseum.org/pollination/bats.html" class='external text' title="http://www.desertmuseum.org/pollination/bats.html">Arizona-Sonora Desert Museum</a></li><li>U.S. Fish and Wildlife Service—<a href="http://www.fws.gov/endangered/bats/bats.htm" class='external text' title="http://www.fws.gov/endangered/bats/bats.htm">Endangered Bats</a></li><li>Lubee Bat Conservancy: <a href="http://www.lubee.org/aboutbats.aspx" class='external text' title="http://www.lubee.org/aboutbats.aspx">About Fruit and Nectar Bats</a> </li><li><a href="http://www.pollinator.org" class='external text' title="http://www.pollinator.org">North American Pollinator Protection Campaign</a> </li></ul><p> <br /> <p><br style="clear: left" /> <center> </p> </center></p> <p><a href='/article/Lesser_Long-nosed_Bat'>Read Full Article...</a></p> http://www.eoearth.org/article/Lesser_Long-nosed_Bat Fri, 20 Nov 2009 05:27:56 GMT http://www.eoearth.org/article/Leads_(sea_ice) <a href='/article/Leads_(sea_ice)'><img border='0' src='/upload/thumb/6/67/Leadice.jpg/250px-Leadice.jpg' width='100'/></a> <p>Leads are narrow, linear cracks in the ice that form when ice floes diverge or shear as they move parallel to each other. The formation of leads is similar to mid-ocean ridges or shear zones that form from Earth&#39;s moving <a href="/article/Plate_tectonics">tectonic plates</a>. The width of leads varies from a couple of meters to over a kilometer. Leads can often branch or intersect, creating a complex network of linear features in the ice. In the winter, leads begin to freeze almost immediately from the cold air.</p> <p>Leads are important for several reasons. First, seasonal changes influence local and regional climate. Leads are much darker than surrounding ice, which during the summer, results in relatively lower <a href="/article/Albedo">albedo</a>, or the ability to reflect light. Because of lower albedo, leads absorb more solar energy than surrounding <a href="/article/Ocean">ocean</a>, which heats the <a href="/article/Seawater">water</a> in the leads and speeds up the melting of surrounding ice. At the beginning of winter, as <a href="/article/Sea_ice">sea ice</a> begins to refreeze in leads, brine adds salt to the open ocean layer. In leads that persist throughout the winter, relatively warm ocean water is exposed to the cold <a href="/article/Atmospheric_composition">atmosphere</a>, releasing heat and moisture into the atmosphere. Thus, leads are often accompanied by low-level <a href="/article/Cloud_formation_processes">clouds</a> downwind. </p> <p>Leads are also important for wildlife. Seals, whales, penguins, and other animals rely on leads for access to <a href="/article/Oxygen">oxygen</a>. Polar bears in the <a href="/article/Arctic">Arctic</a> often hunt near leads, because they know that their prey is likely come to the surface to breathe in such areas.</p> <p>Finally, leads are important for navigation. Even when they freeze, leads tend to contain thinner and weaker ice that allows submarines to more easily surface through the ice and icebreakers to more easily traverse the ice.</p><p><br /> <p><br style="clear: left" /> <center> </p> </center> </p> <p><a href='/article/Leads_(sea_ice)'>Read Full Article...</a></p> http://www.eoearth.org/article/Leads_(sea_ice) Fri, 20 Nov 2009 05:24:13 GMT http://www.eoearth.org/article/Keystone_species <a href='/article/Keystone_species'><img border='0' src='/upload/thumb/0/04/Pisaster.jpg/300px-Pisaster.jpg' width='100'/></a> <p>A keystone species is a species that exerts an impact on its community that is both strong and disproportionate to its abundance. The keystone analogy refers to the architectural element at the apex of an arch that locks the other pieces into position, and is used colloquially to refer to the supporting element of a larger structure. Paine (1969) originally defined a keystone predator as a species that feeds preferentially on the dominant <a href="/article/Competition">competitor</a> among its prey species, such that the keystone predator’s feeding prevents the dominant prey from excluding other species, and therefore maintains a higher <a href="/article/Species_diversity">species diversity</a> in the system than in the keystone’s absence. In the literature of ecological science, keystone <a href="/article/Predation">predation</a> is now often used to refer to predation on a dominant competitor that, as a consequence, maintains high prey diversity in the system.</p> <p>Since Paine’s introduction of the term, the keystone concept has been generalized to a widening range of phenomena loosely grouped by the fact that they have important influences on some aspect of <a href="/article/Ecosystem">ecosystem</a> structure or functioning. In an effort to clarify and standardize the meaning of the keystone species concept, Power et al. (1996) introduced an important practical distinction by defining a <em>keystone </em>species as one whose effect is both “large, and disproportionately large relative to its abundance”. This definition distinguishes keystone species from <em>dominant </em>species--in the latter case, effects are large at least in part because the species is very abundant. For example, in northern boreal <a href="/article/Forest_biome">forests</a>, spruce has a fundamental and large impact on the structure and function of the ecosystem, largely because it is far and away the most abundant plant species—that is, it is a dominant species. In contrast, in the northeastern Pacific Ocean, sea otters have very strong cascading impacts on the structure and functioning of rocky shore ecosystems despite their relatively low abundance. Their disproportionate impacts stem from their voracious appetite for sea urchins, <a href="/article/Herbivory">herbivorous</a> invertebrates whose feeding on kelps in turn determine whether rocky bottoms will become dominated by large kelps (in the absence of urchins) versus by crustose calcified algae (in the presence of urchins). The kelp beds facilitated by sea otter predation on urchins offer both abundant food and physical structure in which fishes and other animals can grow and escape their predators, whereas the crustose algal “pavements” that develop in the absence of sea otters leave the bottom with no structure and little plant biomass to support other animals. Thus, in the northeast Pacific, sea otters are a keystone species because, despite their relatively low abundance, they are largely responsible for maintaining the existence of kelp beds and thus have a fundamental impact on <a href="/article/Coastal_zone">coastal</a> ecosystems. </p><p>Although the keystone species concept originally referred specifically to a <a href="/article/Predation">predator</a>, the definition of Power et al. implies that keystone species can exert their influence through other interactions as well, including <a href="/article/Competition">competition</a>, <a href="/article/Mutualism">mutualism</a>, <a href="/article/Pollination">pollination</a>, dispersal, etc. For example, species that exert a large impact on their ecosystem by modifying habitat have been referred to as “ecosystem engineers”. If an ecosystem engineer performs its function even when it is at low <a href="/article/Population">population</a> abundance, it could be considered a keystone species. Beavers are the classic example. Diseases that have strong impacts on their hosts would also be classic examples of keystone species under the broad definition of Power et al., since the disease organisms generally have a very small biomass in the system. For example, an outbreak of rinderpest in the late 19th century in southern Africa had a catastrophic impact on ungulates, and their loss cascaded to cause a fundamental transition in the African landscape, from <a href="/article/Grassland_biome">grassland</a> to woody savannah.</p><p>The concept of keystone species has also become an important issue in conservation biology insofar as the loss or decline of keystone species may have far-reaching consequences for the structure and functioning of the ecosystems in which they live. For example, there is concern--and some evidence--that declines of relatively rare top predators in <a href="/article/Terrestrial_biome">terrestrial</a> ecosystems have allowed populations of herbivores such as white-tailed deer to explode, with strong impacts on the biomass and species composition of terrestrial vegetation. </p><p><strong><big>Further Reading</big></strong></p><ul><li>Jones, C. G., Lawton, J. H. &amp; Shachak, M. 1994 Organisms as Ecosystem Engineers. <em>Oikos </em>69, 373-386. </li><li>Menge, B.A., Berlow E.L., Blanchette, C.A., et al. 1994. <a href="http://www.esajournals.org/perlserv/?request=get-abstract&amp;doi=10.1043%2F0012-9615(1994)064%5B0249%3ATKSCVI%5D2.0.CO%3B2&amp;ct=1" class='external text' title="http://www.esajournals.org/perlserv/?request=get-abstract&amp;doi=10.1043/0012-9615(1994)064[0249:TKSCVI]2.0.CO;2&amp;ct=1">The keystone species concept - variation in interaction strength in a rocky intertidal habitat</a>. <em>Ecological Monographs</em> 64: 249-286. </li><li> Mills L.S., Soule M.E., Doak D.F. 1993. <a href="http://bio.research.ucsc.edu/people/doaklab/publications/1993mills_soule_doak.pdf" class='external text' title="http://bio.research.ucsc.edu/people/doaklab/publications/1993mills soule doak.pdf">The Keystone-Species Concept In Ecology And Conservation</a>. <em>Bioscience </em>43: 219-224. </li><li>Paine, R.T. 1969. A note on trophic complexity and community stability. <em>American Naturalist</em> 103: 91. </li><li>Power, M. E., Tilman, D., Estes, J. A., Menge, B. A., Bond, W. J., Mills, L. S., Daily, G., Castilla, J. C., Lubchenco, J. &amp; Paine, R. T. 1996. <a href="http://www.nau.edu/~envsci/ENV330website/ENV330/downloads/PowerKeytsoneSpp.pdf" class='external text' title="http://www.nau.edu/~envsci/ENV330website/ENV330/downloads/PowerKeytsoneSpp.pdf">Challenges in the quest for keystones</a>. <em>Bioscience </em>46:609-620.</li><li>Soule, M.E., Estes, J.A., Miller, B. and Honnold, D.L. 2005. Strongly interacting species. conservation policy, management, and ethics. <em>Bioscience </em>55:168-176. </li></ul> <p><a href='/article/Keystone_species'>Read Full Article...</a></p> http://www.eoearth.org/article/Keystone_species Thu, 19 Nov 2009 08:02:24 GMT http://www.eoearth.org/article/Beyond_Old_Growth_(report) <a href='/article/Beyond_Old_Growth_(report)'><img border='0' src='/media/approved/8/82/Beyond_old_growth_cover_smaller.jpg' width='100'/></a> </p> <p><a href='/article/Beyond_Old_Growth_(report)'>Read Full Article...</a></p> http://www.eoearth.org/article/Beyond_Old_Growth_(report) Wed, 18 Nov 2009 05:16:27 GMT http://www.eoearth.org/article/Desertification <a href='/article/Desertification'><img border='0' src='/upload/thumb/9/97/Desertifcation_World_Map.jpg/250px-Desertifcation_World_Map.jpg' width='100'/></a> <p>Desertification is the persistent degradation of dryland ecosystems by variations in climate and human activities. Home to a third of the human population in 2000, drylands occupy nearly half of Earth’s land area. Across the world, desertification affects the livelihoods of millions of people who rely on the benefits that dryland ecosystems can provide. </p><p>In drylands, <a href="/article/Water_resources">water scarcity</a> limits the production of crops, forage, wood, and other services ecosystems provide to humans. Drylands are therefore highly vulnerable to increases in human pressures and climatic variability, especially sub-Saharan and Central Asian drylands. </p><p>Some 10 to 20% of drylands are already degraded, and ongoing desertification threatens the world’s poorest populations and the prospects of poverty reduction. Therefore, desertification is one of the greatest environmental challenges today and a major barrier to meeting basic human needs in drylands. </p> <p><a href='/article/Desertification'>Read Full Article...</a></p> http://www.eoearth.org/article/Desertification Tue, 17 Nov 2009 04:55:31 GMT http://www.eoearth.org/article/Salt_marsh <a href='/article/Salt_marsh'><img border='0' src='/upload/thumb/5/55/Nova_Scotia_salt_marsh.jpg/300px-Nova_Scotia_salt_marsh.jpg' width='100'/></a> <p>Salt marshes are coastal wetlands found throughout the world on protected shorelines and on the edges of estuaries where freshwater mixes with seawater. An <a href="/article/Estuary">estuary</a> is a partially enclosed body of water where freshwater from rivers and streams mixes with salt water from the ocean. Bays, inlets, harbors, and sounds can all be estuaries if they have a mixture of fresh and salt water. Salt marshes are transitional zones between the aquatic and terrestrial world. They are very conspicuous along the shorelines of the East Coast and Gulf Coast of North America. On the Atlantic coast, salt marshes are found in New England, become more extensive from New Jersey to northern Florida, and are most extensive on the coasts of the Carolinas and Georgia. Further south in Florida, they are replaced by mangrove swamps. Salt marshes are relatively scarce on the Pacific Coast, where the shoreline tends to be rocky. In the upper parts of estuaries where the salt water is more diluted with fresh water, they are referred to as “brackish” marshes. Further up the <a href="/article/Estuary">estuary</a> there is a transition to fresh water marshes that are affected by the tides, and still further up are non-tidal fresh water marshes.</p><p>Salt and brackish marshes are also sometimes called tidal marshes, since they occur in the zone between low and high tides. Marshes on the East Coast of the U.S. experience two high and two low tides a day, being alternately flooded and drained. The rise and fall of the tides, an obvious feature of shorelines, is caused by the gravitational pull of the sun and the moon on the Earth’s waters. </p><p>Salt marsh plants cannot grow where waves are strong, but thrive along quiet coasts. Salt marshes are periodically flooded by tides, so the plants living there must be able to deal with being submerged in salt water. This is stressful for two reasons: the salt and the water. The salinity, or salt content, varies depending upon whether the marshes are located directly adjacent to the ocean or further upstream in the <a href="/article/Estuary">estuary</a>. Salt marsh soils tend to be waterlogged and low in <a href="/article/Oxygen">oxygen</a> which is also stressful to a plant. The water level and salinity level determine which species are found in a particular marsh. </p><p>Salt or brackish marshes are home to unique species of grasses, which are flowering plants found only in shallow intertidal areas. These plants are highly specialized and able to live in salt water and salty soil, and are therefore referred to as “halophytes.” They are also able to survive submerged in water part of the time, and are thus classified as “hydrophytes.” Tides play a major role in the lives of marsh animals as well, shaping their surroundings and behavior. Twice every day these marine creatures are exposed to the air and so must be able to cope with two quite different environments: an immersion in seawater during high tide, and exposure to air, sun, wind and possibly a dousing of fresh water in the form of rain during low tide. The higher up their location on the marsh, the longer their exposure to this alien environment. Marine animals must find a way to keep moist during low tide. When the tide is out, there is no food for those that obtain their food from the water. Many of these animals time their reproduction with the tides, often at the time of the full moon or new moon. </p><p>The environmental conditions in salt marshes are highly variable, as the salinity can fluctuate greatly. The <a href="/article/Estuary">estuary</a> is a place where incoming fresh water and ocean water mix, and the salinity can vary depending on the phase in the tidal cycle and the amount of rainfall. Salt marshes may experience salinities ranging from almost freshwater to full seawater, and anything living there must be able to tolerate these wide swings in environmental conditions. Temperature can also be widely variable, as the air in summer is much warmer than the water, and the air in winter is much colder than the water. Air temperature may be below freezing in winter and over 90° F in the summer. Because of these wide fluctuations, salt marshes do not have a great variety (<a href="/article/Biodiversity">biodiversity</a>) of animals and plants; only a limited number of species can tolerate these conditions. Animals and plants in salt marshes include some that have terrestrial origins, like grasses, insects, birds and mammals, and others with marine origins like algae, mollusks, and fish. </p><p><strong>Further reading</strong><br /> <a href="http://www.dnr.sc.gov/marine/pub/seascience/dynamic.html" class='external text' title="http://www.dnr.sc.gov/marine/pub/seascience/dynamic.html">Dynamics of the Salt Marsh</a> (South Carolina Department of Natural Resources)<br /> <a href="http://www.epa.gov/owow/wetlands/types/marsh.html" class='external text' title="http://www.epa.gov/owow/wetlands/types/marsh.html">Marshes</a> (U. S. Environmental Protection Agency)<br /> <a href="http://life.bio.sunysb.edu/marinebio/spartina.html" class='external text' title="http://life.bio.sunysb.edu/marinebio/spartina.html">Spartina Salt Marshes</a> (State University of New York at Stony Brook, Department of Biological Sciences)<br /> <a href="http://www.dep.state.fl.us/COASTAL/habitats/saltmarshes.htm" class='external text' title="http://www.dep.state.fl.us/COASTAL/habitats/saltmarshes.htm">Salt Marshes</a> (Florida Department of Environmental Protection)<br /> </p> <p><a href='/article/Salt_marsh'>Read Full Article...</a></p> http://www.eoearth.org/article/Salt_marsh Mon, 16 Nov 2009 06:18:40 GMT http://www.eoearth.org/article/Poaching <a href='/article/Poaching'><img border='0' src='/upload/thumb/a/af/African_lion_in_queen_Elizabeth_NP.jpg/250px-African_lion_in_queen_Elizabeth_NP.jpg' width='100'/></a> <p style="font: normal normal normal 20px/normal Papyrus; margin: 0px"><span style="font-family: Arial; font-size: 12px; line-height: 18px" class="Apple-style-span">Poaching is the illegal hunting, killing or capturing of animals. This can occur in a variety of ways.  Poaching can refer to the failure to comply with regulations for legal harvest, resulting in the illegal taking of wildlife that would otherwise be allowable. Examples include: Taking without a license or permit, use of a prohibited weapon or trap, taking outside of the designated time of day or year, and taking of a prohibited sex or life stage.  Poaching can also refer to the taking of animals from a gazzetted wildlife sanctuary, such as a national park, game reserve, or zoo. Most countries enforce various sanctions on the hunting of wild animals, and international controls, such as bans, restrictions and monitored <a href="/article/Trade_and_the_environment">trade</a>, are all aimed at controlling poaching. However, it is important to note that hunting, under specific regulations, is in fact often permitted in designated game preserves.</span></p> <p><a href='/article/Poaching'>Read Full Article...</a></p> http://www.eoearth.org/article/Poaching Fri, 13 Nov 2009 04:54:02 GMT http://www.eoearth.org/article/Marine_reserves <a href='/article/Marine_reserves'><img border='0' src='/upload/thumb/1/16/MarineReserves_pub_rate.gif/300px-MarineReserves_pub_rate.gif' width='100'/></a> <p>Marine reserves are areas in the <a href="/article/Ocean">ocean</a> where no extractive activities are allowed. They are also often called ‘no-take zones’, since the killing, harming, or harassing of any plants or animals within the reserve boundaries is not allowed, and they are part of a broader spectrum of marine spatial management tools that fit under the umbrella term ‘Marine Protected Areas’, or MPAs. </p><p>The idea of setting aside fully protected regions of the oceans has been around for a long time, but it is only in the past decade or two that marine reserves have become a common tool for managing and protecting marine resources. Most commonly reserves are established for conservation purposes, but strong interest also exists in using them as a <a href="/article/Marine_fisheries">fisheries</a> management tool. Even so, a relatively small portion of the world’s oceans to date have been set aside in marine reserves – less that 1%. </p> <p><a href='/article/Marine_reserves'>Read Full Article...</a></p> http://www.eoearth.org/article/Marine_reserves Thu, 12 Nov 2009 05:40:10 GMT http://www.eoearth.org/article/Turtle <a href='/article/Turtle'><img border='0' src='/upload/thumb/8/88/Turtleintro.jpg/200px-Turtleintro.jpg' width='100'/></a> <p>To look at a Snapping turtle with its horny shell and scaley tail, you might imagine that you are glimpsing a dinosaur. In fact, turtles are even older than dinosaurs and were common on earth 50 million years before the first dinosaurs appeared. </p><p>The scientific name for turtles, comes from the Latin testudo, which means tortoise. Six <a href="/article/Reptile_families">reptile families</a> of the order Testudines are represented in Canada: Chelydridae, Emydidae, Dermochelyidae, Cheloniidae, Trionychidae, and Kinosternidae.</p><p>&nbsp;</p> <p><a href='/article/Turtle'>Read Full Article...</a></p> http://www.eoearth.org/article/Turtle Wed, 11 Nov 2009 09:36:51 GMT http://www.eoearth.org/article/Rock_cycle <a href='/article/Rock_cycle'><img border='0' src='/upload/thumb/e/e8/Rockscycle.gif/350px-Rockscycle.gif' width='100'/></a> <p>The rock cycle is a general model that describes how various geological processes create, modify, and influence rocks (Figure 1). This model suggests that the origin of all rocks can be ultimately traced back to the solidification of molten magma. Magma consists of a partially melted mixture of elements and compounds commonly found in rocks. Magma exists just beneath the solid crust of the Earth in an interior zone known as the mantle. </p><p><a href="/article/Igneous_rock">Igneous rocks</a> form from the cooling and crystallization of magma as it migrates closer to the Earth's surface. If the crystallization process occurs at the Earth's surface, the rocks created are called extrusive igneous rocks. Intrusive igneous rocks are rocks that form within the Earth's solid lithosphere. Intrusive igneous rocks can be brought to the surface of the Earth by denudation and by a variety of <a href="/article/Plate_tectonics">tectonic</a> processes. </p><p>All rock types can be physically and chemically decomposed by a variety of surface processes collectively known as <a href="/article/Weathering">weathering</a>. The debris that is created by weathering is often transported through the landscape by erosional processes via <a href="/article/Stream">streams</a>, <a href="/article/Glacier">glaciers</a>, <a href="/article/Wind">wind</a>, and gravity. When this debris is deposited as a permanent sediment, the processes of burial, compression, and chemical alteration can modify these materials over long periods of time to produce sedimentary rocks. </p><p>A number of geologic processes, like tectonic <a href="/article/Folding_and_faulting_in_the_Earth%27s_crust">folding and faulting in the Earth's crust</a>, can exert <a href="/article/Heat">heat</a> and <a href="/article/Pressure">pressure</a> on both <a href="/article/Igneous_rock">igneous</a> and sedimentary rocks causing them to be altered physically or chemically. Rocks modified in this way are termed <a href="/article/Metamorphic_rock">metamorphic rocks</a>. </p><p>All of the rock types described above can be returned to the Earth's interior by <a href="/article/Plate_tectonics">tectonic</a> forces at areas known as subduction zones. Once in the Earth's interior, extreme pressures and <a href="/article/Temperature">temperatures</a> melt the rock back into magma to begin the rock cycle again. </p><p>Rock cycle is important for recording the earth's history in the universe and expressing the earth's dynamic. </p><p><b>Further Reading</b> </p> <ul><li> <a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Rock_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Rock_cycle Mon, 09 Nov 2009 06:23:28 GMT http://www.eoearth.org/article/Rock_cycle <a href='/article/Rock_cycle'><img border='0' src='/upload/thumb/e/e8/Rockscycle.gif/350px-Rockscycle.gif' width='100'/></a> <p>The rock cycle is a general model that describes how various geological processes create, modify, and influence rocks (Figure 1). This model suggests that the origin of all rocks can be ultimately traced back to the solidification of molten magma. Magma consists of a partially melted mixture of elements and compounds commonly found in rocks. Magma exists just beneath the solid crust of the Earth in an interior zone known as the mantle. </p><p><a href="/article/Igneous_rock">Igneous rocks</a> form from the cooling and crystallization of magma as it migrates closer to the Earth's surface. If the crystallization process occurs at the Earth's surface, the rocks created are called extrusive igneous rocks. Intrusive igneous rocks are rocks that form within the Earth's solid lithosphere. Intrusive igneous rocks can be brought to the surface of the Earth by denudation and by a variety of <a href="/article/Plate_tectonics">tectonic</a> processes. </p><p>All rock types can be physically and chemically decomposed by a variety of surface processes collectively known as <a href="/article/Weathering">weathering</a>. The debris that is created by weathering is often transported through the landscape by erosional processes via <a href="/article/Stream">streams</a>, <a href="/article/Glacier">glaciers</a>, <a href="/article/Wind">wind</a>, and gravity. When this debris is deposited as a permanent sediment, the processes of burial, compression, and chemical alteration can modify these materials over long periods of time to produce sedimentary rocks. </p><p>A number of geologic processes, like tectonic <a href="/article/Folding_and_faulting_in_the_Earth%27s_crust">folding and faulting in the Earth's crust</a>, can exert <a href="/article/Heat">heat</a> and <a href="/article/Pressure">pressure</a> on both <a href="/article/Igneous_rock">igneous</a> and sedimentary rocks causing them to be altered physically or chemically. Rocks modified in this way are termed <a href="/article/Metamorphic_rock">metamorphic rocks</a>. </p><p>All of the rock types described above can be returned to the Earth's interior by <a href="/article/Plate_tectonics">tectonic</a> forces at areas known as subduction zones. Once in the Earth's interior, extreme pressures and <a href="/article/Temperature">temperatures</a> melt the rock back into magma to begin the rock cycle again. </p><p>Rock cycle is important for recording the earth's history in the universe and expressing the earth's dynamic. </p><p><b>Further Reading</b> </p> <ul><li> <a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Rock_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Rock_cycle Mon, 09 Nov 2009 06:22:55 GMT http://www.eoearth.org/article/Osmoregulator <a href='/article/Osmoregulator'><img border='0' src='/upload/thumb/a/aa/Osmoregulator1.JPG/300px-Osmoregulator1.JPG' width='100'/></a> <p>An osmoregulator is an organism that can regulate or keep the solutes or salts of its body fluid at a higher or lower concentration than the concentration of solutes in the external medium, although this regulation may be limited at extremely high or extremely low external solute concentrations. If the solutes in the organism&#39;s body fluids are kept at a concentration higher than that of the external medium (e.g., lake water), this organism&#39;s body fluids are said to be hyperosmotic to the external medium and the organism is a hyperosmotic osmoregulator. If the solutes of the organism&#39;s body fluids are kept at a concentration lower than that of the external medium (<a href="/article/Seawater">seawater</a> for example), this organism&#39;s body fluids are said to be hypoosmotic to the external medium and the organism is a hypoosmotic osmoregulator. If the solutes of the organism&#39;s body fluids are the same concentration as that of the external medium, the organism is isoosmotic and is at its isoosmotic point (see the Figure). An organism could be hyperosmotic in an external medium of low solute concentration and be isoosmotic in an external medium of higher solute concentration. Conversely, an organism could be hypoosmotic in an external medium of high solute concentration and be isoosmotic in an external medium of low solute concentration. Both of these situations could happen, for example, in a <a href="/article/Tidal_marsh">tidal marsh</a> or other estuarine habitat because in these environments the solute concentrations of the water change with the <a href="/article/Tide">tides</a>, salinity being lower at low tide and higher at high tide as ocean water floods the estuary. In either case the organism is still an osmoregulator as long as the solute concentration of its body fluids are different than the solute concentration of the external medium. An organism could also be hyperosmotic in both low and high solute concentrations in the external medium. This is the case with sharks. They are always hyperosmotic because of the high concentration of urea in their bodies. </p><p>Organisms that are hyperosmotic tend to lose solutes to the external medium by diffusion and to gain water from the external medium by osmosis. The opposite is true of organisms that are hypoosmotic, which tend to gain solutes from the external medium by diffusion and lose water to the external medium by osmosis. Organisms that are isoosmotic are at equilibrium with the external medium and do not gain or lose solutes or water. </p> <p>Hyperosmotic regulators decrease the loss of solutes from the blood to the external medium via chloride cells that actively take up the chloride <a href="/article/Ion">ions</a> that were lost to the external medium due to diffusion. In animals, chloride cells are located in the gills. Hyperosmotic regulators decrease the osmotic gain of water in the blood from the external medium by excreting urine that is hypoosmotic to the blood. Hyperosmotic regulators decrease the osmotic gain of water in their cells from the blood by joining amino acids into proteins. This decreases the gain of water into the cells because the cells become hypoosmotic to the blood when the solute concentration is decreased by joining many amino acids into fewer proteins, and this makes less water move into the cells from the blood. Although proteins are larger than amino acids, they do not increase the solute concentration as much as the many amino acids needed to make a protein. In these ways, regulators can maintain <a href="/article/Homeostasis">homeostasis</a> in their blood and cells. </p><p>Animals that are hypoosmotic regulators decrease the gain of solutes that diffuse into the blood from the external medium by drinking the external medium and having efficient kidneys that can remove the solutes, pumping them into the urine so that the urine is hyperosmotic to the blood. Hypoosmotic regulators decrease the osmotic loss of water from the blood to the external medium by having body surfaces that are relatively impermeable. Hypoosmotic regulators decrease the osmotic loss of water from their cells to their blood by breaking proteins into amino acids. This decreases the loss of water from cells into the surrounding blood because the resulting high concentration of amino acids in the cells makes them hyperosmotic to the blood. This increases the gain of water into the cells from the blood and maintains homeostasis.</p><p>Almost all aquatic animals are physiological osmoregulators. Exceptions include soft-bodied animals such as worms and <a href="/article/Mollusca">mollusks</a>, which are <a href="/article/Osmoconformer">osmoconformers</a>. Some animals are capable of behavioral osmoregulation --  they behave in certain ways that regulate how fast or slowly they encounter the differing solute concentration of the external medium. For example, certain animals may seek out microhabitats with favorable salinity, and bivalved mollusks such as clams may close their shells when bathed by water with unfavorabale solute concentrations.   </p> <p><a href='/article/Osmoregulator'>Read Full Article...</a></p> http://www.eoearth.org/article/Osmoregulator Fri, 06 Nov 2009 06:40:32 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Fri, 06 Nov 2009 06:40:02 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Fri, 06 Nov 2009 06:39:35 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Fri, 06 Nov 2009 06:39:23 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Tue, 03 Nov 2009 05:56:01 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Tue, 03 Nov 2009 05:55:28 GMT http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic <a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'><img border='0' src='/upload/thumb/8/89/Fig9.2_ave_sea_ice_cover.JPG/620px-Fig9.2_ave_sea_ice_cover.JPG' width='100'/></a> <p>This is Section 9.2.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a><br /> Lead Author: Harald Loeng; Contributing Authors: Keith Brander, Eddy Carmack, Stanislav Denisenko, Ken Drinkwater, Bogi Hansen, Kit Kovacs, Pat Livingston, Fiona McLaughlin, Egil Sakshaug;  Consulting Authors: Richard Bellerby, Howard Browman,Tore Furevik, Jacqueline M. Grebmeier, Eystein Jansen, Steingrimur Jónsson, Lis Lindal Jørgensen, Svend-Aage Malmberg, Svein Østerhus, Geir Ottersen, Koji Shimada</p><p>&nbsp;</p><p><a href="/article/Sea_ice_in_the_Arctic">Sea ice</a> controls the exchange of <a href="/article/Heat">heat</a> and other properties between the <a href="/article/Atmosphere_layers">atmosphere</a> and <a href="/article/Ocean">ocean</a> and, together with <a href="/article/Snow_cover_in_the_Arctic">snow cover</a>, determines the penetration of <a href="/article/Solar_radiation">light</a> into the sea. Sea ice also provides a surface for particle and snow deposition, a habitat for <a href="/article/Plankton">plankton</a>, and contributes to stratification through ice melt. The zone seaward of the ice edge is important for plankton production and planktivorous fish. For some <a href="/article/Implications_for_biodiversity_conservation_in_the_Arctic">marine mammals</a> sea ice provides a place for birth and also functions as a nursery area. </p><p>This section describes features of sea ice that are important for physical oceanographic processes and the <a href="/article/Arctic_marine_environments">marine ecosystem</a>. More detailed information about sea ice is given in <a href="/article/Cryosphere_and_Hydrology_in_the_Arctic">Chapter 6</a>. </p> <p><a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic Mon, 02 Nov 2009 07:56:27 GMT http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic <a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'><img border='0' src='/upload/thumb/8/89/Fig9.2_ave_sea_ice_cover.JPG/620px-Fig9.2_ave_sea_ice_cover.JPG' width='100'/></a> <p>This is Section 9.2.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a><br /> Lead Author: Harald Loeng; Contributing Authors: Keith Brander, Eddy Carmack, Stanislav Denisenko, Ken Drinkwater, Bogi Hansen, Kit Kovacs, Pat Livingston, Fiona McLaughlin, Egil Sakshaug;  Consulting Authors: Richard Bellerby, Howard Browman,Tore Furevik, Jacqueline M. Grebmeier, Eystein Jansen, Steingrimur Jónsson, Lis Lindal Jørgensen, Svend-Aage Malmberg, Svein Østerhus, Geir Ottersen, Koji Shimada</p><p>&nbsp;</p><p><a href="/article/Sea_ice_in_the_Arctic">Sea ice</a> controls the exchange of <a href="/article/Heat">heat</a> and other properties between the <a href="/article/Atmosphere_layers">atmosphere</a> and <a href="/article/Ocean">ocean</a> and, together with <a href="/article/Snow_cover_in_the_Arctic">snow cover</a>, determines the penetration of <a href="/article/Solar_radiation">light</a> into the sea. Sea ice also provides a surface for particle and snow deposition, a habitat for <a href="/article/Plankton">plankton</a>, and contributes to stratification through ice melt. The zone seaward of the ice edge is important for plankton production and planktivorous fish. For some <a href="/article/Implications_for_biodiversity_conservation_in_the_Arctic">marine mammals</a> sea ice provides a place for birth and also functions as a nursery area. </p><p>This section describes features of sea ice that are important for physical oceanographic processes and the <a href="/article/Arctic_marine_environments">marine ecosystem</a>. More detailed information about sea ice is given in <a href="/article/Cryosphere_and_Hydrology_in_the_Arctic">Chapter 6</a>. </p> <p><a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic Mon, 02 Nov 2009 07:55:14 GMT http://www.eoearth.org/article/Valuing_environmental_costs_and_benefits <a href='/article/Valuing_environmental_costs_and_benefits'><img border='0' src='/upload/thumb/3/32/Economic_values-environmental_assets.gif/300px-Economic_values-environmental_assets.gif' width='100'/></a> <p>Little and Mirrlees noted that from the mid 1970s to 1990s, there had been a rise and decline of project appraisal in development community<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>. Our view is that natural resource and environmental issues may be critical for making development more sustainable. Therefore, environmental economic analysis should be pursued, preferably early in the project cycle. Even where the valuation is difficult, techniques like <a href="/article/Multi-criteria_analysis_in_environmental_decision-making">multi-criteria analysis</a> are useful to make decisions. </p><p>The first step in the analysis is to determine the environmental (and social) impacts of the project or policy, by comparing the “with project” and the “without project” scenarios (see "Measuring economic costs and benefits"). Transdisciplinary work is essential (see "<a href="/article/Basic_concepts_and_principles_of_sustainomics">Basic concepts and principles of sustainomics</a>"). The quantification of impacts in non-monetary units is a prerequisite not only for accurate economic valuation, but also for the use of other analytical methods like multi-criteria analysis. Such biophysical impacts are themselves complex and often poorly understood. </p><p>The second step in considering environmental effects involves valuing project impacts. Several practical valuation techniques are described below, based on extensions of the framework discussed in the previous section ("Measuring economic costs and benefits"). </p> <p>Conceptually, the <a href="/article/Total_economic_value">total economic value</a> (TEV) of a resource consists of its (i) <a href="/article/Total_economic_value">use value</a> (UV) and (ii) <a href="/article/Total_economic_value">non use value</a> (NUV). Use values may be broken down further into the direct use value (DUV), the indirect use value (IUV) and the <a href="/article/Total_economic_value">option value</a> (OV) (potential use value). One needs to be careful not to double count both the value of indirect supporting functions and the value of the resulting direct use. We may write: </p> TEV = UV + NUV<br />or<br />TEV = [DUV + IUV + OV] + [NUV] <p>Figure 1 shows this disaggregation of TEV in schematic form. A short description of each valuation concept, and a few typical examples of the underlying environmental resources, are provided: </p> <ul><li> direct use value is the contribution to current <a href="/article/Essential_economic_activities">production</a>/<a href="/article/Essential_economic_activities">consumption</a>; </li><li> indirect use value includes benefits from functional services that the environment provides to support current production/consumption (e.g., ecological functions like nutrient recycling); </li><li> option value is the willingness to pay for an unutilized asset, simply to avoid the risk of not having it available in the future (see "Discount rate, risk, and uncertainty in environmental decision-making"); and </li><li> non-use value is the willingness to pay for perceived benefits not related to use value, e.g., <a href="/article/Total_economic_value">existence value</a>, which is based on the satisfaction of merely knowing that an asset exists, even without intending to use it. </li></ul> <p>Economic theory clearly defines TUV, but there is considerable overlap and ambiguity in the breakdown categories, especially with regard to non use values. Thus, <a href="/article/Total_economic_value">option values</a> and <a href="/article/Total_economic_value">non use values</a> are shaded in the figure. These categories are useful as an indicative guide, but the goal of practical estimation to measure TUV rather than its components. </p><p>The distinction between use and non use values is not always clear. The latter tend to be linked to more altruistic motives<span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. Differing forms of altruism include intergenerational altruism, or the bequest motive; interpersonal altruism or the gift motive; stewardship (which has more ethical than utilitarian origins); and q Altruism, which states that the resource has an intrinsic right to exist. This final definition is outside conventional economic theory, and incorporates the notion that the welfare function should be derived from something more than purely human utility<span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span>. </p><p>For the practitioner, the precise conceptual basis of <a href="/article/Total_economic_value">economic value</a> is less important than the various empirical techniques that permit us to estimate a <a href="/article/Monetary_valuation">monetary value</a> for environmental assets. </p> <p><a href='/article/Valuing_environmental_costs_and_benefits'>Read Full Article...</a></p> http://www.eoearth.org/article/Valuing_environmental_costs_and_benefits Thu, 29 Oct 2009 06:11:55 GMT http://www.eoearth.org/article/Indian_Ricegrass <a href='/article/Indian_Ricegrass'><img border='0' src='/media/approved/a/ab/Indian_Ricegrass_achnatherum_hymenoidesUSFS_GaryMonroe.jpg' width='100'/></a> <p><em>Achnatherum hymenoides</em> (Roemer &amp; J.A. Schultes) Barkworth</p><p>As the common name implies, Native Americans utilized this species of grass in a manner analogous to that of rice by peoples of the Old World and their descendants. The name in Spanish is essentially the same: “<em>arroz indio</em>.” It is also known as Indian Millet or Sand-grass, and Latin synonyms are <em>Oryzopsis h., Stipa h.</em>, and<em> Eriocoma cuspidata</em>.</p> <p><em>Achnatherum hymenoides</em> is a member of the Poaceae, or grass family. It likes to live in sandy soils and is adapted to dry places, but also lives in moist areas within drier environments; look for it where you see sagebrush, juniper, or ponderosa pine. Distinguishing Indian ricegrass from other grasses may sound difficult to someone who has not seen it before, but armed with a good picture and an idea of what to look for, it can be done. Look for a bunchgrass from 1 to 2½ feet tall. The leaves are tightly rolled from the edges, giving each leaf the look of a long, straight, skinny tube. The inflorescence is the easiest feature to distinguish. It is an open, branching panicle, consisting of long, undulating stalks that look like hairs. Each branch terminates in a single seed (or, technically, a single fruit, containing a single seed). The seed itself is covered with short hairs, is black, and is the portion used for food.</p> <p>Because of its importance to native Nevadans, <em>A. hymenoides</em> is honoured as the Nevada state grass. In many cultures it was the principle grain, while in others it was only eaten when other crops or wild food plants failed. When mature, the seeds fall easily from the plant. It may be gathered by beating the inflorescence with a light paddle and collecting the seeds in a shallow basket; the Indians of this area produced exquisite paddles and baskets for this purpose. Some seeds would not fall into the basket, but would fall to the ground and produce more plants. After parching the seeds to remove the hairs, the grain can be ground into meal and baked into bread, eaten as porridge, or made into other logical things to make from meal. Another species, <em>A. speciosum</em> is also used for food in a similar manner, though not as extensively.</p> <p>Besides use as food, Indian ricegrass is also used in restoration, planted to help stop wind erosion. It may be planted as a garden plant, but requires well-drained soil. In the United States and <a href="/article/Mexico">Mexico</a>, it is used as good winter forage for livestock, being cold and drought tolerant; this has led in some situations to overgrazing. The seeds are nutritious for birds.</p> <p><strong>For More Information:</strong><br /><a href="http://plants.usda.gov/java/profile?symbol=ACHY" class='external text' title="http://plants.usda.gov/java/profile?symbol=ACHY">PLANTS Profile - &lt;em&gt;Achnatherum hymenoides&lt;/em&gt;, Indian ricegrass</a></p> <p><a href='/article/Indian_Ricegrass'>Read Full Article...</a></p> http://www.eoearth.org/article/Indian_Ricegrass Wed, 28 Oct 2009 06:10:06 GMT http://www.eoearth.org/article/Kyanite <a href='/article/Kyanite'><img border='0' src='/upload/thumb/f/fe/Kyanite.jpg/250px-Kyanite.jpg' width='100'/></a> <p>Kyanite and its related mineral “cousins,” sillimanite and andalusite, are called <em>polymorphs</em>. This means that they are three distinct minerals, but they all have the same chemical formula, Al₂SiO₅ (aluminum silicate). Because they are chemically the same, they can all be used in the same applications. </p><p>All three form in <a href="/article/Metamorphic_rock">metamorphic rocks</a> (rocks that are changed by intense <a href="/article/Heat">heat</a> and <a href="/article/Pressure">pressure</a>), specifically in schists and gneisses that were formed out of sedimentary rocks with a high <a href="/article/Clay">clay</a> content. Studies have shown that each mineral forms under very specific <a href="/article/Temperature">temperature</a>/pressure (T/P) conditions. Relative to one another, kyanite forms in a lower temperature/higher pressure environment; andalusite forms in a lower temperature/lower pressure environment, and sillimanite forms in a higher temperature/higher pressure environment. </p><p>Kyanite forms bladed crystals. It is generally blue, but can also be green or gray. It has a glassy luster. Kyanite has a unique physical feature in that it has two different hardnesses. When its hardness is measured across the crystal, it is 7; when it is measured down the length of the crystal, it is 5. All other minerals have a single hardness no matter where it is measured on the crystal. </p> <p><a href='/article/Kyanite'>Read Full Article...</a></p> http://www.eoearth.org/article/Kyanite Tue, 27 Oct 2009 07:07:25 GMT http://www.eoearth.org/article/Kilogram <a href='/article/Kilogram'><img border='0' src='/upload/thumb/2/23/Kilogram.jpeg/200px-Kilogram.jpeg' width='100'/></a> <p><span> </p> <p></center> </p> <p><a href='/article/Kilogram'>Read Full Article...</a></p> http://www.eoearth.org/article/Kilogram Tue, 27 Oct 2009 07:05:14 GMT http://www.eoearth.org/article/Kilogram <a href='/article/Kilogram'><img border='0' src='/upload/thumb/2/23/Kilogram.jpeg/200px-Kilogram.jpeg' width='100'/></a> <p><span> </p> <p></center> </p> <p><a href='/article/Kilogram'>Read Full Article...</a></p> http://www.eoearth.org/article/Kilogram Tue, 27 Oct 2009 07:02:58 GMT http://www.eoearth.org/article/Weathering <a href='/article/Weathering'><img border='0' src='/upload/thumb/5/52/Rock_weathering.jpg/300px-Rock_weathering.jpg' width='100'/></a> <p>Weathering is the breakdown and alteration of <a href="/article/Composition_of_rocks">rocks</a> and minerals at or near the Earth's surface into products that are more in equilibrium with the conditions found in this environment. Most rocks and minerals are formed deep within the Earth's crust where <a href="/article/Temperature">temperatures</a> and <a href="/article/Pressure">pressures</a> differ greatly from the surface. The physical and chemical nature of materials formed in the Earth's interior are characteristically in disequilibrium with conditions occurring on the surface. Because of this disequilbrium, these materials are easily attacked, decomposed, and eroded by various chemical and physical surface processes. </p><p>Weathering is the first step for a number of other geomorphic and biogeochemical processes. The products of weathering are a major source of sediments for erosion and deposition. Many types of sedimentary rocks are composed of particles that have been weathered, eroded, transported, and terminally deposited in basins. Weathering also contributes to the formation of soil by providing mineral particles like sand, silt, and clay. Elements and compounds extracted from the rocks and minerals by weathering processes supply nutrients for plant uptake. The fact that the oceans are saline in the result of the release of ion salts from rock and minerals on the continents. Leaching and <a href="/article/Surface_runoff_of_water">runoff</a> transport these ions from land to the ocean basins where they accumulate in seawater. In conclusion, weathering is a process that is fundamental to many other aspects of the hydrosphere, lithosphere, and <a href="/article/Biosphere">biosphere</a>. </p><p>There are three broad categories of mechanisms for weathering: chemical, physical and biological. </p> <p><a href='/article/Weathering'>Read Full Article...</a></p> http://www.eoearth.org/article/Weathering Fri, 23 Oct 2009 06:05:32 GMT http://www.eoearth.org/article/Hawk_moth <a href='/article/Hawk_moth'><img border='0' src='/upload/thumb/0/0b/Hawk_moth_USFS_JosephScheer.jpg/150px-Hawk_moth_USFS_JosephScheer.jpg' width='100'/></a> <h2>Hawk Moths or Sphinx Moths (<em>Sphingidae</em>)</h2> <p>Moths live in a wide variety of habitats around the world. They usually go unnoticed, except when flying erratically around your porch light, a streetlight, or other source of light during the darkness of night. Perhaps you notice their handiwork when you find small holes in a woolen garment stored in your closet or you find your tomato plants consumed by a hungry tomato hornworm.</p> <p>Most moths work the night shift, unlike their “respectable cousins” the butterflies, which are out during the daytime, and glorified in prose, poetry, and art. Unfortunately, we usually vilify moths because of their association with the dark of night and our innate fear of darkness and things that go bump in the night. Do you remember the monsters under your bed?</p> <p>They get little respect, except from the relatively few scientists and naturalists who are passionate about their study and who study moths and their ways. Moths represent a biological storehouse of interesting, dramatic, and unusual behaviors, some with roles as pollinators, and others as food for other animals. All have interesting stories to tell if we will only take the time to stop, look, listen and smell the hidden world of moths and their flowers. Planting moonlight or a fragrance garden is a sure way to enjoy not only these wonderful blossoms, but also their nocturnal pollinators, especially the giant hawk moths.</p> <p class="img-caption"> </p> <p>Estimated populations of 11,000 moths are known to occur in the United States. Around the world, another 160,000 species of moths have been catalogued. A staggering 200,000 or more species of moths may exist, just waiting to be discovered. The number of moths far outnumbers the number of world’s species of butterflies (17,500 species). Not all moths are a drab brown or white. Many moths come clothed in a myriad of colors and patterns, some brighter than those flashy butterflies, and just as interesting. Like butterflies, minute scales cover the wings of moth, making them slippery to the touch. If you have ever held or tried to catch a butterfly or moth, the “powder” or “dust” that comes off on your fingers is their scales.</p> <p>Some of the largest moths in the world belong to the hawk moth or Sphingid family within the order Lepidoptera (the animal order that includes butterflies and moths). These magnificent animals have long narrow wings and thick bodies. They are fast flyers and often highly aerobatic. Many species can hover in place. Some can briefly fly backwards or dart away. Hawk moths are experts at finding sweet-smelling flowers after dark. They are especially fond of <em>Datura</em> (Jimpson weeds), <em>Mirabilis</em> (Four O’clocks), and <em>Peniocereus</em> (Queen-of-the-night cactus) blossoms. These flowers are highly fragrant with long floral tubes concealing pools of thin but abundant nectar.</p> <p class="img-caption"> </p> <p>Hawk moths have the world’s longest tongues of any other moth or butterfly (some up to 14 inches long). <a href="/article/Darwin%2C_Charles">Charles Darwin</a> knew of the star orchids (<em>Angraecum</em> spp.) from Madagascar that had nectar spurs over a foot in length. Darwin was ridiculed by other scientists of his day for predicting that these orchids would be pollinated by hawk moths. After his death, hawk moths with tongues long enough to sip of the nectar produced by the star orchids were discovered on the island of Madagascar. </p> <p>The caterpillars (larvae) of hawk moths are the familiar green hornworms or tobacco worms, familiar to gardeners who plant tomatoes. Since some hawk moths are minor crop pests, aerial application of <a href="/article/Pesticide">pesticides</a> to protect crops sometimes affects their numbers. With the populations of all the sphinx moths affected by this agricultural practice there are fewer sphinx moths that pollinate rare plants, like the famous Queen-of-the-night cactus or the sacred Datura, which live in northern Mexico and along the border in the desert southwest.</p> <p>Moths pick up pollen on their legs and wings when they visit flowers and deposit pollen (accidentally) on subsequent floral visits. Two kinds of small moths (Yucca moths and the <em>Senita</em> cactus moth) actually pick up pollen and jam a pollen ball onto the stigmas of their flowers in order to assure food, the resulting immature seeds, for their caterpillars. They are some of the only insects to pollinate flowers “purposefully”.</p><p>&nbsp;</p> <p><a href='/article/Hawk_moth'>Read Full Article...</a></p> http://www.eoearth.org/article/Hawk_moth Thu, 22 Oct 2009 07:17:34 GMT http://www.eoearth.org/article/Zinn,_Walter <a href='/article/Zinn,_Walter'><img border='0' src='/upload/thumb/f/f5/Zinn.gif/200px-Zinn.gif' width='100'/></a> <p>Walter Zinn (1907 – 2000) a Canadian physicist who, on December 2, 1942, pulled out the emergency control rod from the reactor at the University of Chicago that released the world’s first self-sustaining nuclear reaction. Zinn reinserted it to terminate the chain reaction after 28 minutes of operation. Recruited by Enrico Fermi to work on the Manhattan Project, Zinn supervised all phases of the construction of the first experimental nuclear reactor, or "atomic pile" as it was then called. He also served as the first director of Argonne National Laboratory from 1946-1956. Zinn designed the Experimental Breeder Reactor-I, the first nuclear reactor to produce electric power (Dec. 20, 1951) in Idaho at the National Reactor Testing Site. EBR-I is now a National Historic Landmark. It also was the first nuclear reactor to demonstrate the breeding principle (that reactors can generate more nuclear fuel than they consume). In 1963, the EBR-I was the first nuclear reactor to achieve a chain reaction with plutonium as well as the first to demonstrate the feasibility of using liquid metals at high temperatures as a reactor coolant. </p><p><b>Further Readings</b><br /> <a href="http://www.cns-snc.ca/history/pioneers/zinn/zinn.html" class='external text' title="http://www.cns-snc.ca/history/pioneers/zinn/zinn.html">Walter Zinn 1907-2000</a> (Canadian Nuclear Society)<br /> <a href="http://www.nap.edu/readingroom/books/biomems/wzinn.html" class='external text' title="http://www.nap.edu/readingroom/books/biomems/wzinn.html">Walter Henry Zinn</a> (National Academy of Sciences) </p> <p><a href='/article/Zinn,_Walter'>Read Full Article...</a></p> http://www.eoearth.org/article/Zinn,_Walter Wed, 21 Oct 2009 06:26:29 GMT http://www.eoearth.org/article/Macrophytes <a href='/article/Macrophytes'><img border='0' src='/upload/thumb/9/99/Macrophytes_plants.jpg/300px-Macrophytes_plants.jpg' width='100'/></a> <p>Macrophytes are the conspicuous plants that dominate <a href="/article/Wetland">wetlands</a>, shallow lakes, and <a href="/article/Stream">streams</a>. Macroscopic flora include the aquatic angiosperms (flowering plants), pteridophytes (ferns), and bryophytes (mosses, hornworts, and liverworts). An <a href="/article/Aquatic_plants">aquatic plant</a> can be defined as one that is normally found growing in association with standing water whose level is at or above the surface of the <a href="/article/Soil">soil</a>. Standing water includes ponds, shallow lakes, <a href="/article/Marsh">marshes</a>, ditches, reservoirs, <a href="/article/Swamp">swamps</a>, <a href="/article/Bog">bogs</a>, canals, and sewage lagoons. Aquatic plants, though less frequently, also occur in flowing water, in streams, <a href="/article/River">rivers</a>, and <a href="/article/Spring">springs</a>. </p> <p><a href='/article/Macrophytes'>Read Full Article...</a></p> http://www.eoearth.org/article/Macrophytes Tue, 20 Oct 2009 06:42:25 GMT http://www.eoearth.org/article/Backyard_wetland <a href='/article/Backyard_wetland'><img border='0' src='/upload/thumb/3/3e/Wetland.jpg/350px-Wetland.jpg' width='100'/></a> <p><em><a href="/article/Wetland">Wetlands</a> filter excess pesticides and nutrients. Many plants and animals find a home in wetlands.</em></p> <p><a href='/article/Backyard_wetland'>Read Full Article...</a></p> http://www.eoearth.org/article/Backyard_wetland Thu, 15 Oct 2009 05:43:25 GMT http://www.eoearth.org/article/Amphibian <a href='/article/Amphibian'><img border='0' src='/upload/thumb/4/49/Green_treefrog.jpg/225px-Green_treefrog.jpg' width='100'/></a> <p>The word amphibian comes from the Greek <em>amphibios</em> meaning &quot;both lives&quot;. This is an apt description because most adult amphibians are better adapted to life on land than in water, while their larval phases are entirely aquatic. </p><p>For much of their lives, which may last a couple of months or several years depending on the species, larval amphibians bear little resemblance to their adult forms. Then something miraculous happens. In a matter of weeks or even days, the once fish-like larvae metamorphose into terrestrial, air-breathing quadrupeds! </p><p>There are three extant orders in the Class Amphibia: Anura (frogs and toads), Caudata (salamanders), and Apoda (caecilians). The order Anura has the most living species, with 4000 members worldwide. </p><p>Of 390 salamander species that exist worldwide. The third amphibian group, the caecilians, is smaller still with a total of only 162 species, all of which are restricted to the tropics.</p> <p><a href='/article/Amphibian'>Read Full Article...</a></p> http://www.eoearth.org/article/Amphibian Wed, 14 Oct 2009 05:31:08 GMT http://www.eoearth.org/article/Biosphere <a href='/article/Biosphere'><img border='0' src='/upload/thumb/0/03/Earth_spheres.jpg/300px-Earth_spheres.jpg' width='100'/></a> <p>The<strong> biosphere</strong> is the biological component of earth systems, which also include the lithosphere, hydrosphere, <a href="/article/Atmosphere_layers">atmosphere</a> and other &quot;spheres&quot; (e.g. <a href="/article/Cryosphere">cryosphere</a>, anthrosphere, etc.). The biosphere includes all living organisms on earth, together with the dead organic matter produced by them. </p> <p>The biosphere concept is common to many scientific disciplines including astronomy, geophysics, geology, hydrology, biogeography and <a href="/article/Evolution">evolution</a>, and is a core concept in <a href="/article/Ecology">ecology</a>, earth science and <a href="/article/Physical_geography">physical geography</a>. A key component of earth systems, the biosphere interacts with and exchanges <a href="/article/Matter">matter</a> and energy with the other spheres, helping to drive the global biogeochemical cycling of <a href="/article/Carbon_cycle">carbon</a>, <a href="/article/Nitrogen_cycle">nitrogen</a>, phosphorus, sulfur and other <a href="/article/Elements">elements</a>. From an ecological point of view, the biosphere is the &quot;global <a href="/article/Ecosystem">ecosystem</a>&quot;, comprising the totality of <a href="/article/Biodiversity">biodiversity</a> on earth and performing all manner of biological functions, including <a href="/article/Photosynthesis">photosynthesis</a>, respiration, decomposition, nitrogen fixation and denitrification. </p><p>The biosphere is dynamic, undergoing strong seasonal cycles in primary productivity and the many biological processes driven by the energy captured by photosynthesis. Seasonal cycles in solar irradiation of the hemispheres is the main driver of this dynamic, especially by its strong effect on <a href="/article/Terrestrial_biome">terrestrial</a> primary productivity in the temperate and boreal <a href="/article/Biome">biomes</a>, which essentially cease productivity in the winter time. </p><p>The biosphere has evolved since the first single-celled organisms originated 3.5 billion years ago under atmospheric conditions resembling those of our neighboring planets Mars and Venus, which have atmospheres composed primarily of <a href="/article/Carbon_dioxide">carbon dioxide</a>. Billions of years of primary production by plants released <a href="/article/Oxygen">oxygen</a> from this carbon dioxide and deposited the carbon in sediments, eventually producing the oxygen-rich <a href="/article/Atmospheric_composition">atmosphere</a> we know today. Free oxygen, both for breathing (O₂, respiration) and in the stratospheric <a href="/article/Ozone">ozone</a> (O₃) that protects us from harmful UV radiation, has made possible life as we know it while transforming the chemistry of earth systems forever. </p><p>As a result of long-term interactions between the biosphere and the other earth systems, there is almost no part of the earth&#39;s surface that has not been profoundly altered by living organisms. The earth is a living planet, even in terms of its physics and chemistry. A concept related to, but different from, that of the biosphere, is the <a href="/article/Environmental_ethics_and_the_Gaia_theory">Gaia hypotheses</a>, which posits that living organisms have and continue to transform earth systems for their own benefit. </p> <p><a href='/article/Biosphere'>Read Full Article...</a></p> http://www.eoearth.org/article/Biosphere Tue, 13 Oct 2009 04:28:53 GMT http://www.eoearth.org/article/PCBs <a href='/article/PCBs'><img border='0' src='/upload/thumb/6/60/PCb_structure.gif/200px-PCb_structure.gif' width='100'/></a> <p>Polychlorinated Biphenyls (PCBs) are mixtures of human-made chemicals with similar chemical structures. PCBs can range from oily liquids to waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer, and hydraulic equipment; as plasticizers in paints, plastics and rubber products; in pigments, dyes and carbonless copy paper and many other applications. More than 1.5 billion pounds of PCBs were manufactured in the United States prior to cessation of production in 1977. </p><p>Concern over the <a href="/article/Toxicity"> toxicity</a> and persistence (chemical stability) in the environment of Polychlorinated Biphenyls (PCBs) led Congress in 1976 to enact Section 6(e) of the Toxic Substances Control Act (TSCA) that included among other things, prohibitions on the manufacture, processing, and distribution in commerce of PCBs. Thus, TSCA legislated true "cradle to grave" (i.e., from manufacture to disposal) management of PCBs in the United States. </p><p>Polychlorinated biphenyls (PCBs) are chemically related to organochlorine pesticides. Each PCB molecule consists of chlorine atoms attached to a double <a href="/article/Carbon">carbon</a>-<a href="/article/Hydrogen">hydrogen</a> ring (a "biphenyl" ring). There are actually 209 different PCB "congeners", which differ in the number and location of chlorine atoms. There are three categories of PCBs: 1) PCBs that are chlorinated in two or more ortho positions (ortho positions are closest to the single bond joining the two aromatic rings); 2) those that are chlorinated in only one ortho position (mono-ortho); and 3) PCBs lacking any ortho chlorination, known as non-ortho or co-planar PCBs. Early work on PCBs focused on PCB mixtures such as A1254, 1260 or 1248. Later work focused on individual PCB congeners, with the greatest emphasis on the co-planar PCBs. Many of the adverse effects of these co-planar PCBs are similar to the adverse effects of dioxins, and other dioxin-like chemicals. Most recently the focus is shifting back to PCB mixtures and to congeners other than the co-planars because, although the co-planar PCBs may be the most potent congeners, other congeners may have important toxic effects as well. </p><p>Like <a href="/article/Chlorinated_pesticides">chlorinated pesticides</a>, PCBs remain in the environment for long periods of time, have low water solubility, and accumulate in fat tissues. Unlike pesticides, PCBs were never purposefully released into the environment to kill plants or animals. Rather, these mixtures of chlorinated compounds were used in industry, mostly as lubricants and heat dissipators in electrical transformers and capacitors, entering the environment through careless behavior. </p><p>There are a broad range of health effects caused by PCB exposure. In birds and fish, PCBs are known to impact the immune system, reproductive system, nervous system, and endocrine system. They also cause a variety of adverse health effects in humans. Studies provide supportive evidence for potential carcinogenic and non-carcinogenic effects, and PCBs are considered probable carcinogens. The different health effects of PCBs may be interrelated, as alterations in one system may have significant implications for the other systems of the body. </p> <p>The General Electric Co. discharged between 209,000 and 1.3 million PCBs into the river from two capacitor manufacturing plants located in Hudson Falls and Fort Edward. Since that time, the spread of PCBs throughout the river and its food chain has created an extensive toxic waste problem. About 200 miles of the river is designated as a Superfund site. In 1976, because of the concern over the bioaccumulation of PCBs in fish and other aquatic organisms and their subsequent consumption by people, the State of New York banned fishing in the Upper Hudson River and commercial fishing of striped bass, and several other species, in the Lower Hudson. In August 1995, the Upper Hudson was re-opened to fishing, but only on a catch and release basis. </p><p>Though required by Superfund laws (CERCLA) to clean up the PCBs, GE continually battled the U.S. Environmental Protection Agency (EPA) over the regulations, although an agreement was finally reached in 2005. Much of the PCBs in the lower Hudson originate from toxic "hot spots" upstream, then disperse downstream, causing continued contamination of the entire Hudson River. Cleanup is finally getting started, but in the past 30 years the PCB-contaminated sediments have spread out to cover a much more considerable stretch of the river than they did originally, making the effort both more extensive and expensive. Elevated PCB levels are found all around the New York/New Jersey Harbor, about 40% of which originates from local sources rather than the upper Hudson. The level of PCBs in white perch populations is strongly related to the percent of development in the local watershed; when the level of development of the watershed fills about 20% of the area, PCB levels in the fish begin to exceed the recommended levels safe for food consumption. This indicates that <a href="/article/Land-use">land-use</a> (development) near the estuary has important effects on the PCB levels in white perch. Bluefish, being higher up on the food chain and eating mostly other fish, accumulate high levels of PCBs while living in the contaminated estuaries of the system. </p><p>PCBs have been banned in the US since 1976, but they continue to be redistributed and dispersed. More than 25 years after the prohibition, they are still accumulating in fish tissue to an extent that state agencies recommend that people eat no striped bass or blue crabs from the Newark Bay area, and no more than one meal a week from other areas in the New York Harbor estuary. </p><p>Other PCB-contaminated sites include the Housatonic River in Massachusetts which is undergoing remediation, and New Bedford Harbor, Massaschusetts. Some of the highest concentrations of PCBs measured in the country have been measured in wildlife from the Housatonic River or surrounding areas. New Bedfod Harbor is an 18,000-acre tidal estuary with sediments that are highly contaminated with PCBs and heavy metals. Manufacturers in the area used PCBs while producing electric devices from 1940 to the late 1970s, when PCBs were banned. These facilities discharged wastes with PCBs directly into the harbor and into the city's sewage system, which also led into the harbor. PCB levels in fish and lobsters at the site exceed the Food and Drug Administration's (FDA) limit for PCBs in edible seafood. There is an increased risk of cancer and other diseases for people who regularly eat seafood from the area. </p><p>Fish from several highly contaminated sites such as New Bedford Harbor, Newark Bay, New Jersey and the Hudson River have developed resistance to some of the biochemical changes caused by PCBs. These heritable changes are thought to provide some level of protection against <a href="/article/Toxicity">toxicity</a> caused by PCBs and similar chemicals. </p><p><b>Further Reading</b><br /> </p> <ul><li> <a href="http://www.epa.gov/pcb/index.html" class='external text' title="http://www.epa.gov/pcb/index.html">Polychlorinated Biphenyls (PCBs) page at the Environmental Protection Agency</a> </li></ul> <p><br /> <br style="clear: left" /> <center> </p> <p></center> </p> <p><a href='/article/PCBs'>Read Full Article...</a></p> http://www.eoearth.org/article/PCBs Thu, 08 Oct 2009 05:25:17 GMT http://www.eoearth.org/article/PCBs <a href='/article/PCBs'><img border='0' src='/upload/thumb/6/60/PCb_structure.gif/200px-PCb_structure.gif' width='100'/></a> <p>Polychlorinated Biphenyls (PCBs) are mixtures of human-made chemicals with similar chemical structures. PCBs can range from oily liquids to waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer, and hydraulic equipment; as plasticizers in paints, plastics and rubber products; in pigments, dyes and carbonless copy paper and many other applications. More than 1.5 billion pounds of PCBs were manufactured in the United States prior to cessation of production in 1977. </p><p>Concern over the <a href="/article/Toxicity"> toxicity</a> and persistence (chemical stability) in the environment of Polychlorinated Biphenyls (PCBs) led Congress in 1976 to enact Section 6(e) of the Toxic Substances Control Act (TSCA) that included among other things, prohibitions on the manufacture, processing, and distribution in commerce of PCBs. Thus, TSCA legislated true "cradle to grave" (i.e., from manufacture to disposal) management of PCBs in the United States. </p><p>Polychlorinated biphenyls (PCBs) are chemically related to organochlorine pesticides. Each PCB molecule consists of chlorine atoms attached to a double <a href="/article/Carbon">carbon</a>-<a href="/article/Hydrogen">hydrogen</a> ring (a "biphenyl" ring). There are actually 209 different PCB "congeners", which differ in the number and location of chlorine atoms. There are three categories of PCBs: 1) PCBs that are chlorinated in two or more ortho positions (ortho positions are closest to the single bond joining the two aromatic rings); 2) those that are chlorinated in only one ortho position (mono-ortho); and 3) PCBs lacking any ortho chlorination, known as non-ortho or co-planar PCBs. Early work on PCBs focused on PCB mixtures such as A1254, 1260 or 1248. Later work focused on individual PCB congeners, with the greatest emphasis on the co-planar PCBs. Many of the adverse effects of these co-planar PCBs are similar to the adverse effects of dioxins, and other dioxin-like chemicals. Most recently the focus is shifting back to PCB mixtures and to congeners other than the co-planars because, although the co-planar PCBs may be the most potent congeners, other congeners may have important toxic effects as well. </p><p>Like <a href="/article/Chlorinated_pesticides">chlorinated pesticides</a>, PCBs remain in the environment for long periods of time, have low water solubility, and accumulate in fat tissues. Unlike pesticides, PCBs were never purposefully released into the environment to kill plants or animals. Rather, these mixtures of chlorinated compounds were used in industry, mostly as lubricants and heat dissipators in electrical transformers and capacitors, entering the environment through careless behavior. </p><p>There are a broad range of health effects caused by PCB exposure. In birds and fish, PCBs are known to impact the immune system, reproductive system, nervous system, and endocrine system. They also cause a variety of adverse health effects in humans. Studies provide supportive evidence for potential carcinogenic and non-carcinogenic effects, and PCBs are considered probable carcinogens. The different health effects of PCBs may be interrelated, as alterations in one system may have significant implications for the other systems of the body. </p> <p>The General Electric Co. discharged between 209,000 and 1.3 million PCBs into the river from two capacitor manufacturing plants located in Hudson Falls and Fort Edward. Since that time, the spread of PCBs throughout the river and its food chain has created an extensive toxic waste problem. About 200 miles of the river is designated as a Superfund site. In 1976, because of the concern over the bioaccumulation of PCBs in fish and other aquatic organisms and their subsequent consumption by people, the State of New York banned fishing in the Upper Hudson River and commercial fishing of striped bass, and several other species, in the Lower Hudson. In August 1995, the Upper Hudson was re-opened to fishing, but only on a catch and release basis. </p><p>Though required by Superfund laws (CERCLA) to clean up the PCBs, GE continually battled the U.S. Environmental Protection Agency (EPA) over the regulations, although an agreement was finally reached in 2005. Much of the PCBs in the lower Hudson originate from toxic "hot spots" upstream, then disperse downstream, causing continued contamination of the entire Hudson River. Cleanup is finally getting started, but in the past 30 years the PCB-contaminated sediments have spread out to cover a much more considerable stretch of the river than they did originally, making the effort both more extensive and expensive. Elevated PCB levels are found all around the New York/New Jersey Harbor, about 40% of which originates from local sources rather than the upper Hudson. The level of PCBs in white perch populations is strongly related to the percent of development in the local watershed; when the level of development of the watershed fills about 20% of the area, PCB levels in the fish begin to exceed the recommended levels safe for food consumption. This indicates that <a href="/article/Land-use">land-use</a> (development) near the estuary has important effects on the PCB levels in white perch. Bluefish, being higher up on the food chain and eating mostly other fish, accumulate high levels of PCBs while living in the contaminated estuaries of the system. </p><p>PCBs have been banned in the US since 1976, but they continue to be redistributed and dispersed. More than 25 years after the prohibition, they are still accumulating in fish tissue to an extent that state agencies recommend that people eat no striped bass or blue crabs from the Newark Bay area, and no more than one meal a week from other areas in the New York Harbor estuary. </p><p>Other PCB-contaminated sites include the Housatonic River in Massachusetts which is undergoing remediation, and New Bedford Harbor, Massaschusetts. Some of the highest concentrations of PCBs measured in the country have been measured in wildlife from the Housatonic River or surrounding areas. New Bedfod Harbor is an 18,000-acre tidal estuary with sediments that are highly contaminated with PCBs and heavy metals. Manufacturers in the area used PCBs while producing electric devices from 1940 to the late 1970s, when PCBs were banned. These facilities discharged wastes with PCBs directly into the harbor and into the city's sewage system, which also led into the harbor. PCB levels in fish and lobsters at the site exceed the Food and Drug Administration's (FDA) limit for PCBs in edible seafood. There is an increased risk of cancer and other diseases for people who regularly eat seafood from the area. </p><p>Fish from several highly contaminated sites such as New Bedford Harbor, Newark Bay, New Jersey and the Hudson River have developed resistance to some of the biochemical changes caused by PCBs. These heritable changes are thought to provide some level of protection against <a href="/article/Toxicity">toxicity</a> caused by PCBs and similar chemicals. </p><p><b>Further Reading</b><br /> </p> <ul><li> <a href="http://www.epa.gov/pcb/index.html" class='external text' title="http://www.epa.gov/pcb/index.html">Polychlorinated Biphenyls (PCBs) page at the Environmental Protection Agency</a> </li></ul> <p><br /> <br style="clear: left" /> <center> </p> <p></center> </p> <p><a href='/article/PCBs'>Read Full Article...</a></p> http://www.eoearth.org/article/PCBs Thu, 08 Oct 2009 05:24:40 GMT http://www.eoearth.org/article/United_Nations_Millennium_Declaration <a href='/article/United_Nations_Millennium_Declaration'><img border='0' src='/upload/thumb/e/ef/Un_signed_declaration.jpg/350px-Un_signed_declaration.jpg' width='100'/></a> <p>In September 2000, 150 heads of state met at the United Nations and ratified the UN Millennium Declaration. In September 2005, the UN hosted a Millennium+5 Summit to evaluate the progress towards the goals spelled out in the document. Leaders also resolved to meet a number of <a href="/article/Millennium_Development_Goals_%28MDGs%29">Millennium Development Goals (MDGs)</a>, which include halving the proportion of people living in poverty and hunger by 2015, ensuring primary schooling for all children, and reversing the spread of HIV/AIDS, malaria and other major diseases. </p><p>The full text of the 2000 Millennium Declaration is given below. </p> <dl><dd><strong>I. Values and principles</strong> </dd></dl> <ol><li> We, heads of State and Government, have gathered at United Nations Headquarters in New York from 6 to 8 September 2000, at the dawn of a new millennium, to reaffirm our faith in the Organization and its Charter as indispensable foundations of a more peaceful, prosperous and just world. </li><li> We recognize that, in addition to our separate responsibilities to our individual societies, we have a collective responsibility to uphold the principles of human dignity, equality and equity at the global level. As leaders we have a duty therefore to all the world’s people, especially the most vulnerable and, in particular, the children of the world, to whom the future belongs. </li><li> We reaffirm our commitment to the purposes and principles of the Charter of the United Nations, which have proved timeless and universal. Indeed, their relevance and capacity to inspire have increased, as nations and peoples have become increasingly interconnected and interdependent. </li><li> We are determined to establish a just and lasting peace all over the world in accordance with the purposes and principles of the Charter. We rededicate ourselves to support all efforts to uphold the sovereign equality of all States, respect for their territorial integrity and political independence, resolution of disputes by peaceful means and in conformity with the principles of justice and international law, the right to self-determination of peoples which remain under colonial domination and foreign occupation, non-interference in the internal affairs of States, respect for human rights and fundamental freedoms, respect for the equal rights of all without distinction as to race, sex, language or religion and international cooperation in solving international problems of an economic, social, cultural or humanitarian character. </li><li> We believe that the central challenge we face today is to ensure that globalization becomes a positive force for all the world’s people. For while globalization offers great opportunities, at present its benefits are very unevenly shared, while its costs are unevenly distributed. We recognize that developing countries and countries with economies in transition face special difficulties in responding to this central challenge. Thus, only through broad and sustained efforts to create a shared future, based upon our common humanity in all its diversity, can globalization be made fully inclusive and equitable. These efforts must include policies and measures, at the global level, which correspond to the needs of developing countries and economies in transition and are formulated and implemented with their effective participation. </li><li> We consider certain fundamental values to be essential to international relations in the twenty-first century. These include: <ul><li> <strong>Freedom.</strong> Men and women have the right to live their lives and raise their children in dignity, free from hunger and from the fear of violence, oppression or injustice. Democratic and participatory governance based on the will of the people best assures these rights. </li><li> <strong>Equality.</strong> No individual and no nation must be denied the opportunity to benefit from development. The equal rights and opportunities of women and men must be assured. </li><li> <strong>Solidarity.</strong> Global challenges must be managed in a way that distributes the costs and burdens fairly in accordance with basic principles of equity and social justice. Those who suffer or who benefit least deserve help from those who benefit most. </li><li> <strong>Tolerance.</strong> Human beings must respect one other, in all their diversity of belief, culture and language. Differences within and between societies should be neither feared nor repressed, but cherished as a precious asset of humanity. A culture of peace and dialogue among all civilizations should be actively promoted. </li><li> <strong>Respect for nature.</strong> Prudence must be shown in the management of all living species and natural resources, in accordance with the precepts of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>. Only in this way can the immeasurable riches provided to us by nature be preserved and passed on to our descendants. The current unsustainable patterns of production and consumption must be changed in the interest of our future welfare and that of our descendants. </li><li> <strong>Shared responsibility.</strong> Responsibility for managing worldwide economic and social development, as well as threats to international peace and security, must be shared among the nations of the world and should be exercised multilaterally. As the most universal and most representative organization in the world, the United Nations must play the central role. </li></ul> </li><li> In order to translate these shared values into actions, we have identified key objectives to which we assign special significance. <dl><dd> <br /> </dd><dd> <strong>II. Peace, security and disarmament</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our peoples from the scourge of war, whether within or between States, which has claimed more than 5 million lives in the past decade. We will also seek to eliminate the dangers posed by weapons of mass destruction. </li><li> We resolve therefore: <ul><li> To strengthen respect for the rule of law in international as in national affairs and, in particular, to ensure compliance by Member States with the decisions of the International Court of Justice, in compliance with the Charter of the United Nations, in cases to which they are parties. </li><li> To make the United Nations more effective in maintaining peace and security by giving it the resources and tools it needs for conflict prevention, peaceful resolution of disputes, peacekeeping, post-conflict peace-building and reconstruction. In this context, we take note of the report of the Panel on United Nations Peace Operations and request the General Assembly to consider its recommendations expeditiously. </li><li> To strengthen cooperation between the United Nations and regional organizations, in accordance with the provisions of Chapter VIII of the Charter. </li><li> To ensure the implementation, by States Parties, of treaties in areas such as arms control and disarmament and of international humanitarian law and human rights law, and call upon all States to consider signing and ratifying the Rome Statute of the International Criminal Court. </li><li> To take concerted action against international terrorism, and to accede as soon as possible to all the relevant international conventions. </li><li> To redouble our efforts to implement our commitment to counter the world drug problem. </li><li> To intensify our efforts to fight transnational crime in all its dimensions, including trafficking as well as smuggling in human beings and money laundering. </li><li> To minimize the adverse effects of United Nations economic sanctions on innocent populations, to subject such sanctions regimes to regular reviews and to eliminate the adverse effects of sanctions on third parties. </li><li> To strive for the elimination of weapons of mass destruction, particularly nuclear weapons, and to keep all options open for achieving this aim, including the possibility of convening an international conference to identify ways of eliminating nuclear dangers. </li><li> To take concerted action to end illicit traffic in small arms and light weapons, especially by making arms transfers more transparent and supporting regional disarmament measures, taking account of all the recommendations of the forthcoming United Nations Conference on Illicit Trade in Small Arms and Light Weapons. </li><li> To call on all States to consider acceding to the Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-personnel Mines and on Their Destruction, as well as the amended mines protocol to the Convention on conventional weapons. </li></ul> </li><li> We urge Member States to observe the Olympic Truce, individually and collectively, now and in the future, and to support the International Olympic Committee in its efforts to promote peace and human understanding through sport and the Olympic Ideal. <dl><dd> <br /> </dd><dd> <strong>III. Development and poverty eradication</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our fellow men, women and children from the abject and dehumanizing conditions of extreme poverty, to which more than a billion of them are currently subjected. We are committed to making the right to development a reality for everyone and to freeing the entire human race from want. </li><li> We resolve therefore to create an environment – at the national and global levels alike – which is conducive to development and to the elimination of poverty. </li><li> Success in meeting these objectives depends, <em>inter alia</em>, on good governance within each country. It also depends on good governance at the international level and on transparency in the financial, monetary and trading systems. We are committed to an open, equitable, rule-based, predictable and non-discriminatory multilateral trading and financial system. </li><li> We are concerned about the obstacles developing countries face in mobilizing the resources needed to finance their <a href="/article/Sustainomics_and_sustainable_development">sustained development</a>. We will therefore make every effort to ensure the success of the High-level International and Intergovernmental Event on Financing for Development, to be held in 2001. </li><li> We also undertake to address the special needs of the least developed countries. In this context, we welcome the Third United Nations Conference on the Least Developed Countries to be held in May 2001 and will endeavour to ensure its success. We call on the industrialized countries: <ul><li> To adopt, preferably by the time of that Conference, a policy of duty- and quota-free access for essentially all exports from the least developed countries; </li><li> To implement the enhanced programme of debt relief for the heavily indebted poor countries without further delay and to agree to cancel all official bilateral debts of those countries in return for their making demonstrable commitments to poverty reduction; and </li><li> To grant more generous development assistance, especially to countries that are genuinely making an effort to apply their resources to poverty reduction. </li></ul> </li><li> We are also determined to deal comprehensively and effectively with the debt problems of low- and middle-income developing countries, through various national and international measures designed to make their debt sustainable in the long term. </li><li> We also resolve to address the special needs of small island developing States, by implementing the Barbados Programme of Action and the outcome of the twenty-second special session of the General Assembly rapidly and in full. We urge the international community to ensure that, in the development of a vulnerability index, the special needs of small island developing States are taken into account. </li><li> We recognize the special needs and problems of the landlocked developing countries, and urge both bilateral and multilateral donors to increase financial and technical assistance to this group of countries to meet their special development needs and to help them overcome the impediments of <a href="/article/Geography">geography</a> by improving their transit transport systems. </li><li> We resolve further: <ul><li> To halve, by the year 2015, the proportion of the world’s people whose income is less than one dollar a day and the proportion of people who suffer from hunger and, by the same date, to halve the proportion of people who are unable to reach or to afford safe drinking <a href="/article/Society_and_water_resources">water</a>. </li><li> To ensure that, by the same date, children everywhere, boys and girls alike, will be able to complete a full course of primary schooling and that girls and boys will have equal access to all levels of education. </li><li> By the same date, to have reduced maternal mortality by three quarters, and under-five child mortality by two thirds, of their current rates. </li><li> To have, by then, halted, and begun to reverse, the spread of HIV/AIDS, the scourge of <a href="/article/Malaria">malaria</a> and other major diseases that afflict humanity. </li><li> To provide special assistance to children orphaned by HIV/AIDS. </li><li> By 2020, to have achieved a significant improvement in the lives of at least 100 million slum dwellers as proposed in the &quot;Cities Without Slums&quot; initiative. </li></ul> </li><li> We also resolve: <ul><li> To promote gender equality and the empowerment of women as effective ways to combat poverty, hunger and disease and to stimulate development that is truly <a href="/article/Sustainomics_and_sustainable_development">sustainable</a>. </li><li> To develop and implement strategies that give young people everywhere a real chance to find decent and productive work. </li><li> To encourage the pharmaceutical industry to make essential drugs more widely available and affordable by all who need them in developing countries. </li><li> To develop strong partnerships with the private sector and with civil society organizations in pursuit of development and poverty eradication. </li><li> To ensure that the benefits of new technologies, especially information and communication technologies, in conformity with recommendations contained in the United Nations Economic and Social Council (ECOSOC) 2000 Ministerial Declaration, are available to all. </li></ul> <dl><dd> <br /> </dd><dd> <strong>IV. Protecting our common environment</strong> </dd><dd> </dd></dl> </li><li> We must spare no effort to free all of humanity, and above all our children and grandchildren, from the threat of living on a planet irredeemably spoilt by human activities, and whose resources would no longer be sufficient for their needs. </li><li> We reaffirm our support for the principles of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, including those set out in Agenda 21, agreed upon at the United Nations Conference on Environment and Development. </li><li> We resolve therefore to adopt in all our environmental actions a new ethic of conservation and stewardship and, as first steps, we resolve: <ul><li> To make every effort to ensure the entry into force of the <a href="/article/Kyoto_Protocol">Kyoto Protocol</a>, preferably by the tenth anniversary of the United Nations Conference on Environment and Development in 2002, and to embark on the required reduction in emissions of greenhouse gases. </li><li> To intensify our collective efforts for the <a href="/article/Forestry">management</a>, conservation and sustainable development of all types of forests. </li><li> To press for the full implementation of the <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> and the Convention to Combat Desertification in those Countries Experiencing Serious Drought and/or Desertification, particularly in Africa. </li><li> To stop the unsustainable exploitation of <a href="/article/Water_resources">water resources</a> by developing <a href="/article/Water_governance">water management</a> strategies at the regional, national and local levels, which promote both equitable access and adequate supplies. </li><li> To intensify cooperation to reduce the number and effects of natural and man-made disasters. </li><li> To ensure free access to information on the human genome sequence. </li></ul> <dl><dd> <br /> </dd><dd> <strong>V. Human rights, democracy and good governance</strong></dd></dl> </li><li> We will spare no effort to promote democracy and strengthen the rule of law, as well as respect for all internationally recognized human rights and fundamental freedoms, including the right to development. </li><li> We resolve therefore: <br /> <ul><li>To respect fully and uphold the Universal Declaration of Human Rights. </li><li> To strive for the full protection and promotion in all our countries of civil, political, economic, social and cultural rights for all. </li><li> To strengthen the capacity of all our countries to implement the principles and practices of democracy and respect for human rights, including minority rights. <dl><dd> </dd></dl> </li><li> To combat all forms of violence against women and to implement the Convention on the Elimination of All Forms of Discrimination against Women. </li><li> To take measures to ensure respect for and protection of the human rights of migrants, migrant workers and their families, to eliminate the increasing acts of racism and xenophobia in many societies and to promote greater harmony and tolerance in all societies. </li><li> To work collectively for more inclusive political processes, allowing genuine <a href="/article/Global_citizens_movement">participation by all citizens</a> in all our countries. </li><li> To ensure the freedom of the media to perform their essential role and the right of the public to have access to information. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VI. Protecting the vulnerable</strong> </dd></dl> </li><li> We will spare no effort to ensure that children and all civilian populations that suffer disproportionately the consequences of natural disasters, genocide, armed conflicts and other humanitarian emergencies are given every assistance and protection so that they can resume normal life as soon as possible. We resolve therefore: <ul><li> To expand and strengthen the protection of civilians in complex emergencies, in conformity with international humanitarian law. </li><li> To strengthen international cooperation, including burden sharing in, and the coordination of humanitarian assistance to, countries hosting refugees and to help all refugees and displaced persons to return voluntarily to their homes, in safety and dignity and to be smoothly reintegrated into their societies. </li><li> To encourage the ratification and full implementation of the Convention on the Rights of the Child and its optional protocols on the involvement of children in armed conflict and on the sale of children, child prostitution and child pornography. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VII. Meeting the special needs of Africa</strong> </dd></dl> </li><li> We will support the consolidation of democracy in Africa and assist Africans in their struggle for lasting peace, poverty eradication and <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, thereby bringing Africa into the mainstream of the world economy. </li><li> We resolve therefore: <ul><li> To give full support to the political and institutional structures of emerging democracies in Africa. </li><li> To encourage and sustain regional and subregional mechanisms for preventing conflict and promoting political stability, and to ensure a reliable flow of resources for peacekeeping operations on the continent. </li><li> To take special measures to address the challenges of poverty eradication and sustainable development in Africa, including debt cancellation, improved market access, enhanced Official Development Assistance and increased flows of Foreign Direct Investment, as well as transfers of technology. </li><li> To help Africa build up its capacity to tackle the spread of the HIV/AIDS pandemic and other infectious diseases. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VIII. Strengthening the United Nations</strong> </dd></dl> </li><li> We will spare no effort to make the United Nations a more effective instrument for pursuing all of these priorities: the fight for development for all the peoples of the world, the fight against poverty, ignorance and disease; the fight against injustice; the fight against violence, terror and crime; and the fight against the degradation and destruction of our common home. </li><li> We resolve therefore: <ul><li> To reaffirm the central position of the General Assembly as the chief deliberative, policy-making and representative organ of the United Nations, and to enable it to play that role effectively. </li><li> To intensify our efforts to achieve a comprehensive reform of the Security Council in all its aspects. </li><li> To strengthen further the Economic and Social Council, building on its recent achievements, to help it fulfil the role ascribed to it in the Charter. <dl><dd> </dd></dl> </li><li> To strengthen the International Court of Justice, in order to ensure justice and the rule of law in international affairs. </li><li> To encourage regular consultations and coordination among the principal organs of the United Nations in pursuit of their functions. </li><li> To ensure that the Organization is provided on a timely and predictable basis with the resources it needs to carry out its mandates. </li><li> To urge the Secretariat to make the best use of those resources, in accordance with clear rules and procedures agreed by the General Assembly, in the interests of all Member States, by adopting the best management practices and technologies available and by concentrating on those tasks that reflect the agreed priorities of Member States. </li><li> To promote adherence to the Convention on the Safety of United Nations and Associated Personnel. </li><li> To ensure greater policy coherence and better cooperation between the United Nations, its agencies, the Bretton Woods Institutions and the World Trade Organization, as well as other multilateral bodies, with a view to achieving a fully coordinated approach to the problems of peace and development. </li><li> To strengthen further cooperation between the United Nations and national parliaments through their world organization, the Inter-Parliamentary Union, in various fields, including peace and security, economic and social development, international law and human rights and democracy and gender issues. </li><li> To give greater opportunities to the private sector, non-governmental organizations and civil society, in general, to contribute to the realization of the Organization’s goals and programmes. </li></ul> </li><li> We request the General Assembly to review on a regular basis the progress made in implementing the provisions of this Declaration, and ask the Secretary-General to issue periodic reports for consideration by the General Assembly and as a basis for further action. </li><li> We solemnly reaffirm, on this historic occasion, that the United Nations is the indispensable common house of the entire human family, through which we will seek to realize our universal aspirations for peace, cooperation and development. We therefore pledge our unstinting support for these common objectives and our determination to achieve them. </li></ol> <p><strong>Further Reading</strong> </p> <ul><li> <a href="http://www.un.org/" class='external text' title="http://www.un.org/">United Nations Homepage</a> </li><li> <a href="http://www.un.org/millennium/" class='external text' title="http://www.un.org/millennium/">United Nations Millennium Assembly</a> </li></ul> <p><br /> <p><br style="clear: left" /> <center> </p> </center> </p> <p><a href='/article/United_Nations_Millennium_Declaration'>Read Full Article...</a></p> http://www.eoearth.org/article/United_Nations_Millennium_Declaration Wed, 07 Oct 2009 06:38:39 GMT http://www.eoearth.org/article/United_Nations_Millennium_Declaration <a href='/article/United_Nations_Millennium_Declaration'><img border='0' src='/upload/thumb/e/ef/Un_signed_declaration.jpg/350px-Un_signed_declaration.jpg' width='100'/></a> <p>In September 2000, 150 heads of state met at the United Nations and ratified the UN Millennium Declaration. In September 2005, the UN hosted a Millennium+5 Summit to evaluate the progress towards the goals spelled out in the document. Leaders also resolved to meet a number of <a href="/article/Millennium_Development_Goals_%28MDGs%29">Millennium Development Goals (MDGs)</a>, which include halving the proportion of people living in poverty and hunger by 2015, ensuring primary schooling for all children, and reversing the spread of HIV/AIDS, malaria and other major diseases. </p><p>The full text of the 2000 Millennium Declaration is given below. </p> <dl><dd><strong>I. Values and principles</strong> </dd></dl> <ol><li> We, heads of State and Government, have gathered at United Nations Headquarters in New York from 6 to 8 September 2000, at the dawn of a new millennium, to reaffirm our faith in the Organization and its Charter as indispensable foundations of a more peaceful, prosperous and just world. </li><li> We recognize that, in addition to our separate responsibilities to our individual societies, we have a collective responsibility to uphold the principles of human dignity, equality and equity at the global level. As leaders we have a duty therefore to all the world’s people, especially the most vulnerable and, in particular, the children of the world, to whom the future belongs. </li><li> We reaffirm our commitment to the purposes and principles of the Charter of the United Nations, which have proved timeless and universal. Indeed, their relevance and capacity to inspire have increased, as nations and peoples have become increasingly interconnected and interdependent. </li><li> We are determined to establish a just and lasting peace all over the world in accordance with the purposes and principles of the Charter. We rededicate ourselves to support all efforts to uphold the sovereign equality of all States, respect for their territorial integrity and political independence, resolution of disputes by peaceful means and in conformity with the principles of justice and international law, the right to self-determination of peoples which remain under colonial domination and foreign occupation, non-interference in the internal affairs of States, respect for human rights and fundamental freedoms, respect for the equal rights of all without distinction as to race, sex, language or religion and international cooperation in solving international problems of an economic, social, cultural or humanitarian character. </li><li> We believe that the central challenge we face today is to ensure that globalization becomes a positive force for all the world’s people. For while globalization offers great opportunities, at present its benefits are very unevenly shared, while its costs are unevenly distributed. We recognize that developing countries and countries with economies in transition face special difficulties in responding to this central challenge. Thus, only through broad and sustained efforts to create a shared future, based upon our common humanity in all its diversity, can globalization be made fully inclusive and equitable. These efforts must include policies and measures, at the global level, which correspond to the needs of developing countries and economies in transition and are formulated and implemented with their effective participation. </li><li> We consider certain fundamental values to be essential to international relations in the twenty-first century. These include: <ul><li> <strong>Freedom.</strong> Men and women have the right to live their lives and raise their children in dignity, free from hunger and from the fear of violence, oppression or injustice. Democratic and participatory governance based on the will of the people best assures these rights. </li><li> <strong>Equality.</strong> No individual and no nation must be denied the opportunity to benefit from development. The equal rights and opportunities of women and men must be assured. </li><li> <strong>Solidarity.</strong> Global challenges must be managed in a way that distributes the costs and burdens fairly in accordance with basic principles of equity and social justice. Those who suffer or who benefit least deserve help from those who benefit most. </li><li> <strong>Tolerance.</strong> Human beings must respect one other, in all their diversity of belief, culture and language. Differences within and between societies should be neither feared nor repressed, but cherished as a precious asset of humanity. A culture of peace and dialogue among all civilizations should be actively promoted. </li><li> <strong>Respect for nature.</strong> Prudence must be shown in the management of all living species and natural resources, in accordance with the precepts of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>. Only in this way can the immeasurable riches provided to us by nature be preserved and passed on to our descendants. The current unsustainable patterns of production and consumption must be changed in the interest of our future welfare and that of our descendants. </li><li> <strong>Shared responsibility.</strong> Responsibility for managing worldwide economic and social development, as well as threats to international peace and security, must be shared among the nations of the world and should be exercised multilaterally. As the most universal and most representative organization in the world, the United Nations must play the central role. </li></ul> </li><li> In order to translate these shared values into actions, we have identified key objectives to which we assign special significance. <dl><dd> <br /> </dd><dd> <strong>II. Peace, security and disarmament</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our peoples from the scourge of war, whether within or between States, which has claimed more than 5 million lives in the past decade. We will also seek to eliminate the dangers posed by weapons of mass destruction. </li><li> We resolve therefore: <ul><li> To strengthen respect for the rule of law in international as in national affairs and, in particular, to ensure compliance by Member States with the decisions of the International Court of Justice, in compliance with the Charter of the United Nations, in cases to which they are parties. </li><li> To make the United Nations more effective in maintaining peace and security by giving it the resources and tools it needs for conflict prevention, peaceful resolution of disputes, peacekeeping, post-conflict peace-building and reconstruction. In this context, we take note of the report of the Panel on United Nations Peace Operations and request the General Assembly to consider its recommendations expeditiously. </li><li> To strengthen cooperation between the United Nations and regional organizations, in accordance with the provisions of Chapter VIII of the Charter. </li><li> To ensure the implementation, by States Parties, of treaties in areas such as arms control and disarmament and of international humanitarian law and human rights law, and call upon all States to consider signing and ratifying the Rome Statute of the International Criminal Court. </li><li> To take concerted action against international terrorism, and to accede as soon as possible to all the relevant international conventions. </li><li> To redouble our efforts to implement our commitment to counter the world drug problem. </li><li> To intensify our efforts to fight transnational crime in all its dimensions, including trafficking as well as smuggling in human beings and money laundering. </li><li> To minimize the adverse effects of United Nations economic sanctions on innocent populations, to subject such sanctions regimes to regular reviews and to eliminate the adverse effects of sanctions on third parties. </li><li> To strive for the elimination of weapons of mass destruction, particularly nuclear weapons, and to keep all options open for achieving this aim, including the possibility of convening an international conference to identify ways of eliminating nuclear dangers. </li><li> To take concerted action to end illicit traffic in small arms and light weapons, especially by making arms transfers more transparent and supporting regional disarmament measures, taking account of all the recommendations of the forthcoming United Nations Conference on Illicit Trade in Small Arms and Light Weapons. </li><li> To call on all States to consider acceding to the Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-personnel Mines and on Their Destruction, as well as the amended mines protocol to the Convention on conventional weapons. </li></ul> </li><li> We urge Member States to observe the Olympic Truce, individually and collectively, now and in the future, and to support the International Olympic Committee in its efforts to promote peace and human understanding through sport and the Olympic Ideal. <dl><dd> <br /> </dd><dd> <strong>III. Development and poverty eradication</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our fellow men, women and children from the abject and dehumanizing conditions of extreme poverty, to which more than a billion of them are currently subjected. We are committed to making the right to development a reality for everyone and to freeing the entire human race from want. </li><li> We resolve therefore to create an environment – at the national and global levels alike – which is conducive to development and to the elimination of poverty. </li><li> Success in meeting these objectives depends, <em>inter alia</em>, on good governance within each country. It also depends on good governance at the international level and on transparency in the financial, monetary and trading systems. We are committed to an open, equitable, rule-based, predictable and non-discriminatory multilateral trading and financial system. </li><li> We are concerned about the obstacles developing countries face in mobilizing the resources needed to finance their <a href="/article/Sustainomics_and_sustainable_development">sustained development</a>. We will therefore make every effort to ensure the success of the High-level International and Intergovernmental Event on Financing for Development, to be held in 2001. </li><li> We also undertake to address the special needs of the least developed countries. In this context, we welcome the Third United Nations Conference on the Least Developed Countries to be held in May 2001 and will endeavour to ensure its success. We call on the industrialized countries: <ul><li> To adopt, preferably by the time of that Conference, a policy of duty- and quota-free access for essentially all exports from the least developed countries; </li><li> To implement the enhanced programme of debt relief for the heavily indebted poor countries without further delay and to agree to cancel all official bilateral debts of those countries in return for their making demonstrable commitments to poverty reduction; and </li><li> To grant more generous development assistance, especially to countries that are genuinely making an effort to apply their resources to poverty reduction. </li></ul> </li><li> We are also determined to deal comprehensively and effectively with the debt problems of low- and middle-income developing countries, through various national and international measures designed to make their debt sustainable in the long term. </li><li> We also resolve to address the special needs of small island developing States, by implementing the Barbados Programme of Action and the outcome of the twenty-second special session of the General Assembly rapidly and in full. We urge the international community to ensure that, in the development of a vulnerability index, the special needs of small island developing States are taken into account. </li><li> We recognize the special needs and problems of the landlocked developing countries, and urge both bilateral and multilateral donors to increase financial and technical assistance to this group of countries to meet their special development needs and to help them overcome the impediments of <a href="/article/Geography">geography</a> by improving their transit transport systems. </li><li> We resolve further: <ul><li> To halve, by the year 2015, the proportion of the world’s people whose income is less than one dollar a day and the proportion of people who suffer from hunger and, by the same date, to halve the proportion of people who are unable to reach or to afford safe drinking <a href="/article/Society_and_water_resources">water</a>. </li><li> To ensure that, by the same date, children everywhere, boys and girls alike, will be able to complete a full course of primary schooling and that girls and boys will have equal access to all levels of education. </li><li> By the same date, to have reduced maternal mortality by three quarters, and under-five child mortality by two thirds, of their current rates. </li><li> To have, by then, halted, and begun to reverse, the spread of HIV/AIDS, the scourge of <a href="/article/Malaria">malaria</a> and other major diseases that afflict humanity. </li><li> To provide special assistance to children orphaned by HIV/AIDS. </li><li> By 2020, to have achieved a significant improvement in the lives of at least 100 million slum dwellers as proposed in the &quot;Cities Without Slums&quot; initiative. </li></ul> </li><li> We also resolve: <ul><li> To promote gender equality and the empowerment of women as effective ways to combat poverty, hunger and disease and to stimulate development that is truly <a href="/article/Sustainomics_and_sustainable_development">sustainable</a>. </li><li> To develop and implement strategies that give young people everywhere a real chance to find decent and productive work. </li><li> To encourage the pharmaceutical industry to make essential drugs more widely available and affordable by all who need them in developing countries. </li><li> To develop strong partnerships with the private sector and with civil society organizations in pursuit of development and poverty eradication. </li><li> To ensure that the benefits of new technologies, especially information and communication technologies, in conformity with recommendations contained in the United Nations Economic and Social Council (ECOSOC) 2000 Ministerial Declaration, are available to all. </li></ul> <dl><dd> <br /> </dd><dd> <strong>IV. Protecting our common environment</strong> </dd><dd> </dd></dl> </li><li> We must spare no effort to free all of humanity, and above all our children and grandchildren, from the threat of living on a planet irredeemably spoilt by human activities, and whose resources would no longer be sufficient for their needs. </li><li> We reaffirm our support for the principles of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, including those set out in Agenda 21, agreed upon at the United Nations Conference on Environment and Development. </li><li> We resolve therefore to adopt in all our environmental actions a new ethic of conservation and stewardship and, as first steps, we resolve: <ul><li> To make every effort to ensure the entry into force of the <a href="/article/Kyoto_Protocol">Kyoto Protocol</a>, preferably by the tenth anniversary of the United Nations Conference on Environment and Development in 2002, and to embark on the required reduction in emissions of greenhouse gases. </li><li> To intensify our collective efforts for the <a href="/article/Forestry">management</a>, conservation and sustainable development of all types of forests. </li><li> To press for the full implementation of the <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> and the Convention to Combat Desertification in those Countries Experiencing Serious Drought and/or Desertification, particularly in Africa. </li><li> To stop the unsustainable exploitation of <a href="/article/Water_resources">water resources</a> by developing <a href="/article/Water_governance">water management</a> strategies at the regional, national and local levels, which promote both equitable access and adequate supplies. </li><li> To intensify cooperation to reduce the number and effects of natural and man-made disasters. </li><li> To ensure free access to information on the human genome sequence. </li></ul> <dl><dd> <br /> </dd><dd> <strong>V. Human rights, democracy and good governance</strong></dd></dl> </li><li> We will spare no effort to promote democracy and strengthen the rule of law, as well as respect for all internationally recognized human rights and fundamental freedoms, including the right to development. </li><li> We resolve therefore: <br /> <ul><li>To respect fully and uphold the Universal Declaration of Human Rights. </li><li> To strive for the full protection and promotion in all our countries of civil, political, economic, social and cultural rights for all. </li><li> To strengthen the capacity of all our countries to implement the principles and practices of democracy and respect for human rights, including minority rights. <dl><dd> </dd></dl> </li><li> To combat all forms of violence against women and to implement the Convention on the Elimination of All Forms of Discrimination against Women. </li><li> To take measures to ensure respect for and protection of the human rights of migrants, migrant workers and their families, to eliminate the increasing acts of racism and xenophobia in many societies and to promote greater harmony and tolerance in all societies. </li><li> To work collectively for more inclusive political processes, allowing genuine <a href="/article/Global_citizens_movement">participation by all citizens</a> in all our countries. </li><li> To ensure the freedom of the media to perform their essential role and the right of the public to have access to information. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VI. Protecting the vulnerable</strong> </dd></dl> </li><li> We will spare no effort to ensure that children and all civilian populations that suffer disproportionately the consequences of natural disasters, genocide, armed conflicts and other humanitarian emergencies are given every assistance and protection so that they can resume normal life as soon as possible. We resolve therefore: <ul><li> To expand and strengthen the protection of civilians in complex emergencies, in conformity with international humanitarian law. </li><li> To strengthen international cooperation, including burden sharing in, and the coordination of humanitarian assistance to, countries hosting refugees and to help all refugees and displaced persons to return voluntarily to their homes, in safety and dignity and to be smoothly reintegrated into their societies. </li><li> To encourage the ratification and full implementation of the Convention on the Rights of the Child and its optional protocols on the involvement of children in armed conflict and on the sale of children, child prostitution and child pornography. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VII. Meeting the special needs of Africa</strong> </dd></dl> </li><li> We will support the consolidation of democracy in Africa and assist Africans in their struggle for lasting peace, poverty eradication and <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, thereby bringing Africa into the mainstream of the world economy. </li><li> We resolve therefore: <ul><li> To give full support to the political and institutional structures of emerging democracies in Africa. </li><li> To encourage and sustain regional and subregional mechanisms for preventing conflict and promoting political stability, and to ensure a reliable flow of resources for peacekeeping operations on the continent. </li><li> To take special measures to address the challenges of poverty eradication and sustainable development in Africa, including debt cancellation, improved market access, enhanced Official Development Assistance and increased flows of Foreign Direct Investment, as well as transfers of technology. </li><li> To help Africa build up its capacity to tackle the spread of the HIV/AIDS pandemic and other infectious diseases. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VIII. Strengthening the United Nations</strong> </dd></dl> </li><li> We will spare no effort to make the United Nations a more effective instrument for pursuing all of these priorities: the fight for development for all the peoples of the world, the fight against poverty, ignorance and disease; the fight against injustice; the fight against violence, terror and crime; and the fight against the degradation and destruction of our common home. </li><li> We resolve therefore: <ul><li> To reaffirm the central position of the General Assembly as the chief deliberative, policy-making and representative organ of the United Nations, and to enable it to play that role effectively. </li><li> To intensify our efforts to achieve a comprehensive reform of the Security Council in all its aspects. </li><li> To strengthen further the Economic and Social Council, building on its recent achievements, to help it fulfil the role ascribed to it in the Charter. <dl><dd> </dd></dl> </li><li> To strengthen the International Court of Justice, in order to ensure justice and the rule of law in international affairs. </li><li> To encourage regular consultations and coordination among the principal organs of the United Nations in pursuit of their functions. </li><li> To ensure that the Organization is provided on a timely and predictable basis with the resources it needs to carry out its mandates. </li><li> To urge the Secretariat to make the best use of those resources, in accordance with clear rules and procedures agreed by the General Assembly, in the interests of all Member States, by adopting the best management practices and technologies available and by concentrating on those tasks that reflect the agreed priorities of Member States. </li><li> To promote adherence to the Convention on the Safety of United Nations and Associated Personnel. </li><li> To ensure greater policy coherence and better cooperation between the United Nations, its agencies, the Bretton Woods Institutions and the World Trade Organization, as well as other multilateral bodies, with a view to achieving a fully coordinated approach to the problems of peace and development. </li><li> To strengthen further cooperation between the United Nations and national parliaments through their world organization, the Inter-Parliamentary Union, in various fields, including peace and security, economic and social development, international law and human rights and democracy and gender issues. </li><li> To give greater opportunities to the private sector, non-governmental organizations and civil society, in general, to contribute to the realization of the Organization’s goals and programmes. </li></ul> </li><li> We request the General Assembly to review on a regular basis the progress made in implementing the provisions of this Declaration, and ask the Secretary-General to issue periodic reports for consideration by the General Assembly and as a basis for further action. </li><li> We solemnly reaffirm, on this historic occasion, that the United Nations is the indispensable common house of the entire human family, through which we will seek to realize our universal aspirations for peace, cooperation and development. We therefore pledge our unstinting support for these common objectives and our determination to achieve them. </li></ol> <p><strong>Further Reading</strong> </p> <ul><li> <a href="http://www.un.org/" class='external text' title="http://www.un.org/">United Nations Homepage</a> </li><li> <a href="http://www.un.org/millennium/" class='external text' title="http://www.un.org/millennium/">United Nations Millennium Assembly</a> </li></ul> <p><br /> <p><br style="clear: left" /> <center> </p> </center> </p> <p><a href='/article/United_Nations_Millennium_Declaration'>Read Full Article...</a></p> http://www.eoearth.org/article/United_Nations_Millennium_Declaration Wed, 07 Oct 2009 06:38:11 GMT http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics <a href='/article/Rachel_Carson's_environmental_ethics'><img border='0' src='/upload/thumb/f/fd/Rachel_Carson.jpg/180px-Rachel_Carson.jpg' width='100'/></a> <p><a href="/article/Carson%2C_Rachel_Louise">Rachel Carson</a> has been called the founder of the U.S. environmental movement, which some date, plausibly, to the publication of <em>Silent Spring</em> in 1962. That best-selling book focused public attention on the problem of <a href="/article/Pesticide">pesticide</a> and other chemical pollution, and led to such landmark legislation as the U.S. Clean Water Act and the banning of <a href="/article/DDT">DDT</a> in many countries throughout the world. Whatever Carson&#39;s arguments were in <em>Silent Spring</em>, they succeeded. Yet she has received little attention from environmental ethicists.</p><p>I believe Rachel Carson was not just a successful polemicist, but an important environmental thinker. With the recent publication of a definitive biography, <a href="/contributor/Linda.lear">Linda Lear&#39;s</a> <em>Rachel Carson: Witness for Nature</em>, we can better understand her environmental philosophy, for Carson lived that philosophy as well as wrote about it. Meeting Carson the scientist and naturalist clarifies her understanding of the role knowledge can play in a larger relationship to nature. Studying her fifteen-year career as a <a href="/article/United_States_Fish_and_Wildlife_Service">U.S. Fish and Wildlife Service</a> biologist gives valuable insight into her views on practical conservation issues. Carson&#39;s personal story teaches us much about humility and courage, as she triumphed over various setbacks and achieved great literary success, while faithfully discharging her many responsibilities to family, friends, and nature. Still, in order to best understand Carson&#39;s environmental ethics, the place to start is with her final work, <em>Silent Spring</em>. </p> <p><a href='/article/Rachel_Carson's_environmental_ethics'>Read Full Article...</a></p> http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics Wed, 07 Oct 2009 06:33:05 GMT http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics <a href='/article/Rachel_Carson's_environmental_ethics'><img border='0' src='/upload/thumb/f/fd/Rachel_Carson.jpg/180px-Rachel_Carson.jpg' width='100'/></a> <p><a href="/article/Carson%2C_Rachel_Louise">Rachel Carson</a> has been called the founder of the U.S. environmental movement, which some date, plausibly, to the publication of <em>Silent Spring</em> in 1962. That best-selling book focused public attention on the problem of <a href="/article/Pesticide">pesticide</a> and other chemical pollution, and led to such landmark legislation as the U.S. Clean Water Act and the banning of <a href="/article/DDT">DDT</a> in many countries throughout the world. Whatever Carson&#39;s arguments were in <em>Silent Spring</em>, they succeeded. Yet she has received little attention from environmental ethicists.</p><p>I believe Rachel Carson was not just a successful polemicist, but an important environmental thinker. With the recent publication of a definitive biography, <a href="/contributor/Linda.lear">Linda Lear&#39;s</a> <em>Rachel Carson: Witness for Nature</em>, we can better understand her environmental philosophy, for Carson lived that philosophy as well as wrote about it. Meeting Carson the scientist and naturalist clarifies her understanding of the role knowledge can play in a larger relationship to nature. Studying her fifteen-year career as a <a href="/article/United_States_Fish_and_Wildlife_Service">U.S. Fish and Wildlife Service</a> biologist gives valuable insight into her views on practical conservation issues. Carson&#39;s personal story teaches us much about humility and courage, as she triumphed over various setbacks and achieved great literary success, while faithfully discharging her many responsibilities to family, friends, and nature. Still, in order to best understand Carson&#39;s environmental ethics, the place to start is with her final work, <em>Silent Spring</em>. </p> <p><a href='/article/Rachel_Carson's_environmental_ethics'>Read Full Article...</a></p> http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics Tue, 06 Oct 2009 06:32:48 GMT http://www.eoearth.org/article/Yosemite_National_Park,_United_States <a href='/article/Yosemite_National_Park,_United_States'><img border='0' src='/upload/thumb/4/45/Yosemite2.jpg/300px-Yosemite2.jpg' width='100'/></a> <p>Yosemite National Park, (37°30&#39;-38°11&#39;N, 119°12&#39;-119°53&#39;W) is a World Heritage Site located in the heart of California, United States. </p> <p><a href='/article/Yosemite_National_Park,_United_States'>Read Full Article...</a></p> http://www.eoearth.org/article/Yosemite_National_Park,_United_States Fri, 02 Oct 2009 05:46:27 GMT http://www.eoearth.org/article/Yosemite_National_Park,_United_States <a href='/article/Yosemite_National_Park,_United_States'><img border='0' src='/upload/thumb/4/45/Yosemite2.jpg/300px-Yosemite2.jpg' width='100'/></a> <p>Yosemite National Park, (37°30&#39;-38°11&#39;N, 119°12&#39;-119°53&#39;W) is a World Heritage Site located in the heart of California, United States. </p> <p><a href='/article/Yosemite_National_Park,_United_States'>Read Full Article...</a></p> http://www.eoearth.org/article/Yosemite_National_Park,_United_States Fri, 02 Oct 2009 05:45:48 GMT http://www.eoearth.org/article/Whaling_for_scientific_research_purposes <a href='/article/Whaling_for_scientific_research_purposes'><img border='0' src='/upload/thumb/9/99/8janphotobig1.jpg/250px-8janphotobig1.jpg' width='100'/></a> <p>A major area of controversy within the international community has been the issuing of permits by States parties to the 1946 International Convention for the Regulation of Whaling (ICRW) for the killing of whales for scientific research purposes. </p> <p>Article VIII of the ICRW provides that: </p> <dl><dd>…any Contracting Government may grant to any of its nationals a special permit authorizing that national to kill, take and treat whales for purposes of scientific research subject to such restrictions as to number and subject to such other conditions as the Contracting Government thinks fit, and the killing, taking, and treating of whales in accordance with the provisions of this Article shall be exempt from the operation of this Convention. Each Contracting Government shall report at once to the Commission all such authorizations which it has granted. Each Contracting Government may at any time revoke any such special permit which it has granted.<br /><br />Any whales taken under these special permits shall so far as practicable be processed and the proceeds shall be dealt with in accordance with directions issued by the Government by which the permit was granted (...) </dd></dl> <p>Before 1982, when it was decided that a moratorium on commercial whaling would come into effect in 1986, more than 100 permits for scientific research purposes were issued by a number of governments including Canada, USA, USSR, South Africa and Japan. Since the beginning of the moratorium, Japan, Norway and Iceland have issued scientific research permits. Currently, Iceland and Japan are the two countries that are engaged in whaling for “scientific purposes”. </p><p>The applications for the permits are reviewed by the Scientific Committee which has to follow a set of guidelines established by the International Whaling Commission (IWC). One of the most recent guidelines states that: </p> <blockquote> (the IWC) requests the Scientific Committee, with respect to all Special Permit Research Programmes, to provide advice to the Commission, on the research to be undertaken pursuant to any proposed Special Permit or that has been undertaken in respect of any Special Permit, as to whether the information sought in the research programme under each Special Permit is: required for the purposes of management of the species or stock being researched; and whether the information sought could be obtained by non-lethal means. (<i>Report of the International Whaling Commission 45: 82ff.</i>)</blockquote> <p>While plenty of information can be obtained by using non-lethal research methods such as biopsy sampling and photo-identification, according to the Scientific Committee of the IWC, data such as the age of an animal (obtained from earplugs) and the reproductive status and history of females (obtained from ovaries) can be obtained only by lethal methods. The question is whether these data are really ‘essential’, ‘reliable enough’ or ‘critical’ to justify the taking of the whales that are studied. Since 1987, a number of IWC Resolutions have expressed concern over the fact that the "provision permitting special permit whaling enables countries to conduct whaling for commercial purposes despite the moratorium on commercial whaling" (IWC Resolution 2003-2), including the notion that non-lethal techniques usually provide better data at less cost to both animals and budget. In 2006, Japan has responded that its research - including the use of lethal techniques - is" consistent with the unanimous decision of the IWC in 2001 to make the study of interactions between whales and fisheries a priority" (The Government of Japan’s Position for the 58th Annual Meeting of the IWC). </p> <p><a href='/article/Whaling_for_scientific_research_purposes'>Read Full Article...</a></p> http://www.eoearth.org/article/Whaling_for_scientific_research_purposes Thu, 01 Oct 2009 08:12:21 GMT http://www.eoearth.org/article/Whaling_for_scientific_research_purposes <a href='/article/Whaling_for_scientific_research_purposes'><img border='0' src='/upload/thumb/9/99/8janphotobig1.jpg/250px-8janphotobig1.jpg' width='100'/></a> <p>A major area of controversy within the international community has been the issuing of permits by States parties to the 1946 International Convention for the Regulation of Whaling (ICRW) for the killing of whales for scientific research purposes. </p> <p>Article VIII of the ICRW provides that: </p> <dl><dd>…any Contracting Government may grant to any of its nationals a special permit authorizing that national to kill, take and treat whales for purposes of scientific research subject to such restrictions as to number and subject to such other conditions as the Contracting Government thinks fit, and the killing, taking, and treating of whales in accordance with the provisions of this Article shall be exempt from the operation of this Convention. Each Contracting Government shall report at once to the Commission all such authorizations which it has granted. Each Contracting Government may at any time revoke any such special permit which it has granted.<br /><br />Any whales taken under these special permits shall so far as practicable be processed and the proceeds shall be dealt with in accordance with directions issued by the Government by which the permit was granted (...) </dd></dl> <p>Before 1982, when it was decided that a moratorium on commercial whaling would come into effect in 1986, more than 100 permits for scientific research purposes were issued by a number of governments including Canada, USA, USSR, South Africa and Japan. Since the beginning of the moratorium, Japan, Norway and Iceland have issued scientific research permits. Currently, Iceland and Japan are the two countries that are engaged in whaling for “scientific purposes”. </p><p>The applications for the permits are reviewed by the Scientific Committee which has to follow a set of guidelines established by the International Whaling Commission (IWC). One of the most recent guidelines states that: </p> <blockquote> (the IWC) requests the Scientific Committee, with respect to all Special Permit Research Programmes, to provide advice to the Commission, on the research to be undertaken pursuant to any proposed Special Permit or that has been undertaken in respect of any Special Permit, as to whether the information sought in the research programme under each Special Permit is: required for the purposes of management of the species or stock being researched; and whether the information sought could be obtained by non-lethal means. (<i>Report of the International Whaling Commission 45: 82ff.</i>)</blockquote> <p>While plenty of information can be obtained by using non-lethal research methods such as biopsy sampling and photo-identification, according to the Scientific Committee of the IWC, data such as the age of an animal (obtained from earplugs) and the reproductive status and history of females (obtained from ovaries) can be obtained only by lethal methods. The question is whether these data are really ‘essential’, ‘reliable enough’ or ‘critical’ to justify the taking of the whales that are studied. Since 1987, a number of IWC Resolutions have expressed concern over the fact that the "provision permitting special permit whaling enables countries to conduct whaling for commercial purposes despite the moratorium on commercial whaling" (IWC Resolution 2003-2), including the notion that non-lethal techniques usually provide better data at less cost to both animals and budget. In 2006, Japan has responded that its research - including the use of lethal techniques - is" consistent with the unanimous decision of the IWC in 2001 to make the study of interactions between whales and fisheries a priority" (The Government of Japan’s Position for the 58th Annual Meeting of the IWC). </p> <p><a href='/article/Whaling_for_scientific_research_purposes'>Read Full Article...</a></p> http://www.eoearth.org/article/Whaling_for_scientific_research_purposes Thu, 01 Oct 2009 08:12:02 GMT http://www.eoearth.org/article/Latin_America_and_the_Caribbean_(collection) <a href='/article/Latin_America_and_the_Caribbean_(collection)'><img border='0' src='/media/approved/6/6f/LAC_Collection_header_2.jpg' width='100'/></a> </p><p>Welcome to the Latin America and the Caribbean Collection! This collection focuses on environmental and social issues in a diverse political, cultural, and environmental framework. As one of the highest biodiversity hotspots of the world, this collection attempts to address this complexity through three main geographic regions (Mexico and Central America, the Caribbean, and South America) by profiling each country and ecosystem. This collection is a work in progress, so please visit often to learn more about what is being done in the LAC. </p> <p><a href='/article/Latin_America_and_the_Caribbean_(collection)'>Read Full Article...</a></p> http://www.eoearth.org/article/Latin_America_and_the_Caribbean_(collection) Wed, 30 Sep 2009 07:24:59 GMT http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic <a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'><img border='0' src='/upload/thumb/0/03/Figure11.1_management_forces.JPG/320px-Figure11.1_management_forces.JPG' width='100'/></a> <p>This is Section 11.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a> <br />Lead Author: David R. Klein; Contributing Authors: Leonid M. Baskin, Lyudmila S. Bogoslovskaya, Kjell Danell, Anne Gunn, David B. Irons, Gary P. Kofinas, Kit M. Kovacs, Margarita Magomedova, Rosa H. Meehan, Don E. Russell, Patrick Valkenburg </p> <p><a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic Tue, 29 Sep 2009 07:51:06 GMT http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic <a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'><img border='0' src='/upload/thumb/0/03/Figure11.1_management_forces.JPG/320px-Figure11.1_management_forces.JPG' width='100'/></a> <p>This is Section 11.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a> <br />Lead Author: David R. Klein; Contributing Authors: Leonid M. Baskin, Lyudmila S. Bogoslovskaya, Kjell Danell, Anne Gunn, David B. Irons, Gary P. Kofinas, Kit M. Kovacs, Margarita Magomedova, Rosa H. Meehan, Don E. Russell, Patrick Valkenburg </p> <p><a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic Tue, 29 Sep 2009 07:38:27 GMT http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic <a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'><img border='0' src='/upload/thumb/0/03/Figure11.1_management_forces.JPG/320px-Figure11.1_management_forces.JPG' width='100'/></a> <p>This is Section 11.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a> <br />Lead Author: David R. Klein; Contributing Authors: Leonid M. Baskin, Lyudmila S. Bogoslovskaya, Kjell Danell, Anne Gunn, David B. Irons, Gary P. Kofinas, Kit M. Kovacs, Margarita Magomedova, Rosa H. Meehan, Don E. Russell, Patrick Valkenburg </p> <p><a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic Tue, 29 Sep 2009 05:48:18 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Tue, 29 Sep 2009 05:47:23 GMT http://www.eoearth.org/article/Origin_and_age_of_lakes <a href='/article/Origin_and_age_of_lakes'><img border='0' src='/upload/thumb/2/2a/Intro.gif/200px-Intro.gif' width='100'/></a> <p>Lakes are formed by geological, climatological, biological, and extraterrestrial (meteorites) mechanisms. While most lakes are formed by catastrophic events, others are created more gradually.</p> <p><a href='/article/Origin_and_age_of_lakes'>Read Full Article...</a></p> http://www.eoearth.org/article/Origin_and_age_of_lakes Mon, 28 Sep 2009 07:08:54 GMT http://www.eoearth.org/article/Carbon <a href='/article/Carbon'><img border='0' src='/upload/thumb/1/1f/Carbon_atom.gif/200px-Carbon_atom.gif' width='100'/></a> <p><a href='/article/Carbon'>Read Full Article...</a></p> http://www.eoearth.org/article/Carbon Fri, 25 Sep 2009 05:47:55 GMT http://www.eoearth.org/article/Carbon <a href='/article/Carbon'><img border='0' src='/upload/thumb/1/1f/Carbon_atom.gif/200px-Carbon_atom.gif' width='100'/></a> <p><a href='/article/Carbon'>Read Full Article...</a></p> http://www.eoearth.org/article/Carbon Fri, 25 Sep 2009 05:47:38 GMT http://www.eoearth.org/article/Lake_effect_snow <a href='/article/Lake_effect_snow'><img border='0' src='/upload/thumb/a/ae/Lakeeffect_seawifs_big.jpg/300px-Lakeeffect_seawifs_big.jpg' width='100'/></a> <p>During the fall and winter, many areas of the eastern United States and Canada experience tremendous amounts of <a href="/article/Precipitation_and_fog">snowfall</a>. This snow, known as "lake-effect snow," is generated from the <a href="/article/Temperature">temperature</a> contrast between the cold arctic air moving over the relatively warm waters of the Great Lakes (or other large body of water). Unlike most winter storms, lake effect snows do not build their foundation upon strong areas of low <a href="/article/Pressure">pressure</a>. Instead, they are fueled by the same dry arctic air that is responsible for clearing skies over land in other parts of the country. Specifically, cold arctic air passing over the Great Lakes picks up moisture and deposits it as snow inland from the downwind shore. So while other parts of the northeastern United States are clearing up after a recent cold frontal passage, communities near the Great Lakes wait for the lake effect snow machine to fire up! Barny Wiggin, former Meteorologist-In-Charge at the NWS Office in Buffalo, said it best when he claimed that the ‘weather often "clears up stormy" to the lee of the Great Lakes during the winter.' </p><p>Lake effect snow <a href="/article/Cloud_formation_processes">cloud</a> bands are remarkably persistent and have been known to cause continuous snowfall for as long as 48 hours over a sharply defined <a href="/article/Region">region</a>—an amount that often exceeds that of a typical winter storm (i.e., one associated with a low pressure). Lake effect snows yielding as much as 193 <a href="/article/Meter">centimeters</a> (cm) (76 inches) of light-density snow in 24 hours and fall rates as high as 15 cm (6 inches) per hour have been reported. Furthermore, because <a href="/article/Wind">winds</a> accompanying arctic air masses generally originate from a southwest to northwest direction, lake effect snow typically falls on the east or southeast sides of the <a href="/article/Freshwater_biomes">lakes</a>. In general, lake effect snowfall contributes between 30 and 60 percent of the annual winter snowfall on the eastern and southern shores of the Great Lakes. </p> <p><a href='/article/Lake_effect_snow'>Read Full Article...</a></p> http://www.eoearth.org/article/Lake_effect_snow Thu, 24 Sep 2009 05:41:48 GMT http://www.eoearth.org/article/Perlite <a href='/article/Perlite'><img border='0' src='/upload/thumb/2/23/Perlite2.jpg/250px-Perlite2.jpg' width='100'/></a> <p>Perlite is a type of volcanic glass that expands and becomes porous when it is <a href="/article/Heat">heated</a>. When heated, it can expand to as much as twenty times its original volume. This expansion is the result of heated water: when the glassy lava rock is heated to 1,600 degrees Fahrenheit (871 degrees Celsius), the water molecules trapped in the rock turn into vapor which causes the rock to expand. (This is the same principle as the water in pop corn that causes the kernel to pop when it is heated.) Before it is expanded, perlite is commonly gray, but can also be green, brown, blue or red. After it has been heated, perlite is typically light gray to white. </p><p>Volcanic glass forms when molten rock (lava) pours out of a <a href="/article/Volcano">volcano</a> and cools very, very quickly. Because is cools so quickly, there is no time for crystals to form or for water to escape. Instead, the lava hardens immediately into this glass-like material containing 2-5% water. It is a silicate rock, which means that it has a high percentage of silica (<a href="/article/Silicon">Si</a>). </p><p>Perlite is known in industry in two forms. <em>Crude perlite</em> is prepared by the crushing and screening of perlite into various size fractions. <em>Expanded perlite</em> is perlite after it has been heated.</p> <p><a href='/article/Perlite'>Read Full Article...</a></p> http://www.eoearth.org/article/Perlite Wed, 23 Sep 2009 05:38:11 GMT http://www.eoearth.org/article/Food_web <a href='/article/Food_web'><img border='0' src='/upload/thumb/4/4a/Alaska_food_web.jpg/300px-Alaska_food_web.jpg' width='100'/></a> <p>A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom (Fig. 1). It is also a means of showing how energy and materials (e.g., <a href="/article/Carbon">carbon</a>) flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called &quot;links&quot;, and the species are sometimes referred to as &quot;nodes&quot; in food web diagrams. </p><p>The pioneering animal ecologist <a href="/article/Elton%2C_Charles">Charles Elton</a> (1927) introduced the concept of the food web (which he called food cycle) to general <a href="/article/Ecology">ecological science</a>. As he described it: &quot;The herbivores are usually preyed upon by carnivores, which get the energy of the <a href="/article/Solar_radiation">sunlight</a> at third-hand, and these again may be preyed upon by other carnivores, and so on, until we reach an animal which has no enemies, and which forms, as it were, a terminus on this food cycle. There are, in fact, chains of animals linked together by food, and all dependent in the long run upon plants. We refer to these as &#39;food-chains&#39;, and to all the food chains in a community as the &#39;food-cycle.&#39;&quot; </p><p>A food web differs from a food chain in that the latter shows only a portion of the food web involving a simple, linear series of species (e.g., predator, herbivore, plant) connected by feeding links. A food web aims to depict a more complete picture of the feeding relationships, and can be considered a bundle of many interconnected food chains occurring within the community. All species occupying the same position within a food chain comprise a trophic level within the food web. For instance, all of the plants in the foodweb comprise the first or &quot;primary producer&quot; tropic level, all herbivores comprise the second or &quot;primary consumer&quot; trophic level, and carnivores that eat herbivores comprise the third or &quot;secondary consumer&quot; trophic level. Additional levels, in which carnivores eat other carnivores, comprise a tertiary trophic level.</p><p>Elton emphasized early on that food chains tend to show characteristic patterns of increasing body size as one moves up the food chain, for example from <a href="/article/Phytoplankton">phytoplankton</a> to invertebrate grazers to fishes, or from insects to rodents to larger carnivores like foxes. Because individuals of small-bodied species require less energy and food than individuals of larger-bodied species, a given amount of energy can support a greater number of individuals of the smaller-bodied species. Hence, ecological communities typically show what Elton called a pyramid of numbers (later dubbed the Eltonian pyramid), in which the species at lower trophic levels in the food web tend to be more numerous than those at higher trophic levels. </p> <p>A second reason for the pyramid of numbers is low ecological efficiency: some energy is lost at each transfer between consumer and prey, such that the energy that reaches top predators is a very small fraction of that available in the plants at the base of the food web. Although there is wide variation among types of organisms and types of <a href="/article/Ecosystem">ecosystems</a>, a general rule of thumb is that available energy decreases by about an order of magnitude at each step in the food chain. That is, only about 10% of the energy harvested by plants is consumed and converted into herbivore biomass, only 10% of that makes it into biomass of primary carnivores, and so on. Thus, the structure of food webs is dictated in part by basic constraints set by <a href="/article/Thermodynamics">thermodynamics</a>. The predictable dissipation of energy at each step in food chains is one of the factors thought to limit the length of most food chains to a maximum of four or five steps. Cohen et al. (2003) emphasized that the correlations among body size, abundance, and trophic level produce a characteristic trivariate structure to (pelagic) food webs (Fig. 2). </p><p>The pyramid of numbers is less obvious at the most basal levels in terrestrial communities based on trees, which are typically much larger than the herbivores that feed on them. Pyramids of numbers or biomass may even be inverted in cases where the microscopic plants that support the web show very rapid turnover, that is, where they grow and are eaten so rapidly that there is less plant biomass than herbivore biomass present at a given time. </p><p>Decomposers are an assemblage of small organisms, including invertebrates, fungi, and <a href="/article/Bacteria">bacteria</a>, that do not fit neatly into any trophic level because they consume dead biomass of organisms from all trophic levels. Decomposers are a critical component of the food web, however, because they recycle nutrients that otherwise would become sequestered in accumulating detritus.</p><p><strong>References and further reading</strong></p><ul><li>Cohen, J., T. Jonsson, and S.R. Carpenter. 2003. Ecological community description using the food web, species abundance, and body size. Proceedings of the National Academy of Sciences USA. 100: 1781–1786. </li><li>Elton, C. 1927. Animal ecology. Sidgwick and Jackson Ltd, London, UK. </li><li>Hardy, A.C. 1924. The herring in relation to its animate environment, Part I. Ministry of Agriculture and Fisheries, Fishery Investigations, Series 2, Volume 7, number 3. </li><li>Lindemann, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23: 399-418. </li><li>May, R.M. 1973. Stability and complexity in model food webs. Princeton University Press, Princeton, NJ. </li><li>Morin, P.J. 1999. Community ecology. Blackwell Science, Oxford, UK. </li><li>Paine, R.T. 1980. Food Webs: Linkage, Interaction Strength and Community Infrastructure. Journal of Animal Ecology 49:666-685. </li><li>Pimm, S.L. 1982. Food webs. Chapman and Hall, London. </li></ul> <p><a href='/article/Food_web'>Read Full Article...</a></p> http://www.eoearth.org/article/Food_web Tue, 22 Sep 2009 06:12:50 GMT http://www.eoearth.org/article/Food_web <a href='/article/Food_web'><img border='0' src='/upload/thumb/4/4a/Alaska_food_web.jpg/300px-Alaska_food_web.jpg' width='100'/></a> <p>A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom (Fig. 1). It is also a means of showing how energy and materials (e.g., <a href="/article/Carbon">carbon</a>) flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called &quot;links&quot;, and the species are sometimes referred to as &quot;nodes&quot; in food web diagrams. </p><p>The pioneering animal ecologist <a href="/article/Elton%2C_Charles">Charles Elton</a> (1927) introduced the concept of the food web (which he called food cycle) to general <a href="/article/Ecology">ecological science</a>. As he described it: &quot;The herbivores are usually preyed upon by carnivores, which get the energy of the <a href="/article/Solar_radiation">sunlight</a> at third-hand, and these again may be preyed upon by other carnivores, and so on, until we reach an animal which has no enemies, and which forms, as it were, a terminus on this food cycle. There are, in fact, chains of animals linked together by food, and all dependent in the long run upon plants. We refer to these as &#39;food-chains&#39;, and to all the food chains in a community as the &#39;food-cycle.&#39;&quot; </p><p>A food web differs from a food chain in that the latter shows only a portion of the food web involving a simple, linear series of species (e.g., predator, herbivore, plant) connected by feeding links. A food web aims to depict a more complete picture of the feeding relationships, and can be considered a bundle of many interconnected food chains occurring within the community. All species occupying the same position within a food chain comprise a trophic level within the food web. For instance, all of the plants in the foodweb comprise the first or &quot;primary producer&quot; tropic level, all herbivores comprise the second or &quot;primary consumer&quot; trophic level, and carnivores that eat herbivores comprise the third or &quot;secondary consumer&quot; trophic level. Additional levels, in which carnivores eat other carnivores, comprise a tertiary trophic level.</p><p>Elton emphasized early on that food chains tend to show characteristic patterns of increasing body size as one moves up the food chain, for example from <a href="/article/Phytoplankton">phytoplankton</a> to invertebrate grazers to fishes, or from insects to rodents to larger carnivores like foxes. Because individuals of small-bodied species require less energy and food than individuals of larger-bodied species, a given amount of energy can support a greater number of individuals of the smaller-bodied species. Hence, ecological communities typically show what Elton called a pyramid of numbers (later dubbed the Eltonian pyramid), in which the species at lower trophic levels in the food web tend to be more numerous than those at higher trophic levels. </p> <p>A second reason for the pyramid of numbers is low ecological efficiency: some energy is lost at each transfer between consumer and prey, such that the energy that reaches top predators is a very small fraction of that available in the plants at the base of the food web. Although there is wide variation among types of organisms and types of <a href="/article/Ecosystem">ecosystems</a>, a general rule of thumb is that available energy decreases by about an order of magnitude at each step in the food chain. That is, only about 10% of the energy harvested by plants is consumed and converted into herbivore biomass, only 10% of that makes it into biomass of primary carnivores, and so on. Thus, the structure of food webs is dictated in part by basic constraints set by <a href="/article/Thermodynamics">thermodynamics</a>. The predictable dissipation of energy at each step in food chains is one of the factors thought to limit the length of most food chains to a maximum of four or five steps. Cohen et al. (2003) emphasized that the correlations among body size, abundance, and trophic level produce a characteristic trivariate structure to (pelagic) food webs (Fig. 2). </p><p>The pyramid of numbers is less obvious at the most basal levels in terrestrial communities based on trees, which are typically much larger than the herbivores that feed on them. Pyramids of numbers or biomass may even be inverted in cases where the microscopic plants that support the web show very rapid turnover, that is, where they grow and are eaten so rapidly that there is less plant biomass than herbivore biomass present at a given time. </p><p>Decomposers are an assemblage of small organisms, including invertebrates, fungi, and <a href="/article/Bacteria">bacteria</a>, that do not fit neatly into any trophic level because they consume dead biomass of organisms from all trophic levels. Decomposers are a critical component of the food web, however, because they recycle nutrients that otherwise would become sequestered in accumulating detritus.</p><p><strong>References and further reading</strong></p><ul><li>Cohen, J., T. Jonsson, and S.R. Carpenter. 2003. Ecological community description using the food web, species abundance, and body size. Proceedings of the National Academy of Sciences USA. 100: 1781–1786. </li><li>Elton, C. 1927. Animal ecology. Sidgwick and Jackson Ltd, London, UK. </li><li>Hardy, A.C. 1924. The herring in relation to its animate environment, Part I. Ministry of Agriculture and Fisheries, Fishery Investigations, Series 2, Volume 7, number 3. </li><li>Lindemann, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23: 399-418. </li><li>May, R.M. 1973. Stability and complexity in model food webs. Princeton University Press, Princeton, NJ. </li><li>Morin, P.J. 1999. Community ecology. Blackwell Science, Oxford, UK. </li><li>Paine, R.T. 1980. Food Webs: Linkage, Interaction Strength and Community Infrastructure. Journal of Animal Ecology 49:666-685. </li><li>Pimm, S.L. 1982. Food webs. Chapman and Hall, London. </li></ul> <p><a href='/article/Food_web'>Read Full Article...</a></p> http://www.eoearth.org/article/Food_web Tue, 22 Sep 2009 06:12:32 GMT http://www.eoearth.org/article/Food_web <a href='/article/Food_web'><img border='0' src='/upload/thumb/4/4a/Alaska_food_web.jpg/300px-Alaska_food_web.jpg' width='100'/></a> <p>A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom (Fig. 1). It is also a means of showing how energy and materials (e.g., <a href="/article/Carbon">carbon</a>) flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called &quot;links&quot;, and the species are sometimes referred to as &quot;nodes&quot; in food web diagrams. </p><p>The pioneering animal ecologist <a href="/article/Elton%2C_Charles">Charles Elton</a> (1927) introduced the concept of the food web (which he called food cycle) to general <a href="/article/Ecology">ecological science</a>. As he described it: &quot;The herbivores are usually preyed upon by carnivores, which get the energy of the <a href="/article/Solar_radiation">sunlight</a> at third-hand, and these again may be preyed upon by other carnivores, and so on, until we reach an animal which has no enemies, and which forms, as it were, a terminus on this food cycle. There are, in fact, chains of animals linked together by food, and all dependent in the long run upon plants. We refer to these as &#39;food-chains&#39;, and to all the food chains in a community as the &#39;food-cycle.&#39;&quot; </p><p>A food web differs from a food chain in that the latter shows only a portion of the food web involving a simple, linear series of species (e.g., predator, herbivore, plant) connected by feeding links. A food web aims to depict a more complete picture of the feeding relationships, and can be considered a bundle of many interconnected food chains occurring within the community. All species occupying the same position within a food chain comprise a trophic level within the food web. For instance, all of the plants in the foodweb comprise the first or &quot;primary producer&quot; tropic level, all herbivores comprise the second or &quot;primary consumer&quot; trophic level, and carnivores that eat herbivores comprise the third or &quot;secondary consumer&quot; trophic level. Additional levels, in which carnivores eat other carnivores, comprise a tertiary trophic level.</p><p>Elton emphasized early on that food chains tend to show characteristic patterns of increasing body size as one moves up the food chain, for example from <a href="/article/Phytoplankton">phytoplankton</a> to invertebrate grazers to fishes, or from insects to rodents to larger carnivores like foxes. Because individuals of small-bodied species require less energy and food than individuals of larger-bodied species, a given amount of energy can support a greater number of individuals of the smaller-bodied species. Hence, ecological communities typically show what Elton called a pyramid of numbers (later dubbed the Eltonian pyramid), in which the species at lower trophic levels in the food web tend to be more numerous than those at higher trophic levels. </p> <p>A second reason for the pyramid of numbers is low ecological efficiency: some energy is lost at each transfer between consumer and prey, such that the energy that reaches top predators is a very small fraction of that available in the plants at the base of the food web. Although there is wide variation among types of organisms and types of <a href="/article/Ecosystem">ecosystems</a>, a general rule of thumb is that available energy decreases by about an order of magnitude at each step in the food chain. That is, only about 10% of the energy harvested by plants is consumed and converted into herbivore biomass, only 10% of that makes it into biomass of primary carnivores, and so on. Thus, the structure of food webs is dictated in part by basic constraints set by <a href="/article/Thermodynamics">thermodynamics</a>. The predictable dissipation of energy at each step in food chains is one of the factors thought to limit the length of most food chains to a maximum of four or five steps. Cohen et al. (2003) emphasized that the correlations among body size, abundance, and trophic level produce a characteristic trivariate structure to (pelagic) food webs (Fig. 2). </p><p>The pyramid of numbers is less obvious at the most basal levels in terrestrial communities based on trees, which are typically much larger than the herbivores that feed on them. Pyramids of numbers or biomass may even be inverted in cases where the microscopic plants that support the web show very rapid turnover, that is, where they grow and are eaten so rapidly that there is less plant biomass than herbivore biomass present at a given time. </p><p>Decomposers are an assemblage of small organisms, including invertebrates, fungi, and <a href="/article/Bacteria">bacteria</a>, that do not fit neatly into any trophic level because they consume dead biomass of organisms from all trophic levels. Decomposers are a critical component of the food web, however, because they recycle nutrients that otherwise would become sequestered in accumulating detritus.</p><p><strong>References and further reading</strong></p><ul><li>Cohen, J., T. Jonsson, and S.R. Carpenter. 2003. Ecological community description using the food web, species abundance, and body size. Proceedings of the National Academy of Sciences USA. 100: 1781–1786. </li><li>Elton, C. 1927. Animal ecology. Sidgwick and Jackson Ltd, London, UK. </li><li>Hardy, A.C. 1924. The herring in relation to its animate environment, Part I. Ministry of Agriculture and Fisheries, Fishery Investigations, Series 2, Volume 7, number 3. </li><li>Lindemann, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23: 399-418. </li><li>May, R.M. 1973. Stability and complexity in model food webs. Princeton University Press, Princeton, NJ. </li><li>Morin, P.J. 1999. Community ecology. Blackwell Science, Oxford, UK. </li><li>Paine, R.T. 1980. Food Webs: Linkage, Interaction Strength and Community Infrastructure. Journal of Animal Ecology 49:666-685. </li><li>Pimm, S.L. 1982. Food webs. Chapman and Hall, London. </li></ul> <p><a href='/article/Food_web'>Read Full Article...</a></p> http://www.eoearth.org/article/Food_web Tue, 22 Sep 2009 06:12:16 GMT http://www.eoearth.org/article/Glacier <a href='/article/Glacier'><img border='0' src='/upload/thumb/a/af/Antarctica_glacier.gif/250px-Antarctica_glacier.gif' width='100'/></a> <p>Various types of paleoclimatic evidence suggest that the climate of the Earth has <a href="/article/Earth%27s_climatic_history">varied over time</a>. The data suggest that during most of the Earth&#39;s history, global <a href="/article/Temperature">temperatures</a> were probably 8 to 15° Celsius warmer than they are today. However, there were periods of times when the Earth&#39;s average global temperature became cold; cold enough for the formation of alpine glaciers and continental glaciers that extended in to the higher, middle and sometimes lower latitudes. In the last billion years of Earth&#39;s history, glacial periods have started at roughly 925, 800, 680, 450, 330, and 2 million years before present (B.P.). Of these ice ages, the most severe occurred at 800 million years ago when glaciers came within 5 degrees of the equator. </p><p>The last major glacial period began about 2,000,000 years B.P. and is commonly known as the Pleistocene or Ice Age. During this glacial period, large glacial ice sheets covered much of North America, Europe, and Asia for long periods of time. The extent of the glacier ice during the Pleistocene, however, was not static. The Pleistocene had periods when the glaciers retreated (interglacial) because of mild temperatures, and advanced because of colder temperatures (glacial). Average global temperatures were probably 4 to 5° Celsius colder than they are today at the peak of the Pleistocene. The most recent glacial retreat began about 14,000 years B.P. and is still going on. We call this period the Holocene epoch. </p><p>In North America, the Pleistocene glaciers began their formation in the higher altitudes of the Rocky Mountains, and high-latitude locations in Greenland and north-central Canada. From these locations, the ice spread in all directions following the topography of the landscape. In North America, the glaciers from the Rocky Mountains and north-central Canada met each other in the center of the continent creating an ice sheet that stretched from the <a href="/article/Ocean">Pacific</a> to the <a href="/article/Ocean">Atlantic Ocean</a>. At their greatest extent, the ice sheets of North America covered most of Canada and extended into the United States to a latitude of about 40° North. </p><p>A similar pattern of glaciation has also been scientifically documented in Europe and Asia. In Eurasia, ice sheets had their birth place in the Alps Mountains, Scandinavia, northern British Isles, and northern Siberia. The ice sheets of Eurasia, however, did not form a single ice sheet through convergence and their furthest extent south was limited to a latitude of about 45° North. </p> <p><a href='/article/Glacier'>Read Full Article...</a></p> http://www.eoearth.org/article/Glacier Fri, 18 Sep 2009 07:46:12 GMT http://www.eoearth.org/article/Glacier <a href='/article/Glacier'><img border='0' src='/upload/thumb/a/af/Antarctica_glacier.gif/250px-Antarctica_glacier.gif' width='100'/></a> <p>Various types of paleoclimatic evidence suggest that the climate of the Earth has <a href="/article/Earth%27s_climatic_history">varied over time</a>. The data suggest that during most of the Earth&#39;s history, global <a href="/article/Temperature">temperatures</a> were probably 8 to 15° Celsius warmer than they are today. However, there were periods of times when the Earth&#39;s average global temperature became cold; cold enough for the formation of alpine glaciers and continental glaciers that extended in to the higher, middle and sometimes lower latitudes. In the last billion years of Earth&#39;s history, glacial periods have started at roughly 925, 800, 680, 450, 330, and 2 million years before present (B.P.). Of these ice ages, the most severe occurred at 800 million years ago when glaciers came within 5 degrees of the equator. </p><p>The last major glacial period began about 2,000,000 years B.P. and is commonly known as the Pleistocene or Ice Age. During this glacial period, large glacial ice sheets covered much of North America, Europe, and Asia for long periods of time. The extent of the glacier ice during the Pleistocene, however, was not static. The Pleistocene had periods when the glaciers retreated (interglacial) because of mild temperatures, and advanced because of colder temperatures (glacial). Average global temperatures were probably 4 to 5° Celsius colder than they are today at the peak of the Pleistocene. The most recent glacial retreat began about 14,000 years B.P. and is still going on. We call this period the Holocene epoch. </p><p>In North America, the Pleistocene glaciers began their formation in the higher altitudes of the Rocky Mountains, and high-latitude locations in Greenland and north-central Canada. From these locations, the ice spread in all directions following the topography of the landscape. In North America, the glaciers from the Rocky Mountains and north-central Canada met each other in the center of the continent creating an ice sheet that stretched from the <a href="/article/Ocean">Pacific</a> to the <a href="/article/Ocean">Atlantic Ocean</a>. At their greatest extent, the ice sheets of North America covered most of Canada and extended into the United States to a latitude of about 40° North. </p><p>A similar pattern of glaciation has also been scientifically documented in Europe and Asia. In Eurasia, ice sheets had their birth place in the Alps Mountains, Scandinavia, northern British Isles, and northern Siberia. The ice sheets of Eurasia, however, did not form a single ice sheet through convergence and their furthest extent south was limited to a latitude of about 45° North. </p> <p><a href='/article/Glacier'>Read Full Article...</a></p> http://www.eoearth.org/article/Glacier Fri, 18 Sep 2009 07:44:25 GMT http://www.eoearth.org/article/Fossil_fuel_power_plant <a href='/article/Fossil_fuel_power_plant'><img border='0' src='/upload/thumb/0/0a/CF_powerplantbyriver.jpg/199px-CF_powerplantbyriver.jpg' width='100'/></a> <p>A fossil fuel power plant is a system of devices for the conversion of fossil fuel energy to mechanical work or electric energy. The main systems are the steam cycle and the gas turbine cycle. The steam cycle relies on the Rankine cycle in which high pressure and high temperature steam raised in a boiler is expanded through a steam turbine that drives an electric generator. The steam gives up its <a href="/article/Heat">heat</a> of condensation in a condenser to a heat sink such as water from a river or a lake, and the condensate can then be pumped back into the boiler to repeat the cycle. The heat taken up by the cooling water in the condenser is dissipated mostly through cooling towers into the atmosphere. </p><p>The gas turbine cycle relies on the Brayton cycle in which air compressed to high pressure, and heated to high temperature by the combustion of natural gas or light fuel oil, is the working fluid that expands in the turbine to provide the torque for driving both a compressor and the electric generator. The gas turbine demands clean fuels such as natural gas or light fuel oil. <a href="/article/Combustion">Combustion</a> is the prevailing fuel utilization technology in both the above cycles. <a href="/article/Coal">Coal</a> is the preferred fuel for the steam cycle because of its low cost and broad and secure availability worldwide. </p><p><a href="/article/Combustion">Combustion</a>-generated pollutants, such as oxides of nitrogen (NO,_x), of sulfur (SO_x), and particulates, if uncontrolled and emitted into the atmosphere represent environmental and health hazards, such as <a href="/article/Acid_rain">acid rain</a>. Environmental regulations supported by intensive research and developments have reduced pollutant emissions significantly. Improvements in efficiency and emissions come by increasing steam pressure and temperature in the steam cycle, and by increased turbine inlet temperature in the gas turbine cycle. Coal gasification produces a fuel gas that is capable of being used in the gas turbine. By integrating coal gasification with gas turbine and steam cycles, advantage can be taken of high efficiency and low pollutant emission while using <a href="/article/Coal">coal</a>, an inexpensive, secure and indigenous fuel in many countries throughout the world. A potential additional advantage of the Integrated Gasification Combined Cycle (IGCC) is the capability of capturing carbon dioxide (CO₂) from the fuel gas and making it ready for high-pressure pipeline transportation to a carbon sequestration site. This will be key to the commercial and clean co-production of electricity and hydrogen from coal. </p><p><strong>Further reading</strong> <a href="http://www.tva.com/power/fossil.htm" class='external text' title="http://www.tva.com/power/fossil.htm">Fossil-Fuel Generation</a>, Tennessee Valley Authority. </p> <p><a href='/article/Fossil_fuel_power_plant'>Read Full Article...</a></p> http://www.eoearth.org/article/Fossil_fuel_power_plant Thu, 17 Sep 2009 07:15:03 GMT http://www.eoearth.org/article/Water_governance <a href='/article/Water_governance'><img border='0' src='/upload/thumb/b/be/Fig_1_water_governance.JPG/250px-Fig_1_water_governance.JPG' width='100'/></a> <p>The water sector worldwide is increasingly characterized in terms of a crisis situation. The unique and complex characteristics of the water resource entail complex social, political, and economic implications in its management. The water crisis is mainly a crisis of governance and the management forms under which water has been historically governed. In light of the problems in the water sector, <a href="/article/Support_and_opposition_of_public-private_partnerships">public-private partnerships</a> have been increasingly advocated and adopted throughout the world. Proponents of partnerships have often appealed to the financial gains, cost reductions, efficiency gains, environmental compliance, human resource developments, and increased services which have followed private sector engagement. Opponents of partnerships have appealed to the price increases, imbalance of power, labor disputes, inequities, environmental damage, and increased risks associated with private sector participation in water services. This paper reviews these debates to conclude that evidence can be found in support of either position. The paper argues that this dichotomous debate has lead to inconclusive and unconstructive discussions among interested parties. The paper recommended that focus be re-directed away from ideological positions on privatization towards a focus on the principals and standards which can make private participation work for the public good when it is chosen. </p> <p><a href='/article/Water_governance'>Read Full Article...</a></p> http://www.eoearth.org/article/Water_governance Wed, 16 Sep 2009 06:18:47 GMT http://www.eoearth.org/article/Marine_reserves <a href='/article/Marine_reserves'><img border='0' src='/upload/thumb/1/16/MarineReserves_pub_rate.gif/300px-MarineReserves_pub_rate.gif' width='100'/></a> <p>Marine reserves are areas in the <a href="/article/Ocean">ocean</a> where no extractive activities are allowed. They are also often called ‘no-take zones’, since the killing, harming, or harassing of any plants or animals within the reserve boundaries is not allowed, and they are part of a broader spectrum of marine spatial management tools that fit under the umbrella term ‘Marine Protected Areas’, or MPAs. </p><p>The idea of setting aside fully protected regions of the oceans has been around for a long time, but it is only in the past decade or two that marine reserves have become a common tool for managing and protecting marine resources. Most commonly reserves are established for conservation purposes, but strong interest also exists in using them as a <a href="/article/Marine_fisheries">fisheries</a> management tool. Even so, a relatively small portion of the world’s oceans to date have been set aside in marine reserves – less that 1%. </p> <p><a href='/article/Marine_reserves'>Read Full Article...</a></p> http://www.eoearth.org/article/Marine_reserves Tue, 15 Sep 2009 06:26:44 GMT http://www.eoearth.org/article/Transpiration <a href='/article/Transpiration'><img border='0' src='/upload/thumb/e/e3/Transpirationleafsoil.jpg/225px-Transpirationleafsoil.jpg' width='100'/></a> <p>Transpiration is the term used to describe the transport of water through an actual, vegetated plant into the <a href="/article/Atmospheric_composition">atmosphere</a>. Transpiration is an important part of the <a href="/article/Evapotranspiration">evapotranspiration</a> process, and a major mechanism of the water cycle in the atmosphere. Transpiration may also refer to the rate of the water vapor transport through the whole vegetative canopy (that is, through the group of plants). </p><p>Just as you release water vapor when you breathe, plants do, too&mdash;although the term "transpire" is more appropriate than "breath." During this process individual water molecules are released from the surface of the plant body through tiny structures called <a href="/article/Stomata">stomata</a>. There are many more individual water vapor molecules inside the air spaces between the tissues of a plant than in the air surrounding the plant body. Consequently water vapor will always exit the plant along a concentration gradient. As more water vapor molecules exit the plant, the remaining water molecules tug on each other and will pull an entire column of water throughout the plant body through special tissues called xylem during the process of transpiration. One way to visualize transpiration is to put a plastic bag around some plant leaves. As Figure 1 shows, transpired <a href="/article/Physical_properties_of_water">water</a> will condense on the inside of the bag. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also <a href="/article/Evaporation">evaporates</a> from the soil. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year. </p> <p><a href='/article/Transpiration'>Read Full Article...</a></p> http://www.eoearth.org/article/Transpiration Tue, 15 Sep 2009 06:25:13 GMT http://www.eoearth.org/article/Transpiration <a href='/article/Transpiration'><img border='0' src='/upload/thumb/e/e3/Transpirationleafsoil.jpg/225px-Transpirationleafsoil.jpg' width='100'/></a> <p>Transpiration is the term used to describe the transport of water through an actual, vegetated plant into the <a href="/article/Atmospheric_composition">atmosphere</a>. Transpiration is an important part of the <a href="/article/Evapotranspiration">evapotranspiration</a> process, and a major mechanism of the water cycle in the atmosphere. Transpiration may also refer to the rate of the water vapor transport through the whole vegetative canopy (that is, through the group of plants). </p><p>Just as you release water vapor when you breathe, plants do, too&mdash;although the term "transpire" is more appropriate than "breath." During this process individual water molecules are released from the surface of the plant body through tiny structures called <a href="/article/Stomata">stomata</a>. There are many more individual water vapor molecules inside the air spaces between the tissues of a plant than in the air surrounding the plant body. Consequently water vapor will always exit the plant along a concentration gradient. As more water vapor molecules exit the plant, the remaining water molecules tug on each other and will pull an entire column of water throughout the plant body through special tissues called xylem during the process of transpiration. One way to visualize transpiration is to put a plastic bag around some plant leaves. As Figure 1 shows, transpired <a href="/article/Physical_properties_of_water">water</a> will condense on the inside of the bag. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also <a href="/article/Evaporation">evaporates</a> from the soil. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year. </p> <p><a href='/article/Transpiration'>Read Full Article...</a></p> http://www.eoearth.org/article/Transpiration Mon, 14 Sep 2009 07:26:24 GMT http://www.eoearth.org/article/Oil_spill <a href='/article/Oil_spill'><img border='0' src='/upload/thumb/7/7d/Exxon_valdez_aground.jpg/250px-Exxon_valdez_aground.jpg' width='100'/></a> <p>An oil spill is the accidental petroleum release into the environment. On land, oil spills are usually localized and thus their impact can be eliminated relatively easily. In contrast, marine oil spills may result in oil pollution over large areas and present serious environmental hazards. The primary source of accidental oil input into seas is associated with oil transportation by tankers and pipelines (about 70%), whereas the contribution of offshore drilling and production activities is minimal (less than 1%). Large and catastrophic spills releasing more than 30,000 tons of oil are relatively rare events and their frequency in recent decades has decreased perceptibly. Yet, such episodes have the potential to cause the most serious ecological risk (primarily for sea birds and mammals) and result in long-term environmental disturbances (mainly in <a href="/article/Coastal_zone">coastal zones</a>) and economic impact on coastal activities (especially on <a href="/article/Marine_fisheries">fisheries</a> and mariculture). </p><p>Public concern over marine oil spills has been clearly augmented since the 1967 Torrey Canyon <a href="/article/Supertanker">supertanker</a> accident off the UK coast, when 100,000 tonnes of spilled oil caused heavy pollution of the French and British shores with serious ecological and fisheries consequences. More recently, the highly publicized 1989 spill of the <em>Exxon Valdez</em> in <a href="/article/Prince_William_Sound%2C_Alaska">Prince William Sound, Alaska</a> caused unprecedented damage to the fragile <a href="/article/Arctic">Arctic</a> system. Since then, impressive technical, political, and legal experience in managing the problem has been gained in many countries and at the international level, mainly through a number of Conventions initiated by the International Maritime Organization (IMO). As a result of the <a href="/article/Exxon_Valdez_oil_spill">Exxon Valdez oil spill</a>, the U.S. passed legislation requiring all newly built tankers to have a double hull. </p><p>When the oil reaches the shoreline, on rocky shores some components of the oil evaporate, leaving behind the heaviest components and turning the oil into tar. On rocky shores with surf, the tar will erode away from the wave action, and biological communities will return rather quickly. In <a href="/article/Marsh">marshes</a>, however, oil can sink down below the surface and remain for many years. Oil accumulated in marsh sediments undergoes some microbial breakdown, but it is slow. Low-energy environments like marshes are the most vulnerable and show the slowest rates of recovery from oil spills. Effects of a rather small oil spill in Falmouth, MA in the late 1960s were seen to last for a decade by a team of scientists from the nearby Woods Hole Oceanographic Institute. It is seldom that a spill occurs right in an area that has been intensively studied prior to the spill. Fiddler crabs were particularly sensitive, and were still affected after seven years. The oil affected their burrow construction – the burrows did not go straight down, but leveled off to a horizontal plane. While this was not a problem during the summer, when winter came the crabs were not below the freezing zone of the marsh as they should have been and froze to death. Benthic communities took about a decade to return to normal. After 30 years, some abnormalities still are noted in fiddler crab burrows in the oiled areas. </p><p>Marshes and sediments in <a href="/article/Prince_William_Sound%2C_Alaska">Prince William Sound</a> in Alaska retained oil from the massive oil spill of the <em>Exxon Valdez</em> in 1989 for many years, affecting the development of fish embryos on the bottom. After ten years, pockets of oil remained in these <a href="/article/Marsh">marshes</a>, and mussels, clams, ducks and sea otters showed evidence of harm in some localized areas. Remedial actions after oil spills are controversial, and some of the cures (e.g. aggressive cleaning with large heavy equipment) may be worse than the original problem, as was seen in the attempted clean up after the <a href="/article/Exxon_Valdez_oil_spill">Exxon Valdez oil spill</a>. </p><p><strong>Further Reading</strong></p><ul><li>Patin, Stanislav and Elena Cascio (Translator), 1999. <a href="http://www.offshore-environment.com/index.html" class='external text' title="http://www.offshore-environment.com/index.html">Environmental impact of the offshore oil and gas industry</a>. EcoMonitor Pub, East North Port, N.Y. <a href="http://www.amazon.com/dp/0-9671836-0-X/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0-9671836-0-X/?tag=encycofearth-20">ISBN: 0-9671836-0-X</a> </li><li>Patin, Stanislav, 2004. <a href="http://www.sciencedirect.com/science?_ob=ArticleURL&amp;_udi=B7GGD-4CM9GC0-7X&amp;_rdoc=1&amp;_hierId=40165&amp;_refWorkId=222&amp;_explode=39816,40165&amp;_alpha=P&amp;_fmt=summary&amp;_orig=na&amp;_docanchor=&amp;_idxType=AU&amp;view=c&amp;_acct=C000050221&amp;_version=1&amp;_urlVersion=0&amp;_userid=10&amp;md5=363d97b258fc147442d4870d7fa85763" class='external text' title="http://www.sciencedirect.com/science? ob=ArticleURL&amp; udi=B7GGD-4CM9GC0-7X&amp; rdoc=1&amp; hierId=40165&amp; refWorkId=222&amp; explode=39816,40165&amp; alpha=P&amp; fmt=summary&amp; orig=na&amp; docanchor=&amp; idxType=AU&amp;view=c&amp; acct=C000050221&amp; version=1&amp; urlVersion=0&amp; userid=10&amp;md5=363d97b258fc147442d4870d7fa85763">Crude Oil Spills, Environmental Impact of,</a> In: Cutler J. Cleveland (Editor), <em>The Encyclopedia of Energy</em>. Elsevier Science, Oxford, pp. 737-748. </li></ul> <p><a href='/article/Oil_spill'>Read Full Article...</a></p> http://www.eoearth.org/article/Oil_spill Fri, 11 Sep 2009 05:51:10 GMT http://www.eoearth.org/article/Top-down_control <a href='/article/Top-down_control'><img border='0' src='/upload/thumb/c/c6/Topdown.JPG/450px-Topdown.JPG' width='100'/></a> <p>All organisms require energy and nutrients in some form to survive and grow. Thus, the existence and total biomass of ecosystems are ultimately regulated from the &quot;bottom up&quot;, that is, by availability of resources such as light, inorganic nutrients, and water. Nevertheless, on more localized scales, the abundances of organisms at lower trophic levels can be strongly affected by their own predation, that is, by &quot;top-down&quot; control. <a href="/article/Ecosystem">Ecosystems</a> often have been assumed to be controlled from the bottom-up, wherein nutrients and <a href="/article/Solar_radiation">light</a> stimulate primary production by plants, and the greater primary production in turn supports more animal production at higher trophic levels. But this is not the whole story. A simple way to envision top-down control is as follows: because the predator eats prey, the prey population is reduced, so when predators are removed, the prey species can become more abundant. For example, evidence of such top-down control of prey populations was seen when large predators like wolves were extirpated from much of the US and deer became very abundant, indeed a pest, in many areas. Even in <a href="/article/Yosemite_National_Park%2C_United_States">Yosemite National Park</a>, reduced numbers of bobcats, cougars and coyotes led to increased numbers of mule deer, which then led to declines in evening primrose and young black oaks, which are grazed by deer. </p> <h1>Trophic cascades <br /></h1><p>Some other clear examples of strong top-down control are seen in the <a href="/article/Marine_biomes">marine</a> environment. In the Pacific Coast of North America there are “kelp forests” of very large brown algae. These are grazed by sea urchins, which are, in turn, eaten by sea otters. When sea otter populations are reduced (as they were a century ago because of hunting, and again lately due to killer whale <a href="/article/Predation">predation</a>) the sea urchin populations can grow out of control and graze down most the kelp, creating “urchin barrens.” Unchecked by otters, they can bloom and basically destroy the kelp forest by eating huge amounts of kelp. When population control of prey by their predators (as in the sea otter/sea urchin interaction) then affects the next level down, the kelp, it is referred to as a “trophic cascade.” Trophic cascades are now known from a wide range of marine, freshwater, and terrestrial ecosystems.</p> <p>Other systems have been affected by the loss of filter feeders such as oysters. It has been suggested that the populations of oysters in Chesapeake Bay used to be enough to filter all the water (including its <a href="/article/Phytoplankton">phytoplankton</a> residents) in the bay in about one week. Although this has since been considered an overestimate, it is clear that filter-feeding aimals can have strong impacts on water quality. as As a result of overfishing and several devastating diseases, the oyster population is currently only a tiny fraction of what it used to be, and algal blooms are more common, as the phytoplankton can no longer be controlled by the filter feeders (increased levels of nutrients exacerbate this effect). Top-down <a href="/article/Ecology">ecology</a> is also seen in <a href="/article/Freshwater_biomes">lakes</a>, <a href="/article/Composition_of_rocks">rocky</a> shores, <a href="/article/Terrestrial_biome">terrestrial</a>, and many other ecosystems.</p> <h1>Top-down control and behavior: &quot;The ecology of fear&quot; <br /></h1> <p>Top-down control of lower trophic levels as a result of direct consumption and reduction of prey population size is referred to as “density-mediated” control, because predators reduce density of prey. However, predators can affect populations of their prey without actually eating them but in a more indirect ways, for example by influencing their behavior, physiology, or morphology. For example, water-borne chemicals (“risk cues”) released by predators can cause changes in prey behavior such as feeding rates, thereby altering the impact of the prey species on their own resources. When prey species detect the presence of predators they often alter their behavior by spending more time hiding and generally being inconspicuous, thus reducing the amount of time they spend feeding. The reduced food intake by these prey animals can result in slower growth and reproduction, and ultimately result in population reductions. The reduced feeding rates by the prey then cascade down to release the prey&#39;s own food (e.g., plants) from top-down control, causing a trophic cascade based not on changes in prey abundance but by changes in prey behavior. This more subtle mechanism is called “trait-mediated” control. Trait-mediated interactions represent the nonlethal effects of predators, and contrast with the more traditional emphasis on lethal effects. An example of this from the intertidal zones is the effect of risk cues from green crabs that reduce feeding by snails and consequently allow increases in the snails’ food, barnacles and algae. Carnivorous snails exposed to cues from green crabs consumed fewer barnacles, and herbivorous snails exposed to risk cues from crabs consumed far less algae. Both species of snails spent more time in refuges and grew less, while <a href="/article/Population">populations</a> of the barnacles and algae increased as a result of reduced top-down control. </p> <p>Trait-mediated cascades are not restricted to aquatic organisms or environments. Spiders eat grasshoppers, and have direct density-mediated effects on their populations. However, when spiders’ mouths were experimentally glued shut, grasshoppers still showed elevated mortality even though they weren’t being eaten; in the presence of spiders they switched from eating <a href="/article/Grasses">grasses</a> to eating safer, but less nutritious plants, and the reduced energy input led to higher grasshopper mortality. Another way that trait-mediated effects can happen is if the behavioral changes in response to one <a href="/article/Predation">predator</a> make the prey more vulnerable to another. In <a href="/article/Freshwater_biomes">fresh water</a> systems, bass eat darters, and have direct density-mediated effects. To avoid bass, however, the darters tend to hide in rocky shelters, which makes them more susceptible to predation by crayfish that also live in those habitats. Trait-mediated interactions are very common in predator/prey interactions. Some research suggests that the effects of predators on behavior is as important, if not more important, than the direct lethal effects through predation.</p> <h1>Top-down control and inducible defenses <br /></h1><p>Trait-mediated effects can occur through mechanisms other than behavior. For example, pea aphids, which do not generally have wings, produce winged offspring in response to the presence of ladybird predators or other enemies. This trait modification allows the winged aphids to disperse to new habitats. Water fleas (Daphnia) develop defensive spines when exposed to chemical cues from fish. This makes them more difficult to eat, but developing this structure has energetic costs and reduces lifetime fitness. Snails often develop a thicker shell upon exposure to predacious crabs, which affords the snail greater protection and therefore a greater chance of survival. However, it must expend more energy to carry around a heavier shell. Frog tadpoles in the presence of predators reduce their feeding behavior, but also change their morphology to have a relatively larger tail, which allows them to swim faster and escape predators more effectively. This defense comes at the expense of slower growth. Some of these morphological changes are reversible, but others are not. Crucian carp, when exposed to cues from predatory pike become deeper-bodied, and thus harder for a predator to grab. This body change is reversible.</p> <p>Plants can also alter their morphology or chemistry in response to herbivores. They may manufacture toxins or noxious chemicals to deter grazing (a number of these chemicals have been shown to have pharmaceutical value). Plants have developed many secondary metabolites involved in defense, which are collectively known as antiherbivory compounds. Defenses in some systems are very complex. For example, <em>Phaseolus</em> plants infested by spider mites emit specific volatile substances which attract predatory mites that eat the spider mites. In addition to chemical defenses, plants may have many external structural defenses that discourage herbivory. A plant&#39;s leaves and stem may be covered with sharp spines or hairs, often with barbs, sometimes containing irritants or <a href="/article/Poison">poisons</a>. After considerable grazing or defoliation, plants can produce a new set of leaves with increased silica and other characteristics that make them tougher and more difficult and less palatable for herbivores to consume. </p> <p>These altered traits in the presence of predators are referred to as “inducible defenses” or “phenotypic plasticity.” Behavioral, physiological, and morphological plasticity in response to predators can stabilize populations, but the changes can come at a cost. The ultimate effects of top-down processes on the abundance, morphology, behavior, and evolution of populations and communities can be far-reaching. </p><p><strong><big>References</big></strong></p> <ul><li>Borer E.T., Seabloom E.W., Shurin J.B., Anderson K.E., Blanchette C.A., Broitman B., Cooper S.D. &amp; Halpern B.S. 2005. What determines the strength of a trophic cascade? <em>Ecology</em> 86:528-537.</li><li>Miner, B.G., S.E. Sultan, S.G. Morgan, D.K. Padilla and R.A. Relyea 2005. Ecological consequences of phenotypic plasticity. <em>Trends in Ecology and Evolution</em> 20:685-692.</li><li>Pace M.L., Cole J.J., Carpenter S.R. &amp; Kitchell J.F. 1999. Trophic cascades revealed in diverse ecosystems. <em>Trends in Ecology and Evolution</em> 14:483-488.</li><li> Preisser, E.L., D. Bolnick and M.F. Benard 2005. Scared to death? The effects of intimidation and consumption in predator-prey interactions. <em>Ecology</em> 86:501-509.</li><li> Rahel, F. and R. Stein 1988, Complex predator/prey interactions and predator intimidation among crayfish, piscivorous fish, and small benthic fish. <em>Oecologia</em> 75:94-98.</li><li>Schmitz, O. 1998. Direct and indirect effects of predation and predation risk in old-field interaction webs. <em>American Naturalist</em> 151:327-342.</li><li>Schmitz O.J., Krivan V. &amp; Ovadia O. 2004. Trophic cascades: the primacy of trait-mediated indirect interactions. <em>Ecology Letters</em> 7:153-163.</li></ul> <p><a href='/article/Top-down_control'>Read Full Article...</a></p> http://www.eoearth.org/article/Top-down_control Wed, 09 Sep 2009 06:08:09 GMT http://www.eoearth.org/article/Resource_curse <a href='/article/Resource_curse'><img border='0' src='/upload/thumb/b/bd/Saudi_Arabia_map.gif/199px-Saudi_Arabia_map.gif' width='100'/></a> <p>The term &#39;resource curse&#39; refers to the observation that nations with rich endowments of natural resources (oil, metals, timber) often dramatically underperform economically relative to what one would expect. Common sense and simple economics suggest that countries blessed with an abundance of natural resources should live long and prosper. Yet over many years, it has been observed that nations rich in oil, gas, or mineral resources have been disadvantaged in the drive for <a href="/article/Economic_growth">economic progress</a>. In the 1950&#39;s and 1960&#39;s, concern was based upon deteriorating terms of <a href="/article/Trade_and_the_environment">trade</a> between industrialized and developing countries. In the 1970&#39;s, it was driven by the impact of the oil price shocks on the oil exporters where windfall revenues seemed to introduce serious distortions to the economies. In the 1980&#39;s, the phenomenon of &quot;Dutch Disease&quot;—an overvaluation of the real exchange rate and the contraction of <a href="/article/Agriculture">agriculture</a> and industry —attracted attention. In the 1990&#39;s, it was the impact on government behavior—rent seeking and corruption—that dominated discussions. More recently, a revival of interest follows the World Bank&#39;s &quot;Extractive Industry Review&quot; and growing concern over corporate social responsibility. Existence of the &quot;curse&quot; is controversial in the literature and there is growing evidence that its occurrence is far from inevitable. In many countries, natural resource revenues can produce tangible benefits. Where a &quot;curse&quot; has occurred, the main explanation lies in the way large windfall resource revenues affect government behavior. Thus avoidance implies political reform to encourage good governance. Increasingly, analysis addresses how the various players in natural resource projects—international financial institutions, multinational corporations and non-governmental organizations (NGOs)—can assist governments at risk to create capacity to manage the problem. </p><p><strong>Further Reading</strong></p><ul><li>Auty, Richard M. <a href="http://www.wider.unu.edu/research/pr9899d2/pr9899d2s.htm" class='external text' title="http://www.wider.unu.edu/research/pr9899d2/pr9899d2s.htm">The Resource Curse in Developing Countries can be Avoided</a>.</li><li>Sachs, Jeffrey D. &amp; Warner, Andrew M., 1995. &quot;<a href="http://www.nber.org/papers/w5398.pdf" class='external text' title="http://www.nber.org/papers/w5398.pdf">Natural Resource Abundance and Economic Growth</a>&quot;, NBER Working Papers 5398, National Bureau of Economic Research, Inc.</li><li>Sachs, Jeffrey D. &amp; Warner, Andrew M., 2001. &quot;<a href="http://www.elsevier.com/wps/find/journaldescription.cws_home/505541/description#description" class='external text' title="http://www.elsevier.com/wps/find/journaldescription.cws home/505541/description#description">The curse of natural resources</a>&quot;, European Economic Review, Elsevier, vol. 45(4-6), pages 827-838, May. </li></ul> <p><a href='/article/Resource_curse'>Read Full Article...</a></p> http://www.eoearth.org/article/Resource_curse Tue, 08 Sep 2009 05:46:34 GMT http://www.eoearth.org/article/Ross_Ice_Shelf <a href='/article/Ross_Ice_Shelf'><img border='0' src='/upload/thumb/d/d5/Moa_iceshelves.jpg/330px-Moa_iceshelves.jpg' width='100'/></a> <p>See also Ice Shelf and Climate change and ice shelves</p> <p>The Ross Ice Shelf is the largest ice shelf in the world with an area of roughly 182,000 square miles (472,000 km²) - about the size of Spain. It is bordered by the Ross Sea to the north,  the Transantarctic Mountains to the west and south, and by the King Edward the VII Peninsula to the east.</p><p>Facing the Ross Sea, it presents a nearly vertical ice cliff of between 50  and 200 feet (15 and 60 meters) above the water surface and 500 miles (800 km) long between Ross Island and the King Edward the VII Peninsula. The interior of the Shelf entends from 400 to nearly 600 miles.</p><p>Most of the Ross Ice Shelf is located within the Ross Dependency claimed by New Zealand. However, the claim is not recognized by most countries or under the <a href="/article/Antarctic_Treaty_System">Antarctic Treaty System</a>.</p><p>The ice shelf was named after Captain James Clark Ross who discovered it on 28 January 1841. It was originally named the &quot;Great Ice Barrier&quot; or the &quot;Ice Barrier&quot; or the &quot;Barrier.&quot; Ross mapped the ice front eastward to 160°W. </p> <p><a href='/article/Ross_Ice_Shelf'>Read Full Article...</a></p> http://www.eoearth.org/article/Ross_Ice_Shelf Thu, 03 Sep 2009 07:32:06 GMT http://www.eoearth.org/article/Soil_compaction <a href='/article/Soil_compaction'><img border='0' src='/upload/thumb/a/a7/Critical_depth_for_harmful_soil_compaction.jpg/250px-Critical_depth_for_harmful_soil_compaction.jpg' width='100'/></a> <p>Soil compaction in <a href="/article/Agriculture">agriculture</a> and <a href="/article/Forestry">forestry</a> is of growing concern. Heavy wheel loads have the potential to impair soil health by soil compaction. In order to maintain soil functions on a sustainable basis, strategies against further compaction are necessary. Technical solutions of best management practices in agriculture have been developed to minimize soil compaction. But they may not be sufficient to safeguard against damage to soil structure, since they do not compare the compressive forces of farm implements with the soils physical resistance against compaction. The effectiveness of practical means against soil compaction needs to be validated by physical <a href="/article/Soil">soil</a> assessment methods. Soil mechanical research has developed models to predict soil stress propagation below a running tire. Stress sensors have been developed to validate model predictions. Soil physical research has identified the parameters that characterize soil bearing capacity during wheeling. With the help of a bearing capacity model it is possible to assess, for given loading conditions, whether soil compaction in the subsoil will occur. If soil compaction is likely to occur, indicators are needed to assess harmful changes in the soil structure. Soil physical research has identified soil parameters that indicate harmful soil compaction and proposed an indicator set for the protection of soils against compaction integrating practical, mechanical, and soil physical aspects into one unique strategy. </p> <p><a href='/article/Soil_compaction'>Read Full Article...</a></p> http://www.eoearth.org/article/Soil_compaction Wed, 02 Sep 2009 05:57:10 GMT http://www.eoearth.org/article/Agriculture <a href='/article/Agriculture'><img border='0' src='/upload/thumb/d/d0/Agriculture.jpg/250px-Agriculture.jpg' width='100'/></a> <p>Humans began to cultivate food crops about 10,000 years ago. Prior to that time, hunter-gatherers secured their food as they traveled in the nearby environment. When they observed some of the grains left behind at their campsites sprouting and growing to harvest, they began to cultivate these grains. From these humble beginnings agriculture began. <a href="/article/Slash_and_burn">Slash and burn</a>, an early type of crop culture, remains today a truly sustainable agriculture, one that is independent of fossil fuel energy. In such a system, about 10 hectares of productive land is held in fallow for each planted hectare. With this rotation system, a hectare is planted once every 20 years, allowing the <a href="/article/Soil">soil</a> to reaccumulate vital plant nutrients. Although the practice requires large acreages and large labor inputs, the crop yields are adequate. For example, corn with ample <a href="/article/Precipitation_and_fog">rainfall</a> can yield about 2,000 <a href="/article/Kilogram">kilograms</a> per hectare (kg/ha). </p> <p>Over time, human labor in agriculture has decreased, first because of the use of animals and finally with machinery powered by fossil fuels. Currently, plentiful and economical fossil energy supports an era of machinery and agricultural chemicals. About 1,000 liters of oil equivalent are used to produce a hectare of corn with a yield of 9,000 kg/ha. One-third of this energy is used to replace labor, one-third for <a href="/article/Fertilizer">fertilizers</a>, and one-third for others. </p><p>Worldwide, more than 99.7% of human food (<a href="/article/Calorie">calories</a>) comes from the land. Serious environmental impacts, such as soil erosion, <a href="/article/Surface_runoff_of_water">water runoff</a>, and <a href="/article/Pesticide">pesticide</a> pollution, result from fossil fuel-intensive agriculture. A critical need exists to assess fossil energy limits, the <a href="/article/Sustainability">sustainability</a> of agriculture, and the food needs of a <a href="/article/Human_population_explosion">rapidly growing world population</a>. </p> <p><a href='/article/Agriculture'>Read Full Article...</a></p> http://www.eoearth.org/article/Agriculture Tue, 01 Sep 2009 06:55:15 GMT http://www.eoearth.org/article/Coral_reef <a href='/article/Coral_reef'><img border='0' src='/upload/thumb/c/c1/Reefs_vs_sst.jpg/350px-Reefs_vs_sst.jpg' width='100'/></a> <p>The term &quot;coral reef&quot; generally refers to a marine <a href="/article/Ecosystem">ecosystem</a> in which the main organisms are corals that house algal symbionts within their tissues. These ecosystems require: 1) fully marine waters; 2) warm <a href="/article/Temperature">temperatures</a>; and 3) ample <a href="/article/Solar_radiation">sunlight</a>. They are therefore restricted to shallow waters of tropical and subtropical regions. </p> <p>Corals that do not have algal symbionts can also form significant reef communities in deeper, darker, and colder waters, but these communities are distinguished as cold-water coral bioherms. </p><p>The more technical definition of &quot;coral reef&quot; includes an additional geological requirement that the reef organisms produce enough calcium carbonate to build the physical reef structure. The coral reef community lives only on the surface veneer of the reef, on top of already existing skeletal material left behind by previous reef-builders. Many processes act to break down the skeletal material and reef as soon it is laid down by organisms. These include mechanical processes such as waves and currents, and a wide array of biological processes (e.g., bioerosion). Some of the best known bioeroders are large organisms such as parrotfish and sponges, but much of the bioerosion occurs at the microscopic scale by organisms such as algae and fungi. A coral reef is produced only if the coral reef community produces more calcium carbonate than is removed. Indeed, some coral reef communities grow too slowly to build a reef. </p> <p><a href='/article/Coral_reef'>Read Full Article...</a></p> http://www.eoearth.org/article/Coral_reef Mon, 31 Aug 2009 06:04:35 GMT http://www.eoearth.org/article/Human_population_explosion <a href='/article/Human_population_explosion'><img border='0' src='/upload/thumb/8/83/Figure_1_long-term_population_growth.JPG/300px-Figure_1_long-term_population_growth.JPG' width='100'/></a> <p>Approximately 6.6 billion humans now inhabit the Earth. By comparison, there might be 20 million mallard ducks and, among a multitude of threatened and endangered species, perhaps 100,000 gorillas, 50,000 polar bears, and less than 10,000 tigers, 2,000 giant pandas and 200 California condors. Notably, the human population has <a href="/article/Population_growth_rate">grown</a> nearly ten-fold over the past three centuries and has increased by a factor of four in the last century. This monumental historical development has profoundly changed the relationship of our species to its natural support systems and has greatly intensified our <a href="/article/IPAT_equation">environmental impact</a>. Equally amazing are the signs that, in our generation, the human population explosion has begun to abate (Figure 1; note that, here and below, many of the values given are estimates and, after the year 2005, projections). Our numbers are expected to rise by another 50% before reaching a peak late in this century; a decline is likely to follow. What caused this population surge; what caused its reversal; where are we headed; and how might the proliferation of our species affect its future well-being? </p> <p><a href='/article/Human_population_explosion'>Read Full Article...</a></p> http://www.eoearth.org/article/Human_population_explosion Fri, 28 Aug 2009 06:21:46 GMT http://www.eoearth.org/article/Human_population_explosion <a href='/article/Human_population_explosion'><img border='0' src='/upload/thumb/8/83/Figure_1_long-term_population_growth.JPG/300px-Figure_1_long-term_population_growth.JPG' width='100'/></a> <p>Approximately 6.6 billion humans now inhabit the Earth. By comparison, there might be 20 million mallard ducks and, among a multitude of threatened and endangered species, perhaps 100,000 gorillas, 50,000 polar bears, and less than 10,000 tigers, 2,000 giant pandas and 200 California condors. Notably, the human population has <a href="/article/Population_growth_rate">grown</a> nearly ten-fold over the past three centuries and has increased by a factor of four in the last century. This monumental historical development has profoundly changed the relationship of our species to its natural support systems and has greatly intensified our <a href="/article/IPAT_equation">environmental impact</a>. Equally amazing are the signs that, in our generation, the human population explosion has begun to abate (Figure 1; note that, here and below, many of the values given are estimates and, after the year 2005, projections). Our numbers are expected to rise by another 50% before reaching a peak late in this century; a decline is likely to follow. What caused this population surge; what caused its reversal; where are we headed; and how might the proliferation of our species affect its future well-being? </p> <p><a href='/article/Human_population_explosion'>Read Full Article...</a></p> http://www.eoearth.org/article/Human_population_explosion Fri, 28 Aug 2009 06:20:01 GMT http://www.eoearth.org/article/Scabies <a href='/article/Scabies'><img border='0' src='/upload/thumb/0/0f/Sarcoptes_scabei_WHO.jpg/175px-Sarcoptes_scabei_WHO.jpg' width='100'/></a> <p><a href="http://www.cdc.gov/ncidod/dpd/parasites/scabies/factsht_scabies_spanish.htm" class='external text' title="http://www.cdc.gov/ncidod/dpd/parasites/scabies/factsht scabies spanish.htm">En Español</a></p> <p><a href='/article/Scabies'>Read Full Article...</a></p> http://www.eoearth.org/article/Scabies Thu, 27 Aug 2009 06:02:44 GMT http://www.eoearth.org/article/Gallium <a href='/article/Gallium'><img border='0' src='/upload/thumb/5/52/Gallium.jpg/250px-Gallium.jpg' width='100'/></a> <p>Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875. Its existence was predicted in 1871 by a chemist named <a href="/article/Mendeleev%2C_Dimitri_Ivanovich">Mendeleev</a> who said that gallium would be very much like <a href="/article/Aluminum">aluminum</a> in its physical properties, which proved to be quite accurate. In 1875, de Boisbaudran also isolated gallium by electrolysis of a solution of gallium hydroxide Ga(OH)₃ in potassium hydroxide (KOH).</p><p>Gallium has some physical properties that are worth noting. Like water, gallium expands as it freezes which means it becomes less dense. Solid gallium has such a low melting temperature (85.6° F, 29.8° C) it will turn to liquid when held in the hand! It is a liquid over a wider range of <a href="/article/Temperature">temperatures</a> than any other element. By contrast, the boiling point of gallium is unusually high (3999° F, 2204° C).</p><p>Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be <a href="/article/Toxicity">toxic</a>.</p> <p><a href='/article/Gallium'>Read Full Article...</a></p> http://www.eoearth.org/article/Gallium Wed, 26 Aug 2009 06:27:57 GMT http://www.eoearth.org/article/Gallium <a href='/article/Gallium'><img border='0' src='/upload/thumb/5/52/Gallium.jpg/250px-Gallium.jpg' width='100'/></a> <p>Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875. Its existence was predicted in 1871 by a chemist named <a href="/article/Mendeleev%2C_Dimitri_Ivanovich">Mendeleev</a> who said that gallium would be very much like <a href="/article/Aluminum">aluminum</a> in its physical properties, which proved to be quite accurate. In 1875, de Boisbaudran also isolated gallium by electrolysis of a solution of gallium hydroxide Ga(OH)₃ in potassium hydroxide (KOH).</p><p>Gallium has some physical properties that are worth noting. Like water, gallium expands as it freezes which means it becomes less dense. Solid gallium has such a low melting temperature (85.6° F, 29.8° C) it will turn to liquid when held in the hand! It is a liquid over a wider range of <a href="/article/Temperature">temperatures</a> than any other element. By contrast, the boiling point of gallium is unusually high (3999° F, 2204° C).</p><p>Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be <a href="/article/Toxicity">toxic</a>.</p> <p><a href='/article/Gallium'>Read Full Article...</a></p> http://www.eoearth.org/article/Gallium Wed, 26 Aug 2009 06:27:00 GMT http://www.eoearth.org/article/Gallium <a href='/article/Gallium'><img border='0' src='/upload/thumb/5/52/Gallium.jpg/250px-Gallium.jpg' width='100'/></a> <p>Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875. Its existence was predicted in 1871 by a chemist named <a href="/article/Mendeleev%2C_Dimitri_Ivanovich">Mendeleev</a> who said that gallium would be very much like <a href="/article/Aluminum">aluminum</a> in its physical properties, which proved to be quite accurate. In 1875, de Boisbaudran also isolated gallium by electrolysis of a solution of gallium hydroxide Ga(OH)₃ in potassium hydroxide (KOH).</p><p>Gallium has some physical properties that are worth noting. Like water, gallium expands as it freezes which means it becomes less dense. Solid gallium has such a low melting temperature (85.6° F, 29.8° C) it will turn to liquid when held in the hand! It is a liquid over a wider range of <a href="/article/Temperature">temperatures</a> than any other element. By contrast, the boiling point of gallium is unusually high (3999° F, 2204° C).</p><p>Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be <a href="/article/Toxicity">toxic</a>.</p> <p><a href='/article/Gallium'>Read Full Article...</a></p> http://www.eoearth.org/article/Gallium Wed, 26 Aug 2009 06:26:50 GMT http://www.eoearth.org/article/Synroc <a href='/article/Synroc'><img border='0' src='/upload/thumb/c/ca/Synrocsample_m.jpg/250px-Synrocsample_m.jpg' width='100'/></a> <p>Synroc is a particular kind of &quot;Synthetic Rock&quot;, invented in 1978 by the late Professor Ted Ringwood of the Australian National University. It is an advanced ceramic comprising geochemically stable natural titanate minerals that have immobilized <a href="/article/Uranium">uranium</a> and <a href="/article/Thorium">thorium</a> for billions of years. They can incorporate into their crystal structures nearly all of the elements present in high-level radioactive waste (HLW) and thus immobilize them. Originally, some 57% of Synroc was titanium dioxide (rutile, TiO₂). </p><p>Synroc can take various forms depending on its specific use and can be tailored to immobilize particular components in the <a href="/article/Nuclear_waste_management"> high level nuclear waste (HLW).</a> The original form, Synroc-C, was intended mainly for the immobilization of liquid HLW arising from the reprocessing of light water reactor fuel. However, by 1980 those reprocessing used fuel had chosen borosilicate glass as the medium for immobilization because it was the most technically mature technology. </p><p>The main minerals in Synroc-C are hollandite (BaAl₂Ti₆O₁₆), zirconolite (CaZrTi₂O₇) and perovskite (CaTiO₃). Zirconolite and perovskite are the major hosts for long-lived actinides such as <a href="/article/Plutonium">plutonium</a> (Pu), though perovskite is principally for strontium (Sr) and barium (Ba). Hollandite principally immobilises caesium (Cs), along with potassium (K), rubidium (Rb) and barium. Synroc-C can hold up to 30% HLW by weight. </p><p>Over the past few years, different forms of Synroc have been developed to deal with military <a href="/article/Nuclear_waste_management"> radioactive wastes</a>, including a substantial amount of <a href="/article/Plutonium">plutonium</a>. Other applications have been developed related to the partitioning and transmutation of wastes. This involves partitioning HLW into separate components, some of which can then be transmuted, or changed, into different forms that are less radioactive or shorter-lived (usually by neutron bombardment in a reactor or accelerator). Those not suitable for transmutation can then be immobilized in Synroc. </p><p>The waste form is the key component of the immobilization process, as it determines both waste loading (concentration), which directly impacts cost, as well as the chemical durability, which determines environmental risk. To achieve maximum cost savings and optimum performance, the Synroc waste forms are tailored to suit the particular characteristics of [[<a href="/article/Nuclear_waste_management"> nuclear waste</a> to be immobilized rather than adopting a single one-size fits all approach. </p> <p><a href='/article/Synroc'>Read Full Article...</a></p> http://www.eoearth.org/article/Synroc Tue, 25 Aug 2009 05:43:49 GMT http://www.eoearth.org/article/Synroc <a href='/article/Synroc'><img border='0' src='/upload/thumb/c/ca/Synrocsample_m.jpg/250px-Synrocsample_m.jpg' width='100'/></a> <p>Synroc is a particular kind of &quot;Synthetic Rock&quot;, invented in 1978 by the late Professor Ted Ringwood of the Australian National University. It is an advanced ceramic comprising geochemically stable natural titanate minerals that have immobilized <a href="/article/Uranium">uranium</a> and <a href="/article/Thorium">thorium</a> for billions of years. They can incorporate into their crystal structures nearly all of the elements present in high-level radioactive waste (HLW) and thus immobilize them. Originally, some 57% of Synroc was titanium dioxide (rutile, TiO₂). </p><p>Synroc can take various forms depending on its specific use and can be tailored to immobilize particular components in the <a href="/article/Nuclear_waste_management"> high level nuclear waste (HLW).</a> The original form, Synroc-C, was intended mainly for the immobilization of liquid HLW arising from the reprocessing of light water reactor fuel. However, by 1980 those reprocessing used fuel had chosen borosilicate glass as the medium for immobilization because it was the most technically mature technology. </p><p>The main minerals in Synroc-C are hollandite (BaAl₂Ti₆O₁₆), zirconolite (CaZrTi₂O₇) and perovskite (CaTiO₃). Zirconolite and perovskite are the major hosts for long-lived actinides such as <a href="/article/Plutonium">plutonium</a> (Pu), though perovskite is principally for strontium (Sr) and barium (Ba). Hollandite principally immobilises caesium (Cs), along with potassium (K), rubidium (Rb) and barium. Synroc-C can hold up to 30% HLW by weight. </p><p>Over the past few years, different forms of Synroc have been developed to deal with military <a href="/article/Nuclear_waste_management"> radioactive wastes</a>, including a substantial amount of <a href="/article/Plutonium">plutonium</a>. Other applications have been developed related to the partitioning and transmutation of wastes. This involves partitioning HLW into separate components, some of which can then be transmuted, or changed, into different forms that are less radioactive or shorter-lived (usually by neutron bombardment in a reactor or accelerator). Those not suitable for transmutation can then be immobilized in Synroc. </p><p>The waste form is the key component of the immobilization process, as it determines both waste loading (concentration), which directly impacts cost, as well as the chemical durability, which determines environmental risk. To achieve maximum cost savings and optimum performance, the Synroc waste forms are tailored to suit the particular characteristics of [[<a href="/article/Nuclear_waste_management"> nuclear waste</a> to be immobilized rather than adopting a single one-size fits all approach. </p> <p><a href='/article/Synroc'>Read Full Article...</a></p> http://www.eoearth.org/article/Synroc Tue, 25 Aug 2009 05:42:10 GMT http://www.eoearth.org/article/Wetland <a href='/article/Wetland'><img border='0' src='/upload/thumb/6/6f/Suisun_Marsh_wetlands.jpg/300px-Suisun_Marsh_wetlands.jpg' width='100'/></a> <p>The following information focuses primarily on freshwater, inland wetlands and provides brief information about tidal, coastal, estuarine wetlands. It is important to note, that whether inland or coastal, there are several federal agencies that have special interest in and jurisdiction over wetlands and therefore it is important to define some terms and phrases throughout this article. Our intent is to provide the reader who might have special interest in wetland delineation, wetland mitigation, wetland biology, etc. with information or references to additional information that will be helpful. </p> <p>The U. S. Army Corps of Engineers and the Environmental Protection Agency (EPA) in the originally published 1987 Corps of Engineers Wetlands Delineation Manual jointly defined wetlands as: “Those areas that are inundated or saturated by surface or <a href="/article/Groundwater">groundwater</a> at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated <a href="/article/Soil">soil</a> conditions.” They continue to describe specifics of the three core components that constitute whether or not an area is a wetland, i.e., Vegetation, Soil, and Hydrology. Page 2 of the Manual states that “This report should be cited as follows: Environmental Laboratory. 1987. “Corps of Engineers Wetlands Delineation Manual”, Technical Report Y-87-1, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.” To access an electronic version, see Further Reading. </p><p>The U.S. Federal Highway Administration has interest in the location, form, and function of wetlands due to highway construction and maintenance. Their policy memoranda from 1994 refers and defers to the Soil Conservation Service (SCS), the Environmental Protection Agency (EPA), and the Corps of Engineers (COE) (see Further Reading). </p><p>State government agencies often have special considerations regarding wetland delineations. The state of Florida, for example, often has public, state, and federal interests that require careful attention to issues that relate to wetlands. Therefore, special definitions for Hydric soils, Delineation of Wetlands, and Hydrophytic vegetation may be found on their website (see Further Reading). </p><p>Numerous books are dedicated to plants and animals found in wetlands. Birds and vegetation, for example, are some of the most recognizable, distinguishable features in a wetland landscape, and therefore books may focus on the identification of such birds and plants. The Audubon Society uses the U.S. Fish and Wildlife Service definition in The Audubon Society Nature Guides “Wetlands” by William A. Niering (see Further Reading). </p><p>From all of these sources, the common elements of wetlands include water on the surface or under (but near) the surface for sufficient lengths of time that the area is dominated by hydric soils and organisms that are sustained by and physiologically adapted to such saturated and/or inundated conditions. Hydrology largely determines how the soil develops and the types of plant and animal communities living in and on the soil. Wetlands may support species ranging from obligate aquatic to obligate terrestrial. </p><p>When the upper part of the soil is saturated with water at growing season <a href="/article/Temperature">temperatures</a>, soil organisms consume the <a href="/article/Oxygen">oxygen</a> in the soil and cause conditions ([anaerobic]) unsuitable for most plants. Such conditions also cause the development of <a href="/article/Soil">soil</a> characteristics (such as color and texture) of so-called &quot;hydric soils.&quot; The plants that can grow in such conditions, such as marsh grasses, are called &quot;hydrophytes.&quot; Together, hydric soils and hydrophytes give clues that a wetland area is present. </p><p>The presence of water by ponding, flooding, or soil saturation is not always a good indicator of wetlands. Except for wetlands flooded by ocean tides, the amount of water present in wetlands fluctuates as a result of rainfall patterns, snow melt, dry seasons and longer droughts. </p><p>Some of the most well-known wetlands, such as the Everglades and Mississippi bottomland hardwood swamps, may have periods of dryness. In contrast, many upland areas are very wet during and shortly after wet weather. Such natural fluctuations must be considered when identifying areas subject to government regulation. Similarly, the effects of upstream dams, drainage ditches, dikes, irrigation, and other modifications must also be considered. </p> <p><a href='/article/Wetland'>Read Full Article...</a></p> http://www.eoearth.org/article/Wetland Mon, 24 Aug 2009 06:02:23 GMT http://www.eoearth.org/article/Swamp <a href='/article/Swamp'><img border='0' src='/upload/thumb/d/db/Skunk_cabbage.jpg/150px-Skunk_cabbage.jpg' width='100'/></a> <p>A swamp is any <a href="/article/Wetland">wetland</a> dominated by woody plants. There are many different kinds of swamps, ranging from the forested red maple, (<i>Acer rubrum</i>), swamps of the Northeast, to the extensive bottomland hardwood forests found along the sluggish rivers of the Southeast. Swamps are characterized by saturated soils during the growing season, and standing water during certain times of the year. The highly organic soils of swamps form a thick, black, nutrient-rich environment for the growth of water-tolerant trees such as cypress (<i>Taxodium spp.</i>), Atlantic white cedar (<i>Chamaecyparis thyoides</i>), and tupelo (<i>Nyssa aquatica</i>). Some swamps are dominated by shrubs, such as buttonbush or smooth alder. Plants, birds, fish, and invertebrates such as freshwater shrimp, crayfish, and clams require the habitats provided by swamps. Many rare species, such as the endangered American crocodile depend on these ecosystems as well. Swamps may be divided into two major classes, depending on the type of vegetation present: shrub swamps, and forested swamps. </p> <p><a href='/article/Swamp'>Read Full Article...</a></p> http://www.eoearth.org/article/Swamp Fri, 21 Aug 2009 05:41:52 GMT http://www.eoearth.org/article/Lady_Fern <a href='/article/Lady_Fern'><img border='0' src='/upload/thumb/c/cf/Lady_Fern_USFS.jpg/190px-Lady_Fern_USFS.jpg' width='100'/></a> <p><strong><big>Lady Fern (<em>Athyrium filix-femina</em> (L.) Roth)</big></strong></p> <p>Lady Fern is a native perennial upright fern that can reach 2-5 feet in height. The leaves are a bright green, with a fine-textured lacy appearance, and single fronds can measure up to 1’ wide and 3’ in length. The frond stalks are green to purple or red in color. Lady Fern is native to the continental US and Alaska.</p> <p>This graceful fern is a lovely addition to any moist shade gardens. The lacy light green foliage provides a striking contrast to other wide, dark-leaved shade-tolerant plants. Lady Fern is best introduced into a garden using a containerized plant or by propagating the rhizome. The Lady Fern is easy to grow and maintain as it colonizes through rhizomes but growth is slow. It often forms clumps or groups of upright fern leaves, maintaining a compact appearance, although if left unchecked over a long period, it will spread from 3-7 feet in diameter. This is a deciduous fern. It will drop its leaves with the first frost. Lady Fern is relatively tolerant of sun and dry <a href="/article/Soil">soil</a>, compared to other ferns. The best growth will occur in full to partial shade and a rich, moist soil. This hardy fern also makes a nice ground cover plant on the north or east side of buildings.</p> <p>In the wild, Lady Fern grows in moist woods, moist meadows, and <a href="/article/Swamp">swamps</a> and along <a href="/article/Stream">streams</a>, from lowlands to mid-elevations. Because of its easy maintenance, there are several cultivated varieties, in various shades. This deciduous fern is a very low maintenance plant that adds a lot of esthetic value to the landscape.</p> <p><a href='/article/Lady_Fern'>Read Full Article...</a></p> http://www.eoearth.org/article/Lady_Fern Thu, 20 Aug 2009 05:47:26 GMT http://www.eoearth.org/article/Lady_Fern <a href='/article/Lady_Fern'><img border='0' src='/upload/thumb/c/cf/Lady_Fern_USFS.jpg/190px-Lady_Fern_USFS.jpg' width='100'/></a> <p><strong><big>Lady Fern (<em>Athyrium filix-femina</em> (L.) Roth)</big></strong></p> <p>Lady Fern is a native perennial upright fern that can reach 2-5 feet in height. The leaves are a bright green, with a fine-textured lacy appearance, and single fronds can measure up to 1’ wide and 3’ in length. The frond stalks are green to purple or red in color. Lady Fern is native to the continental US and Alaska.</p> <p>This graceful fern is a lovely addition to any moist shade gardens. The lacy light green foliage provides a striking contrast to other wide, dark-leaved shade-tolerant plants. Lady Fern is best introduced into a garden using a containerized plant or by propagating the rhizome. The Lady Fern is easy to grow and maintain as it colonizes through rhizomes but growth is slow. It often forms clumps or groups of upright fern leaves, maintaining a compact appearance, although if left unchecked over a long period, it will spread from 3-7 feet in diameter. This is a deciduous fern. It will drop its leaves with the first frost. Lady Fern is relatively tolerant of sun and dry <a href="/article/Soil">soil</a>, compared to other ferns. The best growth will occur in full to partial shade and a rich, moist soil. This hardy fern also makes a nice ground cover plant on the north or east side of buildings.</p> <p>In the wild, Lady Fern grows in moist woods, moist meadows, and <a href="/article/Swamp">swamps</a> and along <a href="/article/Stream">streams</a>, from lowlands to mid-elevations. Because of its easy maintenance, there are several cultivated varieties, in various shades. This deciduous fern is a very low maintenance plant that adds a lot of esthetic value to the landscape.</p> <p><a href='/article/Lady_Fern'>Read Full Article...</a></p> http://www.eoearth.org/article/Lady_Fern Thu, 20 Aug 2009 05:47:03 GMT http://www.eoearth.org/article/Maps <a href='/article/Maps'><img border='0' src='/upload/thumb/6/6d/Weather_map_pressure_centers.jpg/250px-Weather_map_pressure_centers.jpg' width='100'/></a> <p>A map can be simply defined as a graphic representation of the real world. This representation is always an abstraction of reality. Because of the infinite nature of our Universe it is impossible to capture all of the complexity found in the real world. For example, <a href="/article/Topographic_maps">topographic maps</a> abstract the three-dimensional real world at a reduced scale on a two-dimensional plane of paper. </p><p>Maps are used to display both cultural and physical features of the environment. Standard topographic maps show a variety of information including roads, <a href="/article/Land-use">land-use</a> classification, elevation, rivers and other water bodies, political boundaries, and the identification of houses and other types of buildings. Some maps are created with very specific goals in mind. Figure 1 displays a weather map showing the location of low and high <a href="/article/Atmospheric_pressure">pressure</a> centers and fronts over most of North America. The intended purpose of this map is considerably more specialized than a topographic map. </p><p>The art of map construction is called cartography. People who work in this field of knowledge are called cartographers. The construction and use of maps has a long history. Some academics believe that the earliest maps date back to the fifth or sixth century BC. Even in these early maps, the main goal of this tool was to communicate information. Early maps were quite subjective in their presentation of spatial information. Maps became more objective with the dawn of Western science. The application of scientific method into cartography made maps more ordered and accurate. Today, the art of map making is quite a sophisticated science employing methods from cartography, engineering, computer science, mathematics, and psychology. </p><p>Cartographers classify maps into two broad categories: reference maps and thematic maps. Reference maps normally show natural and human-made objects from the geographical environment with an emphasis on location. Examples of general reference maps include maps found in atlases and <a href="/article/Topographic_maps">topographic maps</a>. Thematic maps are used to display the geographical distribution of one phenomenon or the spatial associations that occur between a number of phenomena. </p> <p><a href='/article/Maps'>Read Full Article...</a></p> http://www.eoearth.org/article/Maps Wed, 19 Aug 2009 06:26:26 GMT http://www.eoearth.org/article/Maps <a href='/article/Maps'><img border='0' src='/upload/thumb/6/6d/Weather_map_pressure_centers.jpg/250px-Weather_map_pressure_centers.jpg' width='100'/></a> <p>A map can be simply defined as a graphic representation of the real world. This representation is always an abstraction of reality. Because of the infinite nature of our Universe it is impossible to capture all of the complexity found in the real world. For example, <a href="/article/Topographic_maps">topographic maps</a> abstract the three-dimensional real world at a reduced scale on a two-dimensional plane of paper. </p><p>Maps are used to display both cultural and physical features of the environment. Standard topographic maps show a variety of information including roads, <a href="/article/Land-use">land-use</a> classification, elevation, rivers and other water bodies, political boundaries, and the identification of houses and other types of buildings. Some maps are created with very specific goals in mind. Figure 1 displays a weather map showing the location of low and high <a href="/article/Atmospheric_pressure">pressure</a> centers and fronts over most of North America. The intended purpose of this map is considerably more specialized than a topographic map. </p><p>The art of map construction is called cartography. People who work in this field of knowledge are called cartographers. The construction and use of maps has a long history. Some academics believe that the earliest maps date back to the fifth or sixth century BC. Even in these early maps, the main goal of this tool was to communicate information. Early maps were quite subjective in their presentation of spatial information. Maps became more objective with the dawn of Western science. The application of scientific method into cartography made maps more ordered and accurate. Today, the art of map making is quite a sophisticated science employing methods from cartography, engineering, computer science, mathematics, and psychology. </p><p>Cartographers classify maps into two broad categories: reference maps and thematic maps. Reference maps normally show natural and human-made objects from the geographical environment with an emphasis on location. Examples of general reference maps include maps found in atlases and <a href="/article/Topographic_maps">topographic maps</a>. Thematic maps are used to display the geographical distribution of one phenomenon or the spatial associations that occur between a number of phenomena. </p> <p><a href='/article/Maps'>Read Full Article...</a></p> http://www.eoearth.org/article/Maps Wed, 19 Aug 2009 06:26:06 GMT http://www.eoearth.org/article/Ozone <a href='/article/Ozone'><img border='0' src='/upload/thumb/e/eb/OHradicalformation.gif/250px-OHradicalformation.gif' width='100'/></a> <p>Ozone is a gas made up of three <a href="/article/Oxygen">oxygen</a> atoms (O₃). It occurs naturally in small (trace) amounts in the upper <a href="/article/Atmosphere_layers">atmosphere</a> (the stratosphere). Ozone protects life on Earth from the Sun’s ultraviolet (UV) <a href="/article/Solar_radiation">radiation</a>. In the lower atmosphere (the troposphere) near the Earth’s surface, ozone is created by chemical reactions between <a href="/article/Air_pollution_emissions">air pollutants</a> from vehicle exhaust, motor gasoline vapors, and other emissions. At ground level, high concentrations of ozone are <a href="/article/Impact_of_ozone_on_health_and_vegetation">toxic to people and plants.</a> </p><p>Ozone comes from the Greek &quot;ozein&quot; meaning &quot;to smell&quot;, and ozone has a characteristic odor that you can detect around high-voltage discharges. A few examples are a photocopy machine, a television, or during a thunderstorm. </p> <p><a href='/article/Ozone'>Read Full Article...</a></p> http://www.eoearth.org/article/Ozone Tue, 18 Aug 2009 06:01:33 GMT http://www.eoearth.org/article/Ozone <a href='/article/Ozone'><img border='0' src='/upload/thumb/e/eb/OHradicalformation.gif/250px-OHradicalformation.gif' width='100'/></a> <p>Ozone is a gas made up of three <a href="/article/Oxygen">oxygen</a> atoms (O₃). It occurs naturally in small (trace) amounts in the upper <a href="/article/Atmosphere_layers">atmosphere</a> (the stratosphere). Ozone protects life on Earth from the Sun’s ultraviolet (UV) <a href="/article/Solar_radiation">radiation</a>. In the lower atmosphere (the troposphere) near the Earth’s surface, ozone is created by chemical reactions between <a href="/article/Air_pollution_emissions">air pollutants</a> from vehicle exhaust, motor gasoline vapors, and other emissions. At ground level, high concentrations of ozone are <a href="/article/Impact_of_ozone_on_health_and_vegetation">toxic to people and plants.</a> </p><p>Ozone comes from the Greek &quot;ozein&quot; meaning &quot;to smell&quot;, and ozone has a characteristic odor that you can detect around high-voltage discharges. A few examples are a photocopy machine, a television, or during a thunderstorm. </p> <p><a href='/article/Ozone'>Read Full Article...</a></p> http://www.eoearth.org/article/Ozone Tue, 18 Aug 2009 06:00:19 GMT http://www.eoearth.org/article/Research_reactors <a href='/article/Research_reactors'><img border='0' src='/upload/thumb/9/92/Kyoto_University_Research_Reactor.jpg/200px-Kyoto_University_Research_Reactor.jpg' width='100'/></a> <p><a href='/article/Research_reactors'>Read Full Article...</a></p> http://www.eoearth.org/article/Research_reactors Mon, 17 Aug 2009 10:56:46 GMT http://www.eoearth.org/article/Research_reactors <a href='/article/Research_reactors'><img border='0' src='/upload/thumb/9/92/Kyoto_University_Research_Reactor.jpg/200px-Kyoto_University_Research_Reactor.jpg' width='100'/></a> <p><a href='/article/Research_reactors'>Read Full Article...</a></p> http://www.eoearth.org/article/Research_reactors Mon, 17 Aug 2009 10:55:45 GMT http://www.eoearth.org/article/Research_reactors <a href='/article/Research_reactors'><img border='0' src='/upload/thumb/9/92/Kyoto_University_Research_Reactor.jpg/200px-Kyoto_University_Research_Reactor.jpg' width='100'/></a> <p><a href='/article/Research_reactors'>Read Full Article...</a></p> http://www.eoearth.org/article/Research_reactors Mon, 17 Aug 2009 10:55:22 GMT http://www.eoearth.org/article/Sea_ice <a href='/article/Sea_ice'><img border='0' src='/upload/thumb/2/25/Intro.jpg/250px-Intro.jpg' width='100'/></a> <h1><strong>What is sea ice?</strong></h1> <p>Sea ice is simply frozen <a href="/article/Sea_water">ocean water</a>. It forms, grows, and melts in the ocean. In contrast, icebergs, <a href="/article/Glacier">glaciers</a>, ice sheets, and ice shelves all originate on land. Sea ice occurs in both the <a href="/article/Arctic">Arctic</a> and Antarctic. In the <a href="/article/Northern_Hemisphere">Northern Hemisphere</a>, it can currently exist as far south as Bohai Bay, China (approximately 38 degrees north latitude), which is actually about 700 <a href="/article/Meter">kilometers</a> (km) (435 miles) closer to the Equator than it is to the North Pole. In the <a href="/article/Southern_Hemisphere">Southern Hemisphere</a>, sea ice only develops around <a href="/article/Antarctica">Antarctica</a>, occurring as far north as 55 degrees south latitude. </p> <p>Sea ice grows during the winter months and melts during the summer months, but some sea ice remains all year in certain <a href="/article/Region">regions</a>. About 15 percent of the world&#39;s oceans are covered by sea ice during part of the year.</p> <h2><strong>Why is sea ice so important, and why do scientists study it?</strong></h2> <p>Even though sea ice occurs primarily in the polar regions, it influences our global climate. Sea ice has a bright surface, so much of the <a href="/article/Solar_radiation">sunlight</a> that strikes it is reflected back into space. As a result, areas covered by sea ice don&#39;t absorb much solar energy, so <a href="/article/Temperature">temperatures</a> in the polar regions remain relatively cool. If gradually <a href="/article/Global_warming">warming</a> temperatures melt sea ice over time, fewer bright surfaces are available to reflect sunlight back into space, more solar energy is absorbed at the surface, and temperatures rise further. This chain of events starts a cycle of warming and melting. This cycle is temporarily halted when the dark days of the polar winter return, but it starts again in the following spring. Even a small increase in temperature can lead to greater warming over time, making the polar regions the most sensitive areas to climate change on Earth. </p> <p>Sea ice also affects the movement of <a href="/article/Ocean">ocean</a> waters. When sea ice forms, most of the salt is pushed into the ocean water below the ice, although some salt may become trapped in small pockets between ice crystals. Water below sea ice has a higher concentration of salt and is more dense than surrounding ocean water, and so it sinks. In this way, sea ice contributes to the ocean&#39;s global &quot;conveyor-belt&quot; <a href="/article/Ocean_circulation">circulation</a>. Cold, dense, polar water sinks and moves along the ocean bottom toward the equator, while warm water from mid-depth to the surface travels from the equator toward the poles. Changes in the amount of sea ice can disrupt normal ocean circulation, thereby leading to changes in global climate. </p> <p>Too much or too little sea ice can be a problem for wildlife and people who hunt and travel in polar regions. In the <a href="/article/Arctic">Arctic</a>, sea ice can be an obstacle to normal shipping routes through the Northern Sea route and Northwest Passage. </p> <h2><strong>What is the difference between sea ice and icebergs, glaciers, and lake ice?</strong></h2> <p>The most basic difference is that sea ice forms from salty <a href="/article/Seawater">ocean water</a>, whereas icebergs, <a href="/article/Glacier">glaciers</a>, and <a href="/article/Freshwater_biomes">lake</a> ice form from <a href="/article/Freshwater">fresh water</a> or snow. Sea ice grows, forms, and melts strictly in the ocean. Glaciers are considered land ice, and icebergs are chunks of ice that break off of glaciers and fall into the <a href="/article/Ocean">ocean</a>. Lake ice is made from fresh water and freezes as a smooth layer, unlike sea ice, which develops into various forms and shapes because of the constant turbulence of ocean water. </p> <p> The process by which sea ice forms is also different from that of lake or <a href="/article/River">river</a> ice. Fresh water is unlike most substances because it becomes less dense as it nears the freezing point. This difference in density explains why ice cubes float in a glass of water. Very cold, low-density fresh water stays at the surface of lakes and rivers, forming an ice layer on the top.</p> <p>In contrast to fresh water, the salt in ocean water causes the density of the water to increase as it nears the freezing point, and very cold ocean water tends to sink. As a result, sea ice forms slowly, compared to freshwater ice, because salt water sinks away from the cold surface before it cools enough to freeze. Furthermore, other factors cause the formation of sea ice to be a slow process. The freezing temperature of <a href="/article/Seawater">salt water</a> is lower than fresh water; ocean <a href="/article/Temperature">temperatures</a> must reach -1.8 degrees Celsius (28.8 degrees Fahrenheit) to freeze. Because oceans are so deep, it takes longer to reach the freezing point, and generally, the top 100 to 150 <a href="/article/Meter">meters</a> (m) (300 to 450 feet) of water must be cooled to the freezing temperature for ice to form. <br /> </p> <h2><strong>Can you drink melted sea ice?</strong></h2> <p>New ice is usually very salty because it contains concentrated droplets called brine that are trapped in pockets between the ice crystals, and so it would not make good drinking water. As ice ages, the brine eventually drains through the ice, and by the time it becomes multiyear ice, nearly all of the brine is gone. Most multiyear ice is fresh enough that someone could drink its melted water. In fact, multiyear ice often supplies the <a href="/article/Freshwater">fresh water</a> needed for polar expeditions. See Salinity and Brine in the Characteristics section for more information</p> <p><a href='/article/Sea_ice'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_ice Fri, 14 Aug 2009 05:28:26 GMT http://www.eoearth.org/article/Watershed <a href='/article/Watershed'><img border='0' src='/upload/thumb/0/02/Watershed_diagram1.gif/250px-Watershed_diagram1.gif' width='100'/></a> <p>The term watershed is used (especially in North America and Europe) to indicate an area of land from which all water falling as <a href="/article/Precipitation_and_fog">rain or snow</a> would flow toward a single point. This includes both surface water flow, such as <a href="/article/Freshwater_biomes">rivers</a>, <a href="/article/Stream">streams</a> and creeks, and the <a href="/article/Groundwater">underground</a> movement of water. The boundaries and the area of such a watershed are determined by first specifying geographic point on land. A line is then drawn which connects all of the points of highest elevation immediately adjacent to that point. The watershed area would be the land area within those boundaries. The watershed of the Amazon River would include all of the tributaries that flow into it so it would actually contain several hundred smaller watersheds. The watershed is thus defined hydrologically, that is, by the specific river or stream. Watershed and <a href="/article/Drainage_basin">drainage basin</a> or catchment are used synonymously and all of them refer to the area of land drained by a river system. Three hydrological types of watershed can be distinguished: </p><ul><li>Exorheic watershed, which empty to the sea and represent the major part of the drainage of all of the continents except Australia. </li><li>Endorheic watershed, which discharge inland, into closed lake basins, and are mainly (but not exclusively) restricted to the arid and semi-arid regions. <br /> </li><li>Arheic regions, which is the region within which no rivers arise (the lower part of the Nile, Oranje and Niger, all in Africa, are a good examples of this category of basin). </li></ul><p>Watershed identification is now a primary tool for environmental planning. Called watershed management areas, these geographic units are utilized to gain an understanding of what happens to the surface or <a href="/article/Groundwater">groundwater</a> in the upper elevations of a watershed because that is imperative for the interpretation of local phenomenon. In some locales, the term &quot;watershed&quot; actually refers to the height of land <em>between</em> two catchment areas.</p> <p><a href='/article/Watershed'>Read Full Article...</a></p> http://www.eoearth.org/article/Watershed Thu, 13 Aug 2009 05:50:19 GMT http://www.eoearth.org/article/Heat_island <a href='/article/Heat_island'><img border='0' src='/upload/thumb/b/bf/Heat_island_profile.gif/250px-Heat_island_profile.gif' width='100'/></a> <p>The term &quot;heat island&quot; refers to urban air and surface <a href="/article/Temperature">temperatures</a> that are higher than nearby rural areas. Many cities and suburbs have air temperatures that are 2 to 10°F (1 to 6°C) warmer than the surrounding natural <a href="/article/Land-cover">land cover</a>. Figure 1 shows a city&#39;s heat island profile. It demonstrates how urban temperatures are typically lower at the urban-rural border than in dense downtown areas. The graphic also show how parks, open land, and bodies of water can create cooler areas. Elevated temperatures can impact communities in a number of ways. Elevated temperatures can impact communities by increasing peak energy demand, air conditioning costs, <a href="/article/Air_pollution_emissions">air pollution</a> levels, and <a href="/article/Heat">heat</a>-related illness and mortality. </p> <p>The remotely sensed image of Sacramento, CA in Figure 2 illustrates the heat island phenomenon. In the aerial photo (left), the white areas, mostly rooftops, are about 140 degrees Fahrenheit (60 degrees Celsius) and the dark areas, primarily vegetative areas or water, are approximately 85-96 degree Fahrenheit (29-36 degrees Celsius). The hottest spots are the buildings, seen as white rectangles of various sizes. In the thermal image (right), Sacramento&#39;s rail yard is the orange area east of the Sacramento River, which flows from top to bottom. Red and yellow areas indicate hot spots and generally correspond with urban development, while blue and green areas are cool and generally correspond to the natural environment. </p><p>Cities in cold climates may actually benefit from the wintertime warming effect of heat islands. Warmer <a href="/article/Temperature">temperatures</a> can reduce heating energy needs and may help melt ice and snow on roads. In the summertime, however, the same city may experience the negative effects of heat islands. </p> <p><a href='/article/Heat_island'>Read Full Article...</a></p> http://www.eoearth.org/article/Heat_island Wed, 12 Aug 2009 05:44:39 GMT http://www.eoearth.org/article/Tide <a href='/article/Tide'><img border='0' src='/upload/thumb/b/b6/Earth_moon_system.jpg/300px-Earth_moon_system.jpg' width='100'/></a> <p>An ocean tide refers to the cyclic rise and fall of seawater. Tides are caused by slight variations in gravitational attraction between the Earth, the moon and the sun in geometric relationship with locations on the Earth's surface. Tides are periodic primarily because of the cyclical influence of the Earth's rotation. </p><p>The moon is the primary factor controlling the temporal rhythm and height of tides (Figure 1). The moon produces two tidal bulges somewhere on the Earth through the effects of gravitational attraction. The height of these tidal bulges is controlled by the moon's gravitational force and the Earth's gravity pulling the water back toward the Earth. At the location on the Earth closest to the moon, seawater is drawn toward the moon because of the greater strength of gravitational attraction. On the opposite side of the Earth, another tidal bulge is produced away from the moon. However, this bulge is due to the fact that at this point on the Earth the force of the moon's gravity is at its weakest. Considering this information, any given point on the Earth's surface should experience two tidal crests and two tidal troughs during each tidal period. </p> <p>The timing of tidal events is related to the Earth's rotation and the revolution of the moon around the Earth. If the moon was stationary in space, the tidal cycle would be 24 hours long. However, the moon is in motion revolving around the Earth. One revolution takes about 27 days and adds about 50 minutes to the tidal cycle. As a result, the tidal period is 24 hours and 50 minutes in length. </p> <p>The second factor controlling tides on the Earth's surface is the sun's gravity. The height of the average solar tide is about 50% the average lunar tide. At certain times during the moon's revolution around the Earth, the direction of its gravitational attraction is aligned with the sun's (Figure 2). During these times the two tide producing bodies act together to create the highest and lowest tides of the year. These spring tides occur every 14-15 days during full and new moons. </p><p>When the gravitational pull of the moon and sun are at right angles to each other, the daily tidal variations on the Earth are at their least (Figure 3). These events are called neap tides and they occur during the first and last quarter of the moon. </p> <p><a href='/article/Tide'>Read Full Article...</a></p> http://www.eoearth.org/article/Tide Tue, 11 Aug 2009 05:22:54 GMT http://www.eoearth.org/article/Lithium <a href='/article/Lithium'><img border='0' src='/upload/thumb/9/9b/Spodume.jpg/200px-Spodume.jpg' width='100'/></a> <p>Lithium, the lightest metal, is in a group of elements called alkali metals or <em>Group I elements </em>and is silvery-white in color<em>.</em> It has the atomic number of 3. The alkali metals group includes lithium (Li), potassium (K), and sodium (Na). The three alkali metals are highly reactive with <a href="/article/Oxygen">oxygen</a> and water, so they are stored in oil. Although lithium will react dramatically when put in water, it is the least reactive alkali metal. When it reacts with water it bounces on the top of the water because it is less dense than water. </p><p>Johan A. Arfvedson, of Stockholm, Sweden, first discovered lithium in 1817. It was first isolated by W.T. Brande and <a href="/article/Davy%2C_Humphry">Humphry Davy</a> in the 19th century, but it was not commercially <a href="/article/Essential_economic_activities">produced</a> until 1923. </p> <p><a href='/article/Lithium'>Read Full Article...</a></p> http://www.eoearth.org/article/Lithium Mon, 10 Aug 2009 05:06:58 GMT http://www.eoearth.org/article/Landslide <a href='/article/Landslide'><img border='0' src='/upload/thumb/c/c7/La_conchita_Village.JPG/175px-La_conchita_Village.JPG' width='100'/></a> <p>Landslides in the United States occur in all 50 States. The primary <a href="/article/Region">regions</a> of landslide occurrence and potential are the coastal and <a href="/article/Mountain">mountainous</a> areas of California, Oregon, and Washington, the States comprising the intermountain west, and the mountainous and hilly regions of the Eastern United States. Alaska and Hawaii also experience all types of landslides. </p><p>Landslides in the United States cause approximately $3.5 billion (year 2001 dollars) in damage, and kill between 25 and 50 people annually. Casualties in the United States are primarily caused by rockfalls, rock slides, and debris flows. Worldwide, landslides occur and cause thousands of casualties and billions in monetary losses annually. </p><p>The information in this publication provides an introductory primer on understanding basic scientific facts about landslides—the different types of landslides, how they are initiated, and some basic information about how they can begin to be managed as a hazard. </p> <p><a href='/article/Landslide'>Read Full Article...</a></p> http://www.eoearth.org/article/Landslide Fri, 07 Aug 2009 05:55:59 GMT http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa <a href='/article/Impacts_of_tourism_and_recreation_in_Africa'><img border='0' src='/upload/thumb/d/d5/Great_Zimbabwe.JPG/350px-Great_Zimbabwe.JPG' width='100'/></a> <p>Land-based tourism is a major economic activity in Africa, drawing millions of visitors to different sites across the region every year and generating millions of dollars in foreign exchange earnings. Sites such as the pyramids of Egypt, the Great Rift Valley of Eastern and Southern Africa, Great Zimbabwe, Table Mountain in South Africa, Mount Kenya in Kenya and Mount Kilimanjaro in Tanzania are some of the major attractions. Mountains, wildlife, wetlands and <a href="/article/Coastal_zone">coastal areas</a> are also major tourist attractions. These and other attractions contributed to the arrival of a total of about 124 million international tourists in the five years of 1990, 1995, 2000, 2002 and 2003. The visitors spent a total of US$52 891 million in those five years. In 2003 and 2004 the region attracted 78.1 million international tourists. In 2004, international tourist arrivals grew at 10 percent worldwide and 14 percent in Africa – to 41.6 million, up from 36.5 million in 2003. However, the region shared only 7.4 percent of the global increase of 69 million tourists, and almost all the increase was concentrated in Northern Africa. </p><p>Ecotourism accounted for 20 percent of total international tourism. In recognition of ecotourism’s growth potential, particularly for developing countries, the United Nations Economic and Social Council (ECOSOC) declared 2002 the International Year of Ecotourism. Many countries in Africa, such as Kenya and South Africa, have invested heavily in ecotourism. </p><p>Tourism in Africa varies widely, from viewing gorillas in the Great Lakes Region to lemurs in Madagascar, from trekking in Ethiopia to birdwatching in Botswana, from looking at rock paintings in South Africa to visiting rainforests in Ghana, from <a href="/article/Mountain">mountain</a>-climbing in Eastern Africa (Mt Kilimanjaro and Mt Kenya, for example) to scuba-diving in the Seychelles and to photographic safaris in Eastern and Southern Africa. In the Great Lakes Region, for example, revenue from tourism based on gorilla viewing and other activities brings in about US$20 million to the region annually. Tourism in the area is certain to be boosted with the news in 2004 that the first census since 1989 revealed that the population of the apes in the Virunga Mountains has grown by 17 percent, increasing from 324 in 1989 to 380 by the end of 2003. </p> <p>Tourism can serve as a powerful incentive to protect natural resources. In Madagascar, where tourism is the country’s second largest foreign exchange earner, the country had by 1998 established 40 new protected areas, covering roughly 2 percent of the country’s <a href="/article/Land_resources_in_Africa">land</a> area. In Southern and Eastern Africa, privately-owned protected areas that support tourism and hunting enterprises are also growing. </p><p>Tourism not only generates revenue to support conservation and management of natural environments but also generates many jobs. For example, hundreds of people live off the Bwindi Impenetrable Forest in Uganda, where foreign tourists trek to view gorillas. It has been argued that tourism has larger multiplier effects, with revenue spreading from hotel accommodation, food and beverages, shopping, entertainment and transport to income of hotel staff, taxi operators, shopkeepers and suppliers of goods and services. </p><p>Despite the growth of tourism, the region still only accounts for less than 4 percent of world tourism, with its revenue share at only 2.5 percent – about US$16,000 million in 2002 of the annual sales of about US$4.5 million million. Therefore, opportunities for further investment and development are vast in the region. In Kenya, for example, new regulations that will allow sport bird shooting are expected to attract up to 2,000 sport hunters annually, boosting revenues by US$5 million each year. New Kenya Wildlife Service (KWS) rules provide for private landowners to obtain special authorization to manage their own game bird populations, including breeding, as well as determine open and closed seasons. </p> <p>Several African countries including Ethiopia, South Africa, Kenya and Benin have significant palaeontology sites. In Ethiopia, the government is using these sites to promote &quot;palaeo-tourism,&quot; and to generate revenue. Ethiopia is home to some of the most famous prehistoric remains ever found, including some of the world’s oldest human remains: Ethiopia’s discoveries chart man’s prehistory from more than 6 million years ago to modern ancestors. Tourism officials in Afar believe that &quot;palaeo-tourism&quot; could generate an additional US$2 million in revenue annually for this region alone. The Ethiopian Tourism Commission has reported that the sector generated more than US$77 million in 2003. This revenue is important in the fight against poverty and plays a key role in the government’s poverty reduction strategy paper (PRSP). South Africa has also made palaeontology and other cultural heritage sites a focus of their tourism industry. </p><p>The tourism industry in Africa also has human and environmental costs, contributing to the displacement of communities and thus undermining rights and livelihoods, the generation of waste and pollution, and the unsustainable use of water. In Africa, for example, tourism’s effects on indigenous peoples have been profound, with the eviction of communities from their <a href="/article/Land_resources_in_Africa">lands</a>, in addition to economic dislocation, breakdown of traditional values, and environmental degradation. Pastoralism has been attacked as primitive and destructive. The massive influx of tourists and their vehicles in the Masai Mara National Park in Kenya and in the Ngorongoro Conservation Area in Tanzania has destroyed grass cover, affecting plant and animal species in the area. Hotels have dumped their sewage in Masai settlement areas while campsites have polluted adjacent rivers. One emerging approach is to focus on promoting community conservation areas and also collaborative tourism initiatives in order to ensure greater benefits to communities. There are different levels of community participation, varying from passive participation to interactive decision making to community empowerment initiatives. </p><p>The challenge facing policymakers in this industry and other land-based activities is to critically assess the costs and benefits to ensure that all options are fully weighed and that the policy responses contribute to <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a> and minimize overexploitation. </p><p>Additionally, measures need to be adopted to ensure that the benefits associated with tourism are spread across society, and that those who are directly involved in conservation are rewarded. </p><p><strong>Further Reading</strong> </p> <ul><li>African Environmental News Services, 2003. <a href="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026" class='external text' title="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026">Kenya Hopes to Boost Tourism Revenue by Sport Bird Shooting.</a> </li><li>Chavez, R., 1999. <a href="http://www.twnside.org.sg/title/chavez-cn.htm" class='external text' title="http://www.twnside.org.sg/title/chavez-cn.htm">Globalisation and tourism: Deadly mix for indigenous peoples.</a> Third World Resurgence, 103. Third World Network. </li><li>ECA, 2005. <a href="http://www.uneca.org/era2005/front.pdf" class='external text' title="http://www.uneca.org/era2005/front.pdf">Economic Report on Africa 2005: Meeting the Challenges of Unemployment and Poverty in Africa.</a> Economic Commission for Africa, Addis Ababa. </li><li>IRIN, 2004. <a href="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn_of_Africa" class='external text' title="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn of Africa">Ethiopia: Archaeology and palaeontology to boost tourism revenue.</a> United Nations Integrated Regional Information Networks. </li><li>Pickrell, J., 2004. <a href="http://news.nationalgeographic.com/news/2004/01/0127_040127_gorillas.html#main" class='external text' title="http://news.nationalgeographic.com/news/2004/01/0127 040127 gorillas.html#main">Africa’s Mountain Gorillas Rebound, Says New Census.</a> National Geographic News, January 27, 2004. </li><li>Saunders, D. J. (undated). <a href="http://www.africaata.org/trade_2.htm" class='external text' title="http://www.africaata.org/trade 2.htm">Africa Needs More Liberalized Trade Initiatives for the Continued Growth and Sustainability of its Travel and Tourism Industry.</a> Africa Travel Magazine. </li><li>UN (undated). <a href="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm" class='external text' title="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm">Sustainable tourism in Kenya</a>. United Nations Division for Economic and Social Affairs, New York. </li><li>UNEP, 2006. <a href="http://www.unep.org/dewa/africa/aeo2_launch/index.asp" class='external text' title="http://www.unep.org/dewa/africa/aeo2 launch/index.asp">Africa Environment Outlook 2</a> </li><li>Vieta, F. E., 1999. <a href="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm" class='external text' title="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm">Ecotourism propels development: But social acceptance depends on economic opportunities for local communities.</a> Africa Recovery, 13(1). </li><li>World Tourism Organization, 2005. <a href="http://www.world-tourism.org/facts/menu.html" class='external text' title="http://www.world-tourism.org/facts/menu.html">International Tourist Arrivals &amp;amp; Tourism Receipts by Country.</a> </li></ul> <p><br /> </center> </p><p> <p>[[category:|Impacts of tourism and recreation in Africa]] </p> </p> <p><a href='/article/Impacts_of_tourism_and_recreation_in_Africa'>Read Full Article...</a></p> http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa Thu, 06 Aug 2009 05:17:06 GMT http://www.eoearth.org/article/Groundwater <a href='/article/Groundwater'><img border='0' src='/upload/thumb/d/d9/Fresh_water_storage_on_earth.gif/400px-Fresh_water_storage_on_earth.gif' width='100'/></a> <p>In the broadest sense, groundwater refers to all subsurface water. The term more commonly refers to water beneath the surface of the earth which saturates the pores and fractures of sand, gravel, and <a href="/article/Composition_of_rocks">rock</a> formations. Groundwater is a major source of water for <a href="/article/Agriculture">agricultural</a> and industrial purposes, and is an important source of drinking water for many people around the world. </p><p>Some water underlies the Earth&#39;s surface almost everywhere, beneath hills, mountains, plains, and deserts. It is not always accessible, or fresh enough for use without treatment, and it&#39;s sometimes difficult to locate or to measure and describe. This water may occur close to the land surface, as in a <a href="/article/Wetland">wetland</a>, or it may lie many hundreds of feet below the surface, as in some arid regions. Water at very shallow depths might be just a few hours old; at moderate depth, it may be hundreds of years old; and at great depth or after having flowed long distances from places of entry, water may be several thousands of years old. </p> <p>Groundwater is stored in, and moves slowly through, moderately to highly permeable rocks called <a href="/article/Aquifer">aquifers</a>. The word aquifer comes from the two Latin words, <em>aqua</em>, or water, and <em>ferre</em>, to bear or carry. Aquifers literally carry water underground. An aquifer may be a layer of gravel or sand, a layer of sandstone or cavernous limestone, a rubbly top or base of lava flows, or even a large body of massive rock, such as fractured granite, that has sizable cracks and fissures. In terms of storage at any one instant in time, groundwater is the largest single supply of fresh water available for use by humans. </p><p>Groundwater has been known to humans for thousands of years. Scripture (Genesis 7:11) on the Biblical Flood states that &quot;the fountains of the great deep (were) broken up,&quot; and Exodus, among its many references to water and to wells, refers (20:4) to &quot;water under the Earth.&quot; Many other ancient chronicles show that humans have long known that much water is contained underground, but it is only within recent decades that scientists and engineers have learned to estimate how much groundwater is stored underground and have begun to document its vast potential for use. An estimated one million cubic miles of the world&#39;s groundwater is stored within one-half mile of the land surface. Only a fraction of this groundwater, however, can be practicably tapped and made available on a perennial basis through wells and <a href="/article/Spring">springs</a>. The amount of groundwater in storage is more than 30 times greater than the nearly 30,000 cubic-miles volume in all the fresh-water lakes and more than the 300 cubic miles of water in all the world&#39;s streams at any given time (<strong>Figure 1</strong>). </p> <p><a href='/article/Groundwater'>Read Full Article...</a></p> http://www.eoearth.org/article/Groundwater Wed, 05 Aug 2009 06:17:13 GMT http://www.eoearth.org/article/Invasive_species <a href='/article/Invasive_species'><img border='0' src='/upload/thumb/1/1d/Chestnut_blight.gif/90px-Chestnut_blight.gif' width='100'/></a> <p>An invasive species is defined legally in the USA as “An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health…‘Alien species’ means, with respect to a particular <a href="/article/Ecosystem">ecosystem</a>, any species…that is not native to that ecosystem.” Novel species can be added to a community either by natural range extensions or because they are introduced as a result of human activity. Some introduced or alien species are beneficial to humans, for example most of our crops and pets. However many alien species have harmful effects; these are referred to as invasive species. Virtually all ecosystems are at risk from the harmful effects of introduced species ( also see <a href="/article/Exotic_species">exotic species</a>, <a href="/article/Marine_invasive_species">marine invasive species</a>, <a href="/article/Aquatic_invasive_species">aquatic invasive species</a>).</p><p>Invasive species are a major threat to our environment because they (1) can change habitats and alter ecosystem function and ecosystem services, (2) crowd out or replace native species, and (3) damage human activities, costing the economy millions of dollars. For example, costs to <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, <a href="/article/Fisheries_and_aquaculture">fisheries</a>, and other human activities by introduced species are estimated at $137 billion per year to the U.S. economy alone.</p> <p><a href='/article/Invasive_species'>Read Full Article...</a></p> http://www.eoearth.org/article/Invasive_species Wed, 05 Aug 2009 06:14:51 GMT http://www.eoearth.org/article/Local_and_regional_wind_systems <a href='/article/Local_and_regional_wind_systems'><img border='0' src='/upload/thumb/2/2e/Uniform_atm_pressure.gif/250px-Uniform_atm_pressure.gif' width='100'/></a> <p><a href="/article/Wind">Winds</a> blow because of differences in <a href="/article/Atmospheric_pressure">atmospheric pressure</a>. Pressure gradients may develop on a local to a global scale because of differences in the heating and cooling of the Earth&#39;s surface. Heating and cooling cycles that develop daily or annually can create several common local or regional thermal wind systems. The basic circulation system that develops is described in the Figure 1. </p> <p>In this first diagram (Figure 1), there is no horizontal temperature or pressure gradient and therefore no <a href="/article/Wind">wind</a>. Atmospheric pressure decreases with altitude as depicted by the drawn isobars (1000 to 980 millibars). In the second diagram (Figure 2), the potential for solar heating is added which creates contrasting surface areas of temperature and atmospheric pressure. The area to the right receives more <a href="/article/Solar_radiation">solar radiation</a> and the air begins to warm from heat energy transferred from the ground through conduction and convection. The vertical distance between the isobars becomes greater as the air rises. To the far left, less radiation is received because of the presence of cloud, and this area becomes relatively cooler than the area to the right. In the upper atmosphere, a pressure gradient begins to form because of the rising air and upward spreading of the isobars. The air then begins to flow in the upper atmosphere from high pressure to low pressure.</p><p>&nbsp;</p><p>Figure 3 shows the full circulation system in action. Beneath the upper atmosphere high is a thermal low pressure center created from the heating of the ground surface. Below the upper atmosphere low is a thermal high created by the relatively cooler air temperatures and the descend air from above. Surface air temperatures are cooler here because of the obstruction of shortwave radiation absorption at the Earth&#39;s surface by the cloud. At the surface, the <a href="/article/Wind">wind</a> blows from the high to the low pressure. Once at the low, the wind rises up to the upper air high pressure system because of thermal buoyancy and outflow in the upper atmosphere. From the upper high, the air then travels to the upper air low, and then back down to the surface high to complete the circulation cell. The circulation cell is a closed system that redistributes air in an equitable manner. It is driven by the greater heating of the surface air in the right of the diagram. </p> <p><a href='/article/Local_and_regional_wind_systems'>Read Full Article...</a></p> http://www.eoearth.org/article/Local_and_regional_wind_systems Tue, 04 Aug 2009 05:41:47 GMT http://www.eoearth.org/article/Local_and_regional_wind_systems <a href='/article/Local_and_regional_wind_systems'><img border='0' src='/upload/thumb/2/2e/Uniform_atm_pressure.gif/250px-Uniform_atm_pressure.gif' width='100'/></a> <p><a href="/article/Wind">Winds</a> blow because of differences in <a href="/article/Atmospheric_pressure">atmospheric pressure</a>. Pressure gradients may develop on a local to a global scale because of differences in the heating and cooling of the Earth&#39;s surface. Heating and cooling cycles that develop daily or annually can create several common local or regional thermal wind systems. The basic circulation system that develops is described in the Figure 1. </p> <p>In this first diagram (Figure 1), there is no horizontal temperature or pressure gradient and therefore no <a href="/article/Wind">wind</a>. Atmospheric pressure decreases with altitude as depicted by the drawn isobars (1000 to 980 millibars). In the second diagram (Figure 2), the potential for solar heating is added which creates contrasting surface areas of temperature and atmospheric pressure. The area to the right receives more <a href="/article/Solar_radiation">solar radiation</a> and the air begins to warm from heat energy transferred from the ground through conduction and convection. The vertical distance between the isobars becomes greater as the air rises. To the far left, less radiation is received because of the presence of cloud, and this area becomes relatively cooler than the area to the right. In the upper atmosphere, a pressure gradient begins to form because of the rising air and upward spreading of the isobars. The air then begins to flow in the upper atmosphere from high pressure to low pressure.</p><p>&nbsp;</p><p>Figure 3 shows the full circulation system in action. Beneath the upper atmosphere high is a thermal low pressure center created from the heating of the ground surface. Below the upper atmosphere low is a thermal high created by the relatively cooler air temperatures and the descend air from above. Surface air temperatures are cooler here because of the obstruction of shortwave radiation absorption at the Earth&#39;s surface by the cloud. At the surface, the <a href="/article/Wind">wind</a> blows from the high to the low pressure. Once at the low, the wind rises up to the upper air high pressure system because of thermal buoyancy and outflow in the upper atmosphere. From the upper high, the air then travels to the upper air low, and then back down to the surface high to complete the circulation cell. The circulation cell is a closed system that redistributes air in an equitable manner. It is driven by the greater heating of the surface air in the right of the diagram. </p> <p><a href='/article/Local_and_regional_wind_systems'>Read Full Article...</a></p> http://www.eoearth.org/article/Local_and_regional_wind_systems Tue, 04 Aug 2009 05:41:25 GMT http://www.eoearth.org/article/River <a href='/article/River'><img border='0' src='/upload/thumb/7/73/Confl2.gif/250px-Confl2.gif' width='100'/></a> <p>Rivers are of immense importance geologically, biologically, historically and culturally. Although they contain only about 0.0001% of the total amount of water in the world at any given time, rivers are vital carriers of water and nutrients to areas all around the earth. They are critical components of the hydrological cycle, acting as <a href="/article/Drainage_basin">drainage channels</a> for surface water – the world&#39;s rivers drain nearly 75% of the earth&#39;s land surface. They provide habitat, nourishment and means of transport to countless organisms; their powerful forces create majestic scenery; they provide travel routes for exploration, commerce and recreation; they leave valuable deposits of sediments, such as sand and gravel; they form vast floodplains where many of our cities are built; and their power provides much of the electrical energy we use in our everyday lives. Rivers are central to many of the environmental issues that concern society, and they are studied by a wide range of specialists including hydrologists, engineers, <a href="/article/Ecology">ecologists</a> and geomorphologists.</p> <p><a href='/article/River'>Read Full Article...</a></p> http://www.eoearth.org/article/River Mon, 03 Aug 2009 05:19:58 GMT http://www.eoearth.org/article/Evolution <a href='/article/Evolution'><img border='0' src='/upload/thumb/3/37/Figure1_evolution.jpg/300px-Figure1_evolution.jpg' width='100'/></a> <h1><strong>Introduction<br /></strong></h1> <p class="MsoNormal">Evolution is most commonly defined as a change in allelic (varieties of genes) frequencies in a <a href="/article/Population">population</a> over time. In other words, evolution encompasses a series of mechanisms that lead to changes in the relative proportion of different types of genes contained in a population where these changes persist from one generation to another. The primary mechanisms that result in such changes are <a href="/article/Natural_selection">selection</a>, genetic drift, mutation, and gene flow. </p> <p class="MsoNormal"> It is a common misconception that evolution occurs only through selection, but all four mechanisms often co-occur and selection is not necessarily the dominant force of evolutionary change. As <a href="/article/Darwin%2C_Charles">Charles Darwin</a> is recognized as the preeminent scientist to write formally about evolution by selection, this mechanism is often termed Darwinian selection. In fact, many scientists were synthesizing their ideas about evolution at the same time as Darwin and the first formal presentation of evolution by <a href="/article/Natural_selection">natural selection</a> was jointly authored by Alfred Russell Wallace and Charles Darwin. However, Darwin’s seminal book entitled <a href="/article/On_the_Origin_of_Species_%28historical_e-book%29"><em>On The Origin of Species by Means of Natural Selection</em></a> is often cited as the genesis of evolutionary theory as it contains a litany of evidence indicating how selection operates and how species are descended from common ancestors. </p> <p class="MsoNormal"> Darwin’s theories on evolution lacked any knowledge of genetic change and it was not until Gregor Mendel’s work on the genetic heritability of pea plant characteristics were incorporated into evolutionary thinking that the new synthesis of evolutionary theory was born. This new synthesis led to a flurry of research in the 1920s to 1960s that described and formalized the genetic mechanisms of evolution. Evolutionary theory has changed substantially since the initial days of Darwin and Wallace. </p> <p class="MsoNormal"> As there are now tens of thousands of scientific studies that demonstrate how evolution works, its characterization as a “theory” is somewhat misleading, and many scientists feel the term theory misrepresents the overwhelming weight of evidence that supports the modern conception of evolution and how it works. </p> <h1><strong>Mechanisms of evolution</strong></h1> <p><a href='/article/Evolution'>Read Full Article...</a></p> http://www.eoearth.org/article/Evolution Fri, 31 Jul 2009 06:09:29 GMT http://www.eoearth.org/article/London_smog_disaster,_England <a href='/article/London_smog_disaster,_England'><img border='0' src='/upload/thumb/b/b7/London_Smog.jpg/300px-London_Smog.jpg' width='100'/></a> <p><strong>London, England</strong> ( 51°29&#39;51.75&quot;N, 0° 7&#39;47.65&quot;W) was the site of a dense <a href="/article/Smog">smog</a> caused by heavy coal <a href="/article/Combustion">combustion</a> during the winter of 1952, which killed approximately 12,000 people. </p> <p><a href='/article/London_smog_disaster,_England'>Read Full Article...</a></p> http://www.eoearth.org/article/London_smog_disaster,_England Wed, 29 Jul 2009 06:15:31 GMT http://www.eoearth.org/article/Deception_Island <a href='/article/Deception_Island'><img border='0' src='/upload/thumb/0/0c/AntDotMap_Livingston.png/150px-AntDotMap_Livingston.png' width='100'/></a> <p>Deception Island is one of the <a href="/article/South_Shetland_Islands">South Shetland Islands</a> of <a href="/article/Antarctica">Antarctica</a>, lying about 60 miles (150 km) north of the <a href="/article/Antarctic_Peninsula">Antarctic Peninsula</a> across the Bransfield Strait. </p><p>The island is ring-shaped (roughly circular with with a flooded interior), from 7-10 miles across. The island is an active <a href="/article/Volcano">volcano</a> with a drowned breached crater which provides a sheltered harbor, named Port Foster (an oval 5x3 miles, 8x5 km). This harbor was popular in the early nineteenth century with seal hunters. It was known as Williams Harbor among British sealers and Yankee Harbor among American sealers (not to be confused with today&#39;s Yankee Harbor on nearby Greenwich Island). The narrow entrance to the harbor (feet, meter wide) is known as Neptune&#39;s Bellows.</p> <p>The island covers 38 miles² (98.5 km²), of which just over half is glaciated. The highest point on the island is Mount Pond at 1,890 feet (550 meters) high. It is also known as Monte Cambell and Monte Estanque <span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>.</p><p>Eruptions have occurred frequently in the past; most recently in 1970. Volcanic vents (Maars) exist at various places on the island <span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. </p> <p>The climate is &#39;&#39;polar maritime&quot; with temperatures ranging from +11°C to -28°C. However, because of volcanic activity and numerous vents, the island exhibits several &quot;microclimates&quot; where far higher temperatures have been measured.</p><p>The island&#39;s plant life is rich in comparison to most of <a href="/article/Antarctica">Antarctica</a>, with 18 species of moss or <a href="/article/Lichen">lichens</a> not found elsewhere on the continent.</p><p>The first known sighting of the island occurred in January, 1820 by a British expedition led by Edward Bransfield and piloted by William Smith. </p><p>It is thought that American seal hunter Nathaniel Palmer was the first to discover the harbor in late 1820 as a haven for seal hunters. Later it was also used by whaling ships and as the site for a whaling station. Whaler&#39;s Cove, just inside the harbor entrance is the site of an abandoned whaling station<span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span>.</p><p>The ice near to the whaling station was used as a landing strip by Hubert Wilkins for the first flights over <a href="/article/Antarctica">antarctica</a> in 1928.</p> <p>While the Island has been claimed by the United Kingdom, <a href="/article/Chile">Chile</a> and <a href="/article/Argentina">Argentina</a>, it comes under the jurisdiction of the <a href="/article/Antarctic_Treaty_System">Antarctic Treaty System</a> (1959). Sovereignty is neither recognized nor disputed by the signatories. The <a href="/article/Antarctic_Treaty_System">Antarctic Treaty System</a> limits military activity and promotes environmental protection and scientific and other peaceful activities. Alternative names include Yaraslav Island (Russia - It was named by the Bellinghausen expedition in 1821), Teil Island, and Isla Decepción.</p><p>Permanent research stations on the islands established by the British in the 1940s and 1960s were abandoned because of the volcanic eruptions. Today, summer research stations are maintained by Spain (Gabriel De Castilla<span class="reference"><sup id="ref_5" class="plainlinksneverexpand"><a href="#endnote_5" class='external autonumber' title="#endnote 5">[4]</a></sup></span>) and <a href="/article/Argentina">Argentina</a> (Decepción station), both at at Fumerole Bay {ref|4}}.</p><p>Because of the high risks associated with volcanic eruptions, there is no permanent human presence on the island, but the hot springs make it an increasingly popular tourist stop during the austral summer.</p><p><strong>References</strong></p><ol><li><cite id="endnote_1" style="font-style: normal"><a href="#ref_1"><strong>^</strong></a></cite><a href="http://www.volcano.si.edu/world/volcano.cfm?vnum=1900-03%3D" class='external text' title="http://www.volcano.si.edu/world/volcano.cfm?vnum=1900-03=">Deception Island, Glabal Volcanism Program, Smithsonian Institute</a> accessed December 4, 2008.</li><li><cite id="endnote_2" style="font-style: normal"><a href="#ref_2"><strong>^</strong></a></cite><a href="http://geonames.usgs.gov/pls/gnispublic/f?p=106:3:788274225708607::NO::P3_ANTAR_ID:11942" class='external text' title="http://geonames.usgs.gov/pls/gnispublic/f?p=106:3:788274225708607::NO::P3 ANTAR ID:11942">USGS Geographic Name Information Service</a></li><li><cite id="endnote_3" style="font-style: normal"><a href="#ref_3"><strong>^</strong></a></cite><a href="http://tryfan.ucsd.edu/antpics/deception_island.htm" class='external text' title="http://tryfan.ucsd.edu/antpics/deception island.htm">Deception Island</a>, Teresa K. Chereskin, Scripps Istitute of Oceanography] accessed December 4, 2008</li><li><cite id="endnote_4" style="font-style: normal"><a href="#ref_4"><strong>^</strong></a></cite><a href="http://tryfan.ucsd.edu/antpics/deception_island.htm" class='external text' title="http://tryfan.ucsd.edu/antpics/deception island.htm">Deception Island</a>, Teresa K. Chereskin, Scripps Istitute of Oceanography] accessed December 4, 2008</li><li><cite id="endnote_5" style="font-style: normal"><a href="#ref_5"><strong>^</strong></a></cite><a href="http://www.newzeal.com/theme/bases/Spain/gabrieldecastilla.htm" class='external text' title="http://www.newzeal.com/theme/bases/Spain/gabrieldecastilla.htm">Gabriel De Castilla</a> accessed December 4, 2008</li></ol><p><strong>Further Reading</strong></p><ul><li><a href="http://www.deceptionisland.aq/" class='external text' title="http://www.deceptionisland.aq/">Deception Island</a></li><li><a href="http://www.amazon.com/Antarctica-Exploring-Extreme-Years-Adventure/dp/1556524285/ref=sr_1_5?ie=UTF8&amp;s=books&amp;qid=1226240236&amp;sr=8-5" class='external text' title="http://www.amazon.com/Antarctica-Exploring-Extreme-Years-Adventure/dp/1556524285/ref=sr 1 5?ie=UTF8&amp;s=books&amp;qid=1226240236&amp;sr=8-5">Antarctica: Exploring the Extreme: 400 Years of Adventure</a>, Marilyn J. Landis, Chicago Review Press, 2001</li><li><a href="http://www.amazon.com/exec/obidos/tg/detail/-/0393039498/ref=pd_luc_mri?%5Fencoding=UTF8&amp;v=glance" class='external text' title="http://www.amazon.com/exec/obidos/tg/detail/-/0393039498/ref=pd luc mri? encoding=UTF8&amp;v=glance">Below the Convergence: Voyages Towards Antarctica, 1699-1839</a>, Alan Gurney, W.W. Norton and Company, 1997</li><li><a href="http://www.amazon.com/Discovery-South-Shetland-Islands-1819-1820/dp/B000PS7EYW/ref=sr_1_2?ie=UTF8&amp;s=books&amp;qid=1226252739&amp;sr=1-2" class='external text' title="http://www.amazon.com/Discovery-South-Shetland-Islands-1819-1820/dp/B000PS7EYW/ref=sr 1 2?ie=UTF8&amp;s=books&amp;qid=1226252739&amp;sr=1-2">The Discovery of the South Shetland Islands, 1819-1820&nbsp;: The Journal of Midshipman C. W. Poynter</a>, R. J. Campbell (editor), Hakluyt Society, 2001</li><li><a href="http://www.amazon.com/exec/obidos/tg/detail/-/0905355253/ref=pd_luc_mri?%5Fencoding=UTF8&amp;v=glance" class='external text' title="http://www.amazon.com/exec/obidos/tg/detail/-/0905355253/ref=pd luc mri? encoding=UTF8&amp;v=glance">Antarctica Observed</a>, A.G.E. Jones, Caedmon of Whitby, 1982</li><li><a href="http://www.gpsvisualizer.com/map?lat1=-62.95&amp;lon1=-60.6&amp;location=&amp;radius=60+miles&amp;format=google&amp;radius_segments=&amp;google_wpt_sym=circleGPS" class='external text' title="http://www.gpsvisualizer.com/map?lat1=-62.95&amp;lon1=-60.6&amp;location=&amp;radius=60 miles&amp;format=google&amp;radius segments=&amp;google wpt sym=circleGPS">Visualizer</a></li><li><a href="http://geonames.usgs.gov/" class='external text' title="http://geonames.usgs.gov/">USGS Geographic Name Information Service</a></li></ul> <p>[[category:|Deception Island]] </p> <p><a href='/article/Deception_Island'>Read Full Article...</a></p> http://www.eoearth.org/article/Deception_Island Tue, 28 Jul 2009 05:46:30 GMT http://www.eoearth.org/article/Adaptations_of_marsh_plants <a href='/article/Adaptations_of_marsh_plants'><img border='0' src='/upload/thumb/7/74/Typha7.jpg/150px-Typha7.jpg' width='100'/></a> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Introduction </h1><p><a href="/article/Marsh">Marshes</a> are permanently or periodically covered with nutrient-rich water. Marshes are characterized by emergent vegetation that is adapted to saturated <a href="/article/Soil">soils</a> and by submerged vegetation that lives at deeper depths. Plants living in marshes are exposed to three environmental stresses: (1) they are frequently covered by water so they must be able to cope with low <a href="/article/Oxygen">oxygen</a> content, (2) they are often exposed to the <a href="/article/Atmospheric_composition">atmosphere</a> so they can be exposed to factors such terrestrial herbivores and fire, and (3) they are sometimes exposed to the effects of wave action or water movement. Thus, these factors have selected for the herbaceous plants with well developed root systems (that provide anchorage and storage). <a href="/article/Salt_marsh">Salt marshes</a> are found in <a href="/article/Estuary">estuarine</a> areas with high (and fluctuating) salt content. Thus, <a href="/article/Salt_marsh">salt marsh</a> plants must have adaptations for dealing with high salt content in the water that surrounds them, a fourth type of stress.</p> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Low soil oxygen content</h1><p><span> </span></p><p><a href="/article/Wetland">Wetland</a> soils have been affected by the permanent cover of water. One problem faced by plants living in marshes is the lack of <a href="/article/Oxygen">oxygen</a> in the <a href="/article/Soil">soil</a>. Oxygen is used by plants (and most other organisms) in the process of cellular respiration in which the energy from glucose (produced by <a href="/article/Photosynthesis">photosynthesis</a>) is released so that the organisms can use the energy to do “biological work.” When glucose is broken down in the presence of oxygen, aerobic respiration occurs and the organisms are able to use a great deal of the stored energy in the glucose. In situations where oxygen is lacking, glucose is broken down by the process of anaerobic respiration which does not release as much energy from each molecule of glucose (aerobic respiration releases about 18 times more energy than anaearobic respiration). Not only is anaerobic much less energy efficient than aerobic respiration, but by products of anaerobic respiration, are toxic.</p><p>Plants lack a circulatory system, so plants are not able to “pump” oxygen from air (where the oxygen concentration is about 21%) below ground to the roots. Thus, the roots of terrestrial plants rely on oxygen in air spaces between soil particles. Oxygen is hard to get in hydrated soils for two reasons. First, water fills the space between soil particles that are typically filled with air in terrestrial soils. Second, because the rate of diffusion of oxygen is much slower in water than in air the rate of movement from the water surface to the root zone is extremely slow, so most hydric soils are either low in oxygen (hypoxic) or lack oxygen (anoxic) because the oxygen in the water in the soil is used up, often by the activity of decomposers (<a href="/article/Bacteria">bacteria</a>).</p><p>So how do the roots of <a href="/article/Marsh">marsh</a> plants get the oxygen that they need to survive? Marsh plants have evolved air spaces (&quot;aerenchyma tissue&quot;) in their stems that allow oxygen to move from the leaves (where oxygen is produced in the process of photosynthesis) to the roots by either diffusion or in some cases, by <a href="/article/Pressure">pressure</a> differences between the leaves and the roots.</p> <p>Other marsh plants are able to survive in low <a href="/article/Oxygen">oxygen</a> conditions by relying on anaerobic respiration. These species apparently have altered their biochemical pathways to allow them to avoid the build-up of high concentrations of toxic ethanol (a waste product of anaerobic respiration).</p> <h1><span>Herbivory</span></h1> <p><span>Because of the high availability of light, water, and nutrients, <a href="/article/Marsh">marshes</a> are among the most productive <a href="/article/Ecosystem">ecosystems</a> on earth (i.e., a lot of sugar is produced by the process of <a href="/article/Photosynthesis">photosynthesis</a>). The production of biomass in <a href="/article/Wetland">wetland</a> systems can be over three times higher than in a terrestrial ecosystem. Because biomass production in marsh ecosystems, there is high there is a lot of potential food for herbivores.<span> However, </span>most emergent macrophytes are of low food quality because they have a relatively high content of structural <a href="/article/Carbon">carbon</a> relative to the amount of <a href="/article/Nitrogen">nitrogen</a> and phosphorus they contain. Thus, a relatively large percentage of the plant biomass is not eaten and when the plants die they become detritus, and enter into detritus-based food webs.  </span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Fire</span></h1></span><p><span>Some <a href="/article/Marsh">marshes</a> become dry enough seasonally or during drought periods that they are potentially burned by fire. The extensive root system of most emergent marsh vegetation allows them to resprout following a fire.</span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Salinity</h1></span><p><span><span>Plants living in <a href="/article/Salt_marsh">salt marshes</a> are exposed to high salinity environments. Plants adapted to living in saline environments are known as halophytes (&quot;salt lovers&quot;). Halophytes have evolved physiological, structural, and biochemical means of dealing with a saline environment. Some halophytes are able to secrete salt through salt glands, whereas other plants have mechanisms for dealing with higher cellular concentrations of salt, or can reduce of the uptake of salt through their roots.</span></span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Further Reading</span></h1></span><ul><li><span>Georgia Conservency, </span><span><a href="http://www.gaconservancy.org/education/ED_saltmarshes.asp" class='external text' title="http://www.gaconservancy.org/education/ED saltmarshes.asp">Coastal Salt Marshes</a>. <br /></span></li><li><span>Ofwell Woodland and Wildlife Trust, </span><span><a href="http://www.countrysideinfo.co.uk/wetland_survey/adaptns.htm" class='external text' title="http://www.countrysideinfo.co.uk/wetland survey/adaptns.htm">Plant Adaptations to Aquatic Life</a>. <br /></span></li></ul> <p><a href='/article/Adaptations_of_marsh_plants'>Read Full Article...</a></p> http://www.eoearth.org/article/Adaptations_of_marsh_plants Tue, 28 Jul 2009 05:45:19 GMT http://www.eoearth.org/article/Adaptations_of_marsh_plants <a href='/article/Adaptations_of_marsh_plants'><img border='0' src='/upload/thumb/7/74/Typha7.jpg/150px-Typha7.jpg' width='100'/></a> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Introduction </h1><p><a href="/article/Marsh">Marshes</a> are permanently or periodically covered with nutrient-rich water. Marshes are characterized by emergent vegetation that is adapted to saturated <a href="/article/Soil">soils</a> and by submerged vegetation that lives at deeper depths. Plants living in marshes are exposed to three environmental stresses: (1) they are frequently covered by water so they must be able to cope with low <a href="/article/Oxygen">oxygen</a> content, (2) they are often exposed to the <a href="/article/Atmospheric_composition">atmosphere</a> so they can be exposed to factors such terrestrial herbivores and fire, and (3) they are sometimes exposed to the effects of wave action or water movement. Thus, these factors have selected for the herbaceous plants with well developed root systems (that provide anchorage and storage). <a href="/article/Salt_marsh">Salt marshes</a> are found in <a href="/article/Estuary">estuarine</a> areas with high (and fluctuating) salt content. Thus, <a href="/article/Salt_marsh">salt marsh</a> plants must have adaptations for dealing with high salt content in the water that surrounds them, a fourth type of stress.</p> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Low soil oxygen content</h1><p><span> </span></p><p><a href="/article/Wetland">Wetland</a> soils have been affected by the permanent cover of water. One problem faced by plants living in marshes is the lack of <a href="/article/Oxygen">oxygen</a> in the <a href="/article/Soil">soil</a>. Oxygen is used by plants (and most other organisms) in the process of cellular respiration in which the energy from glucose (produced by <a href="/article/Photosynthesis">photosynthesis</a>) is released so that the organisms can use the energy to do “biological work.” When glucose is broken down in the presence of oxygen, aerobic respiration occurs and the organisms are able to use a great deal of the stored energy in the glucose. In situations where oxygen is lacking, glucose is broken down by the process of anaerobic respiration which does not release as much energy from each molecule of glucose (aerobic respiration releases about 18 times more energy than anaearobic respiration). Not only is anaerobic much less energy efficient than aerobic respiration, but by products of anaerobic respiration, are toxic.</p><p>Plants lack a circulatory system, so plants are not able to “pump” oxygen from air (where the oxygen concentration is about 21%) below ground to the roots. Thus, the roots of terrestrial plants rely on oxygen in air spaces between soil particles. Oxygen is hard to get in hydrated soils for two reasons. First, water fills the space between soil particles that are typically filled with air in terrestrial soils. Second, because the rate of diffusion of oxygen is much slower in water than in air the rate of movement from the water surface to the root zone is extremely slow, so most hydric soils are either low in oxygen (hypoxic) or lack oxygen (anoxic) because the oxygen in the water in the soil is used up, often by the activity of decomposers (<a href="/article/Bacteria">bacteria</a>).</p><p>So how do the roots of <a href="/article/Marsh">marsh</a> plants get the oxygen that they need to survive? Marsh plants have evolved air spaces (&quot;aerenchyma tissue&quot;) in their stems that allow oxygen to move from the leaves (where oxygen is produced in the process of photosynthesis) to the roots by either diffusion or in some cases, by <a href="/article/Pressure">pressure</a> differences between the leaves and the roots.</p> <p>Other marsh plants are able to survive in low <a href="/article/Oxygen">oxygen</a> conditions by relying on anaerobic respiration. These species apparently have altered their biochemical pathways to allow them to avoid the build-up of high concentrations of toxic ethanol (a waste product of anaerobic respiration).</p> <h1><span>Herbivory</span></h1> <p><span>Because of the high availability of light, water, and nutrients, <a href="/article/Marsh">marshes</a> are among the most productive <a href="/article/Ecosystem">ecosystems</a> on earth (i.e., a lot of sugar is produced by the process of <a href="/article/Photosynthesis">photosynthesis</a>). The production of biomass in <a href="/article/Wetland">wetland</a> systems can be over three times higher than in a terrestrial ecosystem. Because biomass production in marsh ecosystems, there is high there is a lot of potential food for herbivores.<span> However, </span>most emergent macrophytes are of low food quality because they have a relatively high content of structural <a href="/article/Carbon">carbon</a> relative to the amount of <a href="/article/Nitrogen">nitrogen</a> and phosphorus they contain. Thus, a relatively large percentage of the plant biomass is not eaten and when the plants die they become detritus, and enter into detritus-based food webs.  </span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Fire</span></h1></span><p><span>Some <a href="/article/Marsh">marshes</a> become dry enough seasonally or during drought periods that they are potentially burned by fire. The extensive root system of most emergent marsh vegetation allows them to resprout following a fire.</span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Salinity</h1></span><p><span><span>Plants living in <a href="/article/Salt_marsh">salt marshes</a> are exposed to high salinity environments. Plants adapted to living in saline environments are known as halophytes (&quot;salt lovers&quot;). Halophytes have evolved physiological, structural, and biochemical means of dealing with a saline environment. Some halophytes are able to secrete salt through salt glands, whereas other plants have mechanisms for dealing with higher cellular concentrations of salt, or can reduce of the uptake of salt through their roots.</span></span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Further Reading</span></h1></span><ul><li><span>Georgia Conservency, </span><span><a href="http://www.gaconservancy.org/education/ED_saltmarshes.asp" class='external text' title="http://www.gaconservancy.org/education/ED saltmarshes.asp">Coastal Salt Marshes</a>. <br /></span></li><li><span>Ofwell Woodland and Wildlife Trust, </span><span><a href="http://www.countrysideinfo.co.uk/wetland_survey/adaptns.htm" class='external text' title="http://www.countrysideinfo.co.uk/wetland survey/adaptns.htm">Plant Adaptations to Aquatic Life</a>. <br /></span></li></ul> <p><a href='/article/Adaptations_of_marsh_plants'>Read Full Article...</a></p> http://www.eoearth.org/article/Adaptations_of_marsh_plants Tue, 28 Jul 2009 05:44:10 GMT http://www.eoearth.org/article/Tellegen,_Bernard_D.H. <a href='/article/Tellegen,_Bernard_D.H.'><img border='0' src='/upload/thumb/b/bd/Tellegen.jpg/150px-Tellegen.jpg' width='100'/></a> <p>Bernard Tellegen was born 24 June 1900 in the Netherlands. He attended Delft University, where he obtained his degree in electrical engineering in 1923. In 1924 he entered into the service of the Philips Research Laboratories. These laboratories had been founded in 1914 by Holst and Oosterhuis. Tellegen belonged to a fairly small nucleus (van der Pol, de Groot, Penning, Druyvestein, Bouwers) around which one of the largest research centers in the world would grow. As a scientific adviser, he later became a member of its board of directors. </p><p>Tellegen&#39;s first studies concerned vacuum tubes. He became interested in electron motions in triodes and multigrid tubes. In 1926 he invented the penthode, which was patented in a number of countries. It was the first in a series of about 57 patents, which he received either alone or in cooperation with others. </p><p>In the following years Tellegen became interested in electrical circuits on which he published already in 1928, 1933 and 1934. </p><p>In 1932 it was noticed, that the programs of some Italian transmitters, when received in the Netherlands, seemed to carry also the program of Radio Luxemburg and crossmodulation in the receiver tubes was suspected. Tellegen showed that this was really a nonlinear effect in the ionosphere, caused by the powerful Luxemburg transmitter. </p><p>During his further studies in electrical networks, he became more interested in fundamental problems such as duality and geometric configurations and network synthesis in particular of resistanceless four poles. During his basic study of the classical passive network elements, Tellegen arrived at the conclusion that a further element &quot;the gyrator&quot; could complete the series in an elegant way. This new element does not comply with the reciprocity relations, and is antisymmetrical. Tellegen studied the properties of circuits with the &quot;gyrator&quot;. Its first realization came in the microwave field with the use of premagnetized ferrites. The circulator was a further result of this idea. When the miniaturization of electronic circuits led to new possibilities, the gyrator soon became an important building block for selective circuits at low frequencies. In 1952 Dr. Tellegen published an important paper on a general network theorem with applications. Fundamentally &quot;Tellegen&#39;s theorem&quot; gives a simple relation between magnitudes that satisfy the Kirchhoff laws. Many treatises and a book on the application of this theorem were published. A paper on &quot;Synthesis of 2n- poles by networks consisting of a minimum number of elements&quot; proved his interest in economy. He also discussed the ideal amplifier or &quot;nullor&quot;. When he was the guest of honor at the International Symposium on Circuit Theory, London 1970, he gave a paper on circuits with negative resistance elements. </p><p>In the period 1946-1966 Tellegen was professor extraordinary of circuit theory at the University of Delft. Adams, Bordewijk and Duinker were among those who received their doctor&#39;s degree working with him. </p><p>From 1942 to 1952 he was president of the Dutch Electronics and Radio Society, which made him a honorary member at the end of this period. From 1948 to 1960 he was chairman of the Dutch Committee of the International Scientific Radio Union (U.R.S.I.) He was vice-president of U.R.S.I. from 1952 to 1957. From 1957 to 1960 he was vice-chairman of its commission VI, especially charged with circuit theory. </p><p>The Australian Institute of Radio Engineers made Tellegen a honorary life member in 1953. He received the Research Prize of the Royal Dutch Institute of Engineers in 1954, the Fellow Award of the <a href="/contributor/IEEE">IEEE</a> in 1955, and the IEEE Edison Medal in 1973 &quot;For a creative career of significant achievement in electrical circuit theory, including the gyrator&quot;. Tellegen was elected a member of the Royal Academy of Sciences of the Netherlands in 1960. In 1970 the University of Delft conferred on him the degree of doctor honoris causa in technical sciences. </p><p>Tellegen and his wife, the former Gertrud J. van der Lee, reside at the Geulberg in Nuenen, near Eindhoven. They have three children, Ben D. H., Jr., an engineer in computer sciences, John, a physician and Clara, married to a physicist. There are eight grandchildren. The Tellegen&#39;s live amidst the <a href="/article/Forest_biome">woods</a> and fens of the beautiful North Brabant countryside. In long walks they learned to know every part of it. In connection with his international conferences they visited many countries and made a world trip in 1952.</p><p>Dr. Tellegen passed away on 30 August 1990. </p><p><br /> <p><br style="clear: left" /> <center> </p> </center></p> <p><a href='/article/Tellegen,_Bernard_D.H.'>Read Full Article...</a></p> http://www.eoearth.org/article/Tellegen,_Bernard_D.H. Mon, 27 Jul 2009 05:27:36 GMT http://www.eoearth.org/article/Ten_fundamental_principles_of_net_energy <a href='/article/Ten_fundamental_principles_of_net_energy'><img border='0' src='/upload/thumb/c/c9/Snow_geese.jpg/250px-Snow_geese.jpg' width='100'/></a> <p><strong>Introduction</strong><br /><br /> <strong><a href="/article/Energy_return_on_investment_%28EROI%29">Energy return on investment (EROI)</a></strong> is the ratio of the energy extracted or delivered by a process to the energy used directly and indirectly in that process. A common related term is <strong>energy surplus</strong>, which is the gross amount of energy extracted or delivered, minus the energy used directly and indirectly in that process. EROI is a dimensionless number, while energy surplus refers to an actual physical quantity of energy. Suppose an energy delivery system delivers 10 <a href="/article/Joule">joules</a> of energy, but in the processes consumes 2 joules. The EROI for that process is 5 (10 divided by 2), while the energy surplus delivered is 8 joules (10 minus 2). </p><p>EROI is a tool of <a href="/article/Net_energy_analysis">net energy analysis</a>, a methodology that seeks to compare the amount of energy delivered to society by a technology to the total energy required to find, extract, process, deliver, and otherwise upgrade that energy to a socially useful form. Net energy analysis was developed in response to the emergence of energy as an important economic, technological and geopolitical force following the energy price increases of 1973-74 and 1980-81. Interest in net energy analysis was rekindled in recent years following another round of energy price increases, growing concern about energy&#39;s role in climate change, and the debate surrounding the remaining lifetime of conventional fossil fuels, especially crude oil. </p><p><strong>The principles</strong><br /> </p> <p><strong>1. <a href="/article/Net_energy_analysis">Net energy</a> and <a href="/article/Net_energy_analysis">energy surplus</a> are important driving forces in <a href="/article/Ecology">ecology</a> and economic systems</strong><br /><br /> The efficiency and effectiveness of energy capture is a central organizing principle in ecology. Living organisms must capture energy and allocate it among a number of life-sustaining tasks (growth, reproduction, energy storage, defense, competition). A larger surplus produced by a system of energy capture compared to competing strategies gives an organism a competitive advantage. Ecologists have used the principle of net energy to explain a wide range of phenomena, including habitat switching, long distance migration by birds, vertical migration by marine organisms, optimal foraging strategy, the pattern of the distribution and abundance of species, reproductive behavior in bats, and the effects of human disturbance on organisms. </p><p>Biologists such as <a href="/article/Lotka%2C_Alfred_James">Alred Lotka</a> and <a href="/article/Odum%2C_Howard_T.">Howard Odum</a> elevated the concept to the driving force behind <a href="/article/Natural_selection">natural selection</a> itself, where, in the struggle for existence, the advantage goes to those organisms whose energy-capturing devices are more effective in directing available energies into channels favorable to the preservation of the species. </p><p>Scholars from a number of disciplines have applied the same concept of <a href="/article/Net_energy_analysis">net energy</a> to social systems, with widely varying assumptions about the extent to which net energy influences the trajectory of the evolution of culture. The analogy to natural systems is straightforward: societies with access to energy sources with a higher <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a> and a large net energy surplus have an economic and military advantage over societies that use lower <a href="/article/Energy_quality">quality energy sources</a>. A low EROI means that more of a society’s productive resources must be devoted to energy delivery, and thus cannot be used to produce non-energy goods and services, support a powerful military, expand the arts, or be consumed as leisure time. </p><p>Net energy has been used to explain major <a href="/article/Energy_transitions">energy transitions</a>, including the industrial revolution and the emergence of the affluent society, the rise and fall of great civilizations, the pattern of resource depletion, and the impact of technological change on energy technologies. Net energy has been used as a methodological tool to assess and compare energy systems, as a tool to assess the climate impact of energy technologies, and it plays a central role in the longstanding debate on the viability of alternative energy technologies such as ethanol. </p><p><strong>2. The size and rate of delivery of surplus energy is just as important as EROI</strong><br /><br /> The net amount of energy delivered from the energy sector to the non-energy sectors is the energy available to generate non-energy goods and services. The size of that surplus sets broad but distinct limits on human economic aspirations. Falling water, for example, can deliver a large EROI in a specific location, but the total energy surplus available to a society from falling water is limited by the relatively sparse spatial distribution of the resource. The amount of energy surplus potentially available from diffuse energy sources such as solar and wind power is just as important as their EROI. </p> <p>Contrary to popular belief, <a href="/article/Agriculture">agriculture</a> did not supplant hunting and gathering as the major food production technology because it has a higher <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a>. Indeed, hunting and gathering often produced a very high EROI in specific locations and around specific resources. For example, the harvesting of energy-dense biomass in coastal whaling had an EROI in the neighborhood of 2000:1. Some hunting and gathering societies developed sophisticated social and civil institutions, and often consumed their energy surplus in the form of leisure time. But hunting and gathering ultimately is limited by the distribution of edible net primary production in the <a href="/article/Biosphere">biosphere</a>, which limits population densities to about one person per square <a href="/article/Meter">kilometer</a>. </p><p>The advantage of agriculture derives from the large net energy surplus delivered per unit land area and per person compared to hunting and gathering. Agriculture thus erased the energetic limits to <a href="/article/Carrying_capacity">carrying capacity</a> inherent in hunting and gathering, and released human labor and other productive resources from the farm. The latter was a necessary condition for the industrialization of society. </p><p><strong>3. The unprecedented expansion of the human population, the <a href="/article/Global_economy">global economy</a>, and per capita living standards of the last 200 years was powered by high EROI, high energy surplus fossil fuels</strong><br /><br /> The penultimate position of fossil fuels in the energy hierarchy stems from the fact that they have a high EROI and a very large energy surplus. The largest oil and gas fields, which are found early in the exploration process due to their sheer physical size, delivered energy surpluses that dwarfed any previous source (and any source developed since then). That surplus, in combination with other attributes, is what makes conventional fossil fuels unique. The long run challenge society faces is to replace the current system with a combination of alternatives will similar attributes and a much lower carbon intensity. </p> <br /><p><strong>4. The principal economic impact of a shift to a lower EROI energy system is the increased opportunity cost of energy delivery</strong></p><p><br /> A shift to a lower EROI energy system means that more of society&#39;s productive resources are devoted--directly and indirectly-- to delivering the same amount of energy. That energy thus cannot be used for other purposes, notably consumption goods. Energy used to make a drilling rig or wind turbine cannot be used to manufacture iPods or provide medical care. </p> <p><strong>5. <a href="/article/Energy_quality">Energy quality</a> matters</strong><br /><br /> <a href="/article/Net_energy_analysis">Net energy</a> is only one attribute of an energy system that determines it usefulness to society. The usefulness of an energy system is determined by a complex combination of physical, technical, economic, and social attributes. These include gravimetric and volumetric energy density, power density, emissions, cost and efficiency of conversion, financial risk, amenability to storage, risk to human health, and ease of transport. These attributes combine to determine <strong><a href="/article/Energy_quality">energy quality</a>:</strong> differences in the ability of a unit of a fuel to perform useful services for people. No single metric of an energy system captures all such attributes, including EROI. It stands to reason, therefore, that a comprehensive and balanced comparison of energy technologies should employ a range of metrics, with their strengths and weaknesses duly noted. </p><p>Since all forms of energy can be completely converted to <a href="/article/Heat">heat</a>, heat units (Btus, <a href="/article/Joule">joules</a>, <a href="/article/Calorie">calories</a>, <a href="/article/Watt-hour">kilowatt-hours</a>) provide an easy way to aggregate different forms of energy. For example, the world uses about 450x10¹⁵ Btu, or 450 &quot;quads&quot; of energy each year. That quantity is the aggregation of dozens of different energy types added together by multiplying their mass or volume used times their heat content per unit mass or volume. But this approach implicitly assumes that &quot;all Btus are equal,&quot; i.e., that people value a heat unit of electricity the same as a heat unit of <a href="/article/Coal">coal</a>. Of course, this is not the case. Electricity performs important tasks that coal cannot, or it performs them more effectively. People are willing to pay 15 times more for a heat unit of electricity (in the U.S.) because of these differences. Accounting for differences in energy quality can <a href="/article/Energy_quality">dramatically alter the results of net energy analyses</a>. </p> <p><strong>6. <a href="/article/Market_failure">Market imperfections</a> that distort prices and cost also affect <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a></strong><br /><br /> Dollar-based assessments of energy systems are distorted by market imperfections such as <a href="/article/Externality">externalities</a>, <a href="/article/Subsidies_and_market_interventions">subsidies</a>, and government policies. The result is that the full social cost of energy is unaccounted for. However, EROI is plagued by many of the same problems. For example, there is no established methodology to incorporate the ecological and human health impacts of energy production and use in the calculation of EROI, so it too overstates benefits to society. In fact, economic analysis has better developed tools to estimate and aggregate external costs than energy analysis. </p><p>The calculation of <a href="/article/Economic_energy_cost">indirect costs</a> in energy analysis (e.g., the energy used to manufacture a wind turbine) often is based on economic data. Subsidies and other government policies affect decisions made in the <a href="/article/Market">market</a>, and thus affect the economic data often used as inputs to energy analysis, including the pattern of capital investment. A good example of this was government regulation of the natural gas industry in the U.S. in the 1970s. Deep, new, and presumably lower EROI natural gas was assigned a higher price than shallow, old, and presumably higher EROI gas in an attempt to stimulate overall exploration. Any change in the overall EROI for gas extraction caused by this policy had little to do with “resource depletion” per se. </p><p><strong>7. The methodologies to perform <a href="/article/Net_energy_analysis">net energy analysis</a> are well established</strong><br /><br /> Conventional wisdom in the blogsphere and other Internet communities is that there are no guidelines for performing net energy analysis. In fact, there is a rich, well-established literature on the subject, most of which was developed in the first wave of energy research in the 1970s and 1980s. This body of work includes not only methodological detail, but also discussions about how to deal with intractable problems such as joint costs and outputs, the energy cost of human labor, choosing appropriate system boundaries, among many others. The record also has a rich history of debate about the virtues of net energy analysis, particularly in regards to what it adds, if anything, to a discussion that already includes a thorough economic assessment. The current discussion surrounding net energy analysis would be significantly enhanced if participants were better informed by previous work. </p><p><strong>8. The relation between “peak oil” and the EROI for world oil production is unknown</strong><br /><br /> This statement is true for two reasons. The first and most obvious reason is that we do not know when world oil production will peak, and won’t know definitively until sometime afterwards. Second, and more importantly, there is no comprehensive and reliable assessment of the historic <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a> for world oil production. There is a distinct lack of reliable public data on the direct and indirect costs associated with oil production in many regions of the world. </p><p>The lower 48 U.S. is the only region for which we can compare the trends in EROI and oil production. There we see a remarkable convergence: crude oil production peaks in 1970 and then declines, and the EROI for that production peaks at about the same time. The timing of both peaks is consistent with a change in the underlying cost structure of the resource, when the cost-increasing effects of depletion began to outweigh the cost-decreasing effects of technological change. If such as connection holds at the global level, then the timing and impact of “peak oil” takes on added significance. </p> <p><strong>9. Technological change affects EROI just as it affects price and cost</strong><br /><br /> There is a widely held assumption that the EROI for a nonrenewable energy resource such as crude oil or a renewable resource such as wind inexorably decline once the physical quality of the resource base begins to decline (e.g., smaller and deeper fields, or less windy sites). This is not necessarily the case. Technological change that lowers the dollar cost of extraction can also lower the energy cost of extraction. For example, developing the ability to drill multiple and directional wells from a single platform lowered the dollar cost per well, and it may well have lowered the indirect energy embodied in the materials required to extract oil. The well-documented technical improvements in that have lowered the dollar cost of emerging technologies such as wind and solar undoubtedly exert at least some downward pressure on energy costs as well. </p><p>Technological change exogenous to the energy industry also affects the EROI. For example, the development of more efficient combustion engines would, <em>ceteris paribus</em>, improve the EROI for oil extraction that relies on such engines to lift oil to the surface. Similarly, a decrease in the quantity of energy required to produce a <a href="/article/Kilogram">kilogram</a> of steel will, <em>ceteris paribus,</em> improve the EROI by reducing the energy embodied in oil field equipment. </p> <p><strong>10. Alternatives to the dominant energy and power systems show a wide range in EROI</strong><br /><br /> Most alternatives to conventional liquid fuels have very low or unknown EROIs. The EROI for ethanol derived from corn grown in the U.S. is about 1.5:1, well below that for conventional motor gasoline. Ethanol from sugarcane grown in <a href="/article/Brazil">Brazil</a> apparently has a higher EROI, perhaps as high as 8:1, due to higher yields of sugarcane compared to corn, the use of bagasse as an energy input, and significant cost reductions in ethanol production technology. Shale oil and coal liquefaction have low EROIs and high carbon intensities, although little work has been done in this area in more than 20 years. The <a href="/article/Athabasca%2C_Alberta">Alberta oil sands</a> remain an enigma from a net energy perspective. Anecdotal evidence suggests an EROI of 3:1, but these reports lack veracity. Certainly oil sands will have a lower EROI than conventional crude oil due to the more diffuse nature of the resource base and associated increase in direct and indirect processing energy costs. </p><p>On the power generation side, <a href="/article/Coal">coal</a>, and hydropower have the highest EROI among conventional power systems, although the latter has very limited potential for further expansion in most regions of the world. Nuclear power appears to have a lower EROI, but there are very few credible studies that are thorough and unbiased. We do not know what the EROI will be from the new generation of <a href="/article/Nuclear_power_reactor">nuclear reactors</a> that would be built if demand for them returns. <a href="/article/Energy_return_on_investment_%28EROI%29_for_wind_energy">Wind</a> has a very favorable EROI in the right conditions, while solar thermal and photovoltaic systems have lower EROIs compared to <a href="/article/Coal">coal</a> and hydropower. As outlined above, a key issue is the size of the surplus that can realistically be delivered by those renewable power technologies. </p><p>A final point for consideration: <em>Carbon may trump EROI</em>. The growing concern that climate change may impose swift and large costs on society may drive the next major <a href="/article/Energy_transitions">energy transition</a>. It is plausible that carbon intensity, as opposed to net energy, may be the principal attribute of future energy systems that determines the timing and pace of their adoption. Society may choose to forgo the benefits of a larger energy surplus to reduce its exposure to climate-related risks. </p><p><strong>Further Reading</strong><br /> </p> <ul><li>Biopact. 2006. <a href="http://biopact.com/2006/10/brazilian-ethanol-is-sustainable-and.html" class='external text' title="http://biopact.com/2006/10/brazilian-ethanol-is-sustainable-and.html">Brazilian ethanol is sustainable and has a very positive energy balance - IEA report</a><br /> </li><li>Bullard, Clark W., Peter S. Penner and David A. Pilati. 1978. <a href="http://dx.doi.org/10.1016/0165-0572(78)90008-7" class='external text' title="http://dx.doi.org/10.1016/0165-0572(78)90008-7">Net energy analysis: Handbook for combining process and input-output analysis.</a> Resources and Energy, 1978, vol. 1, issue 3, pages 267-313.<br /> </li><li>Cleveland, Cutler J. 2005. <a href="http://www.digitaluniverse.net/portal/net_energy_analysis" class='external text' title="http://www.digitaluniverse.net/portal/net energy analysis">Net energy from oil and gas extraction in the United States, 1954-1997.</a> <em>Energy</em>, 30: 769-782.<br /> </li><li>Cleveland, Cutler J., and Robert Herendeen. Solar Parabolic Troughs: Succeeding Generations Are Better Net Energy Producers. <em>Energy Systems and Policy</em> 13: 63-77 (1989)<br /> </li><li>Cleveland, Cutler J., Robert Costanza, Charles A.S. Hall, and Robert Kaufmann. Energy and the U.S. Economy: A Biophysical Perspective. <em>Science</em> 225: 890-897 (1984). <br /> </li><li>Farrell,, Alexander E. Richard J. Plevin, Brian T. Turner, Andrew D. Jones, Michael O’Hare, Daniel M. Kammen. <a href="http://www.sciencemag.org/cgi/content/short/311/5760/506" class='external text' title="http://www.sciencemag.org/cgi/content/short/311/5760/506">Ethanol Can Contribute to Energy and Environmental Goals.</a> 27 JANUARY 2006 VOL 311 <em>SCIENCE</em> <br /> </li><li>Gever, John, Robert Kaufmann, David Skole, Charles Vorosmarty. 1986. <em><a href="http://www.bu.edu/cees/research/publications/beyond_oil/beyond_oil_title/beyond_oil.html" class='external text' title="http://www.bu.edu/cees/research/publications/beyond oil/beyond oil title/beyond oil.html">Beyond Oil: The Threat to Food and Fuel in the Coming Decades</a></em>. </li><li>Hall, C.A.S., J.A. Stanford and R. Hauer. 1992. The distribution and abundance of organisms as a consequence of energy balances along multiple environmental gradients. <em>Oikos</em> 65: 377-390.<br /> </li><li>Hall, Charles A.S., Cutler J. Cleveland, and Robert K. Kaufmann. <em><a href="http://www.bu.edu/cees/research/publications/energy_rq/book_intro/Energy_Resource_Quality.html" class='external text' title="http://www.bu.edu/cees/research/publications/energy rq/book intro/Energy Resource Quality.html">Energy and Resource Quality: The Ecology of the Economic Process</a></em>. (Wiley Interscience: New York, 1986). (Reprinted by the University of Colorado Press, Niwot, CO 1992).<br /> </li><li>Lenzen, M. and J. Munksgaard. 2002. <a href="http://dx.doi.org/10.1016/S0960-1481(01)00145-8" class='external text' title="http://dx.doi.org/10.1016/S0960-1481(01)00145-8">Energy and CO2 life-cycle analyses of wind turbines-review and applications</a>. <em>Renewable Energy</em>, 26: 3, pp. 339-362. </li><li>Odum, H. T., 1971. <em>Environment, Power and Society.</em> Wiley-Interscience, New York. <a href="http://www.amazon.com/dp/047165275X/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/047165275X/?tag=encycofearth-20">ISBN: 047165275X</a><br /> </li><li>Smil, V. 1991. <a href="http://home.cc.umanitoba.ca/~vsmil/complete_booklist.html" class='external text' title="http://home.cc.umanitoba.ca/~vsmil/complete booklist.html">General Energetics: Energy in the Biosphere and Civilization.</a> John Wiley, New York. <a href="http://www.amazon.com/dp/0471629057/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0471629057/?tag=encycofearth-20">ISBN: 0471629057</a><br /> </li><li>Spreng, Daniel T. 1988. <em>Net Energy Analysis and the Energy Requirements of Energy Systems</em> (Praeger). <a href="http://www.amazon.com/dp/0-275-92796-2/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0-275-92796-2/?tag=encycofearth-20">ISBN: 0-275-92796-2</a><br /> </li><li>Tainter, Joseph A. (1990). <em>The Collapse of Complex Societies</em> (1st paperback ed.). Cambridge: Cambridge University Press. <a href="http://www.amazon.com/dp/0-521-38673-X/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0-521-38673-X/?tag=encycofearth-20">ISBN: 0-521-38673-X</a> </li></ul> <p><a href='/article/Ten_fundamental_principles_of_net_energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Ten_fundamental_principles_of_net_energy Fri, 24 Jul 2009 07:26:13 GMT http://www.eoearth.org/article/Landform_development <a href='/article/Landform_development'><img border='0' src='/upload/thumb/9/94/Landform_development_model.gif/350px-Landform_development_model.gif' width='100'/></a> <p>The landforms that are found on the surface of the Earth can be grouped into 4 categories: </p> <ol><li> <b>Structural Landforms</b> - landforms that are created by massive earth movements due to <a href="/article/Plate_tectonics">plate tectonics</a>. This includes landforms with some of the following geomorphic features: fold mountains, rift valleys, and volcanoes. </li><li> <b>Weathering Landforms</b> - landforms that are created by the physical or chemical decomposition of rock through <a href="/article/Weathering">weathering</a>. Weathering produces landforms where rocks and sediments are decomposed and disintegrated. This includes landforms with some of the following geomorphic features: karst, patterned ground, and <a href="/article/Soil">soil</a> profiles. </li><li> <b>Erosional Landforms</b> - landforms formed from the removal of weathered and eroded surface materials by <a href="/article/Wind">wind</a>, water, <a href="/article/Glacier">glaciers</a>, and gravity. This includes landforms with some of the following geomorphic features: river valleys, glacial valleys, and coastal cliffs. </li><li> <b>Depositional Landforms</b> - landforms formed from the deposition of weathered and eroded surface materials. On occasion, these deposits can be compressed, altered by <a href="/article/Pressure">pressure</a>, <a href="/article/Heat">heat</a> and chemical processes to become sedimentary rocks. This includes landforms with some of the following geomorphic features: beaches, deltas, flood plains, and glacial moraines. </li></ol> <p>Many landforms show the influence of several of the above processes. We call these landforms polygenetic. Processes acting on landforms can also change over time, and a single landscape can undergo several cycles of development. We call this type landscape development polycyclic. </p><p>The graphical model in Figure 1 describes the relationship between geomorphic processes and landform types. </p><p><b>Further Reading</b> </p> <ul><li> <a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Landform_development'>Read Full Article...</a></p> http://www.eoearth.org/article/Landform_development Thu, 23 Jul 2009 05:32:41 GMT http://www.eoearth.org/article/Petroleum_refining <a href='/article/Petroleum_refining'><img border='0' src='/upload/thumb/1/1f/Crude_oil_distillation_column.gif/250px-Crude_oil_distillation_column.gif' width='100'/></a> <p>A petroleum refinery is an installation that manufactures finished petroleum products from crude oil, unfinished oils, natural gas liquids, other hydrocarbons, and alcohol. Refined petroleum products include but are not limited to gasolines, kerosene, distillate fuel oils (including No. 2 fuel oil), liquefied petroleum gas, <a href="/article/Asphalt">asphalt</a>, lubricating oils, diesel fuels, and residual fuels. </p> <p><a href='/article/Petroleum_refining'>Read Full Article...</a></p> http://www.eoearth.org/article/Petroleum_refining Wed, 22 Jul 2009 05:40:07 GMT http://www.eoearth.org/article/Regional_climate_change_assessment <a href='/article/Regional_climate_change_assessment'><img border='0' src='/upload/thumb/9/91/Mt2m.jpg/300px-Mt2m.jpg' width='100'/></a> <p>Our climate varies regionally, and the <a href="/article/Temperature">temperature</a> and <a href="/article/Precipitation_and_fog">precipitation</a> tend to be influenced by local geographical characters such as latitude, altitude, distance from the <a href="/article/Coastal_zone">coast</a>, nearby <a href="/article/Ocean_circulation">ocean currents</a>, prevailing <a href="/article/Wind">winds</a>, <a href="/article/Mountain">mountain</a> ranges and vegetation. Different local and regional climate characteristics were classified by Köppen in the early 20^th Century.  The regional climate has a key role in determining soil type, ecosystem type distibution, hydology, erosion processes etc.  Changes in regional climate alter the fabric of our physical environment.</p><p>A global climate change will have various implications for the local weather statistics (local climate characteristics), but the local climate response will differ from place to place. The local information is important when one wants to study the impacts of a climate change or implement an adaption strategy. How will the <a href="/article/Precipitation_and_fog">rainfall</a> statistics be affected where I live? Is the drainage system adequate? Do the reservoir dams have sufficiently large capacity to buffer droughts? Will the drainage system be able to cope with future rainfall extremes? How much will the local temperature rise? Will high winter temperatures have any implications for the snow conditions? Is the <a href="/article/Tropical_weather_and_hurricanes">storm</a> statistics going to change along the coast? These are but some questions that only can be answered with detailed local climate information. </p> <p>Global Climate models (GCMs) can be used to make projections for large-scale aspects of the climate, but they alone are not yet able to provide accurate and detailed description of the <em>local</em> characters. The reason why the GCMs are not able to provide an accurate description of the local climate is that the planet is represented by a coarse mesh of grid-point values with ~100-300 <a href="/article/Meter">kilometers</a> (km) between each point (varies with the latitude). The computer resources (memory and speed) are still not sufficient for using global coupled climate models with high spatial resolution to capture a high degree of spatial details. Thus the spatial resolution is about ~100-300 km. In addition, the models represent small-scale phenomena by simpler statistical models and solve the dynamics equations discretely though various numerical methods, both which may lead to biases on the smallest grid-box scales. </p><p>Despite the GCMs&#39; inability to give a detailed picture when it comes to local scales, it is possible to infer likely local response to a change on larger scales over the same area. It is well known that the local climate is influenced by the nearby <a href="/article/Geography">geography</a> (&#39;physiography&#39;) and the large-scale climatic conditions in which it is embedded (spatial scales of ~1,000 km). </p><p>The procedure of estimating the response at local scales from larger scales is known as &#39;downscaling&#39;</p> <p>There are two main methods for deriving information about the local climate: (i) <em>dynamical downscaling</em> (also referred to as &#39;nested modeling&#39; using &#39;regional climate models&#39; or &#39;limited area models&#39;) and (ii) <em>statistical downscaling</em> (also referred to as &#39;empirical&#39; or &#39;statistical-empirical&#39; downscaling). </p><p>Dynamical downscaling involves a regional atmospheric model in a similar fashion to ordinary day-to-day numerical weather forecasting. These models are built on laws of physics (Navier-Stokes equations, thermodynamics, ideal gas law, etc). The main difference is that a regional climate model (RCM) is more concerned about slow changes in the boundary conditions (changes in the <a href="/article/Atmospheric_composition">atmospheric composition</a>, e.g. <a href="/article/Carbon_dioxide">CO₂</a>) than the exact description of the initial conditions used for the simulations. </p><p>Dynamical downscaling can in principle yield a wide range of climate elements over a large region, but these data are merely the product of a model and are not perfect. It is therefore important to validate the model against real observations. </p><p>Caveats associated with RCMs include inconsistency between the driving GCM and RCM in terms of describing small-scale processes, differences in representing the coupling between the atmosphere and <a href="/article/Ocean">ocean</a>/land surface, spurious effects related to lateral boundaries (numerical waves or ill-conditioned solutions to the mathematical equations), or inconsistencies in how improved representation of small scale phenomena affect the ambient climate (e.g. <a href="/article/Tropical_weather_and_hurricanes">cyclones</a> play a role in <a href="/article/Heat">heat</a> transport, both vertically and laterally, and improved realism may alter the heat transport). Thus, it is important to compare results from RCMs with independent methods whenever possible (e.g. statistical downscaling).</p><p>Statistical downscaling involve statistical models that have been trained on empirical data. Data representing large-scale atmospheric conditions (<em>predictors</em>) represent one side of the equation and data representing the local parameter (<em>predictand</em>) the other. When these models are developed (or &#39;trained or &#39;calibrated&#39;), then a statistical relationship is sought between the predictors and the predictands for the past. These may involve regression, canonical correlation analysis (CCA), analogs, neural nets, and may involve everything from simple indices to advanced multivariate methods (linear algebra). </p> <p>It is important that the predictors can be reproduced skilfully by the GCMs, so that the statistical models can be &#39;ported&#39; to climate model results. It is also important that the a climate change can be seen in the predictor (i.e. the predictor captures the climate signal), and that the relationship between the predictor and predictand is constant for the future. These assumptions are not guaranteed. Furthermore, the statistical models do not provide a perfect reproduction of the local element. Thus, it is important to compare these results with other independent downscaled results whenever possible (e.g. dynamical downscaling or other types of statistical downscaling). </p><p>Empirical data are important both for calibrating the models and for validating them. The validation of the models involves comparing the model output to independent data not used for the model construction. Note, there are many ways to apply statistical models to data, but many may be inappropriate for the case in question. Therefore, it is important to have a thorough understanding of the problem and the models (their limitations) when using these to study local climate changes.</p><p>Often RCMs do not provide data that are close to the observed values. The RCMs provide a mean value for a box (e.g. 25 km by 25 km by 10 <a href="/article/Meter">meters</a>) whereas the observations are point measurements. Furthermore, the climatic elements may vary strongly over short distances in regions with complex terrain. Thus, it is common to apply a statistical correction to RCM data before using these for impact studies. Sometimes, the correction may resemble simple statistical downscaling in the sense that both involve a statistical model with a set of limitations. </p><p>Statistical downscaling typically yields results for a single site, but it is possible to assemble the information from several sites in order to make maps (e.g. using so-called Geographical Information Systems, or GIS). </p><p><big><strong>Further Reading</strong></big></p><ul><li><a href="http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter11.pdf" class='external text' title="http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter11.pdf">IPCC 2007, Chapter 11</a>.</li><li><a href="http://www.ipcc.ch/ipccreports/tar/wg1/373.htm" class='external text' title="http://www.ipcc.ch/ipccreports/tar/wg1/373.htm">IPCC 2001, Chapter 10</a>. </li><li><a href="http://www.realclimate.org/index.php/archives/2007/05/climate-models-local-climate/" class='external text' title="http://www.realclimate.org/index.php/archives/2007/05/climate-models-local-climate/">Why global climate models do not give a realistic description of the local climate</a>. </li><li><a href="http://www.realclimate.org/index.php/archives/2007/08/regional-climate-projections/" class='external text' title="http://www.realclimate.org/index.php/archives/2007/08/regional-climate-projections/">Regional Climate Projections</a> RealClimate.org.</li><li><a href="http://www.gvc2.gu.se/ngeo/rcg/edu/esd.pdf" class='external text' title="http://www.gvc2.gu.se/ngeo/rcg/edu/esd.pdf">Compendium on Empirical-Statistical Downscaling</a> used at the STATME summerschool in Lodz, Poland, June 2007. </li></ul> <p><a href='/article/Regional_climate_change_assessment'>Read Full Article...</a></p> http://www.eoearth.org/article/Regional_climate_change_assessment Tue, 21 Jul 2009 05:31:49 GMT http://www.eoearth.org/article/Public_Health_Statement_for_Lead <a href='/article/Public_Health_Statement_for_Lead'><img border='0' src='/upload/thumb/f/f9/Lead.jpg/300px-Lead.jpg' width='100'/></a> <p><em>This article is a <u>verbatim</u> version of the original and is not available for edits or additions by </em>EoE<em> editors or authors. Companion articles on the same topic that are editable may exist within the </em>EoE<em>.</em> </p><p><strong>September 2005</strong></p><p><a href="http://www.atsdr.cdc.gov/es/phs/es_phs13.html" class='external text' title="http://www.atsdr.cdc.gov/es/phs/es phs13.html">En Español</a> </p> <p><a href='/article/Public_Health_Statement_for_Lead'>Read Full Article...</a></p> http://www.eoearth.org/article/Public_Health_Statement_for_Lead Mon, 20 Jul 2009 05:28:04 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Mon, 20 Jul 2009 05:27:47 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Mon, 20 Jul 2009 05:26:48 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Mon, 20 Jul 2009 05:26:34 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Fri, 17 Jul 2009 06:26:06 GMT http://www.eoearth.org/article/Subsidies_and_market_interventions <a href='/article/Subsidies_and_market_interventions'><img border='0' src='/upload/thumb/a/a6/Oil_drilling.jpg/250px-Oil_drilling.jpg' width='100'/></a> <p>Government interventions encompass a wide range of regulatory, fiscal, <a href="/article/Taxation_in_the_United_States"> tax,</a> indemnification, and legal actions that modify the rights and responsibilities of various parties in society. Interventions can increase or decrease costs to particular groups, effectively acting either as a subsidy or as a <a href="/article/Taxation_in_the_United_States"> tax.</a> Some of these policies increase societal welfare, while others subsidize powerful groups in society, sometimes making societal imbalances worse. This article provides a general overview of many types of subsidy policies, and describes how to calculate net subsidies to a particular sector.</p> <p><a href='/article/Subsidies_and_market_interventions'>Read Full Article...</a></p> http://www.eoearth.org/article/Subsidies_and_market_interventions Thu, 16 Jul 2009 05:41:27 GMT http://www.eoearth.org/article/Subsidies_and_market_interventions <a href='/article/Subsidies_and_market_interventions'><img border='0' src='/upload/thumb/a/a6/Oil_drilling.jpg/250px-Oil_drilling.jpg' width='100'/></a> <p>Government interventions encompass a wide range of regulatory, fiscal, <a href="/article/Taxation_in_the_United_States"> tax,</a> indemnification, and legal actions that modify the rights and responsibilities of various parties in society. Interventions can increase or decrease costs to particular groups, effectively acting either as a subsidy or as a <a href="/article/Taxation_in_the_United_States"> tax.</a> Some of these policies increase societal welfare, while others subsidize powerful groups in society, sometimes making societal imbalances worse. This article provides a general overview of many types of subsidy policies, and describes how to calculate net subsidies to a particular sector.</p> <p><a href='/article/Subsidies_and_market_interventions'>Read Full Article...</a></p> http://www.eoearth.org/article/Subsidies_and_market_interventions Thu, 16 Jul 2009 05:40:01 GMT http://www.eoearth.org/article/Tax_subsidies <a href='/article/Tax_subsidies'><img border='0' src='/upload/thumb/0/07/Kalinin_nuclear_plant.jpg/300px-Kalinin_nuclear_plant.jpg' width='100'/></a> <p>Tax subsidies are the result of selective <a href="/article/Taxation_in_the_United_States">tax legislation</a> that benefit particular groups of people or industries in the economy. In effect, they share the costs of certain actions between the private sector and the government and impact investment decisions by increasing the expected returns associated with a particular pattern of <a href="/article/Essential_economic_activities">economic activity</a>. Tax subsidies may be applied in a number of ways to any one or a combination of economic variables (land, labor, <a href="/article/Capital">capital</a>). </p><p>While some provisions (e.g., the general investment tax credits) may be available to an entire class of economic activity, such provisions may still be viewed as subsidies because other classes of economic activity are placed at a relative economic disadvantage. In this case, for example, the government has made a decision to favor <a href="/article/Capital">capital</a>-based productive methods rather than alternatives (such as labor). Similarly, subsidies to new investment favor <a href="/article/Supply_and_demand">supply</a> expansions (such as new power plants) over improved efficiency in the use of existing capacity (such as many demand-side management approaches) and constitute a de facto governmental choice of the method by which to meet <a href="/article/Market">market</a> <a href="/article/Supply_and_demand">demand</a>. </p><p>Tax subsidies are generally measured in reference to a normative or baseline <a href="/article/Taxation_in_the_United_States">tax system</a>, and estimates assume no other changes in the tax code. Each tax expenditure is calculated assuming that there is no interaction with other provisions. As a result, the estimates can&#39;t be added directly together without errors. As it is very difficult to estimate the potential interactions from simultaneous removal of multiple subsidies, though, most analyses do add the tax expenditure values together anyway. </p><p>Since the government forgoes revenue that would have been collected had there been no special legislation and must make up those revenues through higher taxes on other economic activities, these policies have real costs. These costs are classified as &quot;tax expenditures.&quot; Within the United States, we are lucky in that two separate groups (the U.S. Treasury and the Joint Committee on Taxation) both independently estimate tax expenditures associate with current and proposed legislation. Many states and countries have no information at all about these special tax rulings. As a general rule of thumb, where there is no light the largest mushrooms grow. However, even within the U.S., the estimates for tax losses for the same provision by the two bodies can differ by hundreds of millions of dollars. The estimation methods or assumptions are not made public, so improving the accuracy of these estimates is not clear-cut. </p><p>The stated goal of tax subsidies, according to the U.S. General Accounting Office, is to promote some policy objective such as &quot;<a href="/article/Economic_growth">economic growth</a> or a desirable expenditure pattern by taxpayers.&quot; However, there is a great deal of disagreement over whether particular tax benefits typically encourage &quot;socially desirable&quot; economic behavior. Further, even if the policies are effective, they are static and may become ineffective or counterproductive as circumstances (be they demographic, technological, or economic) change. For example, percentage depletion allowances were significantly expanded when crucial minerals were needed for war efforts. As these initial conditions changed, the policies did not necessarily evolve with them. </p><p>In summary, tax subsidies are neither inherently right or wrong. They are inherently distortionary, however, in that they alter patterns of <a href="/article/Essential_economic_activities">economic activity</a> to promote particular areas (targeted by Congress) that would not necessarily have received investment or consumer <a href="/article/Supply_and_demand">demand</a> in the absence of the <a href="/article/Subsidies_and_market_interventions">government intervention</a>. The subsidies need to be considered as a real cost when evaluating alternative long-term energy options. These costs include the direct cost of increased <a href="/article/Taxation_in_the_United_States">taxes</a> in other areas to individual taxpayers, and the indirect costs to the economy as a whole through the distortionary effect of the subsidies on R&amp;D, investment, and <a href="/article/Consumption_and_consumer_sovereignty">consumption</a> patterns. </p><p>There are a few issues to keep in mind regarding our net tax expenditure estimates. First, special taxes on energy have been treated as negative subsidies if they are used for general revenue purposes. If they are earmarked for specific energy-related uses, such as <a href="/article/Oil_spill">oil spill</a> cleanup, they are considered user fees and are netted from the total government cost of dealing with the particular energy-related problem. Second, energy-payments such as royalties reflect a return to the resource-owner for selling the oil or minerals in question, and are not a tax. Finally, given the fact that the data regarding Treasury losses from tax provisions are somewhat crude and that interactions between the various tax preferences are not incorporated into these data, our quantification of the tax subsidy magnitude should be viewed as an estimate. </p> <p><a href='/article/Tax_subsidies'>Read Full Article...</a></p> http://www.eoearth.org/article/Tax_subsidies Thu, 16 Jul 2009 05:38:18 GMT http://www.eoearth.org/article/Subsidies_and_market_interventions <a href='/article/Subsidies_and_market_interventions'><img border='0' src='/upload/thumb/a/a6/Oil_drilling.jpg/250px-Oil_drilling.jpg' width='100'/></a> <p>Government interventions encompass a wide range of regulatory, fiscal, <a href="/article/Taxation_in_the_United_States"> tax,</a> indemnification, and legal actions that modify the rights and responsibilities of various parties in society. Interventions can increase or decrease costs to particular groups, effectively acting either as a subsidy or as a <a href="/article/Taxation_in_the_United_States"> tax.</a> Some of these policies increase societal welfare, while others subsidize powerful groups in society, sometimes making societal imbalances worse. This article provides a general overview of many types of subsidy policies, and describes how to calculate net subsidies to a particular sector.</p> <p><a href='/article/Subsidies_and_market_interventions'>Read Full Article...</a></p> http://www.eoearth.org/article/Subsidies_and_market_interventions Thu, 16 Jul 2009 05:36:53 GMT http://www.eoearth.org/article/Folding_and_faulting_in_the_Earth's_crust <a href='/article/Folding_and_faulting_in_the_Earth's_crust'><img border='0' src='/upload/thumb/d/d8/Earth_relief_map.jpg/250px-Earth_relief_map.jpg' width='100'/></a> <p>The topographic map illustrated in Figure 1 suggests that the Earth's surface has been deformed. This deformation is the result of forces that are strong enough to move ocean sediments to an elevation many thousands <a href="/article/Meter">meters</a> above sea level. This displacement of rock can be caused by <a href="/article/Plate_tectonics">tectonic plate</a> movement and subduction, volcanic activity, and intrusive <a href="/article/Formation_of_the_Earth%27s_crust">igneous activity</a>. </p><p>Deformation of rock involves changes in the shape and/or volume of these substances. Changes in shape and volume occur when stress and strain causes rock to buckle and fracture or crumple into folds. A fold can be defined as a bend in rock that is the response to compressional forces. Folds are most visible in rocks that contain layering. For plastic deformation of rock to occur a number of conditions must be met, including: </p> <ul><li> The rock material must have the ability to deform under <a href="/article/Pressure">pressure</a> and <a href="/article/Heat">heat</a>. </li><li> The higher the <a href="/article/Temperature">temperature</a> of the rock the more plastic it becomes. </li><li> Pressure must not exceed the internal strength of the rock. If it does, fracturing occurs. </li><li> Deformation must be applied slowly. </li></ul> <p>A number of different folds have been recognized and classified by geologists. The simplest type of fold is called a monocline (Figure 2). This fold involves a slight bend in otherwise parallel layers of rock. </p><p>An anticline is a convex up fold in rock that resembles an arch-like structure with the rock beds (or limbs) dipping way from the center of the structure (Figure 3). </p> <p><br style="clear: left" /> </p><p>A syncline is a fold where the rock layers are warped downward (Figure 4 and 5). Both anticlines and synclines are the result of compressional stress. </p> <p><br style="clear: left" /> </p><p>More complex fold types can develop in situations where lateral pressures become greater. The greater <a href="/article/Pressure">pressure</a> results in anticlines and synclines that are inclined and asymmetrical (Figure 6). </p><p>A recumbent fold develops if the center of the fold moves from being once vertical to a horizontal position (Figure 7). Recumbent folds are commonly found in the core of <a href="/article/Mountain">mountain</a> ranges and indicate that compression and/or shear forces were stronger in one direction. Extreme stress and <a href="/article/Pressure">pressure</a> can sometimes cause the rocks to shear along a plane of weakness creating a fault. We call the combination of a fault and a fold in a rock an overthrust fault. </p><p>Faults form in rocks when the stresses overcome the internal strength of the rock resulting in a fracture. A fault can be defined as the displacement of once connected blocks of rock along a fault plane. This can occur in any direction with the blocks moving away from each other. Faults occur from both tensional and compressional forces. Figure 8 shows the location of some of the major faults located on the Earth. </p> <p><br style="clear: left" /> There are several different kinds of faults. These faults are named according to the type of stress that acts on the rock and by the nature of the movement of the rock blocks either side of the fault plane. Normal faults occur when tensional forces act in opposite directions and cause one slab of the rock to be displaced up and the other slab down (Figure 9). </p><p>Reverse faults develop when compressional forces exist (Figure 10). Compression causes one block to be pushed up and over the other block. </p> <p><br style="clear: left" /> A graben fault is produced when tensional stresses result in the subsidence of a block of rock. On a large scale these features are known as Rift Valleys (Figure 11). </p><p>A horst fault is the development of two reverse faults causing a block of rock to be pushed up (Figure 12). </p> <p><br style="clear: left" /> </p><p>The final major type of fault is the strike-slip or transform fault. These faults are vertical in nature and are produced where the stresses are exerted parallel to each other (Figure 13). A well-known example of this type of fault is the San Andreas Fault in California. </p><p>Folds and faults have an economic importance. Anticlines and horsts are good sites for oil accumulation forming oil reservoirs whereas synclines and grabens are suitable for water accumulation forming <a href="/article/Aquifer">aquifers</a> or <a href="/article/Groundwater">groundwater</a> basins. </p><p>Faults represent a weak zone so they should be avoided or put in mind in any civil constructions. Also, faults as a weak zone are suitable for upward leakage of either lava forming sills or dykes or <a href="/article/Groundwater">groundwater</a> forming <a href="/article/Spring">springs</a>. </p><p>Folding and faulting reflect the effect of the internal energy of the earth. Consequently, the criteria of folding and faulting represent a kind of eath's ability for stability. </p><p><b>Further Reading</b> </p> <ul><li> <a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Folding_and_faulting_in_the_Earth's_crust'>Read Full Article...</a></p> http://www.eoearth.org/article/Folding_and_faulting_in_the_Earth's_crust Thu, 16 Jul 2009 05:33:02 GMT http://www.eoearth.org/article/Environmental_justice <a href='/article/Environmental_justice'><img border='0' src='/upload/thumb/6/66/Environmental_justice_protest.jpg/300px-Environmental_justice_protest.jpg' width='100'/></a> <p>The concept of environmental justice has surfaced and taken shape over the last thirty years. The first time environmental justice hit the radar screen was in 1976 at a conference entitled: “Working for Environmental and Economic Justice and Jobs" sponsored by the United Automobile Workers of America (UAW) and several other organizations. This conference was held at the Walter May Reuther Family Education Center located at Black Lake near Onaway, Michigan. Over the years, people of color and low-income groups, through struggle to protect their communities from environmental insults, have brought meaning to the concept of environmental justice. Although <a href="/article/Love_Canal%2C_New_York">Love Canal, New York</a> was not the first or the worst of contaminated sites, the struggle that took place there did raise the nation’s consciousness of health impacts of chemical and industrial waste long-buried in a mostly white neighborhood near <a href="/article/Niagara_Falls">Niagara Falls</a>, New York. The Warren County, North Carolina struggle to prevent the burial of <a href="/article/PCBs">PCBs</a> in a landfill in predominantly black area was the first time the connection was made between civil rights and environmental protection. As people struggled in communities across the country for safer and cleaner environments, the Environmental Protection Agency (EPA) was propelled to define environmental justice as follows: </p> <blockquote> <i>The fair treatment and meaningful involvement of people of all races, cultures, incomes and educational levels with respect to the development and enforcement of environmental laws, regulations, and policies. Fair treatment means that no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies. Meaningful involvement means that: (1) people have an opportunity to participate in decisions about activities that may affect their environment and/or health; (2) the publics contribution can influence the regulatory agency's decision; (3) their concerns will be considered in the decision making process; and (4) the decision makers seek out and facilitate the involvement of those potentially affected.</i> </blockquote> <p>The EPA definition can be analyzed from the taxonomy of distributive, procedural, corrective, and social justice. <b>Distributive</b> justice in practice has not meant a redistribution of pollutants equally to all communities, but the enforcement of the equal protection of the law or pollution preventions strategies so that pollutions will not be distributive to any community. The Agency places considerable emphasis upon <b>procedural</b> justice to make rules and regulations transparent in order for communities to access the decision-making process. We can also see that <b>corrective</b> justice is one of the main thrusts of the Agency where it uses legislation, rules and regulations, or lawsuits to reward, compensate, or punish guilty parties for damages done. <b>Social justice</b> attempts to bring about a more just and humane society as a whole, which would put this beyond the scope of EPA policy. Although EPA policy seems to be strongest in support of procedural and corrective justice, it is weakest in support of distributive and social justice. The EPA definition and the taxonomy of definitions, except perhaps for social justice, take a short-term approach to environmental justice. </p><p>Policies to address short-term problems are not the solution. To implement such policies is like fighting a rear guard action. Therefore, we must be visionary and be willing to plan for the future or we will blunder into it with all the alphabet soup of social and environmental problems that have been intensified over the years. The following definition of environmental justice is more visionary and broader in scope: </p> <blockquote> <i>Environmental justice are those cultural norms and values, rules, regulations, behaviors policies, and decisions that support sustainable development, so that people can interact with confidence that their environment is safe, nurturing, and productive. Environmental justice is served when people can realize their highest potential, without experiencing the “isms”. Environmental justice is supported by decent-paying and safe jobs; quality schools and recreation; decent housing and adequate health care; democratic decision-making and personal empowerment; and communities free of violence, drugs, and poverty. Environmental justice communities are where both cultural and biological diversity are respected and highly revered and where distributive justice prevails.</i> </blockquote> <p>This definition makes environmental justice much boarder than the EPA definition. It is not only concerned about short-term policies, but long-term policies that will affect people and the communities they live in. It gives a vision of what an environmentally just community would look like; it reads like a community of the future. To realize this vision of the future will require us to develop cities and systems that mimic nature. In nature there is virtually no waste in that the waste for one life-form becomes the food for another one. Therefore we must build cities and production systems where the waste from one system becomes the raw materials for the other. We must build cities that mimic nature where there will no longer be a need to drill for oil or to mine for <a href="/article/Coal">coal</a>. Although systems that mimic nature will go a long way to eliminate sickness, death, and environmental degradation, such systems fail to address the issue of equity, justice, and fairness, which are critical to an environmentally just society. Without equity and fairness there can be no justice. </p> <p><a href='/article/Environmental_justice'>Read Full Article...</a></p> http://www.eoearth.org/article/Environmental_justice Wed, 15 Jul 2009 05:41:47 GMT http://www.eoearth.org/article/Environmental_justice <a href='/article/Environmental_justice'><img border='0' src='/upload/thumb/6/66/Environmental_justice_protest.jpg/300px-Environmental_justice_protest.jpg' width='100'/></a> <p>The concept of environmental justice has surfaced and taken shape over the last thirty years. The first time environmental justice hit the radar screen was in 1976 at a conference entitled: “Working for Environmental and Economic Justice and Jobs" sponsored by the United Automobile Workers of America (UAW) and several other organizations. This conference was held at the Walter May Reuther Family Education Center located at Black Lake near Onaway, Michigan. Over the years, people of color and low-income groups, through struggle to protect their communities from environmental insults, have brought meaning to the concept of environmental justice. Although <a href="/article/Love_Canal%2C_New_York">Love Canal, New York</a> was not the first or the worst of contaminated sites, the struggle that took place there did raise the nation’s consciousness of health impacts of chemical and industrial waste long-buried in a mostly white neighborhood near <a href="/article/Niagara_Falls">Niagara Falls</a>, New York. The Warren County, North Carolina struggle to prevent the burial of <a href="/article/PCBs">PCBs</a> in a landfill in predominantly black area was the first time the connection was made between civil rights and environmental protection. As people struggled in communities across the country for safer and cleaner environments, the Environmental Protection Agency (EPA) was propelled to define environmental justice as follows: </p> <blockquote> <i>The fair treatment and meaningful involvement of people of all races, cultures, incomes and educational levels with respect to the development and enforcement of environmental laws, regulations, and policies. Fair treatment means that no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies. Meaningful involvement means that: (1) people have an opportunity to participate in decisions about activities that may affect their environment and/or health; (2) the publics contribution can influence the regulatory agency's decision; (3) their concerns will be considered in the decision making process; and (4) the decision makers seek out and facilitate the involvement of those potentially affected.</i> </blockquote> <p>The EPA definition can be analyzed from the taxonomy of distributive, procedural, corrective, and social justice. <b>Distributive</b> justice in practice has not meant a redistribution of pollutants equally to all communities, but the enforcement of the equal protection of the law or pollution preventions strategies so that pollutions will not be distributive to any community. The Agency places considerable emphasis upon <b>procedural</b> justice to make rules and regulations transparent in order for communities to access the decision-making process. We can also see that <b>corrective</b> justice is one of the main thrusts of the Agency where it uses legislation, rules and regulations, or lawsuits to reward, compensate, or punish guilty parties for damages done. <b>Social justice</b> attempts to bring about a more just and humane society as a whole, which would put this beyond the scope of EPA policy. Although EPA policy seems to be strongest in support of procedural and corrective justice, it is weakest in support of distributive and social justice. The EPA definition and the taxonomy of definitions, except perhaps for social justice, take a short-term approach to environmental justice. </p><p>Policies to address short-term problems are not the solution. To implement such policies is like fighting a rear guard action. Therefore, we must be visionary and be willing to plan for the future or we will blunder into it with all the alphabet soup of social and environmental problems that have been intensified over the years. The following definition of environmental justice is more visionary and broader in scope: </p> <blockquote> <i>Environmental justice are those cultural norms and values, rules, regulations, behaviors policies, and decisions that support sustainable development, so that people can interact with confidence that their environment is safe, nurturing, and productive. Environmental justice is served when people can realize their highest potential, without experiencing the “isms”. Environmental justice is supported by decent-paying and safe jobs; quality schools and recreation; decent housing and adequate health care; democratic decision-making and personal empowerment; and communities free of violence, drugs, and poverty. Environmental justice communities are where both cultural and biological diversity are respected and highly revered and where distributive justice prevails.</i> </blockquote> <p>This definition makes environmental justice much boarder than the EPA definition. It is not only concerned about short-term policies, but long-term policies that will affect people and the communities they live in. It gives a vision of what an environmentally just community would look like; it reads like a community of the future. To realize this vision of the future will require us to develop cities and systems that mimic nature. In nature there is virtually no waste in that the waste for one life-form becomes the food for another one. Therefore we must build cities and production systems where the waste from one system becomes the raw materials for the other. We must build cities that mimic nature where there will no longer be a need to drill for oil or to mine for <a href="/article/Coal">coal</a>. Although systems that mimic nature will go a long way to eliminate sickness, death, and environmental degradation, such systems fail to address the issue of equity, justice, and fairness, which are critical to an environmentally just society. Without equity and fairness there can be no justice. </p> <p><a href='/article/Environmental_justice'>Read Full Article...</a></p> http://www.eoearth.org/article/Environmental_justice Wed, 15 Jul 2009 05:40:05 GMT http://www.eoearth.org/article/Environmental_justice <a href='/article/Environmental_justice'><img border='0' src='/upload/thumb/6/66/Environmental_justice_protest.jpg/300px-Environmental_justice_protest.jpg' width='100'/></a> <p>The concept of environmental justice has surfaced and taken shape over the last thirty years. The first time environmental justice hit the radar screen was in 1976 at a conference entitled: “Working for Environmental and Economic Justice and Jobs" sponsored by the United Automobile Workers of America (UAW) and several other organizations. This conference was held at the Walter May Reuther Family Education Center located at Black Lake near Onaway, Michigan. Over the years, people of color and low-income groups, through struggle to protect their communities from environmental insults, have brought meaning to the concept of environmental justice. Although <a href="/article/Love_Canal%2C_New_York">Love Canal, New York</a> was not the first or the worst of contaminated sites, the struggle that took place there did raise the nation’s consciousness of health impacts of chemical and industrial waste long-buried in a mostly white neighborhood near <a href="/article/Niagara_Falls">Niagara Falls</a>, New York. The Warren County, North Carolina struggle to prevent the burial of <a href="/article/PCBs">PCBs</a> in a landfill in predominantly black area was the first time the connection was made between civil rights and environmental protection. As people struggled in communities across the country for safer and cleaner environments, the Environmental Protection Agency (EPA) was propelled to define environmental justice as follows: </p> <blockquote> <i>The fair treatment and meaningful involvement of people of all races, cultures, incomes and educational levels with respect to the development and enforcement of environmental laws, regulations, and policies. Fair treatment means that no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies. Meaningful involvement means that: (1) people have an opportunity to participate in decisions about activities that may affect their environment and/or health; (2) the publics contribution can influence the regulatory agency's decision; (3) their concerns will be considered in the decision making process; and (4) the decision makers seek out and facilitate the involvement of those potentially affected.</i> </blockquote> <p>The EPA definition can be analyzed from the taxonomy of distributive, procedural, corrective, and social justice. <b>Distributive</b> justice in practice has not meant a redistribution of pollutants equally to all communities, but the enforcement of the equal protection of the law or pollution preventions strategies so that pollutions will not be distributive to any community. The Agency places considerable emphasis upon <b>procedural</b> justice to make rules and regulations transparent in order for communities to access the decision-making process. We can also see that <b>corrective</b> justice is one of the main thrusts of the Agency where it uses legislation, rules and regulations, or lawsuits to reward, compensate, or punish guilty parties for damages done. <b>Social justice</b> attempts to bring about a more just and humane society as a whole, which would put this beyond the scope of EPA policy. Although EPA policy seems to be strongest in support of procedural and corrective justice, it is weakest in support of distributive and social justice. The EPA definition and the taxonomy of definitions, except perhaps for social justice, take a short-term approach to environmental justice. </p><p>Policies to address short-term problems are not the solution. To implement such policies is like fighting a rear guard action. Therefore, we must be visionary and be willing to plan for the future or we will blunder into it with all the alphabet soup of social and environmental problems that have been intensified over the years. The following definition of environmental justice is more visionary and broader in scope: </p> <blockquote> <i>Environmental justice are those cultural norms and values, rules, regulations, behaviors policies, and decisions that support sustainable development, so that people can interact with confidence that their environment is safe, nurturing, and productive. Environmental justice is served when people can realize their highest potential, without experiencing the “isms”. Environmental justice is supported by decent-paying and safe jobs; quality schools and recreation; decent housing and adequate health care; democratic decision-making and personal empowerment; and communities free of violence, drugs, and poverty. Environmental justice communities are where both cultural and biological diversity are respected and highly revered and where distributive justice prevails.</i> </blockquote> <p>This definition makes environmental justice much boarder than the EPA definition. It is not only concerned about short-term policies, but long-term policies that will affect people and the communities they live in. It gives a vision of what an environmentally just community would look like; it reads like a community of the future. To realize this vision of the future will require us to develop cities and systems that mimic nature. In nature there is virtually no waste in that the waste for one life-form becomes the food for another one. Therefore we must build cities and production systems where the waste from one system becomes the raw materials for the other. We must build cities that mimic nature where there will no longer be a need to drill for oil or to mine for <a href="/article/Coal">coal</a>. Although systems that mimic nature will go a long way to eliminate sickness, death, and environmental degradation, such systems fail to address the issue of equity, justice, and fairness, which are critical to an environmentally just society. Without equity and fairness there can be no justice. </p> <p><a href='/article/Environmental_justice'>Read Full Article...</a></p> http://www.eoearth.org/article/Environmental_justice Wed, 15 Jul 2009 05:39:22 GMT http://www.eoearth.org/article/Patterns_of_economic_growth_and_development <a href='/article/Patterns_of_economic_growth_and_development'><img border='0' src='/upload/thumb/6/6c/World_Economic_Growth_1961-2004_graph.gif/250px-World_Economic_Growth_1961-2004_graph.gif' width='100'/></a> <p>The <a href="/article/Industrial_Revolution">Industrial Revolution</a>, which began in the British Isles and Western Europe, dramatically changed the nature of <a href="/article/Essential_economic_activities">economic production</a>. It is important not just as a historical episode, but because the pattern of economic development that it established has become in many ways a model for development worldwide. Although, as we will discuss later, there are criticisms of the applicability of this model to current development issues, its strong influence on standard views of <a href="/article/Economic_growth">economic growth</a> makes it an important starting point for understanding development. </p><p>Several elements were critical in creating the Industrial Revolution. First, new agricultural techniques, along with new kinds of tools and machines, made <a href="/article/Agriculture">agriculture</a> more productive. That meant that more agricultural output could be produced per worker and per acre of land. These productivity increases, continuing and eventually spreading across the globe, meant that human populations could grow dramatically – as, indeed they have done, reaching a first billion around 1810, and continuing to increase to the present global numbers of well over six billion. Because of the great increase in agricultural labor productivity, the number of workers needed to produce food for the rest of the population was shrinking even while the population as a whole was growing. </p><p>A second outstanding characteristic of the <a href="/article/Industrial_Revolution">Industrial Revolution</a> was the invention and application of technologies using inanimate sources of power (increasingly, fossil fuels) and machinery for <a href="/article/Essential_economic_activities">production</a> of goods. Mechanization created jobs in factories, largely replacing the previous patterns of producing goods at home. Railroads and other advances in transportation, as well as the new kinds of work organization, made it possible to assemble large numbers of workers in factories, resulting in huge urban agglomerations. </p><p>Another important factor in England’s increasing industrialization was its ability to rely on other countries, including its extensive network of colonies, for supplies of raw materials and as markets for its goods. England imported cotton fiber from India, for example. It discouraged the further development of cotton manufacturing within India by putting high import tariffs on Indian-made cloth, while requiring that India let in British-made cloth tariff-free. </p><p>An ever-increasing variety of things were produced in the emerging industrial sector. Some of these were items never seen before, such as bicycles, flushing toilets, machine-loomed cloth, communication by telegraph, early cameras, and steamships. Other products of industry were household goods, such as china dishes and cotton cloth, which had previously been used only by a small, rich elite. Others were, of course, the various kinds of machinery that were used to produce consumer items. These included the cotton gin, steam-powered textile machines, a steam-powered printing press that could turn out tens of thousands of copies of a page per day, and rotary mixers to make bread in commercial bakeries. </p><p>While the <a href="/article/Industrial_Revolution">Industrial Revolution</a> began in England, by the nineteenth and early twentieth century it was well along in much of Western Europe and other &quot;early industrializing&quot; countries such as the United States, Canada, and Australia. It is important not just as a historical episode, but because the pattern of economic development that it established has become, in many people&#39;s minds, the model for how development should proceed worldwide. The vocabulary of referring to rich countries as &quot;developed&quot; and poorer countries as &quot;developing,&quot; for example, involves an implicit assumption that poorer countries are on a path of industrialization, on the road to perhaps eventually &quot;catching up&quot; to rich country lifestyles and levels of wealth. </p> <p><a href='/article/Patterns_of_economic_growth_and_development'>Read Full Article...</a></p> http://www.eoearth.org/article/Patterns_of_economic_growth_and_development Tue, 14 Jul 2009 05:15:09 GMT http://www.eoearth.org/article/Cell_phone_recycling <a href='/article/Cell_phone_recycling'><img border='0' src='/upload/thumb/c/c7/US_cell_phone_subscribers%2C1985-2004.gif/250px-US_cell_phone_subscribers%2C1985-2004.gif' width='100'/></a> <p>Recycling, a significant factor in the supply of many of the metals used in our society, provides environmental benefits, such as energy savings, reduced volumes of waste, and reduced emissions associated with energy savings. In addition, <a href="/article/Recycling">recycling</a> reduces the amount of virgin metals that must be mined to support our lifestyle. </p><p>Cell phones are ubiquitous in much of the world. There were approximately 1 billion cell phones in use worldwide in 2002. In the United States (Fig. 1), the number of cell phone subscribers increased from 340,000 in 1985 to 180 million in 2004.</p> <p>Worldwide, cell phone sales (Fig. 2) have increased from slightly more than 100 million units per year in 1997 to an estimated 779 million units per year in 2005. As shown in Figure 2, sales increased from 1997 through 2000 and then leveled off through 2002. In 2003, sales began to increase again. Cell phone sales are projected to exceed 1 billion units per year in 2009, with an estimated 2.6 billion cell phones in use by the end of that year. Sales are driven by new subscribers signing up for services, by subscribers purchasing additional phones, and by subscribers replacing obsolete cell phones.</p><p>The <a href="/article/Environmental_Protection_Agency%2C_United_States">U.S. Environmental Protection Agency</a> estimated that, by 2005, as many as 130 million cell phones would be retired annually in the United States. The nonprofit organization INFORM, Inc., anticipated that, by 2005, a total of 500 million obsolete cell phones would have accumulated in <a href="/article/Essential_economic_activities">consumers’</a> desk drawers, store rooms, or other storage, awaiting disposal. Typically, cell phones are used for only 1½ years before being replaced. These unused (or obsolete) cell phones usually are replaced because they do not have desired features, they are not compatible with a new provider, or they no longer function.</p><p>Less than 1 percent of the millions of cell phones retired and discarded annually are <a href="/article/Recycling">recycled</a>. Of this small percentage recovered, most are refurbished and put into use or used for replacement parts. If these options are not possible, core elements (such as <a href="/article/Copper">copper</a>) are recycled.</p><p>When discarded cell phones are not recycled, most eventually end up in municipal solid waste facilities. Although there are cell phone collection and recycling programs, they have had little impact on this waste stream. According to INFORM, Inc., the lack of impact results from an inefficient recycling infrastructure, insufficient publicity for the programs, small-scale collection sites, and few or insufficient financial incentives. Figure 3 shows the cell phone life cycle, including the recycling option.</p> <p><a href='/article/Cell_phone_recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Cell_phone_recycling Mon, 13 Jul 2009 05:32:01 GMT http://www.eoearth.org/article/Nitrogen_cycle <a href='/article/Nitrogen_cycle'><img border='0' src='/upload/thumb/b/b9/Nitrogencycle.jpg/600px-Nitrogencycle.jpg' width='100'/></a> <p>The nitrogen cycle represents one of the most important nutrient cycles found in ecosystems. (Figure 1). <a href="/article/Nitrogen">Nitrogen</a> is a required nutrient for all living organisms to produce a number of complex organic molecules like amino acids, the building blocks of proteins, and nucleic acids, including DNA and RNA. The ultimate store of nitrogen is in the atmosphere, where it exists as nitrogen gas (N₂). This store is about one million times larger than the total nitrogen contained in living organisms. Other major stores of nitrogen include organic matter in <a href="/article/Soil">soil</a> and the oceans. Despite its abundance in the atmosphere, nitrogen is often the most limiting nutrient for plant growth. This problem occurs N₂ gas is not biochemically usable by plants. Plants can only take up nitrogen in the form of ammonium ion (NH₄⁺), nitrate ion (NO₃^-), or, less common, as amino acids. Animals receive the <a href="/article/Nitrogen">nitrogen</a> they need for metabolism, growth, and reproduction by the consumption of living or dead organic matter containing molecules composed partially of nitrogen. <br /> </p> <p><br /> In most ecosystems <a href="/article/Nitrogen">nitrogen</a> is primarily stored in living and dead organic matter. This organic nitrogen is converted into inorganic forms when it re-enters the biogeochemical cycle via decomposition. Decomposers chemically modify the nitrogen found in organic matter to ammonium ion (NH₄⁺). This process is known as mineralization and it is carried out by a variety of <a href="/article/Bacteria">bacteria</a> and fungi. </p><p><a href="/article/Nitrogen">Nitrogen</a> in the form of ammonium can be absorbed onto the surfaces of <a href="/article/Clay">clay</a> particles in the soil. The ammonium ion has a positive molecular charge and is normally held by negatively charged soil colloids. This process is sometimes called micelle fixation (see Figure 1). Ammonium is released from the colloids by way of cation exchange. When released, most of the ammonium is often chemically altered by a specific type of autotrophic <a href="/article/Bacteria">bacteria</a> (bacteria that belong to the genus Nitrosomonas) into nitrite (NO₂^-). Further modification by another type of bacteria (belonging to the genus Nitrobacter) converts the nitrite to nitrate (NO₃-). Both of these processes involve chemical oxidation and are known collectively as nitrification. However, nitrate is very soluble and it is easily lost from the soil system by leaching. Some of this leached nitrate flows through the <a href="/article/Hydrologic_cycle">hydrologic system</a> until it reaches the oceans where it can be returned to the atmosphere by denitrification. Denitrification is also common in anaerobic <a href="/article/Soil">soils</a> and is carried out by heterotrophic bacteria. The process of denitrification involves the metabolic reduction of nitrate (NO₃^-) into nitrogen (N₂) or <a href="/article/Nitrous_oxide">nitrous oxide</a> (N₂O) gas. Both of these gases then diffuse into the atmosphere, thus removing nitrogen from the soil, accounting for the name, denitrification. </p><p>Almost all of the <a href="/article/Nitrogen">nitrogen</a> found in any <a href="/article/Ecosystem">ecosystem</a> originally came from the atmosphere. Significant amounts enter the <a href="/article/Soil">soil</a> in rainfall or through the effects of lightning. The majority, however, is biochemically fixed in ecosystems by specialized micro-organisms, all of which are bacteria of various types, including a varity of Gram-positive and Gram-negative bacteria, actinomycetes, and cyanobacteria. Members of the bean family (legumes) and some other kinds of plants form <a href="/article/Mutualism">mutualistic</a> symbiotic relationships with certain types of nitrogen-fixing bacteria. In exchange for some nitrogen, the bacteria receive from the plants carbohydrates and special structures (nodules) in the roots where they can exist in a protected environment. Scientists estimate that biological fixation globally adds approximately 140 million metric tons of nitrogen to ecosystems every year. </p><p>Humans now fix approximately as much nitrogen industrially as does natural nitrogen fixation, thus dramatically altering the nitrogen cycle. Some of the major processes involved in this alteration include: </p> <ul><li>The application of nitrogen fertilizers to crops has caused increased rates of denitrification and leaching of nitrate into <a href="/article/Groundwater">groundwater</a>. The additional nitrogen entering the groundwater system eventually flows into streams, rivers, lakes, and estuaries. In these systems, the added nitrogen can lead to <a href="/article/Eutrophication">eutrophication</a> and associated hypoxia. </li></ul> <ul><li>Increased deposition of <a href="/article/Nitrogen">nitrogen</a> from atmospheric sources because of fossil fuel <a href="/article/Combustion">combustion</a> and forest burning. Both of these processes release a variety of solid forms of nitrogen through combustion and contribute to <a href="/article/Acid_rain">acid rain</a>. </li></ul> <ul><li>Livestock ranching. Livestock release a large amounts of ammonia into the environment from their wastes. This nitrogen enters the <a href="/article/Soil">soil</a> system and then the <a href="/article/Hydrologic_cycle">hydrologic system</a> through leaching, <a href="/article/Groundwater">groundwater</a> flow, and runoff. </li></ul> <ul><li>Sewage waste and septic tank leaching. </li></ul> <p><strong>Further Reading</strong> </p> <ul><li><a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Nitrogen_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Nitrogen_cycle Fri, 10 Jul 2009 05:22:01 GMT http://www.eoearth.org/article/Nitrogen_cycle <a href='/article/Nitrogen_cycle'><img border='0' src='/upload/thumb/b/b9/Nitrogencycle.jpg/600px-Nitrogencycle.jpg' width='100'/></a> <p>The nitrogen cycle represents one of the most important nutrient cycles found in ecosystems. (Figure 1). <a href="/article/Nitrogen">Nitrogen</a> is a required nutrient for all living organisms to produce a number of complex organic molecules like amino acids, the building blocks of proteins, and nucleic acids, including DNA and RNA. The ultimate store of nitrogen is in the atmosphere, where it exists as nitrogen gas (N₂). This store is about one million times larger than the total nitrogen contained in living organisms. Other major stores of nitrogen include organic matter in <a href="/article/Soil">soil</a> and the oceans. Despite its abundance in the atmosphere, nitrogen is often the most limiting nutrient for plant growth. This problem occurs N₂ gas is not biochemically usable by plants. Plants can only take up nitrogen in the form of ammonium ion (NH₄⁺), nitrate ion (NO₃^-), or, less common, as amino acids. Animals receive the <a href="/article/Nitrogen">nitrogen</a> they need for metabolism, growth, and reproduction by the consumption of living or dead organic matter containing molecules composed partially of nitrogen. <br /> </p> <p><br /> In most ecosystems <a href="/article/Nitrogen">nitrogen</a> is primarily stored in living and dead organic matter. This organic nitrogen is converted into inorganic forms when it re-enters the biogeochemical cycle via decomposition. Decomposers chemically modify the nitrogen found in organic matter to ammonium ion (NH₄⁺). This process is known as mineralization and it is carried out by a variety of <a href="/article/Bacteria">bacteria</a> and fungi. </p><p><a href="/article/Nitrogen">Nitrogen</a> in the form of ammonium can be absorbed onto the surfaces of <a href="/article/Clay">clay</a> particles in the soil. The ammonium ion has a positive molecular charge and is normally held by negatively charged soil colloids. This process is sometimes called micelle fixation (see Figure 1). Ammonium is released from the colloids by way of cation exchange. When released, most of the ammonium is often chemically altered by a specific type of autotrophic <a href="/article/Bacteria">bacteria</a> (bacteria that belong to the genus Nitrosomonas) into nitrite (NO₂^-). Further modification by another type of bacteria (belonging to the genus Nitrobacter) converts the nitrite to nitrate (NO₃-). Both of these processes involve chemical oxidation and are known collectively as nitrification. However, nitrate is very soluble and it is easily lost from the soil system by leaching. Some of this leached nitrate flows through the <a href="/article/Hydrologic_cycle">hydrologic system</a> until it reaches the oceans where it can be returned to the atmosphere by denitrification. Denitrification is also common in anaerobic <a href="/article/Soil">soils</a> and is carried out by heterotrophic bacteria. The process of denitrification involves the metabolic reduction of nitrate (NO₃^-) into nitrogen (N₂) or <a href="/article/Nitrous_oxide">nitrous oxide</a> (N₂O) gas. Both of these gases then diffuse into the atmosphere, thus removing nitrogen from the soil, accounting for the name, denitrification. </p><p>Almost all of the <a href="/article/Nitrogen">nitrogen</a> found in any <a href="/article/Ecosystem">ecosystem</a> originally came from the atmosphere. Significant amounts enter the <a href="/article/Soil">soil</a> in rainfall or through the effects of lightning. The majority, however, is biochemically fixed in ecosystems by specialized micro-organisms, all of which are bacteria of various types, including a varity of Gram-positive and Gram-negative bacteria, actinomycetes, and cyanobacteria. Members of the bean family (legumes) and some other kinds of plants form <a href="/article/Mutualism">mutualistic</a> symbiotic relationships with certain types of nitrogen-fixing bacteria. In exchange for some nitrogen, the bacteria receive from the plants carbohydrates and special structures (nodules) in the roots where they can exist in a protected environment. Scientists estimate that biological fixation globally adds approximately 140 million metric tons of nitrogen to ecosystems every year. </p><p>Humans now fix approximately as much nitrogen industrially as does natural nitrogen fixation, thus dramatically altering the nitrogen cycle. Some of the major processes involved in this alteration include: </p> <ul><li>The application of nitrogen fertilizers to crops has caused increased rates of denitrification and leaching of nitrate into <a href="/article/Groundwater">groundwater</a>. The additional nitrogen entering the groundwater system eventually flows into streams, rivers, lakes, and estuaries. In these systems, the added nitrogen can lead to <a href="/article/Eutrophication">eutrophication</a> and associated hypoxia. </li></ul> <ul><li>Increased deposition of <a href="/article/Nitrogen">nitrogen</a> from atmospheric sources because of fossil fuel <a href="/article/Combustion">combustion</a> and forest burning. Both of these processes release a variety of solid forms of nitrogen through combustion and contribute to <a href="/article/Acid_rain">acid rain</a>. </li></ul> <ul><li>Livestock ranching. Livestock release a large amounts of ammonia into the environment from their wastes. This nitrogen enters the <a href="/article/Soil">soil</a> system and then the <a href="/article/Hydrologic_cycle">hydrologic system</a> through leaching, <a href="/article/Groundwater">groundwater</a> flow, and runoff. </li></ul> <ul><li>Sewage waste and septic tank leaching. </li></ul> <p><strong>Further Reading</strong> </p> <ul><li><a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Nitrogen_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Nitrogen_cycle Fri, 10 Jul 2009 05:17:18 GMT http://www.eoearth.org/article/Health_effects_of_the_Chernobyl_accident <a href='/article/Health_effects_of_the_Chernobyl_accident'><img border='0' src='/upload/thumb/e/e5/Chernobyl.jpg/250px-Chernobyl.jpg' width='100'/></a> <p>April 26, 2006, was the 20th anniversary of the <a href="/article/Chernobyl%2C_Ukraine">Chernobyl accident</a>, the second major single exposure to radiation of a substantial population. The accident produced a significant <a href="/article/International_response_to_the_Chernobyl_accident">international response</a> whose effectiveness is the subject of debate. It is relevant to the current view of the consequences of Chernobyl to reflect on the understanding in 1965 of the health consequences of the first major event, radiation from the atomic bombs in Hiroshima and Nagasaki, Japan, in 1945. The only significant consequences observed in survivors 20 years after the atomic bombs were increases in leukemia and thyroid cancer, and the general view of the future was reassuring. In 1974, a significant increase in solid cancers was detected, and nearly 50 years after the event, an unexpected increase was found in non-cancer diseases. Today, leukemia and thyroid cancer form only a small fraction of the accepted total radiation-related health detriment.</p> <p>In 1990, four years after the Chernobyl accident, an increase in thyroid cancer was found in children exposed to fallout from the accident. Two years later, the first reports in the Western literature of an increase in childhood thyroid cancer (CTC) in Belarus were published. In 2000, about 2,000 cases of thyroid cancer had been reported in those exposed as children in the former Soviet Socialist Union, and in 2005, the number was estimated at 4,000; the latest estimate for the year 2056 ranges from 3,400 to 72,000. The effects are not limited by national borders; Poland has recorded cases in spite of a rapid precautionary distribution of stable <a href="/article/Iodine">iodine</a>. The causative agent, ¹³¹I, was detected in many European countries with as yet unknown effects. Interestingly, a significant increase in leukemia has not been reliably reported in the three most affected countries.</p><p>This dramatic contrast between the two incidents is in part due to the different types of radiation exposure, but both show that the effects of massive exposures to radiation are immensely complex. In comparing the health effects after <a href="/article/Chernobyl%2C_Ukraine">Chernobyl</a> with those after the atomic bombs, it must be remembered that apart from workers in or close to the <a href="/article/Nuclear_power_reactor">power plant</a>, the Chernobyl accident involved mainly exposure to radioactive isotopes, and the atomic bombs primarily involved direct exposure to gamma rays and neutrons. Because of the prominence given to thyroid carcinoma after Chernobyl, less attention has been given to whole-body exposure from the ingestion and inhalation of all isotopes, together with the shine from the radioactive cloud and deposited radioactivity. Consideration of the health effects of Chernobyl must take into account both tissue-specific doses due to <a href="/article/Isotope">isotope</a> concentration and whole-body <a href="/article/Dose">doses</a>.</p><p>The most prominent tissue-specific dose is that to the thyroid, largely from ¹³¹I, with a smaller contribution from short-lived isotopes of <a href="/article/Iodine">iodine</a>. For many in the 30-km zone (135,000), there were relatively high <a href="/article/Absorption_of_toxicants">absorbed</a> doses to other <a href="/article/Organ_systems_and_organs">organs</a> as well as the thyroid until evacuation, and for those living in the contaminated areas around the 30-km zone (5 million), relatively high dose rate exposure (days to weeks) was followed by prolonged (years) exposure to a low dose rate. This exposure was a complex mixture of external radiation and internal emitters. For others living farther from the accident, in Western Europe, for example, their average exposure was equivalent to an additional ≤ 50% of average annual natural background level of radiation. About 600,000 liquidators assisted with the cleanup. Those working at the site shortly after the accident (200,000) received substantial doses. For all of these groups, estimates of numbers of fatal cancers can be derived from the collective doses. However, such estimates depend on the assumed risk coefficient, but of the order of 60,000 such fatalities in total can be estimated, based on the collective dose estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), less than half of which would derive from the declared contaminated areas. A more recent estimate of the numbers of fatal cancers based on a collective dose of less than half the UNSCEAR estimate gives a central value of 16,000 (95% confidence interval, 7,000–38,000).</p> <p><a href='/article/Health_effects_of_the_Chernobyl_accident'>Read Full Article...</a></p> http://www.eoearth.org/article/Health_effects_of_the_Chernobyl_accident Thu, 09 Jul 2009 05:12:53 GMT http://www.eoearth.org/article/Vertical_farming <a href='/article/Vertical_farming'><img border='0' src='/upload/thumb/6/60/C_Jacobs_VFs_solar.jpg/200px-C_Jacobs_VFs_solar.jpg' width='100'/></a> <p>The advent of <a href="/article/Agriculture">agriculture</a> ushered in an unprecedented increase in the human <a href="/article/Population">population</a> and their <a href="/article/Domestication">domesticated animals</a>. Farming catalyzed the transformation of hunter-gatherers into urban dwellers. Today, over 800 million hectares is committed to agriculture, or about 38% of the total landmass of the Earth. Farming has <a href="/article/Land-use_and_land-cover_change">re-arranged the landscape</a> in favor of cultivated fields and herds of cattle, and has occurred at the expense of natural ecozones, reducing most of them to fragmented, semi-functional units, while completely eliminating others. Undeniably, a reliable food supply has allowed for a healthier life style for most of the civilized world, while the very act of farming has created new health hazards. </p> <p>For example, the transmission of numerous infectious disease agents - avian influenza, rabies, yellow fever, dengue fever, <a href="/article/Malaria">malaria</a>, trypanosomiasis, hookworm, <a href="/article/Schistosomiasis">schistosomiasis</a> - occur with relentlessly devastating regularity at the tropical and sub-tropical agricultural interface. Emerging infections, many of which are viral zoonoses (e.g., Ebola, Lassa fever), rapidly adapt to the human host following encroachment into natural environments. Exposure to <a href="/article/Toxicity">toxic</a> levels of some classes of agrochemicals (<a href="/article/Pesticide">pesticides</a>, fungicides) and trauma are two other significant health risks associated with traditional agricultural practices. Over the next 50 years, the human population is expected to rise to at least 8.6 billion, requiring an additional 10⁹ hectares to feed them using current technologies. That quantity of farmland is no longer available. Thus, alternative strategies for obtaining an abundant and varied food supply without encroachment into the few remaining functional ecosystems must be seriously entertained. </p><p>If traditional farming could be replaced by constructing urban food production centers - vertical farms - then a long-term benefit would be the gradual repair of many of the world’s damaged ecosystems through the systematic abandonment of farmland. In temperate and tropical zones, the re-growth of hardwood forests could play a significant role in <a href="/article/Carbon_capture_and_storage">carbon sequestration</a> and may help reverse current trends in global climate change. Social benefits of vertical farming include the creation of a sustainable urban environment that encourages good health for all who choose to live there; new employment opportunities; fewer abandoned lots and buildings; cleaner air; and an abundant supply of safe drinking water. </p> <p><a href='/article/Vertical_farming'>Read Full Article...</a></p> http://www.eoearth.org/article/Vertical_farming Wed, 08 Jul 2009 07:24:34 GMT http://www.eoearth.org/article/Vertical_farming <a href='/article/Vertical_farming'><img border='0' src='/upload/thumb/6/60/C_Jacobs_VFs_solar.jpg/200px-C_Jacobs_VFs_solar.jpg' width='100'/></a> <p>The advent of <a href="/article/Agriculture">agriculture</a> ushered in an unprecedented increase in the human <a href="/article/Population">population</a> and their <a href="/article/Domestication">domesticated animals</a>. Farming catalyzed the transformation of hunter-gatherers into urban dwellers. Today, over 800 million hectares is committed to agriculture, or about 38% of the total landmass of the Earth. Farming has <a href="/article/Land-use_and_land-cover_change">re-arranged the landscape</a> in favor of cultivated fields and herds of cattle, and has occurred at the expense of natural ecozones, reducing most of them to fragmented, semi-functional units, while completely eliminating others. Undeniably, a reliable food supply has allowed for a healthier life style for most of the civilized world, while the very act of farming has created new health hazards. </p> <p>For example, the transmission of numerous infectious disease agents - avian influenza, rabies, yellow fever, dengue fever, <a href="/article/Malaria">malaria</a>, trypanosomiasis, hookworm, <a href="/article/Schistosomiasis">schistosomiasis</a> - occur with relentlessly devastating regularity at the tropical and sub-tropical agricultural interface. Emerging infections, many of which are viral zoonoses (e.g., Ebola, Lassa fever), rapidly adapt to the human host following encroachment into natural environments. Exposure to <a href="/article/Toxicity">toxic</a> levels of some classes of agrochemicals (<a href="/article/Pesticide">pesticides</a>, fungicides) and trauma are two other significant health risks associated with traditional agricultural practices. Over the next 50 years, the human population is expected to rise to at least 8.6 billion, requiring an additional 10⁹ hectares to feed them using current technologies. That quantity of farmland is no longer available. Thus, alternative strategies for obtaining an abundant and varied food supply without encroachment into the few remaining functional ecosystems must be seriously entertained. </p><p>If traditional farming could be replaced by constructing urban food production centers - vertical farms - then a long-term benefit would be the gradual repair of many of the world’s damaged ecosystems through the systematic abandonment of farmland. In temperate and tropical zones, the re-growth of hardwood forests could play a significant role in <a href="/article/Carbon_capture_and_storage">carbon sequestration</a> and may help reverse current trends in global climate change. Social benefits of vertical farming include the creation of a sustainable urban environment that encourages good health for all who choose to live there; new employment opportunities; fewer abandoned lots and buildings; cleaner air; and an abundant supply of safe drinking water. </p> <p><a href='/article/Vertical_farming'>Read Full Article...</a></p> http://www.eoearth.org/article/Vertical_farming Wed, 08 Jul 2009 05:55:47 GMT http://www.eoearth.org/article/Strip_mining <a href='/article/Strip_mining'><img border='0' src='/upload/thumb/5/57/Stripmining.jpg/200px-Stripmining.jpg' width='100'/></a> <p>Strip mining is a type of surface mining that involves excavating earth, rock, and other material to uncover a tabular, lens-shaped, or layered mineral reserve. The mineral extracted is usually <a href="/article/Coal">coal</a> or other rocks of sedimentary origin. The mineral reserve is extracted after the overlying material, called overburden is removed. The excavation of the overburden is completed in rectangular blocks in plain view called pits or strips. The pits are parallel and adjacent to each other with each strip of overburden and the mineral beneath extracted sequentially. The mining process using equipment and explosives move the overburden laterally to the adjacent empty pit where the mineral has been extracted. This lateral movement is called casting or open-casting. The overburden is moved by explosives, draglines, bucketwheel excavators, stripping shovels, dozers, and other equipment. The uncovered mineral is excavated and hauled out of the pit to down-stream processing operations. Filling the adjacent empty pits with the overburden is systemic to the process and therefore insures the genesis of mined-land land reclamation, an advantage of this method of surface mining. Planning strip mining utilizes a cross-section or range diagram of the earth to be removed. Strip mining is also called open-cut mining, open-cast mining, and stripping. </p><p><b>Further reading</b><br /> </p><p>Schissler, Andrew P., “Design and Methods of Coal Mining," in <i>The Encyclopedia of Energy</i>, Volume 1, Cutler J. Cleveland Editor-in-Chief, Elsevier Inc., Kidlington, Oxford, pp. 485-494. </p> <p><a href='/article/Strip_mining'>Read Full Article...</a></p> http://www.eoearth.org/article/Strip_mining Tue, 07 Jul 2009 06:12:45 GMT http://www.eoearth.org/article/Strip_mining <a href='/article/Strip_mining'><img border='0' src='/upload/thumb/5/57/Stripmining.jpg/200px-Stripmining.jpg' width='100'/></a> <p>Strip mining is a type of surface mining that involves excavating earth, rock, and other material to uncover a tabular, lens-shaped, or layered mineral reserve. The mineral extracted is usually <a href="/article/Coal">coal</a> or other rocks of sedimentary origin. The mineral reserve is extracted after the overlying material, called overburden is removed. The excavation of the overburden is completed in rectangular blocks in plain view called pits or strips. The pits are parallel and adjacent to each other with each strip of overburden and the mineral beneath extracted sequentially. The mining process using equipment and explosives move the overburden laterally to the adjacent empty pit where the mineral has been extracted. This lateral movement is called casting or open-casting. The overburden is moved by explosives, draglines, bucketwheel excavators, stripping shovels, dozers, and other equipment. The uncovered mineral is excavated and hauled out of the pit to down-stream processing operations. Filling the adjacent empty pits with the overburden is systemic to the process and therefore insures the genesis of mined-land land reclamation, an advantage of this method of surface mining. Planning strip mining utilizes a cross-section or range diagram of the earth to be removed. Strip mining is also called open-cut mining, open-cast mining, and stripping. </p><p><b>Further reading</b><br /> </p><p>Schissler, Andrew P., “Design and Methods of Coal Mining," in <i>The Encyclopedia of Energy</i>, Volume 1, Cutler J. Cleveland Editor-in-Chief, Elsevier Inc., Kidlington, Oxford, pp. 485-494. </p> <p><a href='/article/Strip_mining'>Read Full Article...</a></p> http://www.eoearth.org/article/Strip_mining Tue, 07 Jul 2009 06:10:50 GMT http://www.eoearth.org/article/Waste-to-energy <a href='/article/Waste-to-energy'><img border='0' src='/upload/thumb/9/96/Waste_combustors.gif/300px-Waste_combustors.gif' width='100'/></a> <p>Waste-to-energy is the process in which waste is used to generate useful energy –electricity, <a href="/article/Heat">heat</a> or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory <a href="/article/Combustion">combustion</a> conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per <a href="/article/Kilogram">kilogram</a>. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery <a href="/article/Boiler">boiler</a> to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families. </p><p>Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of <a href="/article/Methane">methane</a>, a high-fuel value gas. </p><p><strong>Further reading</strong><br /> <a href="http://www.wte.org/" class='external text' title="http://www.wte.org/">Waste to Energy systems</a>, Integrated Waste Services Association </p> <p><a href='/article/Waste-to-energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Waste-to-energy Mon, 06 Jul 2009 05:27:21 GMT http://www.eoearth.org/article/Waste-to-energy <a href='/article/Waste-to-energy'><img border='0' src='/upload/thumb/9/96/Waste_combustors.gif/300px-Waste_combustors.gif' width='100'/></a> <p>Waste-to-energy is the process in which waste is used to generate useful energy –electricity, <a href="/article/Heat">heat</a> or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory <a href="/article/Combustion">combustion</a> conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per <a href="/article/Kilogram">kilogram</a>. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery <a href="/article/Boiler">boiler</a> to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families. </p><p>Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of <a href="/article/Methane">methane</a>, a high-fuel value gas. </p><p><strong>Further reading</strong><br /> <a href="http://www.wte.org/" class='external text' title="http://www.wte.org/">Waste to Energy systems</a>, Integrated Waste Services Association </p> <p><a href='/article/Waste-to-energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Waste-to-energy Mon, 06 Jul 2009 05:26:10 GMT http://www.eoearth.org/article/Waste-to-energy <a href='/article/Waste-to-energy'><img border='0' src='/upload/thumb/9/96/Waste_combustors.gif/300px-Waste_combustors.gif' width='100'/></a> <p>Waste-to-energy is the process in which waste is used to generate useful energy –electricity, <a href="/article/Heat">heat</a> or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory <a href="/article/Combustion">combustion</a> conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per <a href="/article/Kilogram">kilogram</a>. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery <a href="/article/Boiler">boiler</a> to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families. </p><p>Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of <a href="/article/Methane">methane</a>, a high-fuel value gas. </p><p><strong>Further reading</strong><br /> <a href="http://www.wte.org/" class='external text' title="http://www.wte.org/">Waste to Energy systems</a>, Integrated Waste Services Association </p> <p><a href='/article/Waste-to-energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Waste-to-energy Mon, 06 Jul 2009 05:25:37 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Mon, 06 Jul 2009 05:25:18 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Mon, 06 Jul 2009 05:22:34 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Thu, 02 Jul 2009 06:01:29 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Thu, 02 Jul 2009 05:31:49 GMT http://www.eoearth.org/article/Forestry <a href='/article/Forestry'><img border='0' src='/upload/thumb/5/56/Forestry.jpeg/350px-Forestry.jpeg' width='100'/></a> <p>Forestry is the science and practice of managing a <a href="/article/Forest_biome">forest</a> for some goal. Prior to the establishment of forestry as a science-based discipline, the exploitation of forests for various products was carried out without sufficient regard for consequences. For example, trees were cut without ensuring tree regeneration. Logged areas were often burned catastrophically without regard for <a href="/article/Soil">soil</a> resources and logs dragged or flushed down <a href="/article/Stream">stream</a> valleys to a mill without concern for the stream habitat or water quality. </p><p>Scientific forestry is intended to alleviate these unintended consequences by basing management on research and a goal of sustainable management. The practice of forestry encompasses forest protection, forest engineering, silviculture, forest ecology, economics, biometrics, hydrology, wildlife management, and other disciplines. </p><p>Forests face multiple threats, such as fire, disease, insect outbreak, and <a href="/article/Air_pollution_emissions">air pollution</a>. Some of these factors can negatively impact large forest areas over short time periods. Other factors may create chronic stresses which may have long-term consequences on the nature of a forest ecosystem and the species within. Forest management activities are, therefore, undertaken to reduce fire risk, control pests, and to guide forest development processes towards specific, often multiple-use, management goals. Techniques include thinning and controlled burns to reduce fire risk, application of <a href="/article/Pesticide">pesticides</a> to control insect outbreaks, removal of diseased trees, and etc. </p><p>Modern forestry utilizes large equipment, and thus must utilize engineers. Unique achievements of forest engineers include cable yarding systems, the design of forest roads that produce less sediment, and the development of field harvesting equipment that increases efficiency. </p><p>Silviculture is the art and science of growing trees. Various silvicultural systems have been devised to harvest a stand (or selected trees) at lowest cost and with minimal damage, to ensure restocking of the site, to help trees grow rapidly, to favor particular species, and to protect <a href="/article/Biodiversity">biodiversity</a>. </p><p>Forest ecology is the study of the <a href="/article/Forest_biome">forest</a> as an ecological system. Facets of this science include tree physiology and life history, wildlife biology, nutrient cycling, biogeography, and other topics. The results of studies in forest ecology help inform silviculture as well as efforts to document and conserve biodiversity. </p><p>Since forestry is often conducted as a business, the economic aspect of forestry has long received attention. Forest economics encompasses field operations (such as harvesting), long-term stand management strategies, firm-wide (or forest-wide) economic planning, assessments of the impact of forest policy on nearby communities, and even international <a href="/article/Market">market</a> assessments of wood supply and effects of tariffs and tax policies. </p><p>Forest hydrology is concerned with the effects of forestry operations on hydrologic properties of <a href="/article/Stream">streams</a> and <a href="/article/Watershed">watersheds</a>, water yield, water quality, and stream biota. </p><p>Biometrics and forest mensuration are concerned with sampling and measuring properties such as stem form and biomass, site index, stand wood yield, etc. These fields are called upon also for the design of forest inventories and analysis of inventory data. </p><p>Forest management is typically extensive rather than intensive. The basic spatial unit of management is the forest stand, which is a more-or-less homogenous and identifiable spatial unit. When a prescription like thinning or <a href="/article/Fertilizer">fertilization</a> is applied, it is applied to one or more stands as whole units. This is because operational efficiencies can only be achieved in this manner and because detailed spatial manipulations (e.g., fertilizing at different levels for each tree) are not feasible with the information and techniques available. While certain scales of complexity of spatial pattern can be achieved, such as by selection or strip cutting or leaving remnant trees or patches, not all possible configurations are feasible. In addition, there may not be any known prescription that would favor a particular species (such as an endangered species) or remove a pest species. </p><p>Commercial forestry is necessarily carried out based on an expectation of profit. Non-market benefits (e.g., <a href="/article/Biodiversity">biodiversity</a> goals, aesthetics) can and need to be accommodated to maintain a social license to manage the <a href="/article/Forest_biome">forest</a> but they must not be too demanding of corporate resources (e.g., staff time, land area) or competing <a href="/article/Land-use">land-uses</a> will be selected. Forests on public lands, and particular those located in designated wilderness areas, are sometimes managed for non-commercial goals, including wildlife habitat restoration, old-growth preservation, water resource protection, preservation of biodiversity, and rare or endangered species conservation. Management strategies for preservation-related purposes may not generate net income from the harvesting of forest resources although other local and regional economic benefits may be derived from recreation related activities and by other environmental services provided by forests such as water and air protection and purification. </p> <p><a href='/article/Forestry'>Read Full Article...</a></p> http://www.eoearth.org/article/Forestry Wed, 01 Jul 2009 05:40:04 GMT http://www.eoearth.org/article/Land-use_and_land-cover_change <a href='/article/Land-use_and_land-cover_change'><img border='0' src='/upload/thumb/a/af/Brazil_deforestation.jpg/250px-Brazil_deforestation.jpg' width='100'/></a> <p><strong>Land-use and land-cover change</strong> (<strong>LULCC</strong>); also known as <strong>land change</strong>) is a general term for the human modification of Earth&#39;s terrestrial surface. Though humans have been modifying land to obtain food and other essentials for thousands of years, current rates, extents and intensities of LULCC are far greater than ever in history, driving unprecedented changes in ecosystems and environmental processes at local, regional and global scales. These changes encompass the greatest environmental concerns of human populations today, including climate change, <a href="/article/Biodiversity">biodiversity</a> loss and the pollution of water, soils and air. Monitoring and mediating the negative consequences of LULCC while sustaining the production of essential resources has therefore become a major priority of researchers and policymakers around the world.</p> <p><a href='/article/Land-use_and_land-cover_change'>Read Full Article...</a></p> http://www.eoearth.org/article/Land-use_and_land-cover_change Tue, 30 Jun 2009 05:38:56 GMT http://www.eoearth.org/article/Biosphere <a href='/article/Biosphere'><img border='0' src='/upload/thumb/0/03/Earth_spheres.jpg/300px-Earth_spheres.jpg' width='100'/></a> <p>The<strong> biosphere</strong> is the biological component of earth systems, which also include the lithosphere, hydrosphere, <a href="/article/Atmosphere_layers">atmosphere</a> and other &quot;spheres&quot; (e.g. <a href="/article/Cryosphere">cryosphere</a>, anthrosphere, etc.). The biosphere includes all living organisms on earth, together with the dead organic matter produced by them. </p> <p>The biosphere concept is common to many scientific disciplines including astronomy, geophysics, geology, hydrology, biogeography and <a href="/article/Evolution">evolution</a>, and is a core concept in <a href="/article/Ecology">ecology</a>, earth science and <a href="/article/Physical_geography">physical geography</a>. A key component of earth systems, the biosphere interacts with and exchanges <a href="/article/Matter">matter</a> and energy with the other spheres, helping to drive the global biogeochemical cycling of <a href="/article/Carbon_cycle">carbon</a>, <a href="/article/Nitrogen_cycle">nitrogen</a>, phosphorus, sulfur and other <a href="/article/Elements">elements</a>. From an ecological point of view, the biosphere is the &quot;global <a href="/article/Ecosystem">ecosystem</a>&quot;, comprising the totality of <a href="/article/Biodiversity">biodiversity</a> on earth and performing all manner of biological functions, including <a href="/article/Photosynthesis">photosynthesis</a>, respiration, decomposition, nitrogen fixation and denitrification. </p><p>The biosphere is dynamic, undergoing strong seasonal cycles in primary productivity and the many biological processes driven by the energy captured by photosynthesis. Seasonal cycles in solar irradiation of the hemispheres is the main driver of this dynamic, especially by its strong effect on <a href="/article/Terrestrial_biome">terrestrial</a> primary productivity in the temperate and boreal <a href="/article/Biome">biomes</a>, which essentially cease productivity in the winter time. </p><p>The biosphere has evolved since the first single-celled organisms originated 3.5 billion years ago under atmospheric conditions resembling those of our neighboring planets Mars and Venus, which have atmospheres composed primarily of <a href="/article/Carbon_dioxide">carbon dioxide</a>. Billions of years of primary production by plants released <a href="/article/Oxygen">oxygen</a> from this carbon dioxide and deposited the carbon in sediments, eventually producing the oxygen-rich <a href="/article/Atmospheric_composition">atmosphere</a> we know today. Free oxygen, both for breathing (O₂, respiration) and in the stratospheric <a href="/article/Ozone">ozone</a> (O₃) that protects us from harmful UV radiation, has made possible life as we know it while transforming the chemistry of earth systems forever. </p><p>As a result of long-term interactions between the biosphere and the other earth systems, there is almost no part of the earth&#39;s surface that has not been profoundly altered by living organisms. The earth is a living planet, even in terms of its physics and chemistry. A concept related to, but different from, that of the biosphere, is the <a href="/article/Environmental_ethics_and_the_Gaia_theory">Gaia hypotheses</a>, which posits that living organisms have and continue to transform earth systems for their own benefit. </p> <p><a href='/article/Biosphere'>Read Full Article...</a></p> http://www.eoearth.org/article/Biosphere Mon, 29 Jun 2009 04:04:20 GMT http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils <a href='/article/Hillslope_processes_and_mass_movement_of_soils'><img border='0' src='/upload/thumb/f/f7/Scree_slope.jpg/250px-Scree_slope.jpg' width='100'/></a> <p>Hillslopes are an important part of the <a href="/article/Physiography_of_the_Earth%27s_terrestrial_surface">terrestrial landscape</a>. The Earth's landscape can be thought of as being composed of a mosaic of slope types, ranging from steep mountains and cliffs to almost flat plains. On most hillslopes large quantities of <a href="/article/Soil">soil</a> and sediment are moved over time via the mediums of air, water, and ice often under the direct influence of gravity. The form a hillslope takes is dependent on the various geomorphic processes acting on it. Hillslopes are also the source of materials that are used to construct a number of depositional landforms. </p><p>In practical terms, hillslopes have direct and indirect influence on a number of human activities. The steepness and structural stability of hillslopes determines their suitability for <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, and human settlement. Hillslopes can also become a hazard to humans if their materials move rapidly through the process of mass wasting. </p> <p><a href='/article/Hillslope_processes_and_mass_movement_of_soils'>Read Full Article...</a></p> http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils Fri, 26 Jun 2009 05:33:23 GMT http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils <a href='/article/Hillslope_processes_and_mass_movement_of_soils'><img border='0' src='/upload/thumb/f/f7/Scree_slope.jpg/250px-Scree_slope.jpg' width='100'/></a> <p>Hillslopes are an important part of the <a href="/article/Physiography_of_the_Earth%27s_terrestrial_surface">terrestrial landscape</a>. The Earth's landscape can be thought of as being composed of a mosaic of slope types, ranging from steep mountains and cliffs to almost flat plains. On most hillslopes large quantities of <a href="/article/Soil">soil</a> and sediment are moved over time via the mediums of air, water, and ice often under the direct influence of gravity. The form a hillslope takes is dependent on the various geomorphic processes acting on it. Hillslopes are also the source of materials that are used to construct a number of depositional landforms. </p><p>In practical terms, hillslopes have direct and indirect influence on a number of human activities. The steepness and structural stability of hillslopes determines their suitability for <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, and human settlement. Hillslopes can also become a hazard to humans if their materials move rapidly through the process of mass wasting. </p> <p><a href='/article/Hillslope_processes_and_mass_movement_of_soils'>Read Full Article...</a></p> http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils Fri, 26 Jun 2009 05:32:35 GMT http://www.eoearth.org/article/Viral_hemorrhagic_fevers <a href='/article/Viral_hemorrhagic_fevers'><img border='0' src='/upload/thumb/a/ab/BSL4_containment_CDC.jpg/199px-BSL4_containment_CDC.jpg' width='100'/></a> <p>The Centers for Disease Control and Prevention&#39;s National Center for Infectious Diseases has prepared answers to questions about the nature of the group of illnesses characterized as viral hemorrhagic fevers.</p> <p><a href='/article/Viral_hemorrhagic_fevers'>Read Full Article...</a></p> http://www.eoearth.org/article/Viral_hemorrhagic_fevers Thu, 25 Jun 2009 04:17:10 GMT http://www.eoearth.org/article/Viral_hemorrhagic_fevers <a href='/article/Viral_hemorrhagic_fevers'><img border='0' src='/upload/thumb/a/ab/BSL4_containment_CDC.jpg/199px-BSL4_containment_CDC.jpg' width='100'/></a> <p>The Centers for Disease Control and Prevention&#39;s National Center for Infectious Diseases has prepared answers to questions about the nature of the group of illnesses characterized as viral hemorrhagic fevers.</p> <p><a href='/article/Viral_hemorrhagic_fevers'>Read Full Article...</a></p> http://www.eoearth.org/article/Viral_hemorrhagic_fevers Thu, 25 Jun 2009 04:16:46 GMT http://www.eoearth.org/article/Viral_hemorrhagic_fevers <a href='/article/Viral_hemorrhagic_fevers'><img border='0' src='/upload/thumb/a/ab/BSL4_containment_CDC.jpg/199px-BSL4_containment_CDC.jpg' width='100'/></a> <p>The Centers for Disease Control and Prevention&#39;s National Center for Infectious Diseases has prepared answers to questions about the nature of the group of illnesses characterized as viral hemorrhagic fevers.</p> <p><a href='/article/Viral_hemorrhagic_fevers'>Read Full Article...</a></p> http://www.eoearth.org/article/Viral_hemorrhagic_fevers Thu, 25 Jun 2009 04:16:23 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Thu, 25 Jun 2009 04:15:44 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Wed, 24 Jun 2009 04:25:57 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Wed, 24 Jun 2009 04:25:42 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Wed, 24 Jun 2009 04:25:30 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Wed, 24 Jun 2009 04:22:18 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Wed, 24 Jun 2009 04:21:17 GMT http://www.eoearth.org/article/Mauna_Loa_curve <a href='/article/Mauna_Loa_curve'><img border='0' src='/upload/thumb/5/58/Mauna_Loa_map.png/250px-Mauna_Loa_map.png' width='100'/></a> <p>Since 1958, the concentration of <a href="/article/Carbon_dioxide">carbon dioxide</a> (CO₂) in the <a href="/article/Atmospheric_composition">atmosphere</a> has been measured daily at Mauna Loa Observatory, Hawaii (19°32' N, 155°35' W). Mauna Loa Observatory is located on the Island of Hawaii at an elevation of 3,397 meters above mean sea level) on the northern flank of Mauna Loa volcano. Established in 1957, Mauna Lao Observatory has grown to become the premier long-term atmospheric monitoring facility on Earth and is the site where the ever-increasing concentrations of global atmospheric CO₂ were determined. The observatory consists of 10 buildings from which up to 250 different atmospheric parameters are measured by scientists and engineers. </p><p>This air is relatively free from local pollutants, and so is thought to be representative of air in the northern hemisphere. CO₂ measurements at Mauna Loa show two movements. Since 1958, there has been a general increase in the atmospheric concentration of CO₂ due to the <a href="/article/Combustion">combustion</a> of fossil fuels and deforestation. The data also show an annual <a href="/article/Carbon_cycle">cycle</a>. Each year, the concentration of CO₂ rises and falls. The curve is also known as the "Keeling curve", named for <a href="/article/Keeling%2C_Charles_D.">Charles D. Keeling</a> (1928-2005), an American pioneer in the <a href="/article/Monitoring">monitoring</a> of carbon dioxide concentrations in the atmosphere. </p> <p><a href='/article/Mauna_Loa_curve'>Read Full Article...</a></p> http://www.eoearth.org/article/Mauna_Loa_curve Wed, 24 Jun 2009 04:20:10 GMT http://www.eoearth.org/article/Mauna_Loa_curve <a href='/article/Mauna_Loa_curve'><img border='0' src='/upload/thumb/5/58/Mauna_Loa_map.png/250px-Mauna_Loa_map.png' width='100'/></a> <p>Since 1958, the concentration of <a href="/article/Carbon_dioxide">carbon dioxide</a> (CO₂) in the <a href="/article/Atmospheric_composition">atmosphere</a> has been measured daily at Mauna Loa Observatory, Hawaii (19°32' N, 155°35' W). Mauna Loa Observatory is located on the Island of Hawaii at an elevation of 3,397 meters above mean sea level) on the northern flank of Mauna Loa volcano. Established in 1957, Mauna Lao Observatory has grown to become the premier long-term atmospheric monitoring facility on Earth and is the site where the ever-increasing concentrations of global atmospheric CO₂ were determined. The observatory consists of 10 buildings from which up to 250 different atmospheric parameters are measured by scientists and engineers. </p><p>This air is relatively free from local pollutants, and so is thought to be representative of air in the northern hemisphere. CO₂ measurements at Mauna Loa show two movements. Since 1958, there has been a general increase in the atmospheric concentration of CO₂ due to the <a href="/article/Combustion">combustion</a> of fossil fuels and deforestation. The data also show an annual <a href="/article/Carbon_cycle">cycle</a>. Each year, the concentration of CO₂ rises and falls. The curve is also known as the "Keeling curve", named for <a href="/article/Keeling%2C_Charles_D.">Charles D. Keeling</a> (1928-2005), an American pioneer in the <a href="/article/Monitoring">monitoring</a> of carbon dioxide concentrations in the atmosphere. </p> <p><a href='/article/Mauna_Loa_curve'>Read Full Article...</a></p> http://www.eoearth.org/article/Mauna_Loa_curve Thu, 18 Jun 2009 03:01:17 GMT http://www.eoearth.org/article/Mauna_Loa_curve <a href='/article/Mauna_Loa_curve'><img border='0' src='/upload/thumb/5/58/Mauna_Loa_map.png/250px-Mauna_Loa_map.png' width='100'/></a> <p>Since 1958, the concentration of <a href="/article/Carbon_dioxide">carbon dioxide</a> (CO₂) in the <a href="/article/Atmospheric_composition">atmosphere</a> has been measured daily at Mauna Loa Observatory, Hawaii (19°32' N, 155°35' W). Mauna Loa Observatory is located on the Island of Hawaii at an elevation of 3,397 meters above mean sea level) on the northern flank of Mauna Loa volcano. Established in 1957, Mauna Lao Observatory has grown to become the premier long-term atmospheric monitoring facility on Earth and is the site where the ever-increasing concentrations of global atmospheric CO₂ were determined. The observatory consists of 10 buildings from which up to 250 different atmospheric parameters are measured by scientists and engineers. </p><p>This air is relatively free from local pollutants, and so is thought to be representative of air in the northern hemisphere. CO₂ measurements at Mauna Loa show two movements. Since 1958, there has been a general increase in the atmospheric concentration of CO₂ due to the <a href="/article/Combustion">combustion</a> of fossil fuels and deforestation. The data also show an annual <a href="/article/Carbon_cycle">cycle</a>. Each year, the concentration of CO₂ rises and falls. The curve is also known as the "Keeling curve", named for <a href="/article/Keeling%2C_Charles_D.">Charles D. Keeling</a> (1928-2005), an American pioneer in the <a href="/article/Monitoring">monitoring</a> of carbon dioxide concentrations in the atmosphere. </p> <p><a href='/article/Mauna_Loa_curve'>Read Full Article...</a></p> http://www.eoearth.org/article/Mauna_Loa_curve Thu, 18 Jun 2009 03:00:24 GMT http://www.eoearth.org/article/Lesser_Long-nosed_Bat <a href='/article/Lesser_Long-nosed_Bat'><img border='0' src='/upload/thumb/6/61/Lesser_long-nosed_bat1_USFS_MerlinDTuttle.jpg/200px-Lesser_long-nosed_bat1_USFS_MerlinDTuttle.jpg' width='100'/></a> <p><em><strong>This article was prepared for the U.S. Forest Service by Kim Winter of the <a href="http://www.coevolution.org/people.html" class='external text' title="http://www.coevolution.org/people.html">Coevolution Institute</a>. The images were made by Merlin D. Tuttle of <a href="http://www.batcon.org/home/default.asp" class='external text' title="http://www.batcon.org/home/default.asp">Bat Conservation International</a>.</strong></em></p> <p>During late spring in the <a href="/article/Sonoran_desert">Sonoran Desert</a>, the white flowers of Saguaro (<em>Carnegiea gigantea</em>) cacti bloom for just one evening to attract Lesser Long-nosed Bats (<em>Leptonycteris curasoae yerbabuena</em>) and Mexican Long-tongued Bats (<em>Choeronycteris mexicana</em>) for <a href="/article/Pollination">pollination</a>. The bats use their elongated muzzles to reach deep into Saguaro blossoms for nectar, covering their hairy heads with copious amounts of pollen that drop onto other flowers as the bats fly from cactus to cactus throughout the night. The blossoms close by the following afternoon, allowing daytime visitors such as wasps, bees, butterflies, and birds to pick up any remaining nectar or pollen left behind.</p> <p>Lesser long-nosed bats are perfectly adapted to feed and pollinate Saguaros and other large Southwestern and Mexican succulents such as Organ-pipe Cactus (<em>Stenocereus thurberi</em>), agaves (<em>Agave </em>spp.) and Cardón (<em>Pachycereus pringlei</em>). Their narrow snouts easily detect the strong melon scent of the night-blooming flowers, and their brush-tipped tongues extend deeply into flowers to extract rich quantities of nectar and pollen produced by the cacti to ensure that pollinators will find them during their brief period of bloom.</p> <p>Bat pollination of cacti and agaves helps maintain healthy <a href="/article/Desert_biome">desert</a> <a href="/article/Ecosystem">ecosystems</a>. Saguaros, the state flower of Arizona, are <a href="/article/Keystone_species">keystone species</a> in the Sonoran Desert and grow up to 50 feet in height, providing important perching and nesting sites for Red-tailed Hawks (<em>Buteo jamaicensis</em>); and nesting cavities for Gilded Flickers (<em>Colaptes chrysoides</em>) and Gila Woodpeckers (<em>Melanerpes uropygialis</em>), Elf Owls (<em>Micrathene whitneyi</em>), Purple Martins (<em>Progne subis</em>), and other birds. Once the Saguaro fruit ripens in June, Lesser Long-nosed Bats, White-winged Doves (<em>Zenaida asiatica</em>), Gila Woodpeckers, and other birds consume the fleshy red pulp and thereby disperse the seeds, which pass through their guts intact. Agaves provide an important food resource to the Lesser Long-nosed Bat during its annual migration from <a href="/article/Mexico">Mexico</a> to the Sonoran Desert.</p> <p>The Lesser Long-nosed Bat is federally listed as endangered species by the <a href="/article/United_States_Fish_and_Wildlife_Service">U.S. Fish and Wildlife Service</a> under the <a href="/article/Endangered_Species_Act%2C_United_States">Endangered Species Act of 1973</a>. The survival of both bats and their desert food plants are threatened by loss of habitat due to development, <a href="/article/Invasive_species">invasive</a> annual <a href="/article/Grasses">grasses</a>, and changes in <a href="/article/Fire_ecology_fact_sheet">fire</a> regimes. With nature in the balance, ensuring the future of the southwestern desert will depend on appreciating and protecting the roles played by both pollinator and plant in these fragile ecosystems.</p> <p><big><strong>Further Reading</strong></big></p> <ul><li>Celebrating Wildflowers: <a href="http://www.fs.fed.us/wildflowers/pollinators/bats.shtml" class='external text' title="http://www.fs.fed.us/wildflowers/pollinators/bats.shtml">Bat Pollination</a></li><li><a href="http://www.batcon.org/" class='external text' title="http://www.batcon.org/">Bat Conservation International</a></li><li><a href="http://www.desertmuseum.org/pollination/bats.html" class='external text' title="http://www.desertmuseum.org/pollination/bats.html">Arizona-Sonora Desert Museum</a></li><li>U.S. Fish and Wildlife Service—<a href="http://www.fws.gov/endangered/bats/bats.htm" class='external text' title="http://www.fws.gov/endangered/bats/bats.htm">Endangered Bats</a></li><li>Lubee Bat Conservancy: <a href="http://www.lubee.org/aboutbats.aspx" class='external text' title="http://www.lubee.org/aboutbats.aspx">About Fruit and Nectar Bats</a> </li><li><a href="http://www.pollinator.org" class='external text' title="http://www.pollinator.org">North American Pollinator Protection Campaign</a> </li></ul><p> <br /> <p><br style="clear: left" /> <center> </p> </center></p> <p><a href='/article/Lesser_Long-nosed_Bat'>Read Full Article...</a></p> http://www.eoearth.org/article/Lesser_Long-nosed_Bat Wed, 17 Jun 2009 01:33:13 GMT http://www.eoearth.org/article/Land_tenure_and_management_in_the_boreal_region <a href='/article/Land_tenure_and_management_in_the_boreal_region'><img border='0' src='/upload/thumb/c/c9/Figure14.3_russia_forest.jpg/620px-Figure14.3_russia_forest.jpg' width='100'/></a> <p>This is Section 14.3 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a> <br /> Lead Author: Glenn P. Juday; Contributing Authors: Valerie Barber, Paul Duffy, Hans Linderholm, Scott Rupp, Steve Sparrow, Eugene Vaganov, John Yarie; Consulting Authors: Edward Berg, Rosanne D’Arrigo, Olafur Eggertsson,V.V. Furyaev, Edward H. Hogg, Satu Huttunen, Gordon Jacoby,V.Ya. Kaplunov, Seppo Kellomaki, A.V. Kirdyanov, Carol E. Lewis, Sune Linder, M.M. Naurzbaev, F.I. Pleshikov, Ulf T. Runesson,Yu.V. Savva, O.V. Sidorova,V.D. Stakanov, N.M.Tchebakova, E.N.Valendik, E.F.Vedrova, Martin Wilmking </p><p>&nbsp;</p><p>The influence of climate change on forest values and forest users depends on the amount and initial condition of the forest resource and the uses or intangible values of the forest for people, cultures, and economies. This section reviews forest extent, the overall allocation of forest land to different uses, the main patterns of forest use, the management systems, and the values generated by the boreal forest. Where these characteristics can be singled out by political jurisdiction or other means, the discussion is focused on the northern boreal forest. This discussion forms the basis for considering climate change impacts.</p> <p><a href='/article/Land_tenure_and_management_in_the_boreal_region'>Read Full Article...</a></p> http://www.eoearth.org/article/Land_tenure_and_management_in_the_boreal_region Tue, 16 Jun 2009 01:04:54 GMT http://www.eoearth.org/article/Puritan_origins_of_the_American_wilderness_movement <a href='/article/Puritan_origins_of_the_American_wilderness_movement'><img border='0' src='/upload/thumb/f/f8/Puritan_mountain_ramble_1860.jpg/200px-Puritan_mountain_ramble_1860.jpg' width='100'/></a> <?php $page_title = "Puritan origins of the American wilderness movement";?> <?php include($_SERVER['DOCUMENT_ROOT'] . '/e/template/header.php');?> <p><a href='/article/Puritan_origins_of_the_American_wilderness_movement'>Read Full Article...</a></p> http://www.eoearth.org/article/Puritan_origins_of_the_American_wilderness_movement Mon, 15 Jun 2009 01:54:42 GMT http://www.eoearth.org/article/Transboundary_protected_areas <a href='/article/Transboundary_protected_areas'><img border='0' src='/upload/thumb/d/db/Glacier_national_park.jpg/300px-Glacier_national_park.jpg' width='100'/></a> <p>The <a href="/article/World_Conservation_Union_%28IUCN%29">World Conservation Union (IUCN)</a> defines the term <strong>peace park</strong> as an area “formally dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources, and to the promotion of peace and co-operation.” Peace Parks constitute but one type of <strong>transboundary protected area</strong> (TBPA), which in turn is defined as: “An area of land and/or sea that straddles one or more boundaries between states, sub-national units such as provinces and regions, autonomous areas and/or areas beyond the limits of national sovereignty or jurisdiction, whose constituent parts are especially dedicated to the protection and maintenance of biological diversity, and of natural and associated cultural resources, and managed co-operatively through legal or other effective means.” </p><p>An inchoate notion of a “peace park” seems to have been initiated in Europe and not, as commonly thought, in North America. As early as 1780, a Treaty of Alliance between the King of France and the Prince-Bishop of Basel stated that nothing “is more proper for maintaining good relations and peace between two bordering states” than punishing offenses related to forests, hunting, and fishing. Designating “an equal and uniform jurisprudence” over these issues within their shared border region, this treaty was also notable for stipulating that the two parties adopt the early conservation-oriented French Forest Ordinance of 1669. </p><p>The modern concept of a peace park apparently originated in the 1924 Krakow Protocol, which aimed to resolve a boundary dispute between Poland and Czechoslovakia left over from World War I. However, it took eight years for the protocol’s call for an international “reservation of regions for culture, wildlife, plant and local scenery protection” to bear fruit. </p> <p>In the meantime on the other side of the Atlantic, a similar idea had reportedly occurred to park rangers in Glacier National Park of the United States and the adjacent Waterton National Park of Canada—as well as to individual members of the Cardston Rotary Club. About thirty miles east of Waterton, Cardston was a small Mormon town in southern Alberta, and its Rotary Club was one of hundreds scattered around the United States and Canada. At a goodwill meeting in Waterton on July 4, 1931, Rotary Clubs from Alberta and Montana formally proposed an international peace park between Glacier and Waterton. Rotarians on both sides of the border immediately turned to lobbying their respective governments. The official response was remarkably quick, as both the Canadian Parliament and the U.S. Congress were able to pass legislation in time for a dedication ceremony in Glacier Park on June 19, 1932. Since then, an annual assembly of local Rotary Clubs has alternated between the two parks, each meeting culminating in a “hands across the border” ceremony. Notably, two months after the dedication of Waterton-Glacier, Poland and Czechoslovakia formally recognized “the first International Landscape Park in Europe” between the Polish Pieniny National Park and the Slovak National Natural Reserve on August 17. Thus, 1932 can be described as the watershed year for peace parks. </p><p>Only one year later, other European colonial powers were considering the idea of <a href="/article/Transborder_conservation">transborder conservation</a>—but interestingly enough, not in Europe. In 1933, the colonial powers signed the London Convention Relative to the Preservation of Fauna and Flora in their Natural State. Entering into force in 1936, this convention was a follow-up effort to what appears to have been the first multilateral convention on international conservation: the 1900 Convention for the Preservation of Wild Animals, Birds and Fish in Africa. Yet the 1900 convention had contained no specific transborder clauses—and in any case, it had never entered into force. In contrast, the 1933 convention called for “prior consultation” and “cooperation” where “a national park or strict natural reserve” had been or was to be established “contiguous to a park or reserve situated in another territory . . . or to the boundary of such territory” (Article 6). Although the colonial powers probably had certain areas in mind in drafting such specific language, there is no indication that it was ever directly implemented. </p><p>However, by the time the Convention was agreed to, an early form of <a href="/article/Transborder_conservation">transborder conservation</a> had already begun in the Virunga Mountains, where Belgium had established Africa’s first national park in 1925. Originally covering the western half of the Virunga Mountains in the Belgian Congo, the park was named after the ruling King Albert who, having been inspired by several prominent conservationists on a visit to Yellowstone National Park in 1919, had been subsequently convinced by American naturalist Carl Akeley to protect the central African area for its <a href="/article/Mountain">mountain</a> gorillas. In 1929, the Belgian authorities expanded Albert National Park to include all of the Virunga Mountains that traversed the two colonies of the Belgian Congo and Ruanda-Urundi (a League of Nations territory under Belgian rule). This expansion laid the foundation for an incipient transborder park, for when the colonies gained their independence in the 1960s, the park was split into the Virunga National Park of the Democratic Republic of the Congo (Zaire 1971–1997) and Volcanos National Park of Rwanda. Although transborder conservation initiatives in the region have been stymied by civil wars on both sides of the border, in October 2005 the two countries along with Uganda signed a Tripartite Declaration that recognized the need to establish a “Central Albertine Rift Transfrontier Protected Area Network.” </p><p>Notably, while Article 6 of the 1933 London convention concerned the coordinated management of parks and reserves in Africa, it did not refer to the subject of peace. This raises an important point: although “peace” and “park” make mutually admirable goals, they are not one and the same thing. For several reasons, however, peace park will no doubt remain the most common term for site-specific transborder collaboration. First, and most obvious, the phrase is alliterative and colorful. Second, depending on the level of strife occurring in any particular border region, conservationists will recognize that the “peace” side of the equation (viz., matters of international security) will normally achieve greater visibility than the “park” side (viz., matters of biological conservation). Accordingly, few conservationists will hesitate to ride the coattails of what will almost always prove to be the issue of paramount political significance. Finally, early synthesizing scholarship on <a href="/article/Transborder_conservation">transborder conservation</a> tended to focus on peace parks, particularly the work of Arthur Westing. Westing led a broad investigation into the relationship between war and the environment in the wake of the seminal 1972 Stockholm Conference, thereby setting an agenda that the international conservation community would follow in the decades to come. </p><p>Despite the predominance of the label, “peace park” is only one name among many used to describe transborder areas set aside at least in part for conservation. Other names include border park, transborder park, borderline park, friendship park, transnational park, transfrontier reserve, transboundary conservation area, transborder conservation area, cross-border protected natural park, and transboundary natural resource management area. Out of this titular thicket, the generic “transboundary protected area” (TBPA) has become the most widely accepted term in policy and scholarly circles. </p><p>Trying to count the global number of TBPAs has proven challenging. During the 1980s, the IUCN identified approximately 70 protected areas sharing “common international boundaries,” which translated into a total of approximately 35 transborder areas. Subsequent counts identified substantial numbers of either new TBPAs or TBPAs that had not been identified. An extensive search and analysis commenced in the late 1990s resulted in a 2005 listing of 188 “internationally adjoining protected areas.” </p><p>With so many TBPAs worldwide, conservationists have devised several ways of categorizing them. One group of conservation practitioners, for instance, has delineated five different types of TBPAs on the basis of geographic parameters: </p> <ul><li> two or more contiguous protected areas across a national boundary; </li><li> a cluster of protected areas and the intervening land; </li><li> a cluster of separated protected areas without intervening land; </li><li> a transborder area including proposed protected areas; and </li><li> a protected area in one country aided by sympathetic land use over the border. </li></ul> <p>Another group identified three different ways that “transboundary initiatives develop.” First, high-level initiatives involve officials within an administrative capacity above the level of direct land management. Second, locally based initiatives refer to those established at the level of direct “on-the-ground” land management. Finally, third-party initiatives occur “via a conservation non-governmental organisation (NGO) acting as a third party advocate, encouraging and supporting co-operative transboundary management.” </p><p>In 2005, researcher Dorothy Zbicz identified six “hierarchical, increasing levels of transboundary cooperation between adjoining protected areas”: no cooperation, communication, consultation, collaboration, coordination of planning, and full cooperation. A global survey of managers working in TBPAs according to this system found that at the extremes, 18 percent responded that there was no cooperation at all, while 7 percent were cooperating at the level of “full cooperation.” The largest minority, 39 percent, was at the level of “communication.” In her analysis, Zbicz drew out four “factors” correlated to the level of cooperation. In essence, higher levels of cooperation occurred (1) if the idea of transfrontier cooperation and <a href="/article/Ecosystem-based_management">ecosystem-based management</a> was important to the protected area managers and personnel, (2) if there were adequate communication technologies in place, (3) if there were individuals willing to take leadership roles, and (4) if land managers were able to make personal contact across the border. Not surprisingly, it was the latter factor that correlated most strongly with the level of cooperation achieved. </p><p>Despite the myriad benefits of TBPAs (one group of conservationists drew up a list of over twenty such benefits), they have generated significant controversy on both social and biological grounds. Several critiques on social grounds have come from sub-Saharan Africa, which has become a global “hot spot” for the establishment of peace parks, yet where TBPAs often intersect with extreme poverty and significant human rights violations. The critiques range from a general accusation that peace parks represent little more than a contemporary colonialist attitude toward Africa to the more specific argument that they have the ironic effect of actually fostering animosity (e.g., disputes over revenue sharing from ecotourism). </p><p>TBPAs have also become a flashpoint in a larger debate within the conservation community over the relationship between conserving <a href="/article/Biodiversity">biodiversity</a> and meeting the needs of an ever-growing human <a href="/article/Population">population</a>. Running congruent to endless deliberations over what exactly constitutes <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, the debate can be simplistically divided into two ideologies. On one side are the “challengers,” who argue that the traditional form of conservation—that is, putting a wall around “nature” and excluding all but the most transient of human visitors—can work only in limited conditions within the developed world. Rather than throwing barricades around biodiversity, they argue, long-term protection depends on ensuring that people can live sustainably off the habitat to be protected, or at least can find gainful livelihoods in some other fashion. Practical implementation of this approach has come under the banner of “community-based conservation” (CBC) and “integrated conservation and development projects” (ICDPs), the latter of which is generally defined as biodiversity conservation projects with rural development components that are located near protected areas. The opposite encampment, the “defenders,” has responded that the myriad attempts at CBCs and ICDPs have generally failed to protect <a href="/article/Biodiversity">biodiversity</a> and that protecting all the components of biodiversity in any given ecosystem requires direct habitat protection. Furthermore, they argue, traditional efforts to protect habitat already provide many direct and indirect benefits to local people. </p><p>The literature spawned by this debate is copious and, of course, far more nuanced than the above summary suggests. TBPAs have become embroiled in the debate under the accusation that they emanate from the defenders’ encampment and thus constitute little more than a new approach to “bottling up” nature. Practitioners of <a href="/article/Transborder_conservation">transborder conservation</a> disagree vehemently, arguing that human betterment has always been an integral component of their efforts to establish TBPAs. </p><p>To address the practical and ethical problems posed by TBPAs, numerous sets of formal and informal “best practices” have been developed. As early as 1980, the Council of Europe agreed to a European Outline Convention on Transfrontier Co-operation between Territorial Communities or Authorities, Section 1.9 of which consisted of a “Model Agreement on the Creation and Management of Transfrontier Parks.” The Model Agreement called for the parties “to harmonise their methods of management and to co-ordinate all development projects or improvements by means of a comprehensive action programme leading ultimately to joint management of the park based on a joint management plan.” The Model Agreement also called for joint committees whose membership would include “representatives of recognised private nature conservation organizations and organisations which contribute to the safeguarding of the landscape and the environment.” </p><p>A more recent set of general guidelines comes from the World Commission on Protected Areas (WCPA), which put forth a set of “good practice guidelines” under nine primary headings: </p> <ol><li>identifying and promoting common values; </li><li>involving and benefiting local people; </li><li>obtaining and maintaining support of decision makers; </li><li>promoting coordinated and cooperative activities; </li><li>achieving coordinated planning and protected area development; </li><li>developing cooperative agreements; </li><li>working toward funding sustainability; </li><li>monitoring and assessing progress; and </li><li>dealing with tension or armed conflict. </li></ol> <p>Along with these guidelines, the WCPA proposed a “Draft Code for transboundary protected areas in times of peace and armed conflict,” which essentially constitutes an annotated template for a formal bilateral agreement over a transboundary protected area. In 2003 the EUROPARC Federation established a certification system for “exemplary transboundary cooperation between protected areas” according to a set of criteria in the form of seven questions: </p> <ol><li>Do the parks have a common vision for <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a> in the region? </li><li>Is an agreement in place, which is signed by the parks or at political decision-making levels and which guarantees the continuity of the cooperation? </li><li>Does a joint work program exist, which defines the main areas of cooperation in the individual fields of work? </li><li>Are mechanisms for direct cooperation between protected area staff, the regular exchange of experience, and the implementation of joint meetings and decisions established? </li><li>Does observation of changes in parks’ natural values through joint <a href="/article/Monitoring">monitoring</a> and the holding of regular exchanges of data take place? </li><li>Are steps taken to ensure that communication between the protected areas is not held back by language barriers? </li><li>Are joint transboundary projects in existence and has their financing been secured? </li></ol> <p>In terms of international support for TBPAs, at least one observer has called for an international “legal regime” on transborder parks, while others have identified extensive justification for them in international law. Although the text of the <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> does not refer to TBPAs, in 2004 the countries that have ratified the convention (known as the “Conference of the Parties”) adopted the goal of establishing and strengthening “regional networks, transboundary protected areas and collaboration between neighbouring protected areas across national boundaries” under its “Protected Areas Programme of Work.” In addition, the IUCN’s 2004 draft of an International Covenant on Environment and Development states that parties to the convention would “cooperate in the conservation, management and restoration of natural resources which occur in areas under the jurisdiction of more than one State, or fully or partly in areas beyond the limits of national jurisdiction. To this end, (a) Parties sharing the same natural system shall make every effort to manage that system as a single ecological unit notwithstanding national boundaries.” </p><p>Overall, although there are some precedents for a legal regime on TBPAs, such a framework is unlikely to emerge out of the already crowded arena of international environmental law. Nevertheless, institutional support for TBPAs has arisen from within the international community. Two major international financial institutions, for example, have focused their efforts on TBPAs. The World Bank has financially supported a number of transborder protected area projects and investigations, and the International Tropical Timber Organization (ITTO) has funded a minimum of seven transboundary conservation areas. Finally, and perhaps most important, a community of dedicated researchers and practitioners has materialized around TBPAs that since 1988 has held at least seven significant conferences and meetings focused on the subject. This community has manifested itself in several interrelated institutional bodies. First, in 1997 a Parks for Peace initiative was established as a joint undertaking of the South African Peace Parks Foundation and three arms of the IUCN (the WCPA, the Programme on Protected Areas, and the Commission on Environmental Law). From that collaboration arose the WCPA’s Task Force on Transboundary Protected Areas, from which in turn has arisen the Global Transboundary Protected Area Network. </p><p>A growing number of conservationists are working on transborder protected areas, transborder biosphere reserves, and transborder bioregions. With biologists continuing to improve our understanding of the threats to landscape-scale <a href="/article/Biodiversity">biodiversity</a> and the corresponding importance of landscape-scale conservation, it is a trend that seems likely to continue. </p><p><strong><big>Further Reading</big></strong><br /> </p> <ul><li> Chester, Charles C. 2006. Conservation across borders: Biodiversity in an interdependent world. Washington, D.C.: Island Press. [Note: This entry in the Encyclopedia is adapted from this book; extensive parenthetical references can be found therein.] <a href="http://www.amazon.com/dp/1559636114/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/1559636114/?tag=encycofearth-20">ISBN: 1559636114</a> </li><li> <a href="http://www.europarc.org/international/europarc.html" class='external text' title="http://www.europarc.org/international/europarc.html">EUROPARC Federation</a>. 2003. Transboundary parks...following nature&#39;s design. EUROPARC Newsletter, no. 5 August, 2-3. </li><li> Sandwith, Trevor, Clare Shine, Lawrence Hamilton, and David Sheppard. 2001. <a href="http://iucn.org/dbtw-wpd/edocs/PAG-007.pdf" class='external text' title="http://iucn.org/dbtw-wpd/edocs/PAG-007.pdf">Transboundary protected areas for peace and Cco-operation</a>. Gland, Switzerland: <a href="http://www.iucn.org/" class='external text' title="http://www.iucn.org/">World Conservation Union (IUCN)</a>. </li><li> Westing, Arthur H. 1998. Establishment and management of transfrontier reserves for conflict prevention and confidence building. <em><a href="http://www.cambridge.org/journals/journal_catalogue.asp?mnemonic=ENC" class='external text' title="http://www.cambridge.org/journals/journal catalogue.asp?mnemonic=ENC">Environmental Conservation</a></em>. 25(2):91-94. </li><li> Zbicz, Dorothy C. 2003. Imposing Transboundary Conservation: Cooperation Between Internationally Adjoining Protected Areas. In Transboundary protected areas: The viability of regional conservation strategies, ed. Urami Manage Goodale, Marc J. Stern, Cheryl Margoluis, * Ashley G. Lanfer and Matthew Fladeland: 21-37. New York: Food Products Press (published simultaneously in the Journal of Sustainable Forestry, 17: 1/2). <a href="http://www.amazon.com/dp/1560220945/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/1560220945/?tag=encycofearth-20">ISBN: 1560220945</a> </li></ul> <p><a href='/article/Transboundary_protected_areas'>Read Full Article...</a></p> http://www.eoearth.org/article/Transboundary_protected_areas Fri, 12 Jun 2009 01:43:38 GMT http://www.eoearth.org/article/Bottom-up_control <a href='/article/Bottom-up_control'><img border='0' src='/upload/thumb/a/ab/Bottomup1.jpg/250px-Bottomup1.jpg' width='100'/></a> <p>Variation in distribution and abundance of organisms is dependent on interactions between physical and biotic factors. &quot;Bottom-up&quot; effects refer to controls on the abundance and/or community structure of organisms that derive from supply of resources (light or nutrients for plants, prey organisms for animals) or from physical factors such as temperature of the environment. That is, bottom-up controls arise from near the bottom of the <a href="/article/Food_web">food web</a>, below the trophic level in question. In the case of plants, their growth is controlled by the availability of nutrients and <a href="/article/Solar_radiation">sunlight</a>. For example, farmers use <a href="/article/Fertilizer">fertilizers</a> or manure to increase the nutrients in the <a href="/article/Soil">soil</a> and promote crop growth. Soil nutrient availability can directly enhance vegetative growth, flowering, and fruiting. Nutrient addition to alpine shrubs can also increase <a href="/article/Pollination">pollinator</a> visitation, which could affect seed output. Thus, availability of soil <a href="/article/Nitrogen">N</a> or other limiting nutrients can produce strong positive bottom-up effects on the reproductive output of plants.</p> <p>In many temperate-zone areas, aquatic <a href="/article/Phytoplankton">phytoplankton</a> populations undergo large increases (blooms) in the spring when duration of sunlight increases and high levels of nutrients are in the water following winter. The bloom ceases and populations decline when they have used up all the nutrients in the water. Animal populations are dependent on the availability of food, so the phytoplankton bloom provides more food for the zooplankton, whose populations subsequently increase. Some <a href="/article/Plankton">Planktonic</a> populations are regulated by a combination of both resource limitation from the bottom up and <a href="/article/Predation">predation</a> from the <a href="/article/Top-down_control">top down</a>, so the increasing zooplankton populations serve to check the growth of the phytoplankton population.</p> <p>Increased resources such as light or nutrients may increase abundances of not only plants but also animals higher in the food web, in which case the community or ecosystem as a whole (as opposed to a single population or trophic level) is said to show bottom-up control. It is not always clear, however, how many levels up such bottom-up effects can be seen. Does more <a href="/article/Solar_radiation">light</a> or higher nutrients that cause a phytoplankton bloom ultimately result in more fish? Not necessarily. For example, in <a href="/article/Freshwater_biomes">freshwater</a> systems, bottom-up control (i.e. nutrient enhancement) usually affects only the next trophic level up, beyond which the effects are dampened. Similarly, in <a href="/article/Marine_biomes">marine</a> systems, bottom-up effects are sometimes only manifested one trophic level up. For example, nutrient additions lead to increases in phytoplankton biomass, but not necessarily increases at higher levels. </p> <p>However, in some cases, bottom-up effects can be seen two or more levels up. In a plant/aphid/ant food chain, plant genotype strongly affected the aphid <a href="/article/Population_growth_rate">population’s growth rate</a> and also had direct and indirect effects on the third trophic level, affecting the abundance of aphid-tending ants and the <a href="/article/Species_richness">richness</a> of predators like ladybugs that feed on aphids. This shows that bottom up effects (plant genotype in this case) can have effects two levels up and can be one of the most important <a href="/article/Ecology">ecological</a> factors shaping communities with multiple trophic levels.</p> <p>On large scales, there is clear evidence of bottom-up control of ecosystem biomass and productivity. For example, at global scales in the marine environment the greatest biomass of fishes, seabirds and marine mammals are found in regions with highest primary production, e.g. up-welling regions of continental shelves. These large-scale animal distribution patterns are driven by food availability, not the absence of predators. At more local scales however, top-down control in the form of predation (<a href="/article/Top-down_control">top down effects</a>) often shapes distributions and abundance of prey organisms, and even plants. One large-scale study looked at annual fish catch data and chlorophyll a measurements (indication of phytoplankton) for the continental margin of western North America and found substantial alongshore variation in primary production that was highly correlated with the variation in fish yield. Zooplankton data confirmed strong bottom-up trophic linkages between phytoplankton, zooplankton, and resident fish. Yet, top-down impacts on marine pelagic communities are also being found with increasing regularity. </p> <p> In the deep sea environment, fish studied over a 15-year period showed a threefold increase in abundance, which appeared to be related to an increase in the available food. Changes in the deep-sea were likely caused by changes at the <a href="/article/Ocean">ocean</a> surface by <a href="/article/El_Ni%C3%B1o%2C_La_Ni%C3%B1a_and_the_southern_oscillation">El Niño and La Niña</a> events, which can bring more nutrients to surface waters, stimulating phytoplankton. While animals near the surface can benefit quickly, it may take months to years for changes to extend fully to the ocean bottom, increasing abundance of slow-growing bottom-dwelling invertebrates that are part of the food supply of deep-sea fishes.</p> <p><strong><big>References</big></strong></p> <ul><li>Bailey, D.M., H. Ruhl and K. L. Smith Jr. 2006. Long-tem change in benthopelagic fish abundance in the abyssal northeast Pacific Ocean. <em>Ecology</em> 87:549-555.</li><li>Frank K.T., Petrie B. &amp; Shackell N.L. 2007. The ups and downs of trophic control in continental shelf ecosystems. <em>Trends in Ecology &amp; Evolution</em> 22:236-242.</li><li>Johnson, M.T. 2008. Bottom-up effects of plant genotype on aphids, ants, and predators. <em>Ecology</em> 89:145-54.</li><li>Ware, D.M. and R.E. Thomson 2005. Bottom-up ecosystem trophic dynamics determine fish production in the Northeast Pacific. <em>Science </em>308:1280-1284.</li></ul> <p><a href='/article/Bottom-up_control'>Read Full Article...</a></p> http://www.eoearth.org/article/Bottom-up_control Thu, 11 Jun 2009 01:36:30 GMT http://www.eoearth.org/article/Invasive_species <a href='/article/Invasive_species'><img border='0' src='/upload/thumb/1/1d/Chestnut_blight.gif/90px-Chestnut_blight.gif' width='100'/></a> <p>An invasive species is defined legally in the USA as “An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health…‘Alien species’ means, with respect to a particular <a href="/article/Ecosystem">ecosystem</a>, any species…that is not native to that ecosystem.” Novel species can be added to a community either by natural range extensions or because they are introduced as a result of human activity. Some introduced or alien species are beneficial to humans, for example most of our crops and pets. However many alien species have harmful effects; these are referred to as invasive species. Virtually all ecosystems are at risk from the harmful effects of introduced species ( also see <a href="/article/Exotic_species">exotic species</a>, <a href="/article/Marine_invasive_species">marine invasive species</a>, <a href="/article/Aquatic_invasive_species">aquatic invasive species</a>).</p><p>Invasive species are a major threat to our environment because they (1) can change habitats and alter ecosystem function and ecosystem services, (2) crowd out or replace native species, and (3) damage human activities, costing the economy millions of dollars. For example, costs to <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, <a href="/article/Fisheries_and_aquaculture">fisheries</a>, and other human activities by introduced species are estimated at $137 billion per year to the U.S. economy alone.</p> <p><a href='/article/Invasive_species'>Read Full Article...</a></p> http://www.eoearth.org/article/Invasive_species Wed, 10 Jun 2009 01:31:00 GMT http://www.eoearth.org/article/Business_strategy_and_climate_change <a href='/article/Business_strategy_and_climate_change'><img border='0' src='/upload/thumb/c/ca/Cars_in_transport.jpg/250px-Cars_in_transport.jpg' width='100'/></a> <p>In many respects, the scientific debate is irrelevant. For the business community, climate change represents an impending market shift – one that will both alter existing <a href="/article/Market">markets</a> and create new ones. It will not be unlike shifts that have occurred in the past, when <a href="/article/Essential_economic_activities">consumer</a> needs changed, or technology advanced, and some companies declined while others rose to take their place. In the 1980s alone, computers eliminated the typewriter industry, compact discs replaced phonograph records, and the Bell System’s demise wrought structural changes in telecommunications. New competitive environments produce both risks and opportunities, as well as winners and losers.</p><p>This market shift will create new <a href="/article/Supply_and_demand">supply and demand</a> for <a href="/article/Air_pollution_emissions">emission</a>-reducing technologies, new financial instruments for emissions trading, new mechanisms for transferring technologies globally (i.e. Joint Implementation and the Clean Development Mechanism), and new pressures to retire historic sources of <a href="/article/Greenhouse_gas">greenhouse gases</a> (GHG). The shift will affect all companies to varying degrees, and all have a managerial and fiduciary obligation to assess their business exposure and decide whether action is prudent. In short, as the market shift of climate change looms on the business horizon, the argument against action is increasingly harder to make.</p><p>For many within the business community, the future is a <a href="/article/Carbon">carbon</a>-constrained world and the time for action is now. Companies with this perspective already have engaged in GHG reductions. Yet other companies (particularly in the United States) continue to resist and deride their proactive competitors with labels such as ‘carbon cartel’ or ‘Kyoto capitalists.’ Such resistance is a very risky strategy, however, in the face of the coming market shift.</p><p>The debate is thus strategic (not scientific) and companies taking voluntary climate action are not practicing philanthropy or pure social responsibility (although many couch their activities in the language of ‘doing the right thing’). In fact, many companies are agnostic about the science of climate change. They engage the climate-change issue as a way to protect their strategic investments and to search for business opportunities in a changing <a href="/article/Market">market</a> landscape.</p><p>This article seeks to explain the current business phenomenon at three different yet closely related levels of response. First, we look at the early warning signs that suggest a market shift is coming. Second, we identify the various business frameworks that can be and are being used to link climate change to business interests. Third, we describe some specific ways in which companies synergistically integrate climate change and business strategy to contribute to the bottom line.</p> <p><a href='/article/Business_strategy_and_climate_change'>Read Full Article...</a></p> http://www.eoearth.org/article/Business_strategy_and_climate_change Tue, 09 Jun 2009 01:44:31 GMT http://www.eoearth.org/article/Nonpoint_source_pollution <a href='/article/Nonpoint_source_pollution'><img border='0' src='/upload/thumb/3/38/Nonpoint_Sources_NOAA.jpg/350px-Nonpoint_Sources_NOAA.jpg' width='100'/></a> <p>Most nonpoint source pollution occurs as a result of <a href="/article/Surface_runoff_of_water">runoff</a>. When rain or melted snow moves over and through the ground, the water absorbs and assimilates any pollutants it comes into contact with<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>. Following a heavy <a href="/article/Thunderstorm">rainstorm</a>, for example, water will flow across a parking lot and pick up oil left by cars driving and parking on the <a href="/article/Asphalt">asphalt</a>. When you see a rainbow-colored sheen on water flowing across the surface of a road or parking lot, you are actually looking at nonpoint source pollution.</p> <p>This runoff then runs over the edge of the parking lot, and most likely, it eventually empties into a <a href="/article/Stream">stream</a>. The water flows downstream into a larger stream, and then to a lake, <a href="/article/River">river</a>, or <a href="/article/Ocean">ocean</a>. The pollutants in this runoff can be quite harmful, and their sources numerous. We usually can’t point to one discreet location of nonpoint source pollution like we can with a discharge pipe from a factory.</p> <p>Nonpoint source pollution not only affects <a href="/article/Ecosystem">ecosystems</a>; it can also have harmful effects on the economy. U.S. Coastal and marine waters support 28.3 million jobs, generate $54 billion in goods and services through activities like shipping, boating, and tourism, and contribute $30 billion to the U.S. economy through recreational fishing alone<span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. If pollution leads to mass die-offs of fish and dirty-looking water, this area and others like it will experience deep financial losses.</p> <p>Nonpoint source pollution affects the beauty and health of <a href="/article/Coastal_zone">coastal</a> lands and waters. If the physical and environmental well-being of these areas is diminished, people will naturally find it less appealing to visit the coast. Beaches will not provide the tranquility and leisure activities many people expect to experience. You can see how nonpoint source pollution plays an indirect, though powerful role in tourists&#39; contributions to a coastal community&#39;s economic status.</p> <p>The population in many coastal communities is also increasing at a rapid rate, and the value of waterfront property often relies on environmental and aquatic conditions. Excess nonpoint source pollution impacts the overall quality of life, and subsequently can drive property values down. If nonpoint source pollution continues to plague the waters surrounding coastal communities, their economies and social conditions may rapidly deteriorate.</p> <p>Although the concentration of some pollutants from runoff may be lower than the concentration from a point source, the total amount of a pollutant delivered from nonpoint sources may be higher because the pollutants come from many places.</p> <p>With increased control over <a href="/article/Point_source_pollution">point source pollution</a>, scientists have begun to focus on nonpoint source pollution, how it affects the quality of the environment, and, even more importantly, how it can be controlled. Nonpoint source pollution is difficult to control because it comes from multiple locations. It also varies over time in terms of the flow and the types of pollutants it contains.</p> <p><a href='/article/Nonpoint_source_pollution'>Read Full Article...</a></p> http://www.eoearth.org/article/Nonpoint_source_pollution Mon, 08 Jun 2009 01:45:28 GMT http://www.eoearth.org/article/Human_impacts_on_the_biodiversity_of_the_Arctic <a href='/article/Human_impacts_on_the_biodiversity_of_the_Arctic'><img border='0' src='/upload/thumb/5/56/Reef_forming_deep-sea_coral.gif/250px-Reef_forming_deep-sea_coral.gif' width='100'/></a> <p>The projected climatic changes in the <a href="/article/Arctic">Arctic</a>, particularly the projected decrease in <a href="/article/Sea_ice">sea-ice</a> extent and thickness, will result in increased accessibility to the open ocean and surrounding <a href="/article/Coastal_zone">coastal areas</a>. This is very likely to make it easier to exploit marine and coastal species, over a larger area and for a greater proportion of the year. Decreased extent and thickness of sea ice and increased <a href="/article/Seawater">seawater</a> <a href="/article/Temperature">temperatures</a> will, however, also result in changes in the distribution, <a href="/article/Species_diversity">diversity</a>, and productivity of marine species in the Arctic and so will change the environment for hunters and indigenous peoples. However, increased traffic and physical disturbance caused by increased access to the marine areas is likely to pose a more significant threat to <a href="/article/Biodiversity">biodiversity</a> than increased hunting pressure. On land, snow and ice cover in winter enable access into remote areas by snowmobile and the establishment of ice roads; however, in summer, transportation and movement become more difficult. A shorter winter season and increased thawing of permafrost in summer, potentially resulting from a warming climate, could reduce hunting pressure in remote areas. </p><p>There are at least four types of pressure acting on marine, coastal, <a href="/article/Freshwater">freshwater</a>, and terrestrial habitats that affect both their conservation and <a href="/article/Biodiversity">biodiversity</a>: (1) issues relating to the exploitation of species, especially stocks of fish, birds, and mammals, and to forests; (2) the means by which land and water are managed, including the use of terrestrial ecosystems for grazing <a href="/article/Domestication">domesticated</a> stock and aquatic ecosystems for aquaculture; (3) issues relating to pollutants and their long-range transport to the Arctic; and (4) development issues relating to industrial development and to the opening up of the Arctic for recreational purposes. These factors were discussed by Hallanaro and Pylvänäinen<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[4]</a></sup></span> and Bernes<span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[5]</a></sup></span>, who included hydroelectricity generation as a major impact on freshwater systems. </p> <p>Exploitation and harvest of living resources have been shown to pose a threat to arctic <a href="/article/Biodiversity">biodiversity</a>. Species like the Steller sea cow (<i>Hydrodamalis gigas</i>), in the Bering Sea, and the great auk (<i>Pinguinus impennis</i>), in the North Atlantic, were hunted for food by early western explorers and whalers, and became extinct in the 18th and 19th centuries, respectively. Increasing <a href="/article/Supply_and_demand">demands</a> for whale products in Europe, and improvements to the ships and harvesting methods intensified the exploitation of several arctic baleen whale species from the 17th century onward. Over-exploitation resulted in severely depleted <a href="/article/Population">populations</a> of almost all the northern baleen whale species, and few have recovered their pre-17th century population sizes. For example, even though a few individuals have been observed in recent years, the bowhead whale (<i>Balaena mysticetus</i>) is still considered extinct in the North Atlantic. The Pacific population is bigger, but still considered endangered. Both subpopulations used to number in the tens of thousands. Many baleen whales, feeding on zooplankton, were a natural part of the arctic ecosystems 400 years ago. Their large biomass implies that they may have been a <a href="/article/Keystone_species">“keystone” species</a> in shaping the biodiversity of the Arctic Ocean. </p> <p>Many populations of charismatic arctic species have been over-exploited over the last few hundred years. The history of the slaughter of walruses (<i>Odobenus rosmarus</i>) in the North Atlantic and Pacific is well documented<span class="reference"><sup id="ref_4" class="plainlinksneverexpand"><a href="#endnote_4" class='external autonumber' title="#endnote 4">[7]</a></sup></span>. The walrus survived because its range of distribution included inaccessible areas, and the species is now expanding back into its previous distributional range due to its protection and to a ban on harvesting the animals in many areas. The International Polar Bear Treaty (1973) protected the polar bear (<i>Ursus maritimus</i>) after several sub-populations became severely depleted due to hunting<span class="reference"><sup id="ref_5" class="plainlinksneverexpand"><a href="#endnote_5" class='external autonumber' title="#endnote 5">[8]</a></sup></span>. Some subspecies of reindeer/caribou have also been close to extinction due to hunting pressure both in the European and North American <a href="/article/Arctic">Arctic</a><span class="reference"><sup id="ref_6" class="plainlinksneverexpand"><a href="#endnote_6" class='external autonumber' title="#endnote 6">[9]</a></sup></span>. Similarly, several goose populations have approached extinction due to hunting on the breeding and wintering grounds<span class="reference"><sup id="ref_7" class="plainlinksneverexpand"><a href="#endnote_7" class='external autonumber' title="#endnote 7">[10]</a></sup></span>. </p><p>There have also been effects on a number of tree species. Wood has always been a valued commodity and since the first human populations were able to fell trees and process the felled trunks, forests have been cut for their timber. During the last few centuries, systems of <a href="/article/Forestry">forest management</a> have developed to enable the forest to be regenerated more rapidly, either naturally or artificially by planting young trees. The need to exploit these forests for wood is demonstrated by the age structure of the trees in national forest estates (Table 10.4). Natural (unmanaged) forests have a large proportion of old trees compared to young trees, whereas managed forests have a large proportion of younger trees (often managed on rotations of 40 to 80 years). Table 10.4 appears to indicate a positive correlation between northerliness and naturalness (indicated by the index, I). </p> <p>Since around the 1970s, modern management systems, improved control, and changed attitudes have largely diminished threats from sports hunting and harvesting for subsistence purposes. Most of the previously overexploited populations are recovering or showing signs of recovery. However, there are still examples where hunting is a problem. In accordance with the International Polar Bear Treaty, local and indigenous peoples are allowed to hunt polar bears. In Canada, populations in some of the 14 management areas were over-exploited in the 1990s, and hunting was stopped periodically in some of these areas<span class="reference"><sup id="ref_8" class="plainlinksneverexpand"><a href="#endnote_8" class='external autonumber' title="#endnote 8">[11]</a></sup></span>. Similarly, in Greenland, uncertainties about the number of polar bears taken, and about their sex and age composition, have created concerns about the sustainability of the current harvest<span class="reference"><sup id="ref_9" class="plainlinksneverexpand"><a href="#endnote_9" class='external autonumber' title="#endnote 9">[12]</a></sup></span>. In southwestern Greenland, seabird populations have been over-exploited for a number of years by local peoples and the populations of guillemots (<i>Uria</i> spp.) have decreased by more than 90% in this area<span class="reference"><sup id="ref_10" class="plainlinksneverexpand"><a href="#endnote_10" class='external autonumber' title="#endnote 10">[13]</a></sup></span>. </p> <p>Arctic and subarctic oceans, like the Barents, Bering, and Labrador Seas, are among the most productive in the world, and so have been, and are being, heavily exploited. For example, (1) commercial fish landings in Canada decreased from 1.61 million tonnes in 1989 to 1.00 million tonnes in 1998<span class="reference"><sup id="ref_11" class="plainlinksneverexpand"><a href="#endnote_11" class='external autonumber' title="#endnote 11">[14]</a></sup></span>; (2) the five-fold decline in the cod (<i>Gadus morhua</i>) stock in the Arctic Ocean between about 1945 and the early 1990s; and (3) the huge decline (more than 20-fold) in the herring (<i>Clupea harengus</i>) stock in the Norwegian Sea<span class="reference"><sup id="ref_12" class="plainlinksneverexpand"><a href="#endnote_12" class='external autonumber' title="#endnote 12">[15]</a></sup></span>. A report on the status of wildlife habitats in Canada stated that “Canadian <a href="/article/Marine_fisheries">fisheries</a> are the most dramatic example of an industry that has had significant effects on the ocean’s habitats and <a href="/article/Ecosystem">ecosystems</a>”<span class="reference"><sup id="ref_13" class="plainlinksneverexpand"><a href="#endnote_13" class='external autonumber' title="#endnote 13">[16]</a></sup></span>. </p><p>Considerable natural annual variability in productivity, mainly due to variations in the influx of cold and warm waters to the <a href="/article/Arctic">Arctic</a>, is a considerable challenge for fisheries management in the Arctic. Collapses in fish populations caused by over-exploitation in years of low productivity have occurred frequently and have resulted in negative impacts on other marine species. The stocks of almost all the commercially exploitable species in the Arctic have declined, and Bernes<span class="reference"><sup id="ref_14" class="plainlinksneverexpand"><a href="#endnote_14" class='external autonumber' title="#endnote 14">[17]</a></sup></span> went as far as to state that several fish stocks are just about eliminated. Hamre<span class="reference"><sup id="ref_15" class="plainlinksneverexpand"><a href="#endnote_15" class='external autonumber' title="#endnote 15">[18]</a></sup></span> suggested that the relative occurrence of species at some trophic levels has been displaced. Such changes in the few commercially-valuable fish species can have tremendous impacts on the <a href="/article/Coastal_zone">coastal</a> communities which are dependent upon the fishing industry for their livelihoods<span class="reference"><sup id="ref_16" class="plainlinksneverexpand"><a href="#endnote_16" class='external autonumber' title="#endnote 16">[19]</a></sup></span>. Even though supporting information is scarce, it is likely that the disappearance of the big baleen whales and the heavy exploitation (or over-exploitation) of fish stocks over many years have changed the original <a href="/article/Biodiversity">biodiversity</a> and ecosystem processes of the subarctic oceans. </p><p>Heavy exploitation of benthic species, such as shrimps and scallops, also affects other species in the benthic communities. Bottom trawls damage species composition and so affect the <a href="/article/Food_web">food web</a>. An example is the damage that can be caused to the cold water coral community. This <a href="/article/Coral_reef">coral reef</a> habitat, often in deep water near the edge of the continental shelf, supports many other species such as gorgonians and brittle stars (Fig. 10.6). Passes over this community with a trawl leave only fragments of dead coral that can support no other species (Fig. 10.7). It has been estimated that, within <a href="/article/Marine_fisheries">commercial fishing</a> grounds, all points on the sea floor are trawled at least twice per year. </p> <p><a href='/article/Human_impacts_on_the_biodiversity_of_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Human_impacts_on_the_biodiversity_of_the_Arctic Fri, 05 Jun 2009 02:53:22 GMT http://www.eoearth.org/article/Traditional_land-use_and_nature_conservation_in_rural_Europe <a href='/article/Traditional_land-use_and_nature_conservation_in_rural_Europe'><img border='0' src='/upload/thumb/8/87/Grassland_%26_forest_in_Southern_Black_Forest%2C_Germany.gif/250px-Grassland_%26_forest_in_Southern_Black_Forest%2C_Germany.gif' width='100'/></a> <p>Rural Europe offers a great diversity of cultural landscapes. This landscape diversity is, for the most part, a result of the variety of <a href="/article/Land-use">land-uses</a> that have overlaid, refined, or replaced each other throughout history. In European landscape history five basic stages are distinguished: the natural, prehistoric landscape (from Palaeolithic until ancient Greek times); the antique landscape (from ancient Greek times until early Mediaeval times); the mediaeval landscape (from early Mediaeval times until Renaissance); the traditional <a href="/article/Agriculture">agricultural</a> landscape (from Renaissance until 19th century, sometimes until today); and industrial landscapes (mostly from mid-18th until mid-20th century, in many places until today). </p><p>Traditional land-uses, according to Bignal et al. (1995), include all “practices which have been out of fashion for many years and techniques which are not generally part of modern agriculture.” These authors report that these land-uses reached their maximum extent in the second half of the 19th century. Another definition has been delivered by Antrop (1997): “landscapes with a long history, which evolved slowly and where it took centuries to form a characteristic structure reflecting a harmonious integration of abiotic, biotic and cultural elements”. Two common characteristics of most forms of traditional land-use are relatively low nutrient inputs and relatively low output per hectare. Therefore, traditional land-use systems are also termed “low-intensity land-use systems”. However, “traditional land-use” is not in all cases completely congruent with “low-intensity land-use” as there are traditional land-use systems that have been very labor-intensive and had high nutrient and labor inputs. Examples can be found in late medieval and early modern Flanders, northern Italy, the Netherlands and Southwest-England (and on a more local scale in many densely populated areas of Europe). These traditional high-intensity systems also had a high <a href="/article/Biodiversity">biodiversity</a>, caused by the many gradients of nutrient and labor inputs at a local and <a href="/article/Region">regional</a> scale. </p> <p><a href='/article/Traditional_land-use_and_nature_conservation_in_rural_Europe'>Read Full Article...</a></p> http://www.eoearth.org/article/Traditional_land-use_and_nature_conservation_in_rural_Europe Thu, 04 Jun 2009 02:07:32 GMT http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa <a href='/article/Impacts_of_tourism_and_recreation_in_Africa'><img border='0' src='/upload/thumb/d/d5/Great_Zimbabwe.JPG/350px-Great_Zimbabwe.JPG' width='100'/></a> <p>Land-based tourism is a major economic activity in Africa, drawing millions of visitors to different sites across the region every year and generating millions of dollars in foreign exchange earnings. Sites such as the pyramids of Egypt, the Great Rift Valley of Eastern and Southern Africa, Great Zimbabwe, Table Mountain in South Africa, Mount Kenya in Kenya and Mount Kilimanjaro in Tanzania are some of the major attractions. Mountains, wildlife, wetlands and <a href="/article/Coastal_zone">coastal areas</a> are also major tourist attractions. These and other attractions contributed to the arrival of a total of about 124 million international tourists in the five years of 1990, 1995, 2000, 2002 and 2003. The visitors spent a total of US$52 891 million in those five years. In 2003 and 2004 the region attracted 78.1 million international tourists. In 2004, international tourist arrivals grew at 10 percent worldwide and 14 percent in Africa – to 41.6 million, up from 36.5 million in 2003. However, the region shared only 7.4 percent of the global increase of 69 million tourists, and almost all the increase was concentrated in Northern Africa. </p><p>Ecotourism accounted for 20 percent of total international tourism. In recognition of ecotourism’s growth potential, particularly for developing countries, the United Nations Economic and Social Council (ECOSOC) declared 2002 the International Year of Ecotourism. Many countries in Africa, such as Kenya and South Africa, have invested heavily in ecotourism. </p><p>Tourism in Africa varies widely, from viewing gorillas in the Great Lakes Region to lemurs in Madagascar, from trekking in Ethiopia to birdwatching in Botswana, from looking at rock paintings in South Africa to visiting rainforests in Ghana, from <a href="/article/Mountain">mountain</a>-climbing in Eastern Africa (Mt Kilimanjaro and Mt Kenya, for example) to scuba-diving in the Seychelles and to photographic safaris in Eastern and Southern Africa. In the Great Lakes Region, for example, revenue from tourism based on gorilla viewing and other activities brings in about US$20 million to the region annually. Tourism in the area is certain to be boosted with the news in 2004 that the first census since 1989 revealed that the population of the apes in the Virunga Mountains has grown by 17 percent, increasing from 324 in 1989 to 380 by the end of 2003. </p> <p>Tourism can serve as a powerful incentive to protect natural resources. In Madagascar, where tourism is the country’s second largest foreign exchange earner, the country had by 1998 established 40 new protected areas, covering roughly 2 percent of the country’s <a href="/article/Land_resources_in_Africa">land</a> area. In Southern and Eastern Africa, privately-owned protected areas that support tourism and hunting enterprises are also growing. </p><p>Tourism not only generates revenue to support conservation and management of natural environments but also generates many jobs. For example, hundreds of people live off the Bwindi Impenetrable Forest in Uganda, where foreign tourists trek to view gorillas. It has been argued that tourism has larger multiplier effects, with revenue spreading from hotel accommodation, food and beverages, shopping, entertainment and transport to income of hotel staff, taxi operators, shopkeepers and suppliers of goods and services. </p><p>Despite the growth of tourism, the region still only accounts for less than 4 percent of world tourism, with its revenue share at only 2.5 percent – about US$16,000 million in 2002 of the annual sales of about US$4.5 million million. Therefore, opportunities for further investment and development are vast in the region. In Kenya, for example, new regulations that will allow sport bird shooting are expected to attract up to 2,000 sport hunters annually, boosting revenues by US$5 million each year. New Kenya Wildlife Service (KWS) rules provide for private landowners to obtain special authorization to manage their own game bird populations, including breeding, as well as determine open and closed seasons. </p> <p>Several African countries including Ethiopia, South Africa, Kenya and Benin have significant palaeontology sites. In Ethiopia, the government is using these sites to promote &quot;palaeo-tourism,&quot; and to generate revenue. Ethiopia is home to some of the most famous prehistoric remains ever found, including some of the world’s oldest human remains: Ethiopia’s discoveries chart man’s prehistory from more than 6 million years ago to modern ancestors. Tourism officials in Afar believe that &quot;palaeo-tourism&quot; could generate an additional US$2 million in revenue annually for this region alone. The Ethiopian Tourism Commission has reported that the sector generated more than US$77 million in 2003. This revenue is important in the fight against poverty and plays a key role in the government’s poverty reduction strategy paper (PRSP). South Africa has also made palaeontology and other cultural heritage sites a focus of their tourism industry. </p><p>The tourism industry in Africa also has human and environmental costs, contributing to the displacement of communities and thus undermining rights and livelihoods, the generation of waste and pollution, and the unsustainable use of water. In Africa, for example, tourism’s effects on indigenous peoples have been profound, with the eviction of communities from their <a href="/article/Land_resources_in_Africa">lands</a>, in addition to economic dislocation, breakdown of traditional values, and environmental degradation. Pastoralism has been attacked as primitive and destructive. The massive influx of tourists and their vehicles in the Masai Mara National Park in Kenya and in the Ngorongoro Conservation Area in Tanzania has destroyed grass cover, affecting plant and animal species in the area. Hotels have dumped their sewage in Masai settlement areas while campsites have polluted adjacent rivers. One emerging approach is to focus on promoting community conservation areas and also collaborative tourism initiatives in order to ensure greater benefits to communities. There are different levels of community participation, varying from passive participation to interactive decision making to community empowerment initiatives. </p><p>The challenge facing policymakers in this industry and other land-based activities is to critically assess the costs and benefits to ensure that all options are fully weighed and that the policy responses contribute to <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a> and minimize overexploitation. </p><p>Additionally, measures need to be adopted to ensure that the benefits associated with tourism are spread across society, and that those who are directly involved in conservation are rewarded. </p><p><strong>Further Reading</strong> </p> <ul><li>African Environmental News Services, 2003. <a href="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026" class='external text' title="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026">Kenya Hopes to Boost Tourism Revenue by Sport Bird Shooting.</a> </li><li>Chavez, R., 1999. <a href="http://www.twnside.org.sg/title/chavez-cn.htm" class='external text' title="http://www.twnside.org.sg/title/chavez-cn.htm">Globalisation and tourism: Deadly mix for indigenous peoples.</a> Third World Resurgence, 103. Third World Network. </li><li>ECA, 2005. <a href="http://www.uneca.org/era2005/front.pdf" class='external text' title="http://www.uneca.org/era2005/front.pdf">Economic Report on Africa 2005: Meeting the Challenges of Unemployment and Poverty in Africa.</a> Economic Commission for Africa, Addis Ababa. </li><li>IRIN, 2004. <a href="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn_of_Africa" class='external text' title="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn of Africa">Ethiopia: Archaeology and palaeontology to boost tourism revenue.</a> United Nations Integrated Regional Information Networks. </li><li>Pickrell, J., 2004. <a href="http://news.nationalgeographic.com/news/2004/01/0127_040127_gorillas.html#main" class='external text' title="http://news.nationalgeographic.com/news/2004/01/0127 040127 gorillas.html#main">Africa’s Mountain Gorillas Rebound, Says New Census.</a> National Geographic News, January 27, 2004. </li><li>Saunders, D. J. (undated). <a href="http://www.africaata.org/trade_2.htm" class='external text' title="http://www.africaata.org/trade 2.htm">Africa Needs More Liberalized Trade Initiatives for the Continued Growth and Sustainability of its Travel and Tourism Industry.</a> Africa Travel Magazine. </li><li>UN (undated). <a href="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm" class='external text' title="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm">Sustainable tourism in Kenya</a>. United Nations Division for Economic and Social Affairs, New York. </li><li>UNEP, 2006. <a href="http://www.unep.org/dewa/africa/aeo2_launch/index.asp" class='external text' title="http://www.unep.org/dewa/africa/aeo2 launch/index.asp">Africa Environment Outlook 2</a> </li><li>Vieta, F. E., 1999. <a href="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm" class='external text' title="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm">Ecotourism propels development: But social acceptance depends on economic opportunities for local communities.</a> Africa Recovery, 13(1). </li><li>World Tourism Organization, 2005. <a href="http://www.world-tourism.org/facts/menu.html" class='external text' title="http://www.world-tourism.org/facts/menu.html">International Tourist Arrivals &amp;amp; Tourism Receipts by Country.</a> </li></ul> <p><br /> </center> </p><p> <p>[[category:|Impacts of tourism and recreation in Africa]] </p> </p> <p><a href='/article/Impacts_of_tourism_and_recreation_in_Africa'>Read Full Article...</a></p> http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa Wed, 03 Jun 2009 06:03:06 GMT http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa <a href='/article/Impacts_of_tourism_and_recreation_in_Africa'><img border='0' src='/upload/thumb/d/d5/Great_Zimbabwe.JPG/350px-Great_Zimbabwe.JPG' width='100'/></a> <p>Land-based tourism is a major economic activity in Africa, drawing millions of visitors to different sites across the region every year and generating millions of dollars in foreign exchange earnings. Sites such as the pyramids of Egypt, the Great Rift Valley of Eastern and Southern Africa, Great Zimbabwe, Table Mountain in South Africa, Mount Kenya in Kenya and Mount Kilimanjaro in Tanzania are some of the major attractions. Mountains, wildlife, wetlands and <a href="/article/Coastal_zone">coastal areas</a> are also major tourist attractions. These and other attractions contributed to the arrival of a total of about 124 million international tourists in the five years of 1990, 1995, 2000, 2002 and 2003. The visitors spent a total of US$52 891 million in those five years. In 2003 and 2004 the region attracted 78.1 million international tourists. In 2004, international tourist arrivals grew at 10 percent worldwide and 14 percent in Africa – to 41.6 million, up from 36.5 million in 2003. However, the region shared only 7.4 percent of the global increase of 69 million tourists, and almost all the increase was concentrated in Northern Africa. </p><p>Ecotourism accounted for 20 percent of total international tourism. In recognition of ecotourism’s growth potential, particularly for developing countries, the United Nations Economic and Social Council (ECOSOC) declared 2002 the International Year of Ecotourism. Many countries in Africa, such as Kenya and South Africa, have invested heavily in ecotourism. </p><p>Tourism in Africa varies widely, from viewing gorillas in the Great Lakes Region to lemurs in Madagascar, from trekking in Ethiopia to birdwatching in Botswana, from looking at rock paintings in South Africa to visiting rainforests in Ghana, from <a href="/article/Mountain">mountain</a>-climbing in Eastern Africa (Mt Kilimanjaro and Mt Kenya, for example) to scuba-diving in the Seychelles and to photographic safaris in Eastern and Southern Africa. In the Great Lakes Region, for example, revenue from tourism based on gorilla viewing and other activities brings in about US$20 million to the region annually. Tourism in the area is certain to be boosted with the news in 2004 that the first census since 1989 revealed that the population of the apes in the Virunga Mountains has grown by 17 percent, increasing from 324 in 1989 to 380 by the end of 2003. </p> <p>Tourism can serve as a powerful incentive to protect natural resources. In Madagascar, where tourism is the country’s second largest foreign exchange earner, the country had by 1998 established 40 new protected areas, covering roughly 2 percent of the country’s <a href="/article/Land_resources_in_Africa">land</a> area. In Southern and Eastern Africa, privately-owned protected areas that support tourism and hunting enterprises are also growing. </p><p>Tourism not only generates revenue to support conservation and management of natural environments but also generates many jobs. For example, hundreds of people live off the Bwindi Impenetrable Forest in Uganda, where foreign tourists trek to view gorillas. It has been argued that tourism has larger multiplier effects, with revenue spreading from hotel accommodation, food and beverages, shopping, entertainment and transport to income of hotel staff, taxi operators, shopkeepers and suppliers of goods and services. </p><p>Despite the growth of tourism, the region still only accounts for less than 4 percent of world tourism, with its revenue share at only 2.5 percent – about US$16,000 million in 2002 of the annual sales of about US$4.5 million million. Therefore, opportunities for further investment and development are vast in the region. In Kenya, for example, new regulations that will allow sport bird shooting are expected to attract up to 2,000 sport hunters annually, boosting revenues by US$5 million each year. New Kenya Wildlife Service (KWS) rules provide for private landowners to obtain special authorization to manage their own game bird populations, including breeding, as well as determine open and closed seasons. </p> <p>Several African countries including Ethiopia, South Africa, Kenya and Benin have significant palaeontology sites. In Ethiopia, the government is using these sites to promote &quot;palaeo-tourism,&quot; and to generate revenue. Ethiopia is home to some of the most famous prehistoric remains ever found, including some of the world’s oldest human remains: Ethiopia’s discoveries chart man’s prehistory from more than 6 million years ago to modern ancestors. Tourism officials in Afar believe that &quot;palaeo-tourism&quot; could generate an additional US$2 million in revenue annually for this region alone. The Ethiopian Tourism Commission has reported that the sector generated more than US$77 million in 2003. This revenue is important in the fight against poverty and plays a key role in the government’s poverty reduction strategy paper (PRSP). South Africa has also made palaeontology and other cultural heritage sites a focus of their tourism industry. </p><p>The tourism industry in Africa also has human and environmental costs, contributing to the displacement of communities and thus undermining rights and livelihoods, the generation of waste and pollution, and the unsustainable use of water. In Africa, for example, tourism’s effects on indigenous peoples have been profound, with the eviction of communities from their <a href="/article/Land_resources_in_Africa">lands</a>, in addition to economic dislocation, breakdown of traditional values, and environmental degradation. Pastoralism has been attacked as primitive and destructive. The massive influx of tourists and their vehicles in the Masai Mara National Park in Kenya and in the Ngorongoro Conservation Area in Tanzania has destroyed grass cover, affecting plant and animal species in the area. Hotels have dumped their sewage in Masai settlement areas while campsites have polluted adjacent rivers. One emerging approach is to focus on promoting community conservation areas and also collaborative tourism initiatives in order to ensure greater benefits to communities. There are different levels of community participation, varying from passive participation to interactive decision making to community empowerment initiatives. </p><p>The challenge facing policymakers in this industry and other land-based activities is to critically assess the costs and benefits to ensure that all options are fully weighed and that the policy responses contribute to <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a> and minimize overexploitation. </p><p>Additionally, measures need to be adopted to ensure that the benefits associated with tourism are spread across society, and that those who are directly involved in conservation are rewarded. </p><p><strong>Further Reading</strong> </p> <ul><li>African Environmental News Services, 2003. <a href="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026" class='external text' title="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026">Kenya Hopes to Boost Tourism Revenue by Sport Bird Shooting.</a> </li><li>Chavez, R., 1999. <a href="http://www.twnside.org.sg/title/chavez-cn.htm" class='external text' title="http://www.twnside.org.sg/title/chavez-cn.htm">Globalisation and tourism: Deadly mix for indigenous peoples.</a> Third World Resurgence, 103. Third World Network. </li><li>ECA, 2005. <a href="http://www.uneca.org/era2005/front.pdf" class='external text' title="http://www.uneca.org/era2005/front.pdf">Economic Report on Africa 2005: Meeting the Challenges of Unemployment and Poverty in Africa.</a> Economic Commission for Africa, Addis Ababa. </li><li>IRIN, 2004. <a href="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn_of_Africa" class='external text' title="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn of Africa">Ethiopia: Archaeology and palaeontology to boost tourism revenue.</a> United Nations Integrated Regional Information Networks. </li><li>Pickrell, J., 2004. <a href="http://news.nationalgeographic.com/news/2004/01/0127_040127_gorillas.html#main" class='external text' title="http://news.nationalgeographic.com/news/2004/01/0127 040127 gorillas.html#main">Africa’s Mountain Gorillas Rebound, Says New Census.</a> National Geographic News, January 27, 2004. </li><li>Saunders, D. J. (undated). <a href="http://www.africaata.org/trade_2.htm" class='external text' title="http://www.africaata.org/trade 2.htm">Africa Needs More Liberalized Trade Initiatives for the Continued Growth and Sustainability of its Travel and Tourism Industry.</a> Africa Travel Magazine. </li><li>UN (undated). <a href="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm" class='external text' title="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm">Sustainable tourism in Kenya</a>. United Nations Division for Economic and Social Affairs, New York. </li><li>UNEP, 2006. <a href="http://www.unep.org/dewa/africa/aeo2_launch/index.asp" class='external text' title="http://www.unep.org/dewa/africa/aeo2 launch/index.asp">Africa Environment Outlook 2</a> </li><li>Vieta, F. E., 1999. <a href="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm" class='external text' title="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm">Ecotourism propels development: But social acceptance depends on economic opportunities for local communities.</a> Africa Recovery, 13(1). </li><li>World Tourism Organization, 2005. <a href="http://www.world-tourism.org/facts/menu.html" class='external text' title="http://www.world-tourism.org/facts/menu.html">International Tourist Arrivals &amp;amp; Tourism Receipts by Country.</a> </li></ul> <p><br /> </center> </p><p> <p>[[category:|Impacts of tourism and recreation in Africa]] </p> </p> <p><a href='/article/Impacts_of_tourism_and_recreation_in_Africa'>Read Full Article...</a></p> http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa Wed, 03 Jun 2009 00:55:46 GMT http://www.eoearth.org/article/Eco-Management_and_Audit_Scheme <a href='/article/Eco-Management_and_Audit_Scheme'><img border='0' src='/upload/thumb/6/68/EMAS_logo.gif/180px-EMAS_logo.gif' width='100'/></a> <p>The Eco-Management and Audit Scheme (EMAS) is the European Union&#39;s voluntary instrument that acknowledges organizations that improve their environmental performance on a continuous basis. EMAS-registered organizations are legally compliant, run an environmental management system, and report on their environmental performance through the publication of an independently verified environmental statement. They are recognized by the EMAS logo, which guarantees the reliability of the information provided. </p><p><strong>Further Reading</strong><br /> <a href="http://www.emas.org.uk/index.htm" class='external text' title="http://www.emas.org.uk/index.htm">EMAS Homepage</a> </p> <p><a href='/article/Eco-Management_and_Audit_Scheme'>Read Full Article...</a></p> http://www.eoearth.org/article/Eco-Management_and_Audit_Scheme Tue, 02 Jun 2009 02:02:40 GMT http://www.eoearth.org/article/General_description_of_the_Arctic_biota <a href='/article/General_description_of_the_Arctic_biota'><img border='0' src='/upload/thumb/5/5f/Fig9.17_benthic_faunal.JPG/320px-Fig9.17_benthic_faunal.JPG' width='100'/></a><p><a href='/article/General_description_of_the_Arctic_biota'>Read Full Article...</a></p> http://www.eoearth.org/article/General_description_of_the_Arctic_biota Mon, 01 Jun 2009 03:17:28 GMT http://www.eoearth.org/article/Tide <a href='/article/Tide'><img border='0' src='/upload/thumb/b/b6/Earth_moon_system.jpg/300px-Earth_moon_system.jpg' width='100'/></a> <p>An ocean tide refers to the cyclic rise and fall of seawater. Tides are caused by slight variations in gravitational attraction between the Earth, the moon and the sun in geometric relationship with locations on the Earth's surface. Tides are periodic primarily because of the cyclical influence of the Earth's rotation. </p><p>The moon is the primary factor controlling the temporal rhythm and height of tides (Figure 1). The moon produces two tidal bulges somewhere on the Earth through the effects of gravitational attraction. The height of these tidal bulges is controlled by the moon's gravitational force and the Earth's gravity pulling the water back toward the Earth. At the location on the Earth closest to the moon, seawater is drawn toward the moon because of the greater strength of gravitational attraction. On the opposite side of the Earth, another tidal bulge is produced away from the moon. However, this bulge is due to the fact that at this point on the Earth the force of the moon's gravity is at its weakest. Considering this information, any given point on the Earth's surface should experience two tidal crests and two tidal troughs during each tidal period. </p> <p>The timing of tidal events is related to the Earth's rotation and the revolution of the moon around the Earth. If the moon was stationary in space, the tidal cycle would be 24 hours long. However, the moon is in motion revolving around the Earth. One revolution takes about 27 days and adds about 50 minutes to the tidal cycle. As a result, the tidal period is 24 hours and 50 minutes in length. </p> <p>The second factor controlling tides on the Earth's surface is the sun's gravity. The height of the average solar tide is about 50% the average lunar tide. At certain times during the moon's revolution around the Earth, the direction of its gravitational attraction is aligned with the sun's (Figure 2). During these times the two tide producing bodies act together to create the highest and lowest tides of the year. These spring tides occur every 14-15 days during full and new moons. </p><p>When the gravitational pull of the moon and sun are at right angles to each other, the daily tidal variations on the Earth are at their least (Figure 3). These events are called neap tides and they occur during the first and last quarter of the moon. </p> <p><a href='/article/Tide'>Read Full Article...</a></p> http://www.eoearth.org/article/Tide Fri, 29 May 2009 01:47:55 GMT http://www.eoearth.org/article/Marine_ecosystem_services <a href='/article/Marine_ecosystem_services'><img border='0' src='/upload/thumb/e/e9/MEA_coastal_population.jpg/400px-MEA_coastal_population.jpg' width='100'/></a> <p>Marine ecosystem services refer to benefits that people obtain from marine ecosystems, including the open ocean, coastal seas, and estuaries. More than one third of the world's population lives in coastal areas (Table 1), and people throughout the world depend intimately on the oceans and coasts, and the resources they provide, for survival and well-being. Yet marine ecosystems, and the resources they provide, are increasingly threatened by <a href="/article/Land-use_and_land-cover_change">land-use change</a>, overfishing, climate change, invasion of non-native species, and other impacts of a rapidly growing human population. </p> <p><a href='/article/Marine_ecosystem_services'>Read Full Article...</a></p> http://www.eoearth.org/article/Marine_ecosystem_services Thu, 28 May 2009 01:53:47 GMT http://www.eoearth.org/article/Desert_willow <a href='/article/Desert_willow'><img border='0' src='/upload/thumb/8/8c/Desert_willow_USFS_CharlieMcDonald.jpg/249px-Desert_willow_USFS_CharlieMcDonald.jpg' width='100'/></a> <p><strong><big>Desert willow (<em>Chilopsis linearis</em>)</big></strong></p> <p>Sometimes plant names are just plain confusing. The desert willow is not a true willow, but it does grow in <a href="/article/Desert_biome">deserts</a>. Actually, desert willow is in the trumpet creeper family (Bignoniaceae), which has many showy-flowered species found mostly in the tropics. Catalpa (<em>Catalpa bignonioides</em> and <em>Catalpa speciosa</em>) and trumpet creeper (<em>Campsis radicans</em>) are native North American species closely related to desert willow.</p> <p>Desert willow, which grows as a shrub or small tree, is at home in desert arroyos. An arroyo (literally <em>creek</em> in Spanish) is a usually dry creek bed or gulch that temporarily fills with water after heavy rains. Each rain gives the desert willow a good watering and it responds with a spurt of new growth and new flower clusters at the end of its branches. It may have two or three growth spurts during a wet summer.</p> <p>Desert willow has become a popular landscaping plant in the Southwest. It grows rapidly when regularly watered, but also tolerates long periods without water making it a good low-maintenance plant. And, its beautiful flowers add to its appeal. The flowers are usually whitish with a tinge of purple, but cultivars have been selected with colors ranging from white to deep purple.</p> <p>Horticulturists have used desert willow to come up with a completely new cultivar, the chitalpa. This tree is a sterile hybrid between desert willow (<em>Chilopsis linearis</em>) and southern catalpa (<em>Catalpa bignonioides</em>). The chitalpa combines the good features of both parents. It can grow in more northern climates than desert willow, it is more drought tolerant than catalpa, and as a hybrid, it makes no fruits; and, yes it still has those glorious flowers. </p> <p><a href='/article/Desert_willow'>Read Full Article...</a></p> http://www.eoearth.org/article/Desert_willow Wed, 27 May 2009 02:22:03 GMT http://www.eoearth.org/article/Exploration_of_the_Antarctic <a href='/article/Exploration_of_the_Antarctic'><img border='0' src='/upload/thumb/e/ee/Antarctica_2.jpg/300px-Antarctica_2.jpg' width='100'/></a> <p>   See also <a href="/article/Chronology_of_Antarctic_Exploration">Chronology of Antarctic Exploration</a>.</p><ol><li><a href="/article/The_Antarctic_Myth">The Antarctic Myth</a></li><li><a href="/article/Sighting_Antarctica">Sighting Antarctica</a> </li><li><a href="/article/Early_Exploration_of_Antarctica">Early Exploration of Antarctica</a>: Sealers</li><li><a href="/article/Three_National_Expeditions_to_Antarctica">Three National Expeditions to Antarctica</a></li><li><a href="/article/Exploration_of_the_Antarctic_in_the_Second_Half_of_the_Nineteenth_Century">Exploration of the Antarctic in the Second Half of the Nineteenth Century</a>: Whalers and Others</li><li><a href="/article/The_%22Heroic_Age%22_of_Antarctic_Exploration">The &quot;Heroic Age&quot; of Antarctic Exploration</a> </li><li><a href="/article/Perspective_of_Antarctica_in_1911">Perspective of Antarctica in 1911</a></li><li><a href="/article/Amundsen_and_Scott_at_the_South_Pole">Amundsen and Scott at the South Pole</a> </li><li><a href="/article/Mawson%2C_Shackleton_and_the_end_of_the_%22Heroic_Age%22">Mawson, Shackleton and the end of the &quot;Heroic Age&quot;</a></li><li><a href="/article/Aerial_Exploration_of_the_Antarctic">Aerial Exploration of the Antarctic</a></li><li><a href="/article/Antarctica_and_the_International_Geophysical_Year">Antarctica and the International Geophysical Year</a> </li><li><a href="/article/Antarctic_Exploration_and_the_Antarctic_Treaty_System">Antarctic Exploration and the Antarctic Treaty System</a></li></ol><p><strong>Further Reading:</strong></p><ol><li>Antarctica: Exploring the Extreme: 400 Years of Adventureby Marilyn J. Landis, Chicago Review Press, 2001 <a href="http://www.amazon.com/dp/1556524285/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/1556524285/?tag=encycofearth-20">ISBN: 1556524285</a>. </li><li>South Pole: A Narrative History of the Exploration of Antarctica by Anthony Brandt, NG Adventure Classics, 2004 <a href="http://www.amazon.com/dp/0792267974/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0792267974/?tag=encycofearth-20">ISBN: 0792267974</a>.</li><li>Exploring Polar Frontiers: An Historical Encyclopedia, William James Mills, ABC-CLIO, 2003 <a href="http://www.amazon.com/dp/1576074226/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/1576074226/?tag=encycofearth-20">ISBN: 1576074226</a>.</li><li>Below the Convergence: Voyages Towards Antarctica, 1699-1839, Alan Gurney, W.W. Norton and Company, 1997 <a href="http://www.amazon.com/dp/0393039498/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0393039498/?tag=encycofearth-20">ISBN: 0393039498</a>.</li><li>The Race to the White Continent, Alan Gurney, W.W. Norton and Company, 2002 <a href="http://www.amazon.com/dp/0393323218/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0393323218/?tag=encycofearth-20">ISBN: 0393323218</a>.</li><li><a href="http://www.spri.cam.ac.uk/resources/expeditions/" class='external text' title="http://www.spri.cam.ac.uk/resources/expeditions/">Index to Antarctic Expeditions</a>, Scott Polar Research Institute, retrieved November 1, 2008 </li><li><a href="http://www.polarconservation.org/education/antarctic-history" class='external text' title="http://www.polarconservation.org/education/antarctic-history">Antarctic History</a>, Polar Conservation Organization, retrieved February 16, 2009</li><li><a href="http://www.nsf.gov/pubs/1997/antpanel/" class='external text' title="http://www.nsf.gov/pubs/1997/antpanel/">The United States in Antarctica</a>, Report of the U. S. Antarctic Program External Panel, National Science Foundation, 1997</li><li><a href="http://www.antarcticaonline.com/antarctica/history/history.htm" class='external text' title="http://www.antarcticaonline.com/antarctica/history/history.htm">Antarctic History</a>, Antarctica Online, retrieved February 16, 2009</li><li><a href="http://www.antarctic-circle.org/" class='external text' title="http://www.antarctic-circle.org/">The Antarctic Circle</a>, retrieved February 16, 2009</li></ol> <p><a href='/article/Exploration_of_the_Antarctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Exploration_of_the_Antarctic Wed, 27 May 2009 02:20:52 GMT http://www.eoearth.org/article/Viral_hemorrhagic_fevers <a href='/article/Viral_hemorrhagic_fevers'><img border='0' src='/upload/thumb/a/ab/BSL4_containment_CDC.jpg/199px-BSL4_containment_CDC.jpg' width='100'/></a> <p>The Centers for Disease Control and Prevention&#39;s National Center for Infectious Diseases has prepared answers to questions about the nature of the group of illnesses characterized as viral hemorrhagic fevers.</p> <p><a href='/article/Viral_hemorrhagic_fevers'>Read Full Article...</a></p> http://www.eoearth.org/article/Viral_hemorrhagic_fevers Tue, 26 May 2009 03:01:40 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Tue, 26 May 2009 03:00:44 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Tue, 26 May 2009 03:00:00 GMT http://www.eoearth.org/article/Biological_diversity_in_the_Horn_of_Africa <a href='/article/Biological_diversity_in_the_Horn_of_Africa'><img border='0' src='/upload/thumb/d/d1/Map_of_the_Horn_of_Africa.gif/200px-Map_of_the_Horn_of_Africa.gif' width='100'/></a> <h1><span class="pagetitle">Overview</span> </h1> <p>The <a href="/article/Horn_of_Africa">Horn of Africa</a> has been a renowned source of biological resources for thousands of years. The ancient Egyptians, Greeks and Romans sent expeditions and caravans to the region for frankincense, myrrh and other natural commodities to be taken back North along the incense route through the Arabian deserts.</p><p><span class="bodytext">Centered on the arid Horn, east of the Ethiopian Highlands, this hotspot also covers the Rift Valley, which divides the Ethiopian Highlands into two major blocks, the xeric bushlands of northeastern <a href="/article/Kenya">Kenya</a> and the southern coastal parts of the Arabian Peninsula. Politically, this includes most of <a href="/article/Somalia">Somalia</a>, all of <a href="/article/Djibouti">Djibouti</a>, parts of <a href="/article/Ethiopia">Ethiopia</a>, <a href="/article/Eritrea">Eritrea</a>, <a href="/article/Kenya">Kenya</a>, Yemen and Oman, and a small piece of far eastern <a href="/article/Sudan">Sudan</a>. Also included in this hotspot are the Socotra Archipelago off the coast of northeastern Somalia, and a few hundred tiny islands in the Red Sea. </span>Although the entire hotspot covers more than 1.5 million km², a relatively large portion of the land area has very limited flora (for example, the Danakil Depression), and most of the plants known from the region actually occupy only a small percentage of the area. The dominant vegetation type is <em>Acacia-Commiphora</em> bushland, although evergreen bushland, succulent shrubland, dry evergreen forest and woodland, semi-desert grassland and low-growing dune and rock vegetation also occupy portions of the region. Small areas of mangrove are found on both the African and Arabian sides of the hotspot, as well as riverine vegetation along major rivers such as the Wabe Shabelle and Awash. </p><span class="bodytext"><p>The Horn of Africa is one of only two hotspots that is entirely arid; the other is the <a href="/article/Succulent_Karoo">Succulent Karoo</a> in southwestern Africa. It is believed that these two arid regions were united by an arid corridor during drier and colder periods in the Pleistocene, and possibly also in the earlier Tertiary. Several genera of flowering plants are entirely restricted to just these two regions, such as <em>Kissenia</em>, with one species in the arid Horn and one in the Succulent Karoo, and <em>Wellstedia</em> with six species in the arid Horn and one in the Succulent Karoo. </p> <h1><span class="pagetitle">Unique and Threatened Biodiversity</span> </h1> <p><a href='/article/Biological_diversity_in_the_Horn_of_Africa'>Read Full Article...</a></p> http://www.eoearth.org/article/Biological_diversity_in_the_Horn_of_Africa Fri, 22 May 2009 00:48:08 GMT http://www.eoearth.org/article/Soil_erosion_and_deposition <a href='/article/Soil_erosion_and_deposition'><img border='0' src='/upload/thumb/3/3d/Erosion_deposition.jpg/300px-Erosion_deposition.jpg' width='100'/></a> <p>Erosion is defined as the removal of soil, sediment, regolith, and rock fragments from the landscape. Most landscapes show obvious evidence of erosion. Erosion is responsible for the creation of hills and valleys. It removes sediments from areas that were once glaciated, shapes the shorelines of lakes and coastlines, and transports material downslope from elevated sites. In order for erosion to occur, three processes must take place: detachment, entrainment and transport. Erosion also requires a medium to move material. <a href="/article/Wind">Wind</a>, water, and ice are the environmental media primarily responsible for erosion. Finally, the process of erosion stops when the transported particles fall out of the transporting medium and settle on a surface. This process is called deposition. Figure 1 illustrates an area of Death Valley, California where the effects of erosion and deposition can be easily seen. </p> <p>Figure 1 is an image that was created from DEMs (Digital Elevation Model) for the following 1:24,000 scale topographic quadrangles: Telescope Peak, Hanaupah Canyon, and Badwater, California. To the left is the Panamint Mountain Range. To the right is Death Valley. Elevation spans from 3,368 to -83 <a href="/article/Meter">meters</a> and generally decreases from left to right. The blue line represents an elevation of 0 meters. Large alluvial fans extending from a number of mountain valleys to the floor of Death Valley can be seen in the right side of the image. The sediments that make up these depositional features came from the <a href="/article/Weathering">weathering</a> and erosion of bedrock in the mountains located on the left side of the image. (This image was created with MacDEM software). </p> <p><a href='/article/Soil_erosion_and_deposition'>Read Full Article...</a></p> http://www.eoearth.org/article/Soil_erosion_and_deposition Thu, 21 May 2009 07:37:45 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Wed, 20 May 2009 02:42:10 GMT http://www.eoearth.org/article/Atrazine_in_the_environment <a href='/article/Atrazine_in_the_environment'><img border='0' src='/upload/thumb/9/97/Atrazine_chemical_structure.JPG/158px-Atrazine_chemical_structure.JPG' width='100'/></a> <p><strong><em>This article was researched and written by a student at Mount Holyoke College participating in the Encyclopedia of Earth&#39;s (EoE) <a href="/article/Student_Science_Communication_Project">Student Science Communication Project</a>. The project encourages students in undergraduate and graduate programs to write about timely scientific issues under close faculty guidance. All articles have been reviewed by internal EoE editors, and by independent experts on each topic.</em></strong></p> <p><a href='/article/Atrazine_in_the_environment'>Read Full Article...</a></p> http://www.eoearth.org/article/Atrazine_in_the_environment Tue, 19 May 2009 02:27:18 GMT http://www.eoearth.org/article/Sacred_places_and_biodiversity_conservation <a href='/article/Sacred_places_and_biodiversity_conservation'><img border='0' src='/upload/thumb/3/3a/Medicine_Lake_and_Mount_Shasta.jpg/300px-Medicine_Lake_and_Mount_Shasta.jpg' width='100'/></a> <h1> Sacred places, biodiversity, and conservation </h1><p> Sacred places are a new frontier for interdisciplinary research on their own merits and for their relevance for biodiversity conservation. The religious or cultural designation of an area as sacred, especially those which are relatively natural, may either intentionally or coincidentally promote the conservation of its associated <a href="/article/Biodiversity">biodiversity</a>. Such sacred places can complement national parks and other <a href="/article/Protected_areas">protected areas</a> established by governments. Collaboration among religious, governmental, scientific, and/or conservation agencies may be desirable for the protection of sacred sites and landscapes. </p> <p><a href='/article/Sacred_places_and_biodiversity_conservation'>Read Full Article...</a></p> http://www.eoearth.org/article/Sacred_places_and_biodiversity_conservation Mon, 18 May 2009 01:33:22 GMT http://www.eoearth.org/article/Crown-of-thorn_sea_star <a href='/article/Crown-of-thorn_sea_star'><img border='0' src='/upload/thumb/a/a6/Crown_of_thorn_sea_star.jpg/250px-Crown_of_thorn_sea_star.jpg' width='100'/></a> <p><em>Acanthaster planci</em>, more commonly known as the crown-of-thorns, is a large sea star found throughout the <a href="/article/Ocean">Indian</a> and <a href="/article/Ocean">Pacific Oceans</a>. Crown-of-thorns live and prey on live corals, often killing them in the process. Through this destructive feeding, crown-of- thorns disrupt the entire reef <a href="/article/Ecosystem">ecosystem</a>. There are numerous records of sea star outbreaks, which demonstrate the massive amounts of damage they can cause. Although up to this point <a href="/article/Coral_reef">coral reef</a> ecologists do not know of a good solution to deal with these harmful pests, there are a few indirect methods that can help prevent their outbreaks.</p> <p><a href='/article/Crown-of-thorn_sea_star'>Read Full Article...</a></p> http://www.eoearth.org/article/Crown-of-thorn_sea_star Fri, 15 May 2009 02:23:49 GMT http://www.eoearth.org/article/Doppler_effect <a href='/article/Doppler_effect'><img border='0' src='/media/approved/6/66/Doppler_effect_no_shift.gif' width='100'/></a> <p>Regardless of the frequency of a source of electromagnetic waves, they are subject to the Doppler effect. The effect was discovered by the Austrian mathematician and physicist <a href="/article/Doppler%2C_Christian_Andreas">Christian Doppler</a> (1803-1853). It causes the observed frequency of any source (sound, radio, light, etc.) to differ from the radiated frequency of the source if there is motion that is increasing or decreasing the distance between the source and the observer. The effect is readily observable as variation in the pitch of sound between a moving source and a stationary observer, or vice-versa. </p> <ol><li> When the distance between the source and receiver of electromagnetic waves remains constant, the frequency of the source and received wave forms is the same. This is illustrated in Figure 1. The waveform at the top represents the source, and the one at the bottom represents the received signal. Since the source and the receiver are not moving toward or away from each other, the received signal appears the same as the source. </li><li>When the distance between the source and receiver of electromagnetic waves is increasing, the frequency of the received wave forms appears to be lower than the actual frequency of the source wave form. This is illustrated in Figure 2. Each time the source has completed a wave, it has also moved farther away from the receiver, so the waves arrive less frequently. </li><li>When the distance is decreasing, the frequency of the received wave form will be higher than the source wave form. This is illustrated in Figure 3. Since the source is getting closer, the waves arrive more frequently. </li></ol> <p>Cases 2 and 3 are illustrated in Figure 2 and 3. Notice that when the receiver is in motion toward or away from the source, the waveform at the receiver (the lower waveform) changes. It only changes, though, while there is actual motion toward or away; when it stops, the received waveform appears the same as the source. </p><p>The Doppler effect is routinely measured in the frequency of the signals received by ground receiving stations when tracking spacecraft. The increasing or decreasing distances between the spacecraft and the ground station may be caused by a combination of the spacecraft's trajectory, its orbit around a planet, <a href="/article/Earth-Sun_geometry">Earth's revolution</a> about the sun, and <a href="/article/Earth-Sun_geometry">Earth's daily rotation</a> on its axis. A spacecraft approaching Earth will add a positive frequency bias to the received signal. However, if it flies by Earth, the received Doppler bias will become zero as it passes Earth, and then become negative as the spacecraft moves away from Earth. </p><p>A spacecraft's revolutions around another planet such as Mars adds alternating positive and negative frequency biases to the received signal, as the spacecraft first moves toward and then away from Earth. </p><p>The <a href="/article/Earth-Sun_geometry">Earth's daily rotation</a> adds a positive frequency bias to the received signal as the spacecraft rises in the east at a particular tracking station, and it adds a negative frequency bias to the received signal as the spacecraft sets in the west. </p><p>The <a href="/article/Earth-Sun_geometry">Earth's revolution</a> about the sun adds a positive frequency bias to the received signal during that portion of the year when the Earth is moving toward the spacecraft, and it adds a negative frequency bias during the part of the year when the Earth is moving away. </p> <p><a href='/article/Doppler_effect'>Read Full Article...</a></p> http://www.eoearth.org/article/Doppler_effect Thu, 14 May 2009 03:20:53 GMT http://www.eoearth.org/article/Wetland_regions_in_Canada <a href='/article/Wetland_regions_in_Canada'><img border='0' src='/upload/thumb/7/73/Map.gif/300px-Map.gif' width='100'/></a> <p>Canada contains one-fourth of the world&#39;s <a href="/article/Wetland">wetlands</a> and has been divided into seven wetland <a href="/article/Region">regions</a> by the National Wetlands Working Group. These regions (<a href="/article/Arctic">arctic</a>, subarctic, boreal, prairie, temperate, <a href="/article/Ocean">oceanic</a> and <a href="/article/Mountain">mountain</a> ) generally resemble broad climatic/vegetation zones. In Canada, these climatic zones follow a north-south <a href="/article/Temperature">temperature</a> gradient and east-west precipitation gradient. The division of wetlands into regions aids in both their study and conservation. </p> <p><a href='/article/Wetland_regions_in_Canada'>Read Full Article...</a></p> http://www.eoearth.org/article/Wetland_regions_in_Canada Wed, 13 May 2009 01:30:37 GMT http://www.eoearth.org/article/Nuclear_winter <a href='/article/Nuclear_winter'><img border='0' src='/upload/thumb/3/3b/BCabsopred.gif/280px-BCabsopred.gif' width='100'/></a> <p>Nuclear winter is a term that describes the climatic effects of nuclear war. In the 1980&#39;s, work conducted jointly by Western and Soviet scientists showed that for a full-scale nuclear war between the United States and the Soviet Union the climatic consequences, and indirect effects of the collapse of society, would be so severe that the ensuing nuclear winter would produce famine for billions of people far from the target zones. </p><p>There are several wrong impressions that people have about nuclear winter. One is that there was a flaw in the theory and that the large climatic effects were disproven. Another is that the problem, even if it existed, has been solved by the end of the nuclear arms race. But these are both wrong. Furthermore, new nuclear states threaten global climate change even with arsenals that are much less than 1% of the current global arsenal. </p> <p><a href='/article/Nuclear_winter'>Read Full Article...</a></p> http://www.eoearth.org/article/Nuclear_winter Tue, 12 May 2009 01:36:46 GMT http://www.eoearth.org/article/Global_dust_budget <a href='/article/Global_dust_budget'><img border='0' src='/upload/thumb/d/d5/Saharan_dust_traveling_over_Atlantic.gif/300px-Saharan_dust_traveling_over_Atlantic.gif' width='100'/></a> <p>The global dust budget refers to an accounting of the emission, atmospheric loading, and deposition of the mineral dust <a href="/article/Aerosols">aerosol</a> on a global scale. The topic covers the location and strength of sources, transport paths, atmospheric distribution, and deposition of mineral dust aerosol. </p> <p><a href="/article/Soil">Soil</a> particles are entrained into the air by wind erosion caused by strong <a href="/article/Wind">winds</a> over bare ground. While large sand particles quickly fall onto the ground, smaller particles (less than about 10 <a href="/article/Meter">micrometers</a> [&mu;m]) stay suspended in the air as mineral (or soil) dust aerosol. Billions of tons of mineral dust aerosols are released each year from arid and semi-arid <a href="/article/Region">regions</a> to the <a href="/article/Atmospheric_composition">atmosphere</a>. Mineral dust aerosol can be transported long distances, and can influence the air quality far beyond the source region. For example, North African (Saharan) dust is often transported over the <a href="/article/Ocean">Atlantic Ocean</a>, reaching the North or South American continents, and dust from East Asian deserts travels over the <a href="/article/Ocean">Pacific Ocean</a> and occasionally influences air quality in North America. Since these large-scale dust events have been captured by <a href="/article/Remote_sensing">satellite imagery</a>, the issue of mineral dust has been recognized as a global-scale problem. </p><p>The global dust budget has been recognized as an important research topic related to the atmospheric environment and climate. Mineral dust <a href="/article/Aerosols">aerosol</a> can cause air quality hazards such as visibility impairment and respiratory problems, which can pose risks to human health and society. Mineral dust aerosols also play an important role in the Earth&#39;s climate in several ways, including exerting a significant direct and indirect influence on the atmospheric <a href="/article/Earth%27s_energy_balance">radiation balance</a>. They do so directly through scattering and absorbing shortwave and longwave <a href="/article/Solar_radiation">radiation</a>, and indirectly by acting as cloud condensation nuclei or ice nuclei and modifying the optical properties of clouds. In addition, dust aerosol can serve as a reaction surface for reactive gases, thus affecting atmospheric photochemistry. When these aerosols falls onto the <a href="/article/Ocean">ocean</a>, the <a href="/article/Iron">iron</a> content in dust acts as a nutrient for marine <a href="/article/Phytoplankton">phytoplankton</a> and can thus enhance <a href="/article/Photosynthesis">photosynthesis</a>, in turn influencing the global <a href="/article/Carbon_cycle">carbon cycle</a>. </p><p>Quantification of the global dust budget is still a challenging issue because direct observation of dust emission and deposition over a wide area is difficult. Because of the difficulty of estimating the dust budget at the global scale, most of the currently reported dust budget values are based on numerical simulations using global dust transport models. </p> <p><a href='/article/Global_dust_budget'>Read Full Article...</a></p> http://www.eoearth.org/article/Global_dust_budget Mon, 11 May 2009 05:05:28 GMT http://www.eoearth.org/article/Nitrogen_cycle <a href='/article/Nitrogen_cycle'><img border='0' src='/upload/thumb/b/b9/Nitrogencycle.jpg/600px-Nitrogencycle.jpg' width='100'/></a> <p>The nitrogen cycle represents one of the most important nutrient cycles found in ecosystems. (Figure 1). <a href="/article/Nitrogen">Nitrogen</a> is a required nutrient for all living organisms to produce a number of complex organic molecules like amino acids, the building blocks of proteins, and nucleic acids, including DNA and RNA. The ultimate store of nitrogen is in the atmosphere, where it exists as nitrogen gas (N₂). This store is about one million times larger than the total nitrogen contained in living organisms. Other major stores of nitrogen include organic matter in <a href="/article/Soil">soil</a> and the oceans. Despite its abundance in the atmosphere, nitrogen is often the most limiting nutrient for plant growth. This problem occurs N₂ gas is not biochemically usable by plants. Plants can only take up nitrogen in the form of ammonium ion (NH₄⁺), nitrate ion (NO₃^-), or, less common, as amino acids. Animals receive the <a href="/article/Nitrogen">nitrogen</a> they need for metabolism, growth, and reproduction by the consumption of living or dead organic matter containing molecules composed partially of nitrogen. <br /> </p> <p><br /> In most ecosystems <a href="/article/Nitrogen">nitrogen</a> is primarily stored in living and dead organic matter. This organic nitrogen is converted into inorganic forms when it re-enters the biogeochemical cycle via decomposition. Decomposers chemically modify the nitrogen found in organic matter to ammonium ion (NH₄⁺). This process is known as mineralization and it is carried out by a variety of <a href="/article/Bacteria">bacteria</a> and fungi. </p><p><a href="/article/Nitrogen">Nitrogen</a> in the form of ammonium can be absorbed onto the surfaces of <a href="/article/Clay">clay</a> particles in the soil. The ammonium ion has a positive molecular charge and is normally held by negatively charged soil colloids. This process is sometimes called micelle fixation (see Figure 1). Ammonium is released from the colloids by way of cation exchange. When released, most of the ammonium is often chemically altered by a specific type of autotrophic <a href="/article/Bacteria">bacteria</a> (bacteria that belong to the genus Nitrosomonas) into nitrite (NO₂^-). Further modification by another type of bacteria (belonging to the genus Nitrobacter) converts the nitrite to nitrate (NO₃-). Both of these processes involve chemical oxidation and are known collectively as nitrification. However, nitrate is very soluble and it is easily lost from the soil system by leaching. Some of this leached nitrate flows through the <a href="/article/Hydrologic_cycle">hydrologic system</a> until it reaches the oceans where it can be returned to the atmosphere by denitrification. Denitrification is also common in anaerobic <a href="/article/Soil">soils</a> and is carried out by heterotrophic bacteria. The process of denitrification involves the metabolic reduction of nitrate (NO₃^-) into nitrogen (N₂) or <a href="/article/Nitrous_oxide">nitrous oxide</a> (N₂O) gas. Both of these gases then diffuse into the atmosphere, thus removing nitrogen from the soil, accounting for the name, denitrification. </p><p>Almost all of the <a href="/article/Nitrogen">nitrogen</a> found in any <a href="/article/Ecosystem">ecosystem</a> originally came from the atmosphere. Significant amounts enter the <a href="/article/Soil">soil</a> in rainfall or through the effects of lightning. The majority, however, is biochemically fixed in ecosystems by specialized micro-organisms, all of which are bacteria of various types, including a varity of Gram-positive and Gram-negative bacteria, actinomycetes, and cyanobacteria. Members of the bean family (legumes) and some other kinds of plants form <a href="/article/Mutualism">mutualistic</a> symbiotic relationships with certain types of nitrogen-fixing bacteria. In exchange for some nitrogen, the bacteria receive from the plants carbohydrates and special structures (nodules) in the roots where they can exist in a protected environment. Scientists estimate that biological fixation globally adds approximately 140 million metric tons of nitrogen to ecosystems every year. </p><p>Humans now fix approximately as much nitrogen industrially as does natural nitrogen fixation, thus dramatically altering the nitrogen cycle. Some of the major processes involved in this alteration include: </p> <ul><li>The application of nitrogen fertilizers to crops has caused increased rates of denitrification and leaching of nitrate into <a href="/article/Groundwater">groundwater</a>. The additional nitrogen entering the groundwater system eventually flows into streams, rivers, lakes, and estuaries. In these systems, the added nitrogen can lead to <a href="/article/Eutrophication">eutrophication</a> and associated hypoxia. </li></ul> <ul><li>Increased deposition of <a href="/article/Nitrogen">nitrogen</a> from atmospheric sources because of fossil fuel <a href="/article/Combustion">combustion</a> and forest burning. Both of these processes release a variety of solid forms of nitrogen through combustion and contribute to <a href="/article/Acid_rain">acid rain</a>. </li></ul> <ul><li>Livestock ranching. Livestock release a large amounts of ammonia into the environment from their wastes. This nitrogen enters the <a href="/article/Soil">soil</a> system and then the <a href="/article/Hydrologic_cycle">hydrologic system</a> through leaching, <a href="/article/Groundwater">groundwater</a> flow, and runoff. </li></ul> <ul><li>Sewage waste and septic tank leaching. </li></ul> <p><strong>Further Reading</strong> </p> <ul><li><a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Nitrogen_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Nitrogen_cycle Fri, 08 May 2009 02:38:58 GMT http://www.eoearth.org/article/Physical_environment_of_lakes <a href='/article/Physical_environment_of_lakes'><img border='0' src='/upload/thumb/2/23/Lakeintro.gif/200px-Lakeintro.gif' width='100'/></a> <p>The sun provides the energy which drives the world&#39;s wind patterns. Wind energy generates waves which lead to the vertical mixing of water in <a href="/article/Freshwater_biomes">lakes</a>. The light energy transmitted directly to the aquatic environment through <a href="/article/Solar_radiation">solar radiation</a> also influences the distribution of organisms and water temperature, as well as powering plant <a href="/article/Photosynthesis">photosynthesis</a>. Physical structural components of lakes include their shape, distribution of light, distribution of heat, and movement of water. </p> <p><a href='/article/Physical_environment_of_lakes'>Read Full Article...</a></p> http://www.eoearth.org/article/Physical_environment_of_lakes Thu, 07 May 2009 01:55:04 GMT http://www.eoearth.org/article/Nematomorpha <a href='/article/Nematomorpha'><img border='0' src='/upload/thumb/c/ca/Gordius.jpg/200px-Gordius.jpg' width='100'/></a> <h1><strong>Introduction</strong></h1> <p><strong> </strong>Nematomorphs are often referred to as &quot;horsehair worms&quot; as these worms are very long and thin without a distinct head. Until the late 1800&#39;s it was believed that these worms were shed into the water from horse&#39;s manes and tails. In reality their life cycles are much more interesting. Hair worms are not closely related to any other group of known invertebrates. They derived from an ancient worm-like body plan very early in <a href="/article/Evolution">evolution</a>. Their closest known relatives are the <a href="/article/Nematoda">nematodes</a> and the <a href="/article/Rotifera">rotifers</a>. The characteristics that link these three groups are the presence of a pseudocoel, as well as their general body plans and musculature.</p> <h1><strong>Morphology</strong></h1><p>Nematomorphs are only a <a href="/article/Meter">millimeter</a> or two in diameter but are usually 10 to 100 centimeters in length. They lack a distinct head, but possess a thick iridescent cuticle that is made up of cris-crossed fibers for added strength. </p><p> This group has only longitudinal muscles, but they are thick and run the entire length of the body. Adults achieve locomotion by contracting these muscles in whipping undulations. Juveniles have no need to move because they are <a href="/article/Parasite">parasitic</a>. </p> <h1><strong>Metabolism</strong> <br /></h1><p>Osmoregulation and <a href="/article/Oxygen">oxygen</a> requirements are unknown for this group of organisms and circulation is limited to the movement of fluid through the large pseudocoel. </p><p>Nematomorphs lack excretory organs, although the vestigial midgut may be used as a kidney<strong>. </strong>However, it does not filter waste and reabsorb the usable contents as do more complex kidneys. Instead,<strong> </strong>wastes are collected, concentrated, and secreted into the midgut as a holding tank. As adult horsehair worms don&#39;t live very long, the limited holding capacity is not a concern. </p> <h1><strong>Reproduction/Development</strong> <br /> </h1><p><strong> </strong> All nematomorphs species reproduce sexually. The male wraps himself around the female in many coils. Depending on species the sperm is placed directly inside the cloaca of the female or a packaged spermatophore is attached near her cloaca and the sperm swim inside. <br /> </p><p> Horsehair worms have 4 life stages: egg, pre-parasitic larva, parasitic larva, and free-living adult. Details of their life histories vary in three ways. </p><ol><li> In some species the egg hatches in the water and the pre-parasitic larva is ingested by the proper host. Here it changes from pre-parasitic to parasitic stage to adult without ever having to transfer hosts. <br /> </li><li><strong> </strong>In other species, typically found in temporary <a href="/article/Freshwater_biomes">ponds</a>, the pre-parasitic larva hatches from an egg, and as the pond begins to dry up it encysts on plant matter. When a definitive host arrives and feeds on the plant matter, ingesting the cysts accidentally, the parasitic larva emerges from the cyst and infects it. <br /> </li><li> Finally, a pre-parasitic larva hatches and does not soon encounter a definitive host. It either dies due to lack of nourishment or uses an alternate, though less suitable, host in which it encysts but cannot feed. These temporary hosts can be just about any type of vertebrate or invertebrate, even a human. These larvae burrow into the flesh or are ingested by the host and encyst in the body tissues. If this host host is eaten by a definitive host (such as when a praying mantis eats an infected mayfly) the parasitic larva emerges and enters the gut of its final host. Cysts can survive even in if a temporary host dies, and if scavengers feed on the dead tissues, the cysts can be passed into the new host by that route.<br /></li></ol><p>It is not known how selective the larvae are about hosts. It is also unknown for how long the pre-parasitic forms can encyst before they exhaust their metabolic reserves and die.</p> <h1><strong>Ecology</strong></h1> <p>As soon as horsehair worms transform from larvae into adults, their pharynx (muscular feeding structure at the mouth) becomes non-functional, and their digestive tract degenerates. As a results the adults never feed. The sole purpose of the adult form is to mate. </p><p> All nematomorphs have parasitic larvae. The goal of a larva is to be ingested by an adult insect such as Orthoptera (e.g. grasshopper) and Coleoptera (e.g. giant water beetle). Once inside the digestive system of their host they burrow into its gut lining and feed on the nutritious haemolymph. </p><p>All horsehair worms, excepting the genus <em>Nectonema, </em>occur in <a href="/article/Freshwater_biomes">freshwater</a>. They are found in both temporary ponds and flowing waters. </p> <h1><strong>Idiosyncratic inverts</strong></h1> <p>When a large number of adult nematomorphs are crowded into a small area, they wind themselves together into a giant mass resembling a Gordian knot. In Greek mythology, the king Gordius, fastened his wagon to his horse&#39;s yoke with a knot that was impossible to untie. An oracle announced that whoever released the knot would be the next ruler of Asia. Alexander the Great cut the Gordian knot with his sword, and went on to conquer Asia. </p> <p><a href='/article/Nematomorpha'>Read Full Article...</a></p> http://www.eoearth.org/article/Nematomorpha Wed, 06 May 2009 05:32:32 GMT http://www.eoearth.org/article/Heat_transfer <a href='/article/Heat_transfer'><img border='0' src='/upload/thumb/1/10/Coin_internal_KE.jpg/250px-Coin_internal_KE.jpg' width='100'/></a> <p align="left"> </p><p align="left">An object’s kinetic energy can be classified as internal or external. For example, a falling coin has a certain external kinetic energy that is related to its overall mass and to its velocity as it falls. The coin is also composed of particles that, like all particles, are moving in a random way, independent of the overall motion (or position) of the coin. The particles in the coin are constantly moving, colliding, changing direction, and changing their velocities. The energy associated with this internal motion is internal kinetic energy (Figure 1).</p> <p>The internal kinetic energy of an object can be increased by putting it in contact with another object at a higher <a href="/article/Temperature">temperature</a>. Temperature is proportional the average internal kinetic energy of an object, so higher temperature means a greater average internal energy for the particles within the object. The particles in a higher-temperature object collide with other particles with greater average force than the particles of a lower-temperature object. Thus collisions between the particles of two objects at different temperatures cause the particles of the lower-temperature object to speed up, increasing the object’s energy, and cause the particles of the higher-temperature object to slow down, decreasing this object’s energy. In this way, energy is transferred from the higher-temperature object to the lower-temperature object. We call energy that is transferred in this way <a href="/article/Heat">heat</a>. The energy that is transferred through an object, as from the bottom of a cooking pan to its handle, is also called heat. Heat is the energy that is transferred from a region of higher temperature to a region of lower temperature as a consequence of the collisions of particles (Figure 2).</p><p>The internal kinetic energy of an object, and therefore its temperature, can be increased in three general ways. The first way is to rub, compress, or distort the object. For example, after a good snowball fight, you can warm your hands by rubbing them together. Likewise, if you beat on metal with a hammer, it will get hot. The second way to increase the internal kinetic energy of an object is to put it in contact with another object at a higher temperature. This process by which heat is transferred by direct contact between an object at a higher temperature to one at a lower temperature is often called <strong>conduction</strong>. The term <strong>convection</strong> is often used to describe heat transfer that ccurs between a object and a fluid flowing across it. Convection is, in essence, a type of conduction. The third way an object’s internal kinetic energy and temperature are increased is by exposure to <strong>radiant energy</strong>, such as the energy coming from the sun. The radiant energy is converted to kinetic energy of the particles in the object. This is why we get hot in the sun. </p><p><strong><big>Further Reading</big></strong></p><ul><li>The initial version of this article was an exerpt from the preparatory chemistry text <em><a href="http://preparatorychemistry.com" class='external text' title="http://preparatorychemistry.com">An Introduction to Chemistry</a></em> by Mark Bishop.</li></ul> <p><a href='/article/Heat_transfer'>Read Full Article...</a></p> http://www.eoearth.org/article/Heat_transfer Tue, 05 May 2009 02:21:51 GMT http://www.eoearth.org/article/Kachemak_Bay_National_Estuarine_Research_Reserve,_Alaska <a href='/article/Kachemak_Bay_National_Estuarine_Research_Reserve,_Alaska'><img border='0' src='/upload/thumb/8/84/Kachemak_Bay_Reserve%2C_Alaska_map.jpg/250px-Kachemak_Bay_Reserve%2C_Alaska_map.jpg' width='100'/></a> <p>The Kachemak Bay Research Reserve (KBRR) is the only fjord in the <a href="/article/National_Estuarine_Research_Reserve_System">National Estuarine Research Reserve (NERR) System</a>, which includes 27 estuaries nationwide. Like other NERRs, the KBRR emphasizes long-term ecological research and education. Kachemak Bay is one of the most productive, diverse, and intensively used estuaries in Alaska. The natural beauty and recreational opportunities of the Bay attract both residents and thousands of summer tourists. The local economy depends upon a lucrative fishing industry and the breathtaking scenery. Its natural, protected deep-water harbor, connection to the road system, and location in lower Cook Inlet makes Homer an ideal connection to the Alaska Marine Highway, loading of cargo, and pilot transfer to vessels traveling up Cook Inlet. </p><p>Kachemak Bay was federally designated by the National Oceanic and Atmospheric Administration (NOAA) as a National Estuarine Research Reserve on February 12, 1999. The research reserve boundary includes areas of land and water that were owned by the public prior to its designation. Designation of the Kachemak Bay Reserve does not change existing ownership, regulations or management authority, nor does it result in any additional regulations. The reserve&#39;s research and education programs extend beyond the designated boundaries to include the surrounding <a href="/article/Watershed">watershed</a> for the Bay, as well as other areas that may benefit from reserve programs. </p><p>The Reserve includes approximately 4,000 km² (365,000 acres) of terrestrial and marine habitats, making it the largest reserve in the NERR system. The Reserve extends from the Fox River Flats at the head of the Bay to Point Pogibshi and Anchor Point at the mouth. The bathymetry is characterized by a submerged moraine or sill at the mouth of the Bay and deep trenches and holes extending to almost 200 meters (m) deep within the Bay. The Bay is separated into an inner and outer bay by a 6 km long spit extending south from the village of Homer (pop. 5,000). This relict moraine restricts the surface circulation in the Bay. The south side of the bay is mostly rocky and lined by rugged, snow-covered mountains. Because the tree-line elevation at this latitude is only 500 m, the 2000 m alpine summits resemble those of much loftier mountain ranges. </p> <p>Seven glaciers flow into Kachemak Bay from the Harding and other ice fields, some of the last remaining ice fields in North America. The large volume of sediments derived from these glaciers help build and sustain the predominantly sand and gravel beaches surrounding the estuary. The Fox River Flats, at the head of the bay, is a huge salt marsh complex supporting thousands of migratory birds every spring and fall. During the summer, glacier meltwater contributes approximately 70,000 cubic meters of fresh water each day to the inner Bay. Another 14 billion cubic meters of cold, nutrient-rich <a href="/article/Seawater">seawater</a> from the Gulf of Alaska flows in and out of the outer Bay, partly driven by an amazing 8.7 meter tidal range that results from the complex geomorphology of the Gulf of Alaska and Cook Inlet. </p><p>Fjords such as Kachemak Bay often have a seasonally stratified water column that results when a surface layer of fresh water develops above denser cold <a href="/article/Seawater">seawater</a>. But one unique feature of this high-latitude NERR is that during the 6-month long winter, when the watershed is frozen, this fresh surface layer disappears and the bay becomes wholly marine. Interestingly, an annual decrease in benthic <a href="/article/Biodiversity">biological diversity</a> accompanies this shift from a marine to an estuarine system. But because many of the marine mammals, birds, and fishes in the Bay are migratory, the overall annual diversity is still very high compared to similar systems further south. </p> <p><a href='/article/Kachemak_Bay_National_Estuarine_Research_Reserve,_Alaska'>Read Full Article...</a></p> http://www.eoearth.org/article/Kachemak_Bay_National_Estuarine_Research_Reserve,_Alaska Mon, 04 May 2009 02:45:57 GMT http://www.eoearth.org/article/Coral_reefs_and_climate_change <a href='/article/Coral_reefs_and_climate_change'><img border='0' src='/upload/thumb/3/32/BoultreefGBR.jpg/225px-BoultreefGBR.jpg' width='100'/></a> <h1>Introduction<br /></h1> <p><span style="font-family: Arial">Research on the current and future impacts of human-induced climate change on reef-building corals is causing scientists and managers to become increasingly concerned about the future of coral reefs. A healthy reef ecosystem literally buzzes with sounds, activity and colors and is populated by incredibly dense aggregations of fish and invertebrates. In this respect, tropical reefs are more reminiscent of the African Serengeti</span><span style="font-family: Arial"> than of the tropical rainforest</span><span style="font-family: Arial"> they are often compared to, where the resident birds and mammals can be secretive and difficult to see. A coral reef can contain tens of thousands of species and some of the world’s most dense and diverse communities of vertebrate animals. Unfortunately, very few remaining <a href="/article/Coral_reef">coral reefs</a> resemble this pristine condition; on mos</span>t, corals and fishes are much less abundant than they were only a few decades ago.</p> <p><a href='/article/Coral_reefs_and_climate_change'>Read Full Article...</a></p> http://www.eoearth.org/article/Coral_reefs_and_climate_change Thu, 30 Apr 2009 06:22:57 GMT http://www.eoearth.org/article/Seagrass_meadows <a href='/article/Seagrass_meadows'><img border='0' src='/upload/thumb/6/67/Posidonia.jpg/300px-Posidonia.jpg' width='100'/></a> <p>Seagrasses are angiosperms that are restricted to life in the sea. Seagrasses colonized the sea, from terrestrial angiosperm ancestors, about 100 million years ago, which indicates a relatively early appearance of seagrasses in angiosperm evolution. With a rather low number of species (about 50-60), seagrass comprise &lt; 0.02% of the angiosperm flora. Seagrasses are assigned to two families, Potamogetonaceae and Hydrocharitaceae, encompassing 12 genera of angiosperms containing about 50 species (Table 1). Three of the genera, <em>Halophila</em>, <em>Zostera</em> and <em>Posidonia</em>, which may have evolved from lineages that appeared relatively early in seagrass evolution, comprise most (55%) of the species, while <em>Enhalus</em>, the most recent seagrass genus, is represented by a single species (<em>Enhalus acoroides</em>, Table 1). Most seagrass meadows are monospecific, but may develop multispecies, with up to 12 species, meadows in subtropical and tropical waters.</p> <p><a href='/article/Seagrass_meadows'>Read Full Article...</a></p> http://www.eoearth.org/article/Seagrass_meadows Wed, 29 Apr 2009 03:27:45 GMT http://www.eoearth.org/article/Vertical_farming <a href='/article/Vertical_farming'><img border='0' src='/upload/thumb/6/60/C_Jacobs_VFs_solar.jpg/200px-C_Jacobs_VFs_solar.jpg' width='100'/></a> <p>The advent of <a href="/article/Agriculture">agriculture</a> ushered in an unprecedented increase in the human <a href="/article/Population">population</a> and their <a href="/article/Domestication">domesticated animals</a>. Farming catalyzed the transformation of hunter-gatherers into urban dwellers. Today, over 800 million hectares is committed to agriculture, or about 38% of the total landmass of the Earth. Farming has <a href="/article/Land-use_and_land-cover_change">re-arranged the landscape</a> in favor of cultivated fields and herds of cattle, and has occurred at the expense of natural ecozones, reducing most of them to fragmented, semi-functional units, while completely eliminating others. Undeniably, a reliable food supply has allowed for a healthier life style for most of the civilized world, while the very act of farming has created new health hazards. </p> <p>For example, the transmission of numerous infectious disease agents - avian influenza, rabies, yellow fever, dengue fever, <a href="/article/Malaria">malaria</a>, trypanosomiasis, hookworm, <a href="/article/Schistosomiasis">schistosomiasis</a> - occur with relentlessly devastating regularity at the tropical and sub-tropical agricultural interface. Emerging infections, many of which are viral zoonoses (e.g., Ebola, Lassa fever), rapidly adapt to the human host following encroachment into natural environments. Exposure to <a href="/article/Toxicity">toxic</a> levels of some classes of agrochemicals (<a href="/article/Pesticide">pesticides</a>, fungicides) and trauma are two other significant health risks associated with traditional agricultural practices. Over the next 50 years, the human population is expected to rise to at least 8.6 billion, requiring an additional 10⁹ hectares to feed them using current technologies. That quantity of farmland is no longer available. Thus, alternative strategies for obtaining an abundant and varied food supply without encroachment into the few remaining functional ecosystems must be seriously entertained. </p><p>If traditional farming could be replaced by constructing urban food production centers - vertical farms - then a long-term benefit would be the gradual repair of many of the world’s damaged ecosystems through the systematic abandonment of farmland. In temperate and tropical zones, the re-growth of hardwood forests could play a significant role in <a href="/article/Carbon_capture_and_storage">carbon sequestration</a> and may help reverse current trends in global climate change. Social benefits of vertical farming include the creation of a sustainable urban environment that encourages good health for all who choose to live there; new employment opportunities; fewer abandoned lots and buildings; cleaner air; and an abundant supply of safe drinking water. </p> <p><a href='/article/Vertical_farming'>Read Full Article...</a></p> http://www.eoearth.org/article/Vertical_farming Tue, 28 Apr 2009 03:59:23 GMT http://www.eoearth.org/article/Wetland_regions_in_Canada <a href='/article/Wetland_regions_in_Canada'><img border='0' src='/upload/thumb/7/73/Map.gif/300px-Map.gif' width='100'/></a> <p>Canada contains one-fourth of the world&#39;s <a href="/article/Wetland">wetlands</a> and has been divided into seven wetland <a href="/article/Region">regions</a> by the National Wetlands Working Group. These regions (<a href="/article/Arctic">arctic</a>, subarctic, boreal, prairie, temperate, <a href="/article/Ocean">oceanic</a> and <a href="/article/Mountain">mountain</a> ) generally resemble broad climatic/vegetation zones. In Canada, these climatic zones follow a north-south <a href="/article/Temperature">temperature</a> gradient and east-west precipitation gradient. The division of wetlands into regions aids in both their study and conservation. </p> <p><a href='/article/Wetland_regions_in_Canada'>Read Full Article...</a></p> http://www.eoearth.org/article/Wetland_regions_in_Canada Mon, 27 Apr 2009 02:05:42 GMT http://www.eoearth.org/article/Clostridium_botulinum <a href='/article/Clostridium_botulinum'><img border='0' src='/upload/thumb/7/79/Clostridium_botulinum.gif/165px-Clostridium_botulinum.gif' width='100'/></a> <h1>Introduction<br /></h1> <p>The U.S. Department of Agriculture&#39;s Food Safety and Inspection Service and the Centers for Disease Control and Prevention have characterized <em><u>Clostridium botulinum</u></em><strong> </strong>as the name of a group of <a href="/article/Bacteria">bacteria</a> commonly found in <a href="/article/Soil">soil</a>. These rod-shaped organisms grow best in low <a href="/article/Oxygen">oxygen</a> conditions.</p><p> The bacteria form spores which allow them to survive in a dormant state until exposed to conditions that can support their growth. There are seven types of botulism toxin designated by the letters A through G; only types A, B, E and F cause illness in humans. <em>Clostridium botulinum</em> is the bacterium that produces the nerve toxin that causes <a href="/article/Botulism">botulism</a>.</p> <p><a href='/article/Clostridium_botulinum'>Read Full Article...</a></p> http://www.eoearth.org/article/Clostridium_botulinum Fri, 24 Apr 2009 02:41:42 GMT http://www.eoearth.org/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali <a href='/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali'><img border='0' src='/upload/thumb/7/77/Bandiagaratown.JPG/300px-Bandiagaratown.JPG' width='100'/></a> <p>Cliffs of Bandiagara (Land of the Dragons) is a World Heritage Site in Mali located at 14°00&#39;-14°45&#39;N, 3°00&#39;-3°50&#39;W.</p> <h1><strong>Geographical Location</strong></h1> <p>The village of Sangha (Sanga or Songo), on the crest of the Bandiagara escarpment, lies at the center of the sanctuary. It overlooks the village of Banani at the base of the escarpment, 44 <a href="/article/Meter">kilometers</a> (km) north-east of Bandiagara Town and 107 km east of Mopti, in the fifth administrative and economic <a href="/article/Region">region</a> of Mopti. 14°00&#39;-14°45&#39;N, 3°00&#39;-3°50&#39;W</p> <h1><strong>Date and History of Establishment</strong></h1> <p>Existing legal provisions relate only to the sanctuary&#39;s cultural heritage and include the following: Ordinance No. 52 of 3 October 1969 regulating the export of objects of art, Law No. 85-40/AN-RM of 26 July 1985 dealing with the protection and promotion of the national cultural heritage and Decree No. 275/PG-RM of 4 November 1985 regulating archaeological excavations. Both Law No. 86-61/AN-RM of 26 July 1986 and Decree No. 299/PG-RM of 19 September 1986 specifically control excavations, commerce and the export of cultural objects. Inscribed on the World Heritage List in 1989. </p> <h1><strong>Area</strong></h1> <p>400,000 hectares (ha).</p> <h1> <strong>Land Tenure</strong></h1> <p>Some land is privately owned by Sangha residents, the rest is state-owned. </p> <h1><strong>Altitude</strong></h1> <p>Ranges from 518 <a href="/article/Meter">meters</a> (m) near Sangha to 777 m at Mount Bamba in the north-east. </p> <h1><strong> Physical Features</strong></h1> <p>The area exhibits three distinctive geomorphological features: Bandiagara plateau, Bandiagara escarpment and the plaine du Séno. The escarpment and plateau extend beyond the sanctuary to the Mossi Massif, which separates the Séno plain from the low-lying <a href="/article/Wetland">wetlands</a> of the inner delta of the Niger. The site consists of an ancient <a href="/article/Soil_erosion_and_deposition">eroded</a> terrain of flat tablelands, messa and sandstone buttes. <a href="/article/Composition_of_rocks">Rocks</a> are predominantly upper sandstone of the Cambrian and Ordovician periods, horizontally bedded and characterized by a great variety of facies. Exposed horizontal strata periodically result in rock polygonation. In some areas the plateau is crowned by a hard layer of laterite, ironstone shield or impervious conglomerates. Bandiagara plateau comprises sandstone, with rock slabs riddled with holes, faults and caves that link up with springlines along the base of the cliffs. At low levels the ravines are blocked by immense detached blocks of rock. The escarpment extends over 150 km in a south-west to north-east direction from Douentza in the north to Ouo in the south, and varies in height from 100 m in the south to over 500 m in the north. The escarpment has been shaped into numerous irregularities, indentations, and promontories, and is pierced by thalweg ravines, gorges, and rocky passages connecting the plain and plateau. It is noted for the abrupt escarpment near Sangha-Bongo. Thalwegs feature a <a href="/article/Atmospheric_humidity">humid</a> and shaded microclimate which supports dense vegetation. Water is also retained in rock fissures, resulting in seasonally <a href="/article/Bog">boggy</a> areas on horizontal or gently sloping rock strata. </p> <h1><strong>Climate</strong></h1> <p>Average rainfall for 1994 was 600 <a href="/article/Meter">millimeters</a> (mm), with 849.4mm falling in 59 days at Bandiagara and 715.4 mm in 54 days at Sangha. Droughts last for up to eight months of the year. <a href="/article/Precipitation_and_fog">Rain</a> falls irregularly mainly from June to September. Shade <a href="/article/Temperature">temperatures</a> in May are reported to be some of the highest in the Sahel <a href="/article/Region">region</a>.</p> <h1><strong>Vegetation</strong></h1> <p>Sudano-Sahelian vegetation encircles Bandiagara and Sangha, dominated by open savanna and steppe with scattered <em>Acacia raddiana</em>, <em>A. albida</em>, <em>Balanites aegyptiaca</em> and <em>Cenchrus ciliaris</em>. The plateau of Bandiagara is covered in a typically Sudanian savanna flora, including communities of <em>Daniellia oliveri</em> in association with <em>Butyrospermum parkii</em>, <em>Parkia biglobosa</em>, <em>Terminalia macroptera</em>, <em>Khaya</em> <em>senegalensis</em>, <em>Vitex cienkowskii</em>, <em>Prosopis africana</em> and brush species such as <em>Combretum micranthum</em>, <em>Heeria insignis</em> and <em>Guiera senegalensis</em>. Along the edge of the plateau, where the terrain is rocky, characteristic species are <em>Caralluma dalziellii</em>, <em>Euphorbia balsamifera</em> and <em>Senecio cliffordianus</em>. Open scattered vegetation includes xerophytes, cryptograms and deep-rooted trees in rock fissures where they are protected from <a href="/article/Fire_ecology_fact_sheet">fire</a>. Cliff and ravine vegetation is often very <a href="/article/Biodiversity">diverse</a> and dense; the chasmophytic flora includes <em>Cissus quadrangularis</em>, <em>Ficus lecardii</em>, <em>Boscia angustifolia</em>, <em>Euphorbia sudanica</em>, <em>Lannea microcarpa</em> and <em>Combretum lecardii</em>. In rainy seasons the horizontal <a href="/article/Composition_of_rocks">rock</a> strata contain water, creating <a href="/article/Bog">boggy</a> areas which act as refugia for species such as <em>Cyanotis rubescens</em> and <em>Bulbostylis</em> sp. The humid microclimate of the escarpment thalwegs supports <em>Combretum</em> along with <em>Stereospermum kunthianum</em>, <em>Gloriosa simplex</em>, <em>Cissus populnea</em>, <em>Acacia</em> <em>ataxacantha</em> and <em>A. sieberiana</em>. Notable hygrophilic species include <em>Celtis</em> <em>integrifolia</em>, <em>Pachystela pobeguiniana</em> and <em>Diospyros mespiliformis</em>, as well as <em>Selaginella</em> sp., <em>Begonia rostrata</em>, <em>Fleurya aestuans</em> and <em>Ceratopteris cornuta</em>. At the foot of the escarpment, in the plain of Douentza, there is a preponderance of Sahelian species such as <em>Acacia albida</em>, <em>A. raddiana</em>, <em>Dalbergia melanoxylon</em>, <em>Combretum aculeatum</em> and <em>Tamarindus indica</em>. The Sangha rock pool depressions support <a href="/article/Aquatic_plants">aquatic plants</a> such as <em>Nymphaea</em> <em>maculata</em>, <em>Najas graminea</em>, <em>Ottelia ulvaefolia</em>, <em>Cyperus</em> sp., <em>Sacciolepis</em> sp. and <em>Melochia corchorifolia</em>. Other shallow water vegetation includes floating carpets of <em>Pistia stratiotes</em>, <em>Neptunia oleracea</em>, <em>Ipomoea reptans</em> and <em>Najas</em> <em>graminea</em>. </p> <h1><strong>Fauna</strong></h1> <p>The <a href="/article/Biodiversity">diverse</a> vegetation communities support a notable resident and migratory bird fauna, including cliff species such as fox-kestrel <em>Falco alopex</em>, Gabar goshawk <em>Melierax gabar</em>, yellow-billed shrike <em>Corvinella corvina</em> scarlet-chested sunbird Chalcomitra senegalensis,, rose-ringed parakeet <em>Psittacula krameri</em>, cliff chat <em>Thamnolea cinnamomeiventris </em>(abundant) and rock dove <em>Columbia livia</em>. The pools are a haven for Egyptian plover <em>Pluvianus aegyptius</em> and grey-headed kingfisher <em>Halcyon leucocephala</em>, whilst tree, shrub and savanna species include bustard <em>Eupodotis senegalensis</em>, stone partridge <em>Ptilopachus petrosus</em> and laughing dove <em>Streptopelia senegalensis</em>. Species abundant around villages include grey-headed sparrow <em>Passer griseus </em>and hooded vulture <em>Necrosytres monachus.</em> Mammals which occur in the region and probably exist in the vicinity of Bandiagara escarpment include rock hyrax <em>Procavia capensis</em>, porcupine <em>Hystrix</em> spp, common jackal <em>Canis aureus</em> and pale fox<em> Vulpes pallida.</em> Dorcas gazelle <em>Gazella dorcas</em>, dama gazelle <em>G. dama</em> and wild dog <em>Lycaon pictus</em> are no longer found in the area. </p> <h1><strong>Cultural Heritage</strong></h1> <p>The <a href="/article/Region">region</a> is one of the main centers for the Dogon culture, rich in ancient traditions and rituals, art culture and folklore. The village of Sangha is celebrated for its triennial circumcision ceremonies and its rock carvings. Archaeological evidence suggests human occupancy of the cliffs for at least the last 1,000 years, although the Dogons themselves did not arrive until the 15th and 16th centuries. Traditionally, they consisted of four tribes, the Dyon, Ono, Arou and Domno which migrated from the land of Mandé. The present-day local Dogon <a href="/article/Population">population</a> is divided into small village communities, each Dogon member having a village surname shared by every inhabitant. Village communities are divided into the <em>inneomo</em> and <em>innepuru</em>, living men and dead man respectively, which exist in symbiotic union with each other. In some cases secret languages have developed. Symbolic relationships exist with respect to the environment, such as with the pale fox and jackal, and the development of elaborate masks and head dresses. Semi-domestic crocodiles are kept as sacred protectors of Bandiagara Village and its ancient founder, Nangabanou Tembèly. They are also revered in ritual rain dances. The Bandiagara features an unique architecture, ranging from thatched flat-roofed huts to distinctive tapering granaries each capped with thatch. Bandiagara escarpment abounds in a whole series of cliff cemeteries reached by Dogon-style ladders.</p> <h1><strong>Local Human Population</strong></h1> <p>The resident <a href="/article/Population">population </a> consists of desert-edge subsistence farmers who inhabit the plateau area. According to the 1986-1987 census, there were 199,291 Dogon inhabitants in Bandiagara and 20,940 in Sangha, representing a significant proportion of the estimated 701,460 Dogons in Mali. Subsistence crops include millet and also sorghum, calabash and cassava. Rice is grown in cultivated rock pools and gardens are found on horizontal sections of the cliffs. Dogons rely for permanent water on springlines along the base of Bandiagara escarpment. </p> <h1><strong>Visitors and Visitor Facilities</strong></h1> <p>There is a small airfield at Bandiagara and another at Mopti. Rest houses are located at Sangha and Bandiagara. Mopti is a center of tourism and a hotel has been constructed. The Mali Office of Tourism publicizes the historic sites of the Bandiagara region. </p> <h1><strong>Scientific Research and Facilities</strong></h1> <p>The Division de la Recherche Forestière et Hydrobiologique of the Ministère de l&#39;Elevage et des Eaux et Forêts maintains a hydrological laboratory at Mopti. The laboratory carries out research on fish systematics and biology. Work on the botany of the area was initiated between 1950-1952 by G. Dieterlenand followed by Jaeger and Winkoun in the 1960s for the Institut Français d&#39;Afrique Noir. A herbarium collection of 300 species was made from the region of Sangha. A fauna and flora survey is currently being undertaken on behalf of the &quot;cantonnements forestiers&quot;.</p> <h1><strong>Conservation Value</strong></h1> <p>These cliffs protect architectural structures which for centuries, have been the soul of traditional, secular Dogon culture. The Bandiagara plateau is one of the most impressive geological and landscape features in West Africa.</p> <h1><strong>Conservation Management</strong></h1> <p>The government is conserving the site because of its exceptional architectural structures and the interaction between man and the natural environment. One of the key management aims is the maintenance of the Dogon culture and associated houses, granaries, ritual sanctuaries and &quot;toguna&quot;. Also of importance are the surrounding natural features and landscape. Bandiagara plateau near Sangha-Bongo has been described as one of the most impressive geological and landscape features in West Africa. The botany of the region is of great phytogeographic interest. The escarpment supports important refugial biotopes rich in relict species and vegetation types otherwise felled or burnt by man&#39;s activities in more accessible localities. The Sangha flora communities represent an interface between different phytogeographic regions (Sudano-Sahelian and Sahelian) and consist of relict ravine vegetation (ancient <a href="/article/Atmospheric_humidity">humid</a> flora) in an otherwise arid Sahelian climate. Species with restricted distributions include the localized endemic <em>Acridocarpus monodii</em> (R) found in the Bandiagara escarpment at Kikara. </p> <p> Responsibility for cultural heritage management belongs to the Ministry of Culture and Communications, with local management under the authority of Cultural Mission. The chief of the Cultural Mission is charged with conserving the cultural heritage of the <a href="/article/Region">region</a>. </p> <h2><strong>Management Constraints</strong></h2> <p>The greatest threats to the area include drought and <a href="/article/Desertification">desertification</a>. Uncontrolled tourism is affecting the economic structure and menacing the basis of the Dogon culture. The savanna vegetation has been profoundly <a href="/article/Land-use_and_land-cover_change">degraded</a> by fire and scrub <a href="/article/Land-use_and_land-cover_change">clearance</a>, most notably in the vicinity of village communities. Insufficient funding means that the site is inadequately patrolled. </p> <h2><strong>Staff</strong></h2> <p>A total of three.</p> <h2><strong>Budget</strong></h2> <p>Five million CFA per annum from the government (US$10,000).</p> <h1><strong>IUCN Management Category</strong></h1> <ul><li>III (Natural Monument) </li><li> Natural/Cultural World Heritage Site - Natural Criterion iii/Cultural Criterion v</li></ul> <h1><strong>Further Reading<br /></strong></h1> <ul><li>Calame-Griaule, G. (1955). Notes sur l&#39;habitation du plateau central nigérian. <em>Bulletin de l&#39;Institut français d&#39;Afrique noire</em> 27(B): 481-485. </li><li> Diakite, S. (1988). Sanctuaire Naturel et Culturel de la Falaise de Bandiagara. Proposition d&#39;Inscription sur la Liste du Patrimoine Mondial Soumise par le Mali. Ministère des Sports, des Arts et de la Culture Letter No. 101889/MSAC-DNAC, 13 December 1988. </li><li> Dieterlen, G. (1952). Classification des Végétaux chez les Dogon. <em>Journal</em> <em>de la Société des Africanistes</em> 22: 115-158. </li><li> FAO (1985). Aménagement de la faune, des Parcs et Réserves. FAO, Rome. Report No. TA2698. 19 pp. </li><li> Griaule, M. (1941). Les Mammifères dans la religion des Dogons (Soudan fr.). <em>Mammalia</em> 5: 104-109. </li><li> Jaeger, P. and Winkoun, D. (1962). Premier contact avec la flore et la végétation du plateau de Bandiagara. <em>Bulletin de l&#39;Institut français de l&#39;Afrique noire</em> 24A: 69-111. </li><li> Laude, J. (1973). <em>African art of the Dogon, the myths of the cliff dwellers</em>. The Brooklyn Museum, New York. <a href="http://www.amazon.com/dp/0670109282/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0670109282/?tag=encycofearth-20">ISBN: 0670109282</a> </li><li> Paulme, D. (1973). La divination par les chacals chez les Dogon de Sangha. <em>Journal de la Société des Africanistes</em> 7: 1-13. </li><li> Pern, S. (1985). The Dogon of Mali, existing on the edge. <em>World Magazine</em> 17: 40-47. </li><li> Rousselot, R. (1939). Notes sur la faune ornithologique du cercle de Mopti, Soudan Français. <em>Bulletin de l&#39;Institut français de l&#39;Afrique Noire</em> 1: 1-88. </li><li> Sayer, J.A. (1977). Conservation of large mammals in the Republic of Mali. <em>Biological Conservation</em> 12: 245-263. </li><li> Yaro, J. and Diko, S. (1940). A propos des crocodiles sacrés de Bandiagara. <em>Bulletin de l&#39;Institut français de l&#39;Afrique noire</em> 2: 211-216</li></ul> <p><br /> <p><br style="clear: left" /> <center> </p> </center> </p> <p><a href='/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali'>Read Full Article...</a></p> http://www.eoearth.org/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali Thu, 23 Apr 2009 03:46:47 GMT http://www.eoearth.org/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali <a href='/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali'><img border='0' src='/upload/thumb/7/77/Bandiagaratown.JPG/300px-Bandiagaratown.JPG' width='100'/></a> <p>Cliffs of Bandiagara (Land of the Dragons) is a World Heritage Site in Mali located at 14°00&#39;-14°45&#39;N, 3°00&#39;-3°50&#39;W.</p> <h1><strong>Geographical Location</strong></h1> <p>The village of Sangha (Sanga or Songo), on the crest of the Bandiagara escarpment, lies at the center of the sanctuary. It overlooks the village of Banani at the base of the escarpment, 44 <a href="/article/Meter">kilometers</a> (km) north-east of Bandiagara Town and 107 km east of Mopti, in the fifth administrative and economic <a href="/article/Region">region</a> of Mopti. 14°00&#39;-14°45&#39;N, 3°00&#39;-3°50&#39;W</p> <h1><strong>Date and History of Establishment</strong></h1> <p>Existing legal provisions relate only to the sanctuary&#39;s cultural heritage and include the following: Ordinance No. 52 of 3 October 1969 regulating the export of objects of art, Law No. 85-40/AN-RM of 26 July 1985 dealing with the protection and promotion of the national cultural heritage and Decree No. 275/PG-RM of 4 November 1985 regulating archaeological excavations. Both Law No. 86-61/AN-RM of 26 July 1986 and Decree No. 299/PG-RM of 19 September 1986 specifically control excavations, commerce and the export of cultural objects. Inscribed on the World Heritage List in 1989. </p> <h1><strong>Area</strong></h1> <p>400,000 hectares (ha).</p> <h1> <strong>Land Tenure</strong></h1> <p>Some land is privately owned by Sangha residents, the rest is state-owned. </p> <h1><strong>Altitude</strong></h1> <p>Ranges from 518 <a href="/article/Meter">meters</a> (m) near Sangha to 777 m at Mount Bamba in the north-east. </p> <h1><strong> Physical Features</strong></h1> <p>The area exhibits three distinctive geomorphological features: Bandiagara plateau, Bandiagara escarpment and the plaine du Séno. The escarpment and plateau extend beyond the sanctuary to the Mossi Massif, which separates the Séno plain from the low-lying <a href="/article/Wetland">wetlands</a> of the inner delta of the Niger. The site consists of an ancient <a href="/article/Soil_erosion_and_deposition">eroded</a> terrain of flat tablelands, messa and sandstone buttes. <a href="/article/Composition_of_rocks">Rocks</a> are predominantly upper sandstone of the Cambrian and Ordovician periods, horizontally bedded and characterized by a great variety of facies. Exposed horizontal strata periodically result in rock polygonation. In some areas the plateau is crowned by a hard layer of laterite, ironstone shield or impervious conglomerates. Bandiagara plateau comprises sandstone, with rock slabs riddled with holes, faults and caves that link up with springlines along the base of the cliffs. At low levels the ravines are blocked by immense detached blocks of rock. The escarpment extends over 150 km in a south-west to north-east direction from Douentza in the north to Ouo in the south, and varies in height from 100 m in the south to over 500 m in the north. The escarpment has been shaped into numerous irregularities, indentations, and promontories, and is pierced by thalweg ravines, gorges, and rocky passages connecting the plain and plateau. It is noted for the abrupt escarpment near Sangha-Bongo. Thalwegs feature a <a href="/article/Atmospheric_humidity">humid</a> and shaded microclimate which supports dense vegetation. Water is also retained in rock fissures, resulting in seasonally <a href="/article/Bog">boggy</a> areas on horizontal or gently sloping rock strata. </p> <h1><strong>Climate</strong></h1> <p>Average rainfall for 1994 was 600 <a href="/article/Meter">millimeters</a> (mm), with 849.4mm falling in 59 days at Bandiagara and 715.4 mm in 54 days at Sangha. Droughts last for up to eight months of the year. <a href="/article/Precipitation_and_fog">Rain</a> falls irregularly mainly from June to September. Shade <a href="/article/Temperature">temperatures</a> in May are reported to be some of the highest in the Sahel <a href="/article/Region">region</a>.</p> <h1><strong>Vegetation</strong></h1> <p>Sudano-Sahelian vegetation encircles Bandiagara and Sangha, dominated by open savanna and steppe with scattered <em>Acacia raddiana</em>, <em>A. albida</em>, <em>Balanites aegyptiaca</em> and <em>Cenchrus ciliaris</em>. The plateau of Bandiagara is covered in a typically Sudanian savanna flora, including communities of <em>Daniellia oliveri</em> in association with <em>Butyrospermum parkii</em>, <em>Parkia biglobosa</em>, <em>Terminalia macroptera</em>, <em>Khaya</em> <em>senegalensis</em>, <em>Vitex cienkowskii</em>, <em>Prosopis africana</em> and brush species such as <em>Combretum micranthum</em>, <em>Heeria insignis</em> and <em>Guiera senegalensis</em>. Along the edge of the plateau, where the terrain is rocky, characteristic species are <em>Caralluma dalziellii</em>, <em>Euphorbia balsamifera</em> and <em>Senecio cliffordianus</em>. Open scattered vegetation includes xerophytes, cryptograms and deep-rooted trees in rock fissures where they are protected from <a href="/article/Fire_ecology_fact_sheet">fire</a>. Cliff and ravine vegetation is often very <a href="/article/Biodiversity">diverse</a> and dense; the chasmophytic flora includes <em>Cissus quadrangularis</em>, <em>Ficus lecardii</em>, <em>Boscia angustifolia</em>, <em>Euphorbia sudanica</em>, <em>Lannea microcarpa</em> and <em>Combretum lecardii</em>. In rainy seasons the horizontal <a href="/article/Composition_of_rocks">rock</a> strata contain water, creating <a href="/article/Bog">boggy</a> areas which act as refugia for species such as <em>Cyanotis rubescens</em> and <em>Bulbostylis</em> sp. The humid microclimate of the escarpment thalwegs supports <em>Combretum</em> along with <em>Stereospermum kunthianum</em>, <em>Gloriosa simplex</em>, <em>Cissus populnea</em>, <em>Acacia</em> <em>ataxacantha</em> and <em>A. sieberiana</em>. Notable hygrophilic species include <em>Celtis</em> <em>integrifolia</em>, <em>Pachystela pobeguiniana</em> and <em>Diospyros mespiliformis</em>, as well as <em>Selaginella</em> sp., <em>Begonia rostrata</em>, <em>Fleurya aestuans</em> and <em>Ceratopteris cornuta</em>. At the foot of the escarpment, in the plain of Douentza, there is a preponderance of Sahelian species such as <em>Acacia albida</em>, <em>A. raddiana</em>, <em>Dalbergia melanoxylon</em>, <em>Combretum aculeatum</em> and <em>Tamarindus indica</em>. The Sangha rock pool depressions support <a href="/article/Aquatic_plants">aquatic plants</a> such as <em>Nymphaea</em> <em>maculata</em>, <em>Najas graminea</em>, <em>Ottelia ulvaefolia</em>, <em>Cyperus</em> sp., <em>Sacciolepis</em> sp. and <em>Melochia corchorifolia</em>. Other shallow water vegetation includes floating carpets of <em>Pistia stratiotes</em>, <em>Neptunia oleracea</em>, <em>Ipomoea reptans</em> and <em>Najas</em> <em>graminea</em>. </p> <h1><strong>Fauna</strong></h1> <p>The <a href="/article/Biodiversity">diverse</a> vegetation communities support a notable resident and migratory bird fauna, including cliff species such as fox-kestrel <em>Falco alopex</em>, Gabar goshawk <em>Melierax gabar</em>, yellow-billed shrike <em>Corvinella corvina</em> scarlet-chested sunbird Chalcomitra senegalensis,, rose-ringed parakeet <em>Psittacula krameri</em>, cliff chat <em>Thamnolea cinnamomeiventris </em>(abundant) and rock dove <em>Columbia livia</em>. The pools are a haven for Egyptian plover <em>Pluvianus aegyptius</em> and grey-headed kingfisher <em>Halcyon leucocephala</em>, whilst tree, shrub and savanna species include bustard <em>Eupodotis senegalensis</em>, stone partridge <em>Ptilopachus petrosus</em> and laughing dove <em>Streptopelia senegalensis</em>. Species abundant around villages include grey-headed sparrow <em>Passer griseus </em>and hooded vulture <em>Necrosytres monachus.</em> Mammals which occur in the region and probably exist in the vicinity of Bandiagara escarpment include rock hyrax <em>Procavia capensis</em>, porcupine <em>Hystrix</em> spp, common jackal <em>Canis aureus</em> and pale fox<em> Vulpes pallida.</em> Dorcas gazelle <em>Gazella dorcas</em>, dama gazelle <em>G. dama</em> and wild dog <em>Lycaon pictus</em> are no longer found in the area. </p> <h1><strong>Cultural Heritage</strong></h1> <p>The <a href="/article/Region">region</a> is one of the main centers for the Dogon culture, rich in ancient traditions and rituals, art culture and folklore. The village of Sangha is celebrated for its triennial circumcision ceremonies and its rock carvings. Archaeological evidence suggests human occupancy of the cliffs for at least the last 1,000 years, although the Dogons themselves did not arrive until the 15th and 16th centuries. Traditionally, they consisted of four tribes, the Dyon, Ono, Arou and Domno which migrated from the land of Mandé. The present-day local Dogon <a href="/article/Population">population</a> is divided into small village communities, each Dogon member having a village surname shared by every inhabitant. Village communities are divided into the <em>inneomo</em> and <em>innepuru</em>, living men and dead man respectively, which exist in symbiotic union with each other. In some cases secret languages have developed. Symbolic relationships exist with respect to the environment, such as with the pale fox and jackal, and the development of elaborate masks and head dresses. Semi-domestic crocodiles are kept as sacred protectors of Bandiagara Village and its ancient founder, Nangabanou Tembèly. They are also revered in ritual rain dances. The Bandiagara features an unique architecture, ranging from thatched flat-roofed huts to distinctive tapering granaries each capped with thatch. Bandiagara escarpment abounds in a whole series of cliff cemeteries reached by Dogon-style ladders.</p> <h1><strong>Local Human Population</strong></h1> <p>The resident <a href="/article/Population">population </a> consists of desert-edge subsistence farmers who inhabit the plateau area. According to the 1986-1987 census, there were 199,291 Dogon inhabitants in Bandiagara and 20,940 in Sangha, representing a significant proportion of the estimated 701,460 Dogons in Mali. Subsistence crops include millet and also sorghum, calabash and cassava. Rice is grown in cultivated rock pools and gardens are found on horizontal sections of the cliffs. Dogons rely for permanent water on springlines along the base of Bandiagara escarpment. </p> <h1><strong>Visitors and Visitor Facilities</strong></h1> <p>There is a small airfield at Bandiagara and another at Mopti. Rest houses are located at Sangha and Bandiagara. Mopti is a center of tourism and a hotel has been constructed. The Mali Office of Tourism publicizes the historic sites of the Bandiagara region. </p> <h1><strong>Scientific Research and Facilities</strong></h1> <p>The Division de la Recherche Forestière et Hydrobiologique of the Ministère de l&#39;Elevage et des Eaux et Forêts maintains a hydrological laboratory at Mopti. The laboratory carries out research on fish systematics and biology. Work on the botany of the area was initiated between 1950-1952 by G. Dieterlenand followed by Jaeger and Winkoun in the 1960s for the Institut Français d&#39;Afrique Noir. A herbarium collection of 300 species was made from the region of Sangha. A fauna and flora survey is currently being undertaken on behalf of the &quot;cantonnements forestiers&quot;.</p> <h1><strong>Conservation Value</strong></h1> <p>These cliffs protect architectural structures which for centuries, have been the soul of traditional, secular Dogon culture. The Bandiagara plateau is one of the most impressive geological and landscape features in West Africa.</p> <h1><strong>Conservation Management</strong></h1> <p>The government is conserving the site because of its exceptional architectural structures and the interaction between man and the natural environment. One of the key management aims is the maintenance of the Dogon culture and associated houses, granaries, ritual sanctuaries and &quot;toguna&quot;. Also of importance are the surrounding natural features and landscape. Bandiagara plateau near Sangha-Bongo has been described as one of the most impressive geological and landscape features in West Africa. The botany of the region is of great phytogeographic interest. The escarpment supports important refugial biotopes rich in relict species and vegetation types otherwise felled or burnt by man&#39;s activities in more accessible localities. The Sangha flora communities represent an interface between different phytogeographic regions (Sudano-Sahelian and Sahelian) and consist of relict ravine vegetation (ancient <a href="/article/Atmospheric_humidity">humid</a> flora) in an otherwise arid Sahelian climate. Species with restricted distributions include the localized endemic <em>Acridocarpus monodii</em> (R) found in the Bandiagara escarpment at Kikara. </p> <p> Responsibility for cultural heritage management belongs to the Ministry of Culture and Communications, with local management under the authority of Cultural Mission. The chief of the Cultural Mission is charged with conserving the cultural heritage of the <a href="/article/Region">region</a>. </p> <h2><strong>Management Constraints</strong></h2> <p>The greatest threats to the area include drought and <a href="/article/Desertification">desertification</a>. Uncontrolled tourism is affecting the economic structure and menacing the basis of the Dogon culture. The savanna vegetation has been profoundly <a href="/article/Land-use_and_land-cover_change">degraded</a> by fire and scrub <a href="/article/Land-use_and_land-cover_change">clearance</a>, most notably in the vicinity of village communities. Insufficient funding means that the site is inadequately patrolled. </p> <h2><strong>Staff</strong></h2> <p>A total of three.</p> <h2><strong>Budget</strong></h2> <p>Five million CFA per annum from the government (US$10,000).</p> <h1><strong>IUCN Management Category</strong></h1> <ul><li>III (Natural Monument) </li><li> Natural/Cultural World Heritage Site - Natural Criterion iii/Cultural Criterion v</li></ul> <h1><strong>Further Reading<br /></strong></h1> <ul><li>Calame-Griaule, G. (1955). Notes sur l&#39;habitation du plateau central nigérian. <em>Bulletin de l&#39;Institut français d&#39;Afrique noire</em> 27(B): 481-485. </li><li> Diakite, S. (1988). Sanctuaire Naturel et Culturel de la Falaise de Bandiagara. Proposition d&#39;Inscription sur la Liste du Patrimoine Mondial Soumise par le Mali. Ministère des Sports, des Arts et de la Culture Letter No. 101889/MSAC-DNAC, 13 December 1988. </li><li> Dieterlen, G. (1952). Classification des Végétaux chez les Dogon. <em>Journal</em> <em>de la Société des Africanistes</em> 22: 115-158. </li><li> FAO (1985). Aménagement de la faune, des Parcs et Réserves. FAO, Rome. Report No. TA2698. 19 pp. </li><li> Griaule, M. (1941). Les Mammifères dans la religion des Dogons (Soudan fr.). <em>Mammalia</em> 5: 104-109. </li><li> Jaeger, P. and Winkoun, D. (1962). Premier contact avec la flore et la végétation du plateau de Bandiagara. <em>Bulletin de l&#39;Institut français de l&#39;Afrique noire</em> 24A: 69-111. </li><li> Laude, J. (1973). <em>African art of the Dogon, the myths of the cliff dwellers</em>. The Brooklyn Museum, New York. <a href="http://www.amazon.com/dp/0670109282/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0670109282/?tag=encycofearth-20">ISBN: 0670109282</a> </li><li> Paulme, D. (1973). La divination par les chacals chez les Dogon de Sangha. <em>Journal de la Société des Africanistes</em> 7: 1-13. </li><li> Pern, S. (1985). The Dogon of Mali, existing on the edge. <em>World Magazine</em> 17: 40-47. </li><li> Rousselot, R. (1939). Notes sur la faune ornithologique du cercle de Mopti, Soudan Français. <em>Bulletin de l&#39;Institut français de l&#39;Afrique Noire</em> 1: 1-88. </li><li> Sayer, J.A. (1977). Conservation of large mammals in the Republic of Mali. <em>Biological Conservation</em> 12: 245-263. </li><li> Yaro, J. and Diko, S. (1940). A propos des crocodiles sacrés de Bandiagara. <em>Bulletin de l&#39;Institut français de l&#39;Afrique noire</em> 2: 211-216</li></ul> <p><br /> <p><br style="clear: left" /> <center> </p> </center> </p> <p><a href='/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali'>Read Full Article...</a></p> http://www.eoearth.org/article/Cliffs_of_Bandiagara_(Land_of_the_Dogons),_Mali Thu, 23 Apr 2009 03:45:40 GMT http://www.eoearth.org/article/Sustainable_development_triangle <a href='/article/Sustainable_development_triangle'><img border='0' src='/upload/thumb/9/99/Sustainable_development_triangle.gif/300px-Sustainable_development_triangle.gif' width='100'/></a> <p><b>Note:</b> The author welcomes comments, which may be sent to <a href="mailto:mind@mindlanka.org" class='external text' title="mailto:mind@mindlanka.org">MIND</a>. </p> <p>Economic progress is evaluated in terms of welfare (or utility) – measured as willingness to pay for goods and services consumed. Thus, economic policies typically seek to increase conventional gross national product (GNP), and induce more efficient <a href="/article/Essential_economic_activities">production</a> and <a href="/article/Essential_economic_activities">consumption</a> of (mainly marketed) goods and services. The stability of prices and <a href="/article/Employment%2C_unemployment%2C_and_well-being">employment</a> are among other important objectives. Mainstream (neoclassical) economics provides the concepts underlying this framework. </p><p>At the same time, the equation of welfare with monetary income and consumption has been challenged for many years. For example, Buddhist philosophy (over 2500 years old) classified a comprehensive list of human desires and stressed that contentment is not synonymous with material consumption <span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>. More recently, Maslow <span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span> and others have identified hierarchies of needs that provide psychic satisfaction, beyond mere goods and services. Alkire <span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span> provides a detailed review of the widely varying dimensions of human development in the literature (see section on <a href="/article/Tools_and_methods_for_integrated_analysis_and_assessment_of_sustainable_development">indicators</a>). </p><p>At the macro level, some researchers have highlighted the role of economic forces like international trade to explain differences in <a href="/article/Economic_growth">growth</a> rates among nations <span class="reference"><sup id="ref_4" class="plainlinksneverexpand"><a href="#endnote_4" class='external autonumber' title="#endnote 4">[4]</a></sup></span>. </p> <p><a href='/article/Sustainable_development_triangle'>Read Full Article...</a></p> http://www.eoearth.org/article/Sustainable_development_triangle Wed, 22 Apr 2009 03:08:01 GMT http://www.eoearth.org/article/Desertification <a href='/article/Desertification'><img border='0' src='/upload/thumb/9/97/Desertifcation_World_Map.jpg/250px-Desertifcation_World_Map.jpg' width='100'/></a> <p>Desertification is the persistent degradation of dryland ecosystems by variations in climate and human activities. Home to a third of the human population in 2000, drylands occupy nearly half of Earth’s land area. Across the world, desertification affects the livelihoods of millions of people who rely on the benefits that dryland ecosystems can provide. </p><p>In drylands, <a href="/article/Water_resources">water scarcity</a> limits the production of crops, forage, wood, and other services ecosystems provide to humans. Drylands are therefore highly vulnerable to increases in human pressures and climatic variability, especially sub-Saharan and Central Asian drylands. </p><p>Some 10 to 20% of drylands are already degraded, and ongoing desertification threatens the world’s poorest populations and the prospects of poverty reduction. Therefore, desertification is one of the greatest environmental challenges today and a major barrier to meeting basic human needs in drylands. </p> <p><a href='/article/Desertification'>Read Full Article...</a></p> http://www.eoearth.org/article/Desertification Tue, 21 Apr 2009 02:35:25 GMT http://www.eoearth.org/article/Antimicrobial_resistance <a href='/article/Antimicrobial_resistance'><img border='0' src='/upload/thumb/7/7c/Alexander_Fleming_NLM.jpg/159px-Alexander_Fleming_NLM.jpg' width='100'/></a> <h2>U.S. Department of Agriculture <br /></h2><p>The U.S. Department of Agriculture&#39;s Food Safety and Inspection Service characterizes <u>Antimicrobial Resistance</u><strong> </strong>as the remarkable ability of <a href="/article/Bacteria">bacteria</a> and other disease-causing organisms to mutate and acquire resistance genes from other organisms—and through that acquisition to develop resistance to antimicrobial drugs.</p><p> When an antimicrobial drug is used, the selective pressure exerted by the drug favors the growth of organisms that are resistant to the drug’s action.</p> <p><a href='/article/Antimicrobial_resistance'>Read Full Article...</a></p> http://www.eoearth.org/article/Antimicrobial_resistance Mon, 20 Apr 2009 07:11:42 GMT http://www.eoearth.org/article/Exclusive_economic_zone_(EEZ) <a href='/article/Exclusive_economic_zone_(EEZ)'><img border='0' src='/media/approved/e/e0/EEZ.png' width='100'/></a> <p>The expressions “patrimonial sea”, “economic zone” or “exclusive economic zone” were first used in the early 1970s in regional meetings and organizations in Latin America, the Caribbean, Asia and Africa. However, the concept of an extended exclusive economic zone for economic purposes was already used in the late 40s and early 50s: it is rooted in the 1945 Truman Proclamations (on the natural resources of the subsoil and sea bed of the continental shelf and the conservation of coastal <a href="/article/Marine_fisheries">fisheries</a> in certain areas of the high seas), the national claims of several Latin American countries (Chile and Peru), and the Santiago Declaration of 1952. The second Truman Proclamation has in particular influenced ocean-related policies in Latin American countries, especially where it states that it is appropriate for the United States &quot;to establish conservation zones...where fishing activities have been or in the future may be developed (..)&quot;. </p><p><strong>The 1952 Santiago Declaration.</strong> The Santiago Declaration in its preamble affirms that &quot;governments are bound to ensure for their peoples access to necessary food supplies and to furnish them with the means of developing their economy&quot;. The declaration also affirms how the economic zone should extend no less than 200 miles from the <a href="/article/Coastal_zone">coast</a>. The motivation for the establishment of the zone was economic; there is anecdotal evidence that the basis for the 200-mile breadth was a <a href="/article/Maps">map</a> in a magazine article discussing the 1939 Panama Declaration, in which the United Kingdom and the United States agreed to establish a zone of security and neutrality around the American continents in order to prevent the re-supplying of Axis ships in South American ports. The map showed the breadth of the neutrality zone off the Chilean coast to be about 200 miles. </p><p><strong>The 1964 European Fisheries Convention.</strong> In Europe, the economic zone, conceived more as a <a href="/article/Marine_fisheries">fisheries</a> area, did not have the magnitude and sweep of the American equivalent. After failing to address fisheries zones in the 1958 and 1960 Geneva Conventions, the 1964 European Fisheries Convention provided among other things that each coastal State had the exclusive right to fish in a 6-mile belt measured from the baselines of its territorial sea; it also provided that in the area between the 6-mile limit and 12 miles from the baseline, other States known to have fished in that area between 1953 and 1962 had the right to continue doing so. This was an effort to reconcile th desire of coastal States to extend their jurisdiction over a greater portion of the sea and yet preserve fishing rights of other States. </p><p><strong>The 1970 Declaration of the Latin American States on the law of the sea.</strong> This later declaration further added that the decision to extend the jurisdiction beyond the territorial sea limits is a consequence of &quot;the dangers and damage resulting from indiscriminate and abusive practices in the extraction of marine resources&quot; as well as the &quot;utilization of the marine environment&quot; giving rise to &quot;grave dangers of contamination of the waters and disturbance of the ecological balance&quot;. </p> <p><a href='/article/Exclusive_economic_zone_(EEZ)'>Read Full Article...</a></p> http://www.eoearth.org/article/Exclusive_economic_zone_(EEZ) Fri, 17 Apr 2009 02:36:31 GMT http://www.eoearth.org/article/Lead_in_paint,_dust,_and_soil <a href='/article/Lead_in_paint,_dust,_and_soil'><img border='0' src='/upload/thumb/f/f9/Lead.jpg/200px-Lead.jpg' width='100'/></a> <p>En Español<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span></p> <p><a href='/article/Lead_in_paint,_dust,_and_soil'>Read Full Article...</a></p> http://www.eoearth.org/article/Lead_in_paint,_dust,_and_soil Thu, 16 Apr 2009 02:21:54 GMT http://www.eoearth.org/article/Monitor_National_Marine_Sanctuary <a href='/article/Monitor_National_Marine_Sanctuary'><img border='0' src='/upload/thumb/5/5c/Monitor_map.jpg/200px-Monitor_map.jpg' width='100'/></a> <p>The Monitor National Marine Sanctuary protects the wreck of the famed Civil War ironclad USS Monitor, best known for its battle with the Confederate ironclad Virginia in Hampton Roads, Virginia, on March 9, 1862. </p><p>On January 31, 1975, the resting place of the Civil War ironclad USS Monitor was designated this nation&#39;s first marine sanctuary. The Monitor National Marine Sanctuary, and all areas subsequently designated marine sanctuaries, are part of the National Marine Sanctuary Program administered by the Sanctuaries and Reserves Division (SRD) of the National Oceanic and Atmospheric Administration (NOAA). The Monitor National Marine Sanctuary is located approximately 16 miles south-southeast of the Cape Hatteras lighthouse. The Sanctuary is an area one mile in diameter that reaches from the surface of the <a href="/article/Ocean">ocean</a> to the sea bed. Water depth is 230 feet. Bottom conditions, including visibility, current, and <a href="/article/Temperature">temperature</a>, are variable. </p> <h1>The <em>Monitor</em></h1> <p>The <em>Monitor</em> was the first of a class of low-freeboard, turreted war ships developed during the Civil War by Swedish-American engineer and inventor <a href="/article/Ericsson%2C_John">John Ericsson</a>. The Monitor was launched at Greenpoint, Long Island, on January 30, 1862. The ship was approximately 172 feet long with a beam of approximately 42 feet and was constructed almost entirely of <a href="/article/Iron">iron</a>. When fully loaded, it drew 9 feet of water. The Monitor was the first ship to have the engines and living spaces below the water line. The revolving turret housed two XI-inch Dahlgren guns. In early March, the ship was sent to Hampton Roads, Virginia, to face the Confederate ironclad Virginia , (ex-USS Merrimack). On the morning of March 9, the Monitor and Virginia fought the first battle between ironclad warships. Despite the Virginia&#39;s much larger size and firepower, the Monitor clearly demonstrated the advantages of the revolving turret over traditional broadside guns. The battle marked the beginning of the end for traditional wooden ships of war and forever changed the way naval warfare was waged. The Monitor was lost in a storm off Cape Hatteras on December 31, 1862. Sixteen of her officers and crew were also lost. </p> <p><a href='/article/Monitor_National_Marine_Sanctuary'>Read Full Article...</a></p> http://www.eoearth.org/article/Monitor_National_Marine_Sanctuary Wed, 15 Apr 2009 02:45:40 GMT http://www.eoearth.org/article/Agricultural_Exports_and_the_2007_Farm_Bill <a href='/article/Agricultural_Exports_and_the_2007_Farm_Bill'><img border='0' src='/upload/thumb/7/71/US_Agricultural_Exports%2C_Imports_98-08.JPG/180px-US_Agricultural_Exports%2C_Imports_98-08.JPG' width='100'/></a> <p>On December 14, 2007, the Senate passed its version of the 2007 farm bill. The House of Representatives passed its version of the 2007 farm bill (H.R. 2419) on July 27, 2007. Both bills, which would establish U.S. farm policy for 2008 through 2012, contain a trade title (Title III) that authorizes and amends U.S. <a href="/article/Department_of_Agriculture_%28USDA%29">Department of Agriculture (USDA)</a> agricultural export programs and U.S. international food aid programs. This report assesses 2007 farm bill trade title provisions for U.S. agricultural export programs. (See CRS Report RL33553, Agricultural Export and Food Aid Programs, for additional detail. For an analysis of food aid issues and the farm bill, see CRS Report RL34145, International Food Aid and the 2007 Farm Bill.) </p><p>The bills incorporate a number of the recommendations made by the Administration in its farm bill trade proposals, especially changes to USDA’s export credit guarantee programs and export market development programs. Both bills modify the export credit guarantee programs to make them compatible with World Trade Organization (WTO) rules limiting export subsidies. Both bills also provide increased funding for export market promotion and for addressing sanitary and phytosanitary (food safety) barriers to U.S. agricultural exports. The bills also reflect provisions of farm legislation introduced earlier in the 110th Congress, notably legislation introduced by Members representing the interests of fruit, vegetable, and tree nut (specialty crop) producers to increase federal support for their production and marketing activities, including export market promotion. </p><p>U.S. agricultural exports for FY2008 are forecast by USDA to be a record high $91 billion, while imports will reach $75.5 billion, also a record. If this forecast holds, the U.S. agricultural trade balance in FY2008 would be $15.5 billion. Many variables interact to determine the level of U.S. agricultural exports — income, population growth, and tastes and preferences in foreign markets; U.S. and foreign supply and prices; foreign import barriers and exchange rates; and domestic farm policy and trade agreements. While many of these factors are beyond the scope of congressional action, farm bills have typically included programs that help to finance, <a href="/article/Subsidies_and_market_interventions">subsidize</a>, and promote U.S. commercial agricultural exports, or to address foreign trade barriers. </p> <p><a href='/article/Agricultural_Exports_and_the_2007_Farm_Bill'>Read Full Article...</a></p> http://www.eoearth.org/article/Agricultural_Exports_and_the_2007_Farm_Bill Tue, 14 Apr 2009 02:14:08 GMT http://www.eoearth.org/article/Marine_microbial_loop <a href='/article/Marine_microbial_loop'><img border='0' src='/upload/thumb/5/5d/Marine_food_web_pathways_of_carbon.gif/300px-Marine_food_web_pathways_of_carbon.gif' width='100'/></a> <p>The material presented here tends to resume the literature dealing mainly with the structural description of the microbial loop and discusses some functional aspect in action within the microbial <a href="/article/Food_web">food webs</a>. For more detailed information, the interested readers can refer to the literature listed below. </p><p>Since Pomeroy (1974), it has been shown that the microbial consortia play a key role in both structure and function of open <a href="/article/Ocean">ocean</a> ecosystems (Azam et al., 1983). Figure 1 shows a cartoon representation of the oceanic global carbon cycling. </p><p>Two major <a href="/article/Herbivory">herbivorous</a> and microbial pathways determine transformation and transfer of matters in the ocean (Fig. 2). The relative flux intensity within each pathway depends upon a “competition” between <a href="/article/Bacteria">bacteria</a> and the particle grazers’ pathways. Due to the dominance of the bacterial production in oligotrophic environments and in most of the mesoplelagic water column, fluxes are highly diverted towards the pathway n°1. However, it is important to appreciate conditions that determine flux partitioning between these paths. </p> <p>Transfer pathways hypothesis: In <a href="/article/Marine_biomes">marine ecosystems</a>, the “Microbial Loop” can be distinguished from the “Microbial Food Webs” in that the former likely consists of the pathways relating heterotrophic bacteria to bacterivorus protests (zooflagellates) and Dissolved Organic Matter (DOM), and the latter includes all microbial communities below ca 100 µm including all the ≤ 10 µm primary producing organisms. Therefore, as much as it is true that the Microbial Loop can mainly act as a carbon sink, the Microbial Food Web is the crucial link for the whole ecosystems. The sink aspect is mostly due to the fact that a considerable amount of Particulate Organic Matter (POC) passes through bacterial production that end up in DOM pools. Four issues are considered: </p> <ol><li> Transfer pathways hypothesis – size of primary producers: It can be appreciated that the size of the primary producers is what determines whether a microbial community is going to act mainly as a trophic sink or link in the marine ecosystems. For instance, when cyanobacteria dominate an ecosystem, the primary production is mostly trapped within the Microbial Loop. Under such conditions not more than 6% of the primary production can reach higher trophic levels. Whereas, when &gt; 2 µm <a href="/article/Phytoplankton">phytoplankton</a> dominate, then up to 20% is transferred, which would constitute the total basic supply for the whole system. </li><li> Transfer pathways hypothesis – patchiness: In addition to the size of the primary producers, patchiness in the oligotrophic pelagial is probably the most important feature in the structure and function of the water column ecosystem. We believe that the primary productivity is regulated by small-scale microbial interactions, mainly through feed-backs (“mutualism”) between free-living bacteria and phytoplankton, optimizing the use of mineral nutriments at low concentrations; condition characterizing the oligotrophic environments that represent the most open ocean ecosystems. Patchiness must also be important for protozoan survival, because oligotrophic concentrations of prey (≤ 20 µg C l^-1) hardly support optimal growth conditions (Km) for most microphagous organisms that develop, however, normally in such poor conditions. Therefore, appropriate space distribution of both nutrient and prey appears as essential survival conditions: “hot spots”. </li><li> Transfer pathways hypothesis – protozoan feeding mechanisms: The importance of distributional patterns of <a href="/article/Bacteria">bacteria</a>, for instance, can be seen in its effect on the composition of the bacterivorous community. For protistan bacterivores, the food intake is dominated either by encounter or filter feeding mechanisms, often occurring in phagotrophic flagellates and ciliates, respectively. The phagotrophic flagellates (zooflagellates) control mainly the bacterial production, at rather high bacterial concentrations, and the ciliates remove production of &gt; 1 µm both hetero- and autotrophic cells, and to some extent of bacteria. Indeed, open ocean’s ciliates are mostly Polyhymenophorean, multiple mouth surrounding membranelles that have relatively high specific water filtration flux, due to large inter-membranelle spacing, allowing them to survive on nano-sized prey at regular low oligotrophic concentrations. However, one can notice that some polymenophorean ciliates are so small (≤ 12 µm) that they can retain bacteria as well, while at low concentrations (high water flux through mouth filtration structure) in open ocean, where zooflagellates can become almost inefficient grazers on bacteria at oceanic bulk phase concentrations. The size differential between predator and prey in a microbial food web (in this instance, bacteria and bacterivores) can depend on prey concentrations.<br /><br /> </li><li> Transfer pathways hypothesis – spatial organization of <a href="/article/Food_web">food web</a>: with regard to the NH₄⁺ [a major phytoplanktonic regenerated inorganic supply, supplied mainly by protozoan excretion through the gazing of the “extra-biomass” production in both bacteria and microalgae], the bacteria-phytoplankton mutualism depends upen low K_m-low V_max(low flow) and High K_m-High Vmax (high flow) uptake systems for NH₄⁺ in free-living bacteria and phytoplankton, respectively. Bacteria could thus be more active than phytoplankton at low NH₄⁺ concentrations (outside of phytoplankton-bacteria “hot spots” or “nutrient spheres”, and vice versa, at high NH₄⁺ concentration (inside of “nutrient spheres” at vicinity of phytoplankton cells). A similar situation seems to exist for the bacterial affinity for their own their own (5’-nucleotidase mediated) orthophosphate liberated within these “hot-spots”. Figure 3 shows a cartoon diagram, suggesting that as well as for the bacteria-phytoplankton uptake system for the NH₄⁺, the protozoan activity itself seems also to be regulated through Km-Vmax ingestion system for particulate foods. Some experimental results suggested that zooflagellates and small polyhymenophorean oligotrichous ciliates both seem to exhibit High Km-High Vmax ingestion behaviour for bacteria and zooflagellates, respectively. This situation involves an effective ingestion of both bacteria and zooflagellates at vicinities of phytoplankton cells, ultimately leading to an important liberation of NH₄⁺ in that “hot-spots”. On the other hand, there are large polyhymenophorean, oligotrichous, ciliates such as large Oligotrichina and Tintinnina that exhibit low K_m-either Low or high V_max (high flow, Polyhymenophorean, that feed on both zooflagellates and phytoplankton cells outsite and inside of “hot-spots” as well as on whole “hot-spots” themselves widely dispersed in space. </li></ol> <p>These large ciliates appear thus as major pathway between microbial as well as primary production and higher trophic level at open ocean oligotrophic situations. Indeed, metazoans such as copepods show both preference and high clearance rates on large ciliates relative to small ciliates, further supporting the idea that link to higher trophic levels is through large ciliates which can exist between “hot-spots” patches. </p><p>Pushing further the speculation, we could imagine that whole ocean ecosystem is organized in series of nesting boxes (like Russian dolls) of “patches” and “inter-patches” environments inhabited by communities with high K_m-high Vmax, and low K_m-low V_max, respectively.</p><p><strong><big>Further Reading</big></strong> </p> <ul><li> Ammerman JW, Azam F (1985) Science 227: 1338-1340. </li><li> Azam, F (1998) Science 280: 694-696 </li><li> Azam F, Ammerman JW (1984) In Flow of energy and materials in marine ecosystems (ed Fasham MJR) 345-360 (Plenum). </li><li> Azam F, Cho BC (1987) In Ecology of microbial communities (eds) 261-281 (Cambridge University Press). </li><li> Azam F, Smith DC (1991) In Particle analysis in oceanography. (ed Demers S) 213-236 (NATO Series, G27. Springer). </li><li> Azam F, Fenchel T, Field JG, Fray JS, Meyer-Reil LA, Thingstad F (1983) Mar Ecol Prog Ser 10: 257-263. </li><li> Bratback G, Thingstad TF (1985) Mar Ecol Prog Ser 25: 23-30. </li><li> Caron DA, Goldman JC (1990) In Ecology of marine protozoa (ed capriulo GM) 283-306 (Oxford University Press). </li><li> Dolan J (1991) Estuarine, Coastal and Shelf Science 33: 137-152. </li><li> Ducklow HW, Purdie DA, Williams LeBPJ, davis JM (1986) Science 232: 865-867. </li><li> Fenclel T (1980a) Limnol Oceanogr 25: 735-740. </li><li> Fenchel T (1980b) Arch. Protistenk 123: 239-260. </li><li> Ferrier C, Rassoulzadegan F (1991) Limnol Oceanogr 36: 657-669. </li><li> Hagström A, Azam F, Andersson A, Wikner J, Rassoulzadegan F (1988) Mar Ecol Progr Ser 49: 171-178. </li><li> Kirchman, DL (ed) (2000) Microbial Ecology of the Oceans. (Wiley-Liss New York) </li><li> Pomeroy LR (1974) BioScience 24: 499-504. </li><li> Rassoulzadegan F (1990) Zoological science 7 (S): 189-196. </li><li> Rassoulzadegan F (1993) In Trends in Microbial Ecology (eds Guerrero R. &amp; Pedros-Alio C) 435-439 (Spanish Society for Microbiology). </li><li> Rassoulzadegan F, Sheldon RW (1986) Limnol Oceanogr 31: 1010-1021. </li><li> Rivier A, Browlee, DC, Sheldon RW, Rassoulzadegan F (1985) mar Micro Food Webs 1: 36-51. </li><li> Sherr EB, Sherr BF, Fallon RD, Newell SY (1986) Limnol Oceanogr 31: 177-183. </li><li> Stoecker DK, Capuzzo JM (1990) J Plankton Res 12: 891-908. </li><li> Tiselius P (1989) mar Ecol Prog ser 56: 49-56. </li><li> Wiadnyana NN, Rassoulzadegan F (1989) Mar Ecol Prog Ser 53: 37-45. </li></ul> <p><a href='/article/Marine_microbial_loop'>Read Full Article...</a></p> http://www.eoearth.org/article/Marine_microbial_loop Mon, 13 Apr 2009 02:14:26 GMT http://www.eoearth.org/article/Impact_of_ozone_on_Mediterranean_forests <a href='/article/Impact_of_ozone_on_Mediterranean_forests'><img border='0' src='/upload/thumb/8/84/Days_with_90_ppb_info_exceedancees%2C_2006.gif/300px-Days_with_90_ppb_info_exceedancees%2C_2006.gif' width='100'/></a> <p>Tropospheric <a href="/article/Ozone">ozone</a> (O₃) concentrations are increasing all over the world. The troposphere extends to between 10 and 18 kilometers above the surface of the Earth and consists of many layers. Ozone is more concentrated above the mixing layer, or ground layer. Ground-level ozone is a serious problem because of its environmental effects. Ground level ozone pollution is pronounced in <a href="/article/Region">regions</a> with strong photochemical activity, such as the <a href="/article/Mediterranean_Basin">Mediterranean Basin</a>. For a general description of the Mediterranean basin climate and vegetation, see &quot;<a href="/article/Mediterranean_conifer_and_mixed_forests">Mediterranean conifer and mixed forests</a>&quot;. </p><p>The physical and chemical processes affecting O₃ formation vary greatly even within the Mediterranean Basin. In summer, the Western basin is under the influence of weak levels of Azores anti-cyclonic subsidence, low <a href="/article/Wind">winds</a>, and strong insolation. These conditions favor massive photochemical production of O₃, with development of mesoscale processes and recirculation within air masses. During the same period, the Eastern basin is under conditions of weak ascent and strong advection, i.e. the Etesian winds, that largely inhibit the development of recirculation, even if peaks of 150-220 parts per billion (ppb) occur. The boundary between the two major O₃ formation areas is located over Italy. Due to its central position in the Mediterranean, Italy may be considered as a hot-spot for O₃ and representative of O₃ <a href="/article/Impact_of_ozone_on_health_and_vegetation">impacts on Mediterranean vegetation</a>. </p><p>Southern Europe is affected by dangerous ground level <a href="/article/Ozone">ozone</a> concentrations. In 2006, the frequency of ozone level exceedances was higher than in previous years, though not as high as in the record year 2003. The European Environmental Agency reports that the highest one-hour ozone concentration occurred in Italy. Other high hourly ozone concentrations were reported in Austria, France, Italy, Portugal, Romania and Spain (Figure 1). North-western, central and eastern Europe did not escape either. </p><p>In the <a href="/article/Mediterranean_Basin">Mediterranean Basin</a>, the detrimental impact of <a href="/article/Ozone">O₃</a> on forests remains largely under-investigated. Detecting plant, or vegetative effects is necessary to give biological significance to O₃ standards. Field evidence of direct effects of O₃ on Mediterranean forests are controversial. Significant relationships between O₃exposure and effects (crown transparency, radial growth and foliar symptoms) often fail. Possible causes for this discrepancy are: </p><ul><li>The critical level established to protect Mediterranean forests against ozone is inappropriate. Ozone effects on trees have been mainly inferred from controlled-condition experiments on seedlings rather than multi-factorial analysis of forest conditions in the field. Extrapolating O₃ sensitivity from young to mature trees creates substantial overestimations. A number of studies have raised doubts about conclusions drawn from O₃ exposures in closed and open-top chambers. In addition, the current approach used by the European Union (EU) to assess and predict risk to vegetation is based on the concept of exposure of vegetation to <a href="/article/Atmospheric_composition">air</a> concentrations of <a href="/article/Ozone">ozone</a> rather that on uptake of this substance by vegetation. The exposure-based approach is functionally wrong, as effects are caused by the amount of ozone uptaken into the leaf and detoxified inside the leaf (flux). The complexity of this approach, however, may interfere with an extensive use for <a href="/article/Risk_assessment">risk assessment</a> and still needs to be evaluated;</li><li>Response indicators are improper or improperly investigated. Ozone effects on plants are aspecific. Thus, all indicators are ambiguous. Multivariate statistical analysis may help in decoding the role of different predictors. It is somehow surprising that we are searching for O₃ effects on tree radial growth under field conditions, when experiments have not yet determined if ambient O₃ levels actually impair it; and<br /></li><li>Site and plant characteristics increase O₃ tolerance in Mediterranean vegetation. Mediterranean forest vegetation appears to be adapted to face oxidative stress factors, such as elevated O₃ concentrations, drought and high <a href="/article/Solar_radiation">radiation</a>, including UV-B. Some reasons to explain why Mediterranean vegetation may tolerate potentially harmful O₃ concentrations are: sclerophyllous leaves (little intercellular air space, thick cuticle and cell wall, high <a href="/article/Stomata">stomatal</a> density); low gas exchange rates; emission of volatile organic compounds (VOC); and active antioxidant pool. The prevailing environmental conditions in the <a href="/article/Mediterranean_Basin">Mediterranean Basin</a> (excess light, elevated <a href="/article/Temperature">temperature</a>, reduced <a href="/article/Precipitation_and_fog">precipitation</a>) reduce stomatal conductance (and thus the uptake of <a href="/article/Ozone">ozone</a>) at the time of the highest O₃ levels, and promote sclerophylly, VOC emission, and content and activity of antioxidants. </li></ul> <p>In conclusion, Mediterranean forests are at the highest ozone risk in Europe because of the high ozone concentrations they experience. Even if field injury is not as high as expected on the basis of concentration-based standards, visible ozone-like foliar injury has been observed for several years on a number of tree species in Spain, France and Italy at permanent <a href="/article/Monitoring">monitoring</a> sites where high O₃ concentrations occur. Visible <a href="/article/Ozone">ozone</a>-like <a href="/article/Impact_of_ozone_on_health_and_vegetation">injury to vegetation</a> is often in the form of spotty brown discolorations on leaves (Figure 2). Two Mediterranean pine species &ndash; <em>Pinus ponderosa</em> and <em>P. halepensis</em> &ndash; are among the most symptomatic conifers under field conditions. This suggests that ozone affects Mediterranean forests, even if the extent of ozone impairment is still to be quantified. </p> <p><a href='/article/Impact_of_ozone_on_Mediterranean_forests'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_of_ozone_on_Mediterranean_forests Fri, 10 Apr 2009 02:05:45 GMT http://www.eoearth.org/article/Predation <a href='/article/Predation'><img border='0' src='/upload/thumb/4/44/LadybirdPredation.jpg/250px-LadybirdPredation.jpg' width='100'/></a> <p>Predation is an interaction between species in which one species uses another species as food. Predation is a process of major importance in influencing the distribution, abundance, and <a href="/article/Species_diversity">diversity of species</a> in ecological communities. Generally, successful predation leads to an increase in the population size of the predator and a decrease in population size of the prey. These effects on the prey population may then ripple out through the ecological community, indirectly changing the abundances of other species. One example of such indirect effects of predation involves the trophic cascade. As the name implies, a trophic cascade occurs when the effects of predation &quot;cascade&quot; down the food chain to affect plants or other species that are not direcrtly eaten by the predator. Typically, a trophic cascade involves a predator feeding on herbivores and reducing their abundance, which then releases plants from grazing pressure and increases the biomass of vegetation. In addition to such ecological effects of predation, which occur on time scales of one or a few generations of the organisms involved, predation has also played, and continues to play, a major role over evolutionary time in molding the phenotypes of many species. </p> <p><a href='/article/Predation'>Read Full Article...</a></p> http://www.eoearth.org/article/Predation Thu, 09 Apr 2009 03:11:28 GMT http://www.eoearth.org/article/Bovine_spongiform_encephalopathy_(BSE) <a href='/article/Bovine_spongiform_encephalopathy_(BSE)'><img border='0' src='/upload/thumb/e/e2/Beef_Cattle_Grazing_USDA.gif/200px-Beef_Cattle_Grazing_USDA.gif' width='100'/></a> <h1>Introduction<br /></h1> <p><a href='/article/Bovine_spongiform_encephalopathy_(BSE)'>Read Full Article...</a></p> http://www.eoearth.org/article/Bovine_spongiform_encephalopathy_(BSE) Wed, 08 Apr 2009 02:32:36 GMT http://www.eoearth.org/article/Northeast_U.S._Continental_Shelf_large_marine_ecosystem <a href='/article/Northeast_U.S._Continental_Shelf_large_marine_ecosystem'><img border='0' src='/upload/thumb/3/3b/Neusshelf1.jpg/250px-Neusshelf1.jpg' width='100'/></a> <h1><strong>Introduction</strong></h1> <p>The Northeast US Continental Shelf <a href="/article/Large_marine_ecosystems">Large Marine Ecosystem</a> (LME) is characterized by its temperate climate. It extends from the Gulf of Maine to Cape Hatteras along the <a href="/article/Atlantic_Ocean">Atlantic Ocean</a>. Intensive fishing is the primary force driving in the LME, with climate as the secondary driving force. Important hypotheses concerned with the growing impacts of pollution, overexploitation, and environmental changes on sustained biomass yields are under investigation. Efforts to examine changing <a href="/article/Ecosystem">ecosystem</a> states and the relative health of this LME are underway in four major subareas: the Gulf of Maine, Georges Bank, Southern New England and the <a href="/article/Estuary">estuarine</a>-dominated waters of the Mid-Atlantic Bight. This LME is structurally very complex, with marked <a href="/article/Temperature">temperature</a> and climate changes, <a href="/article/Wind">winds</a>, river runoff, estuarine exchanges, <a href="/article/Tide">tides</a> and complex <a href="/article/Ocean_circulation">circulation</a> regimes. It is historically a very productive LME of the <a href="/article/Northern_Hemisphere">Northern Hemisphere</a>. LME book chapters and articles pertaining to this LME include Falkowski, 1991, Sissenwine and Cohen, 1991, Sherman, Jaworski and Smayda, 1996, Murawski, 1996, Sherman et al, 2002, and Sherman et al, 2003. </p> <h1><strong>Productivity</strong> </h1> <p>This LME is bounded on the east or seaward side by the Gulf Stream. Its complex circulation with meanders and rings greatly influence the LME. The gyre systems of the Gulf of Maine and Georges Bank, and the nutrient enrichment of estuaries in the southern half of the LME contribute to the maintenance on the shelf of relatively high levels of <a href="/article/Phytoplankton">phytoplankton</a> and zooplankton prey fields for planktivores including fish larvae, menhaden, herring, mackerel, sand lance, butterfish, and marine birds and mammals. For a map of surface <a href="/article/Ocean_circulation">circulation</a>, see Sherman et al, 2003, p. 96. For an overview of the physical oceanography of the Shelf, see Brooks, 1996. The Northeast U.S. Continental Shelf is considered a Category I (&gt;300 gC/m²-yr), highly productive, <a href="/article/Ecosystem">ecosystem</a> according to SeaWiFS global primary productivity estimates. Since 1977, the NOAA Northeast Fisheries Science Center has monitored this LME for estimates of primary productivity and chlorophyll a. Productivity varies in the 4 major sub-areas, and from season to season. For a map of estimated annual primary production in this LME, see Sherman et al, 2003, p. 98. For a general summary of the structure, function and productivity of the LME, see Sherman et al, 1996a,b, and c. Zooplankton is used as an indicator of major changes in stability of the lower levels of the <a href="/article/Food_web">food web</a> and of biofeedback responses to oceanographic changes. For zooplankton dynamics in the LME, see Durbin and Durbin, 1996. For a graph and discussion of zooplankton biomass showing peaks and troughs between 1977 to 2001, see Sherman et al, 2003, p. 101-102. While species shifts and interannual and decadal variability have been observed for zooplankton biomass, there appears to be sufficient residual <a href="/article/Sustainability">sustainability</a> in <a href="/article/Biodiversity">biodiversity</a> and abundance to support the recovery of herring and mackerel from their low levels in the mid 1970s. From the systematic monitoring it appears that zooplankton has not undergone any significant decline during the rebuilding of fish stocks (see &quot;Fish and Fisheries&quot;). </p> <h1><strong>Fish and Fisheries</strong></h1> <p>For <a href="/article/Population">population</a> assessments in this LME, see Sherman, Jaworski and Smayda, 1996. For a report on the status of living <a href="/article/Marine_biomes">marine</a> resources in this LME, see NOAA, 1999, and NEFSC Status of the Stocks Report. The catch composition of this LME is quite diverse (see FAO, 2003, figure 5). In the late 1960s and early 1970s, there was intense foreign fishing within the LME. The precipitous decline in biomass of fish stocks was the result of excessive fishing mortality (see Sherman and Busch, 1995). The catch declined from 2.5 million tons in 1990 to 750,000 tons in 1999 (see FAO, 2003, figure 16). The <a href="/article/Food_and_Agriculture_Organization_%28FAO%29">Food and Agriculture Organization (FAO)</a> 10-year trend (1990-1999, click on graph to enlarge) shows a marked decrease of gadiformes (cods, hakes and haddocks) catches in the early 1990s leading to the cod collapse of 1993-1994. Significant biomass flips have occurred among dominant species. Dogfish and skates increased in abundance in the 1970s, as groundfish and flounders declined. But a decrease of dogfish and skates has been observed since 1990. For a graph of historic landings of skates and spiny dogfish between 1960 and 1997, see NOAA, 1999, p. 92. For an article on New England groundfish, see NOAA, 1999, p. 71-80. For landings and an abundance index of principal groundfish and flounders from 1960 to 2000, see Sherman et al, 2003. An increase in crustacean catches has been noted in recent years, but it is not clear if this is due to <a href="/article/Ecology">ecological</a> or to economical reasons (see Caddy and Garibaldi, 2000). For the status of Northeast demersal <a href="/article/Marine_fisheries">fisheries</a> resources, and for pelagic fisheries (Atlantic mackerel, Atlantic herring, bluefish and butterfish), see NOAA, 1999. The long-term potential yield (a term analogous to the concept of Maximum Sustainable Yield in fisheries science) is set at 1,589,158 tons for this LME (source: NOAA, 1999). The long-term <a href="/article/Sustainability">sustainability</a> of high economic yield species depends on the rebuilding of fish stocks through the application of adaptive management strategies. For an article on multispecies fisheries management, see Murawski, 1996. The recovery trend of George’s Bank yellowtail and haddock observed in the late 1990s is linked to reductions in the exploitation rate (see Sherman et al, 2003, p. 107). For information on fishery management plans for this LME, see NOAA, 1999, appendix 2. After 1994, there was an emergency closure of portions of Georges Bank, and severe restrictions on the fishing of haddock. The New England Fishery Management Council (NEFMC) imposed strict restrictions on the fishing of groundfish, and there are efforts to reduce the currently high fishing mortality on lobsters. The Council took measures to reduce fishing effort through reductions of days at sea, a moratorium on new vessel entrants, area closures and an increase in the ring diameter of scallop dredges. For a map of closure areas in this LME, see NOAA, 1999. The closure of half of the U.S. portion of Georges Bank to scallop harvesting to protect groundfish stocks appears to have contributed to an increase in sea scallop stock biomass (see status of fisheries resources off of the Northeastern United States). Other agencies involved in fisheries management are the Atlantic States Marine Fisheries Commission and the Mid Atlantic Fishery Management Council. Click on New England and Mid-Atlantic Fishery Management Councils to view the efforts of these agencies to control overfishing with management actions. Several alternative management strategies for the fish stocks of this LME are under consideration by the New England Fisheries Management Council and the Atlantic States Marine Fisheries Commission (see Sherman and Busch, 1995). The Northeast Region has a long history of surveys, but a critical feature of the monitoring strategy is the development of a consistent long term data base for understanding interannual changes and multi year trends in biomass yields (see Sherman and Busch, 1995). Recent stock assessment reports are also available from NMFS Northeast Fisheries Science Center. The Northeast Fisheries Science Center compiled available information on the distribution, abundance, and habitat requirements for each of the 38 commercially valuable species managed by the New England and Mid-Atlantic Fishery Management Councils. Although there is not yet a full understanding of fish and fisheries within the context of ecosystem structure and function, advances have been made towards an <a href="/article/Ecosystem-based_management">ecosystem-based strategy</a> for recovering lost biomass. The University of British Columbia Fisheries Center has detailed fish catch statistics for this LME. </p> <h1><strong>Pollution and Ecosystem Health</strong></h1> <p>This LME is under considerable stress from growing near-coastal <a href="/article/Eutrophication">eutrophication</a> resulting from high levels of phosphate and nitrate discharges into <a href="/article/Drainage_basin">drainage basins</a> (see Sherman and Busch, 1995). Whether the increases in the frequency and extent of nearshore <a href="/article/Plankton">plankton</a> blooms are responsible for the rise in incidence of biotoxin-related shellfish closures (see White and Robertson, 1996) and marine mammals mortalities, remains an important open question. It is of considerable concern to state and federal management agencies (see Sherman et al, 1992a; Smayda, 1991). For this LME as a whole, water clarity is good, dissolved <a href="/article/Oxygen">oxygen</a> and coastal <a href="/article/Wetland">wetlands</a> are fair, eutrophic condition, sediment, benthos and fish tissue are poor (see <a href="/article/Environmental_Protection_Agency%2C_United_States">EPA</a>, 2001 for these 7 primary indicators). 60% of <a href="/article/Estuary">estuarine</a> areas have a high potential of increasing eutrophication or existing high concentrations of chlorophyll a. Over 25% of sediments are enriched or exceed the ERL/ERM guidance. Nearly 40% of wetlands along the <a href="/article/Coastal_zone">coast</a> were eliminated between 1780 and 1980. About 10% of fish have elevated levels of contaminants in their edible tissues. Benthic community degradation, fish tissue contamination and eutrophication are increasing. Coastal contamination is especially high along the urbanized and densely populated areas and in poorly flushed waters. Flux levels of zinc, <a href="/article/Cadmium">cadmium</a>, <a href="/article/Copper">copper</a>, <a href="/article/Lead">lead</a> and <a href="/article/Nickel">nickel</a> are highest in the southern New England <a href="/article/Region">region</a>, reflecting the level of urbanization and industrialization. Heavy metal concentrations in demersal fish, crustaceans and bivalve mollusks continue to be monitored as biological indicators (see Schwartz et al, 1996). <br /> </p> <h1><strong>Socioeconomic Conditions</strong></h1> <p>The <a href="/article/Population">population</a> of the coastal counties of the Northeast coast <a href="/article/Population_growth_rate">increased</a> 52% between 1970 and 1990 (U.S. Bureau of the Census, 1996). Major <a href="/article/River">rivers</a> systems (Hudson, Delaware, Chesapeake) contribute nitrates to <a href="/article/Estuary">estuaries</a> and <a href="/article/Coastal_zone">coastal</a> systems due to <a href="/article/Agriculture">agriculture</a>, atmospheric deposition and sewage. During the late 1960s and early 1970s, there was intense foreign fishing for mackerel and herring in this LME. Marked alterations in fish abundances were recorded (see Sherman and Busch, 1995). Analyses of catch per unit effort and fishery independent bottom trawling survey data were critical sources of information used to implicate overfishing as the cause of the shifts in relative abundance among the species of the fish community. Overfishing resulted in reduced landings with excessive effort. Northeast fishermen were adversely affected by the collapse of the groundfish <a href="/article/Fisheries_and_aquaculture">fishery</a>. Effort reductions led to curtailed revenues for fishermen (see NOAA, 1999). A vessel buyout program (1995-1998) provided economic assistance to fishermen adversely affected. This resulted in an approximate 20% reduction in fishing effort (see NOAA, 1999). But local fishermen, especially in the New England area, are at odds with the imposition of fishery management rules which they say jeopardize their ability to earn a living. Pollution reduced the utilization by humans of the marine and coastal resources, but there have been improvements in sewage treatment facilities and the treatment of storm water. <br /> </p> <h1><strong> Governance</strong> </h1> <p>Governance in this LME is complex, with evidence of progress since 1994. In the 1970s, excessive fishing mortality imposed on the LME’s resources by European factory ships precipitated the passage of US legislation. The 1976 Magnuson Fishing Management Act established a 200-mile <a href="/article/Exclusive_economic_zone_%28EEZ%29">Exclusive Economic Zone</a> for the United States that extended jurisdiction over marine fish and <a href="/article/Marine_fisheries">fisheries</a>. But the Act’s single species focus neglected predator-prey relationships and other interactions. This focus has often resulted in conflicting goals and bycatch kills (see Murawski, 1996). A joint MAFMC-ASMFC Summer Flounder Fishery Management Plan, initially approved in 1988, has resulted in increased biomass. Regulatory measures since 1994 aimed at a managed recovery of depleted fish stocks through reductions in days at sea, increased minimum mesh sizes, expanded closed areas, and trip limits for depleted cod and haddock stocks. As a result, fishing effort has been reduced. The New England Fishery Management Council’s multispecies fishery management plan sought to eliminate the overfished condition of cod and yellowtail flounder in 5 years, and haddock in 10 years. An amendment in 1996 accelerated the existing days at sea reduction schedule and imposed tighter restrictions through the closure of two fishing areas. It remains difficult to forecast the recovery of cod, haddock and flounders dependent on zooplankton during their <a href="/article/Plankton">planktonic</a> developmental stages. The capacity of the LME to support pelagic and demersal fish still needs study. Fishing effort must continue to be reduced for the long term <a href="/article/Sustainability">sustainability</a> of preferred high <a href="/article/Supply_and_demand">demand</a> and high priced species. In terms of pollution and ecosystem health, major programs are being implemented to address the existing problems. For instance, the <a href="/article/Chesapeake_Bay_National_Estuarine_Research_Reserve%2C_Maryland">Chesapeake Bay</a> Program is a partnership with deadline dates to restore the bay (see <a href="/article/Environmental_Protection_Agency%2C_United_States">EPA</a> 2001, p. 84). <a href="/article/Wetland">Wetlands</a> protection regulations have resulted in a decreased loss of wetlands. Coordinated programs with participation from states, academic institutions, the private sector and federal government, are underway to improve monitoring strategies aimed at mitigating the detrimental effects of habitat loss, coastal pollution, <a href="/article/Eutrophication">eutrophication</a> and overexploitation. <br /> </p> <h1><strong>References</strong> </h1> <h2><strong>Articles and LME Volumes</strong></h2> <ul><li>Anthony, V. C., 1996. The State of Groundfish Resources Off the Northeastern United States. p153-167 In K.Sherman, N.A. Jaworski, T.J. Smayda. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564p. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Bigford, T. E., 1996. Habitat Mitigation. p. 361-366 In Kenneth Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Brooks, D. A., 1996. Physical Oceanography of the Shelf and Slope Seas from Cape Hatteras to Georges Bank: A Brief Overview. p.47-74 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564p. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Capuzzo, J.E.M., 1996. Biological Effects of Cotaminants on Shellfish Populations in Coastal Habitats: A Case History of New Bedford, Massachusetts, p.457-466 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management, Blackwell Science, Cambridge, MA , 564pp. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Durban, E. G. and A. G. Durbin. 1996. Zooplankton Dynamics in the Northeast Shelf Ecosystem, p.129-152 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management, Blackwell Science, Cambridge, MA. 564pp. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>EPA, 2001. National Coastal Condition Report.<br /> </li><li>Epstein, P. R. 1996. Emergent Stressors and Public Health Implications in Large marine Ecosystems: An Overview, p.417-438 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Falkowski, 1991. A carbon budget for the northeast continental shelf ecosystem: results of the shelf edge exchange process studies. In K Sherman, L.M. Alexander and B.D Gold, “Food chains, yields, models, and management of large marine ecosystems”. <a href="http://www.amazon.com/dp/0813383862/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813383862/?tag=encycofearth-20">ISBN: 0813383862</a>. </li><li>FAO, 2003. Trends in oceanic captures and clustering of large marine ecosystems—2 studies based on the FAO capture database. FAO fisheries technical paper 435. 71 pages. <a href="http://www.amazon.com/dp/9251048932/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/9251048932/?tag=encycofearth-20">ISBN: 9251048932</a>. </li><li>Ingham, M. C. 1996. Effects of Closure of a Continental Shelf Dump Site, p.441-456 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA., 564pp. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Jaworski, N. A. and R. Howarth. 1996. Preliminary Estimates of the Pollutant Loads and Fluxes into the Northeast Shelf Ecosystem, p.351-357 In K. Sherman, N.A. Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA. 564pp. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Juda, L. 1996. &quot;Developing International Law and Ecosystem-Based Fisheries Management,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.527-533. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Kenney, R.D., P.M. Payne, D.W. Heinemann and H.E. Winn. 1996. &quot;Shifts in Northeast Shelf Cetacean Distributions Relative to Trends in Gulf of Maine/Georges Bank Finfish Abundance,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.169-196. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Malone, T. C. and D. J. Conley. 1996. Trends in Nutrient Loading and Eutrophication: A Comparison of the Chesapeake Bay and the Hudson River Estuarine Systems, in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.327-349. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Murawski, S. A. 1996. &quot;Can we Manage Our Multispecies Fisheries?,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.491-510. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>NOAA, 1999. Our living oceans—report on the status of U.S. Living Marine Resources. 301 pages.<br /> </li><li>O’Connor, T. P. 1996. &quot;Coastal Sediment Contamination in the Northeast Shelf Large Marine Ecosystem,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.239-257. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Peters, D. S. and F. A. Cross. 1996. &quot;Relating Habitat Stress to Fish Productivity: Problems and Approaches,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.397-404. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Schneider, D. and D. W. Heinemann. 1996. &quot;The State of Marine Bird Populations from Cape Hatteras to the Gulf of Maine,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.197-216. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Schwartz, J. P., N.M. Duston, and C.A. Batdorf. 1996. Metal Concentrations in Winter Flounder, American Lobster, and Bivalve Molluscs from Boston harbor, Salem Harbor, and Coastal Massachusetts: A Summary of Data on Tissues Collected from 1986 to 1991, p.285-312 In Kenneth Sherman, N.A.Jaworski, T.J. Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management. Blackwell Science, Cambridge, MA , 564pp. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Sherman, K, Grosslein, M, Mountain, D, O’Reilly, J and R. Theroux, 1988. The continental shelf ecosystem off the northeast coast of the United States. In: Postma, H.; Zijlstra, J.J., eds. Ecosystems of the world 27: continental shelves. Amsterdam, The Netherlands: Elsevier; p. 279-337. <a href="http://www.amazon.com/dp/0444426094/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0444426094/?tag=encycofearth-20">ISBN: 0444426094</a>. </li><li>Sherman, K. and DA Busch, 1995. Assessment and monitoring of large marine ecosystems. In: Rapport D.J, Guadet, C.L. and Calow, P. (Eds.) Evaluating and monitoring the health of large-scale ecosystems. Springer-Verlag, Berlin. (Published in cooperation with NATO Scientific Affairs Division). NATO Advanced Science Institutes Series. Series 1: Global Environmental Change, Vol. 28. pp. 385-430. <a href="http://www.amazon.com/dp/3540588051/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/3540588051/?tag=encycofearth-20">ISBN: 3540588051</a>. </li><li>Sherman, K., N.A. Jaworski, T.J. Smayda, 1996. The Northeast Shelf Ecosystem—Assessment, Sustainability, and Management. Blackwell Science. 564 pages. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Sherman, K. et al. 1996a. &quot;The Northeast Shelf Ecosystem: An Initial Perspective,&quot; in Sherman, Jaworski and Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and <br /> Management (Cambridge, MA: Blackwell Science, 1996) pp. 103-126. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Sherman, K. et al. 1996b. &quot;Zooplankton Prey Field Variability During Collapse and Recovery of Pelagic Fish in the Northeast Shelf Ecosystem,&quot; in Sherman, Jaworski and Smayda (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.217-236. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Sherman, K. et al. 1996c. &quot;Summary and Recommendations for the Mitigation of Stress,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.535-537. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Sherman, K., J. Kane, S. Murawski, W. Overholtz and A. Solow. 2002. The U.S. Northeast Shelf Large Marine Ecosystem: Zooplankton trends in Fish Biomass Recovery. p.195-215 In K. Sherman and H.R. Skjoldal, (eds.). Large Marine Ecosystems of the North Atlantic—Changing states and Sustainability. Volume in press, Elsevier Science B.V., New York. 449pp. <a href="http://www.amazon.com/dp/0444510117/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0444510117/?tag=encycofearth-20">ISBN: 0444510117</a>. </li><li>Sherman, K., J. O’Reilly and J. Kane, 2003. “Assessment and sustainability of the US Northeast Shelf Ecosystem. In: K. Sherman and G. Hempel, Large Marine Ecosystems of the World – Trends in Exploitation, Protection and Research. <a href="http://www.amazon.com/dp/0444510273/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0444510273/?tag=encycofearth-20">ISBN: 0444510273</a>. </li><li>Sissenwine, M. and E. Cohen, 1991. Resource productivity and fisheries management of the Northeast Shelf Ecosystem. In: K. Sherman, LM Alexander and BD Gold (eds), “Food Chains, Yields, Models, and Management of Large Marine Ecosystems”. Westview Press, Boulder. <a href="http://www.amazon.com/dp/0813383862/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813383862/?tag=encycofearth-20">ISBN: 0813383862</a>. </li><li>Smith, T. et al. 1996. &quot;Multispecies Approaches to Management of Large Marine Predators,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.467-490. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Thomas, J. P. 1996. &quot;Status, Trends, and Health of Wetlands: A 200-Year Overview,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.367-396. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>White, H. H. and A. Robertson. 1996. &quot;Biological Responses to Toxic Contaminants in the Northeast Shelf Large Marine Ecosystem,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.259-283. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li><li>Windom, H. L. 1996. &quot;Riverine Contributions to Heavy Metal Inputs to the Northeast Shelf Ecosystem,&quot; in Kenneth Sherman, et al. (eds.), The Northeast Shelf Ecosystem: Assessment, Sustainability, and Management (Cambridge, MA: Blackwell Science, 1996) pp.313-325. <a href="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0865424683/?tag=encycofearth-20">ISBN: 0865424683</a>. </li></ul> <h2><strong>Other References</strong></h2> <ul><li>Anderson, E.D., R.K. Mayo, K. Sosebee, M. Terceiro, and S.E. Wigley. 1999. Northeast Demersal Fisheries. p. 89-97 In Our Living Oceans: Report on the Status of U.S. Living Marine Resources, 1999. U.S. Dep&#39;t. of Commerce, NOAA Tech. Mem. NMFS-F/SPE-41, 301pp </li><li>Anderson, E.D., K.D. Friedland, and W.J. Overholtz. 1999. Northeast Pelagic Fisheries. p. 99-102 In Our Living Oceans: Report on the Status of U.S. Living Marine Resources, 1999. U.S. Dep&#39;t. of Commerce, NOAA Tech. Mem. NMFS-F/SPE-41, 301pp. </li><li>Anderson, E.D., S.X. Cadrin, L.C. Hendrickson, J.S. Idoine, H.-L. Lai, and J.R. Weinberg. 1999. Northeast Invertebrate Fisheries. p. 109-115 In Our Living Oceans: Report on the Status of U.S. Living Marine Resources, 1999. U.S. Dep&#39;t. of Commerce, NOAA Tech. Mem. NMFS-F/SPO-41, 301pp. </li><li>Behrenfeld, M.J. and P.G. Falkowski. 1997. Photosynthetic Rates Derived from Satellite-based Chlorophyll Concentration. Limnol. Oceanogr., 42(1)1-20. </li><li>Caddy, JF and L Garibaldi, 2000. Apparent changes in the trophic composition of world marine harvests: the perspective from the FAO capture database. Ocean and Coastal Management. 43 (8-9): 615-655.</li><li>Heinz, H. John III Center for Science, Economics and the Environment. 2000. Fishing Grounds: Defining a New Era for American Fisheries Management. Island Press. Washington, DC. 241 pp. <a href="http://www.amazon.com/dp/1559638044/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/1559638044/?tag=encycofearth-20">ISBN: 1559638044</a>. </li><li>O&#39;Reilly, J.E., M. Behrenfeld, J. Yoder, and G. Wood. 1999. Primary Production in the Northeast US Shelf Ecosystem Using the VGPM and High-Resolution Satellite Ocean Color Data from CZCS and SeaWiFS. EOS, Trans. Amer. Geophys. Union. 80(49)154. </li><li>O&#39;Reilly, J.E. and C. Zetlin. 1998. Seasonal, Horizontal, and Vertical Distribution of Phytoplankton Chlorophyll a in the Northeast U.S. Continental Shelf Ecosystem. U.S. Dep&#39;t. of Commerce. NOAA Tech. Rep. NMFS 139, 120pp. </li><li>O&#39;Reilly, J.E., C. Evans-Zetlin, and D.A. Busch. 1987. Primary Production. p. 220-233 In: R. Backus (ed.). Georges Bank, MIT Press, Cambridge, MA. 593pp. </li></ul> <p><br /> <p><br style="clear: left" /> <center> </p> </center></p> <p><a href='/article/Northeast_U.S._Continental_Shelf_large_marine_ecosystem'>Read Full Article...</a></p> http://www.eoearth.org/article/Northeast_U.S._Continental_Shelf_large_marine_ecosystem Tue, 07 Apr 2009 03:04:46 GMT http://www.eoearth.org/article/Strip_mining <a href='/article/Strip_mining'><img border='0' src='/upload/thumb/5/57/Stripmining.jpg/200px-Stripmining.jpg' width='100'/></a> <p>Strip mining is a type of surface mining that involves excavating earth, rock, and other material to uncover a tabular, lens-shaped, or layered mineral reserve. The mineral extracted is usually <a href="/article/Coal">coal</a> or other rocks of sedimentary origin. The mineral reserve is extracted after the overlying material, called overburden is removed. The excavation of the overburden is completed in rectangular blocks in plain view called pits or strips. The pits are parallel and adjacent to each other with each strip of overburden and the mineral beneath extracted sequentially. The mining process using equipment and explosives move the overburden laterally to the adjacent empty pit where the mineral has been extracted. This lateral movement is called casting or open-casting. The overburden is moved by explosives, draglines, bucketwheel excavators, stripping shovels, dozers, and other equipment. The uncovered mineral is excavated and hauled out of the pit to down-stream processing operations. Filling the adjacent empty pits with the overburden is systemic to the process and therefore insures the genesis of mined-land land reclamation, an advantage of this method of surface mining. Planning strip mining utilizes a cross-section or range diagram of the earth to be removed. Strip mining is also called open-cut mining, open-cast mining, and stripping. </p><p><b>Further reading</b><br /> </p><p>Schissler, Andrew P., “Design and Methods of Coal Mining," in <i>The Encyclopedia of Energy</i>, Volume 1, Cutler J. Cleveland Editor-in-Chief, Elsevier Inc., Kidlington, Oxford, pp. 485-494. </p> <p><a href='/article/Strip_mining'>Read Full Article...</a></p> http://www.eoearth.org/article/Strip_mining Mon, 06 Apr 2009 01:35:23 GMT http://www.eoearth.org/article/Global_marine_biodiversity_trends <a href='/article/Global_marine_biodiversity_trends'><img border='0' src='/upload/thumb/3/36/Coral_reef.jpg/250px-Coral_reef.jpg' width='100'/></a><p><a href='/article/Global_marine_biodiversity_trends'>Read Full Article...</a></p> http://www.eoearth.org/article/Global_marine_biodiversity_trends Fri, 03 Apr 2009 03:06:24 GMT http://www.eoearth.org/article/Avalanche <a href='/article/Avalanche'><img border='0' src='/upload/thumb/3/30/Anatomy.jpg/250px-Anatomy.jpg' width='100'/></a> <p>All that is necessary for an avalanche is a mass of snow and a slope for it to slide down. For example, have you ever noticed the snowpack on a car windshield after a <a href="/article/Precipitation_and_fog">snowfall</a>? While the <a href="/article/Temperature">temperature</a> is cold, the snow sticks to the surface and doesn&#39;t slide off. After temperatures warm up a little, however, the snow will &quot;sluff,&quot; or slide, down the front of the windshield, often in small slabs. This is an avalanche on a miniature scale.</p> <p>Of course, <a href="/article/Mountain">mountain</a> avalanches are much larger and the conditions that cause them are more complex. A large avalanche in North America might release 300,000 cubic yards of snow. That&#39;s the equivalent of 20 football fields filled 10 feet deep with snow. However, such large avalanches are often naturally released. Skiers and recreationists are usually caught in smaller, but often more deadly avalanches. </p> <p>Slab avalanches are the most common and most deadly avalanches, where layers of a snowpack fail and slide down the slope. Since 1950, 235 people in the U.S. have been killed in slab avalanches. Hard slab avalanches involve large blocks of snow and debris sliding down a slope. In soft slab avalanches, the snow breaks up in smaller blocks as it falls.</p> <p>An avalanche has three main parts. The <strong>starting zone</strong> is the most volatile area of a slope, where unstable snow can fracture from the surrounding snowcover and begin to slide. Typical starting zones are higher up on slopes, including the areas beneath cornices and &quot;bowls&quot; on mountainsides. However, given the right conditions, snow can fracture at any point on the slope.</p> <p>The <strong>avalanche track</strong> is the path or channel that an avalanche follows as it goes downhill. When crossing terrain, be aware of any slopes that look like avalanche &quot;chutes.&quot; Large vertical swaths of trees missing from a slope or chute-like clearings are often signs that large avalanches run frequently there, creating their own tracks. There may also be a large pile-up of snow and debris at the bottom of the slope, indicating that avalanches have run.</p> <p>The <strong>runout zone</strong> is where the snow and debris finally come to a stop. Similarly, this is also the location of the deposition zone, where the snow and debris pile the highest. Although underlying terrain variations, such as gullies or small boulders, can create conditions that will bury a person further up the slope during an avalanche, the deposition zone is where a victim will most likely be buried.</p> <p><a href='/article/Avalanche'>Read Full Article...</a></p> http://www.eoearth.org/article/Avalanche Thu, 02 Apr 2009 02:56:22 GMT http://www.eoearth.org/article/Lichen <a href='/article/Lichen'><img border='0' src='/upload/thumb/4/43/Tidal_zone_showing_marine_lichens.jpg/200px-Tidal_zone_showing_marine_lichens.jpg' width='100'/></a> <p>Lichens have traditionally been referred to as a prime example of a symbiotic relationship. Each lichen consists of an intimate association between a fungus and a species of algae. The algae within the lichen photosynthesizes, providing food for both symbionts. The fungus protects the alga from harmful light intensities, produces a substance that accelerates <a href="/article/Photosynthesis">photosynthesis</a> in the algae, and absorbs and retains <a href="/article/Physical_properties_of_water">water</a> and minerals for both organisms. There is physiological and ultrastructural evidence that suggests the fungus <a href="/article/Parasite">parasitizes</a> the algae in a controlled fashion and, in some instances, actually destroys the algal cells. There are about 25,000 species of lichens known and they are capable of living in environmental conditions that kill most other forms of life. The number of aquatic lichens is limited as most live under the blazing <a href="/article/Solar_radiation">sun</a> often on bare <a href="/article/Composition_of_rocks">rocks</a>. Aquatic lichens typically live in the intertidal zone along <a href="/article/Coastal_zone">sea shores</a> or in shallow <a href="/article/Stream">streams</a>. </p> <p><a href='/article/Lichen'>Read Full Article...</a></p> http://www.eoearth.org/article/Lichen Wed, 01 Apr 2009 02:11:55 GMT http://www.eoearth.org/article/Lesser_Long-nosed_Bat <a href='/article/Lesser_Long-nosed_Bat'><img border='0' src='/upload/thumb/6/61/Lesser_long-nosed_bat1_USFS_MerlinDTuttle.jpg/200px-Lesser_long-nosed_bat1_USFS_MerlinDTuttle.jpg' width='100'/></a> <p><em><strong>This article was prepared for the U.S. Forest Service by Kim Winter of the <a href="http://www.coevolution.org/people.html" class='external text' title="http://www.coevolution.org/people.html">Coevolution Institute</a>. The images were made by Merlin D. Tuttle of <a href="http://www.batcon.org/home/default.asp" class='external text' title="http://www.batcon.org/home/default.asp">Bat Conservation International</a>.</strong></em></p> <p>During late spring in the <a href="/article/Sonoran_desert">Sonoran Desert</a>, the white flowers of Saguaro (<em>Carnegiea gigantea</em>) cacti bloom for just one evening to attract Lesser Long-nosed Bats (<em>Leptonycteris curasoae yerbabuena</em>) and Mexican Long-tongued Bats (<em>Choeronycteris mexicana</em>) for <a href="/article/Pollination">pollination</a>. The bats use their elongated muzzles to reach deep into Saguaro blossoms for nectar, covering their hairy heads with copious amounts of pollen that drop onto other flowers as the bats fly from cactus to cactus throughout the night. The blossoms close by the following afternoon, allowing daytime visitors such as wasps, bees, butterflies, and birds to pick up any remaining nectar or pollen left behind.</p> <p>Lesser long-nosed bats are perfectly adapted to feed and pollinate Saguaros and other large Southwestern and Mexican succulents such as Organ-pipe Cactus (<em>Stenocereus thurberi</em>), agaves (<em>Agave </em>spp.) and Cardón (<em>Pachycereus pringlei</em>). Their narrow snouts easily detect the strong melon scent of the night-blooming flowers, and their brush-tipped tongues extend deeply into flowers to extract rich quantities of nectar and pollen produced by the cacti to ensure that pollinators will find them during their brief period of bloom.</p> <p>Bat pollination of cacti and agaves helps maintain healthy <a href="/article/Desert_biome">desert</a> <a href="/article/Ecosystem">ecosystems</a>. Saguaros, the state flower of Arizona, are <a href="/article/Keystone_species">keystone species</a> in the Sonoran Desert and grow up to 50 feet in height, providing important perching and nesting sites for Red-tailed Hawks (<em>Buteo jamaicensis</em>); and nesting cavities for Gilded Flickers (<em>Colaptes chrysoides</em>) and Gila Woodpeckers (<em>Melanerpes uropygialis</em>), Elf Owls (<em>Micrathene whitneyi</em>), Purple Martins (<em>Progne subis</em>), and other birds. Once the Saguaro fruit ripens in June, Lesser Long-nosed Bats, White-winged Doves (<em>Zenaida asiatica</em>), Gila Woodpeckers, and other birds consume the fleshy red pulp and thereby disperse the seeds, which pass through their guts intact. Agaves provide an important food resource to the Lesser Long-nosed Bat during its annual migration from <a href="/article/Mexico">Mexico</a> to the Sonoran Desert.</p> <p>The Lesser Long-nosed Bat is federally listed as endangered species by the <a href="/article/United_States_Fish_and_Wildlife_Service">U.S. Fish and Wildlife Service</a> under the <a href="/article/Endangered_Species_Act%2C_United_States">Endangered Species Act of 1973</a>. The survival of both bats and their desert food plants are threatened by loss of habitat due to development, <a href="/article/Invasive_species">invasive</a> annual <a href="/article/Grasses">grasses</a>, and changes in <a href="/article/Fire_ecology_fact_sheet">fire</a> regimes. With nature in the balance, ensuring the future of the southwestern desert will depend on appreciating and protecting the roles played by both pollinator and plant in these fragile ecosystems.</p> <p><big><strong>Further Reading</strong></big></p> <ul><li>Celebrating Wildflowers: <a href="http://www.fs.fed.us/wildflowers/pollinators/bats.shtml" class='external text' title="http://www.fs.fed.us/wildflowers/pollinators/bats.shtml">Bat Pollination</a></li><li><a href="http://www.batcon.org/" class='external text' title="http://www.batcon.org/">Bat Conservation International</a></li><li><a href="http://www.desertmuseum.org/pollination/bats.html" class='external text' title="http://www.desertmuseum.org/pollination/bats.html">Arizona-Sonora Desert Museum</a></li><li>U.S. Fish and Wildlife Service—<a href="http://www.fws.gov/endangered/bats/bats.htm" class='external text' title="http://www.fws.gov/endangered/bats/bats.htm">Endangered Bats</a></li><li>Lubee Bat Conservancy: <a href="http://www.lubee.org/aboutbats.aspx" class='external text' title="http://www.lubee.org/aboutbats.aspx">About Fruit and Nectar Bats</a> </li><li><a href="http://www.pollinator.org" class='external text' title="http://www.pollinator.org">North American Pollinator Protection Campaign</a> </li></ul><p> <br /> <p><br style="clear: left" /> <center> </p> </center></p> <p><a href='/article/Lesser_Long-nosed_Bat'>Read Full Article...</a></p> http://www.eoearth.org/article/Lesser_Long-nosed_Bat Tue, 31 Mar 2009 01:44:19 GMT http://www.eoearth.org/article/Everglades <a href='/article/Everglades'><img border='0' src='/upload/thumb/9/96/Nt0904a_lg.jpg/250px-Nt0904a_lg.jpg' width='100'/></a> <p>The Everglades, located at the southern tip of peninsular Florida, is the most famous <a href="/article/Wetland">wetland</a> in the United States and one of the most distinct in the world. The Everglades is unique among the world&#39;s large wetlands because it derives its water from rainfall. Other large and famous wetlands, such as the <a href="/article/Pantanal">Pantanal</a> of South America, the Okavango of <a href="/article/Botswana">Botswana</a>, and the <a href="/article/Llanos">Llanos</a> in <a href="/article/Venezuela">Venezuela</a> and <a href="/article/Colombia">Colombia</a>, derive most of their water and nutrient inputs from <a href="/article/River">river</a> flooding. The unique sheet flow, the slow flow of water over shallow, broad tracts of <a href="/article/Marsh">marsh</a>, inspired Douglas to name the Everglades, River of Grass. As important as sheet flow is, the <a href="/article/Groundwater">groundwater</a> connections of the Everglades to Lake Okeechobee, the second largest <a href="/article/Freshwater">freshwater</a> lake entirely within the U.S., are also essential for the maintenance of the wetland. The linkages between the Everglades, Lake Okeechobee, and the Kissimmee River, which provides 80 percent of the surface flow into Lake Okeechobee, illustrate the importance of connectivity among ecoregions to maintain integrity. </p> <p>The boundaries of this ecoregion extend to include the Big Cypress <a href="/article/Swamp">Swamp</a> to the northwest, the southern edge of Lake Okeechobee to the north, and the Atlantic coastal ridge to the east. The Everglades climate has been classified as subtropical, featuring hot <a href="/article/Atmospheric_humidity">humid</a> summers, when 80 percent of rainfall occurs, and mild winters. Rainfall varies spatially across southern Florida so that the inland <a href="/article/Marsh">marshes</a> and Lake Okeechobee only receive about 60 percent of the rainfall levels recorded in the coastal areas. The most important climatic feature is also the most important natural disturbance factor: the recurrent <a href="/article/Tropical_weather_and_hurricanes">hurricanes</a> that strike most frequently from August through October. Extensive habitat destruction can occur from high <a href="/article/Wind">winds</a>, storm surge, and rainfall. Frosts also limit the northern distribution of many tropical species to this ecoregion and help to further define its boundaries. </p><p>Many observers have identified the Everglades as one of the most endangered of North American ecoregions as a result of <a href="/article/Land-use_and_land-cover_change">clearing</a> for <a href="/article/Agriculture">agriculture</a>, diversion of water flow, and other developments. Recovery efforts are now underway, supported by a broad association of environmentalists active in the region. </p> <p><a href='/article/Everglades'>Read Full Article...</a></p> http://www.eoearth.org/article/Everglades Mon, 30 Mar 2009 01:28:11 GMT http://www.eoearth.org/article/Biodiversity <a href='/article/Biodiversity'><img border='0' src='/upload/thumb/7/7d/NWHI_reef_fish.jpg/300px-NWHI_reef_fish.jpg' width='100'/></a> <p>The word &quot;biodiversity&quot; is a contracted version of &quot;biological diversity&quot;. The <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> defines biodiversity as:<br /> </p><p>&quot;the variability among living organisms from all sources including, <em>inter alia</em>, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and of ecosystems.&quot;<br /> </p><p>Thus, biodiversity includes genetic variation within species, the variety of species in an area, and the variety of habitat types within a landscape. Perhaps inevitably, such an all-encompassing definition, together with the strong emotive power of the concept, has led to somewhat cavalier use of the term biodiversity, in extreme cases to refer to life or biology itself. But biodiversity properly refers to the variety of living organisms. </p><p>Biological diversity is of fundamental importance to the functioning of all natural and human-engineered ecosystems, and by extension to the ecosystem services that nature provides free of charge to human society. Living organisms play central roles in the cycles of major elements (<a href="/article/Carbon">carbon</a>, <a href="/article/Nitrogen">nitrogen</a>, and so on) and water in the environment, and diversity specifically is important in that these cycles require numerous interacting species. </p><p>General interest in biodiversity has grown rapidly in recent decades, in parallel with the growing concern about nature conservation generally, largely as a result of the accelerating rates of natural habitat loss and degradation, and resulting extinctions of species. The IUCN Red List estimates that 12-52% of species within well-studied higher taxa such as vertebrates and vascular plants are threatened with extinction. Based on data on recorded extinctions of known species over the past century, scientists estimate that current rates of species extinction are about 100 times higher than long-term average rates based on fossil data. More speculative, but also quite plausuble, estimates suggest that extinction rates now and in the near future may reach 1000 to 10,000 times the average over past geologic time. These estimates are the basis of the growing consensus that the Earth is in the midst of the sixth mass extinction event in its history. </p> <p><a href='/article/Biodiversity'>Read Full Article...</a></p> http://www.eoearth.org/article/Biodiversity Fri, 27 Mar 2009 05:24:15 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Thu, 26 Mar 2009 02:41:52 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Thu, 26 Mar 2009 02:34:39 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Thu, 26 Mar 2009 02:34:07 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Thu, 26 Mar 2009 02:33:19 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Thu, 26 Mar 2009 02:31:27 GMT http://www.eoearth.org/article/Forests_and_woodlands_and_development_challenges_in_Africa <a href='/article/Forests_and_woodlands_and_development_challenges_in_Africa'><img border='0' src='/upload/thumb/9/9f/Women_cleaning_nuts.JPG/250px-Women_cleaning_nuts.JPG' width='100'/></a> <p>The endowment value of <a href="/article/Forests_and_woodlands_in_Africa">forests and woodlands in Africa</a> is enormous, and can be used to promote a wide range of livelihood opportunities, including increased income and enhanced livelihood security. However, as forests and woodlands are declining, primarily as a result of increased woodfuel collection, clearing of forests for <a href="/article/Agriculture">agriculture</a>, illegal and poorly regulated timber extraction, conflicts, increasing urbanization and industrialization, these opportunities are diminishing. Between 1990 and 2000, Africa’s forests and woodlands receded faster than the global average; deforestation in Africa took place at an average of 0.8 percent, as compared to the world average of 0.2 percent. </p><p>Policy, legal, institutional, technical and economic constraints have undermined wider adoption of sustainable forest management as well as limited opportunities for development. </p><p>One major constraint is that Africa has not been able to take advantage of its wealth of raw materials and traditional knowledge to invest in processing. This continues to undermine opportunities for employment and income generation. With increasing private-sector involvement, including foreign-based companies, there is a good opportunity for governments to foster viable partnerships with the communities and civil societies in the protection of traditional rights of forest-adjacent communities, and equitable sharing of benefits from forest resources to promote livelihood security and ensure sustainable use of forest and woodland resources. This is consistent with obligations under the <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> (CBD). Additionally, it is essential for there to be increased investment in the development of micro- and small and medium enterprises (SMEs) if people are to have the opportunity to move away from subsistence-based livelihoods. </p> <p><a href='/article/Forests_and_woodlands_and_development_challenges_in_Africa'>Read Full Article...</a></p> http://www.eoearth.org/article/Forests_and_woodlands_and_development_challenges_in_Africa Wed, 25 Mar 2009 01:33:23 GMT http://www.eoearth.org/article/Oyashio_Current_large_marine_ecosystem <a href='/article/Oyashio_Current_large_marine_ecosystem'><img border='0' src='/upload/thumb/0/08/LME51location.jpg/250px-LME51location.jpg' width='100'/></a> <p>The Oyashio Current Large Marine Ecosystem (LME) is characterized by its sub-arctic climate. It is influenced by the cold Oyashio Current (“parent current”), also known as the Kurile Current. The Oyashio Current originates in the Sea of Okhotsk and flows south along the southern <a href="/article/South_Sakhalin-Kurile_mixed_forests">Kurile Islands</a>. It meets the warmer Kuroshio Current off the coast of Japan’s Honshu Island. The topography of the LME includes the Kuril-Kamchatka Trench and Rise. The countries bordering the LME are Russia and Japan. LME book chapters and articles include Minoda, 1989<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>.</p> <p><a href='/article/Oyashio_Current_large_marine_ecosystem'>Read Full Article...</a></p> http://www.eoearth.org/article/Oyashio_Current_large_marine_ecosystem Tue, 24 Mar 2009 02:36:06 GMT http://www.eoearth.org/article/Carbon_footprint <a href='/article/Carbon_footprint'><img border='0' src='/upload/thumb/3/3d/Per_capita_emissions.JPG/180px-Per_capita_emissions.JPG' width='100'/></a> <p>A carbon footprint is the measure of the amount of <a href="/article/Greenhouse_gas">greenhouse gases</a>, measured in units of <a href="/article/Carbon_dioxide">carbon dioxide</a>, produced by human activities. A carbon footprint can be measured for an individual or an organization, and is typically given in tons of CO₂-equivalent (CO₂-eq) per year. For example, the average North American generates about 20 tons of CO₂-eq each year. The global average carbon footprint is about 4 tons of CO₂-eq per year (Figure 1).</p> <p><a href='/article/Carbon_footprint'>Read Full Article...</a></p> http://www.eoearth.org/article/Carbon_footprint Mon, 23 Mar 2009 02:03:21 GMT http://www.eoearth.org/article/Bumblebee <a href='/article/Bumblebee'><img border='0' src='/upload/thumb/a/a4/Cuckoo_bumblebee_USFS_DavidInouye.jpg/200px-Cuckoo_bumblebee_USFS_DavidInouye.jpg' width='100'/></a> <h2>Bumblebees (<em>Bombus</em> spp.)</h2> <p class="img-caption"> </p> <p>Bumblebees (of the genus <em>Bombus</em>) are common native bees and important <a href="/article/Pollination">pollinators</a> in most areas of North America. In spring, queens emerge from underground where they have spent the winter, and look for a nest site, often found underground in an old mouse nest or rodent burrow. Bumblebees visit flowers for the nectar and pollen upon which they feed, and once the eggs they lay have hatched, they use those plant resources to feed larval worker bees. Bumblebees can generate heat with their flight muscles, and queens will use this ability to incubate their brood and speed up development of the workers. After the first generation of workers hatches, the empty cocoons may be used for short-term storage of nectar, but bumblebees do not make and store large quantities of honey like honeybees (which need ample supplies of honey to make it through the winter).</p> <p>The bumblebee queen produces a few generations of workers during the summer, which then take over the task of collecting nectar and pollen and help rear the final generation of the colony, queens for the next summer, and males to mate with them. By late fall, the colony has died out except for a few final workers and males, and the new queens burrow into the ground to wait for the following spring.</p> <h2>A Pollinator&#39;s Life<br /> </h2> <p>Bumblebees are important pollinators for many wildflowers. There are 49 species of bumblebees in the United States, which can be separated into three different classes of proboscis (tongue) length: short, medium, and long. This variation in tongue size allows different species of bees to visit different sizes and shapes of flowers. A few of the short-tongued species, however, manage to feed on long-tube flowers by “nectar robbing”. They bite holes in the flowers near the nectaries and extract the nectar through the hole instead of visiting the flowers “legitimately”.</p> <p>Another reason bumble bees are important pollinators is their behavior of buzzing, or sonicating, flowers that require this behavior for pollination. For example, tomatoes and some other flowers in that plant family don’t produce nectar but the bees visit them anyway in order to collect pollen, which they do by vibrating their wing muscles (making a buzzing noise) to shake pollen grains out of the anthers.</p> <p>As one of the few species of commercially developed pollinators, a few species of bumblebees have been shipped to a variety of places around the world where they are not native but are wanted for greenhouse pollination. They typically forage outside of the greenhouses as well. As a result, they have been implicated in transmitting new diseases to wild, native bumblebees. They have also escaped from the greenhouses becoming feral in places where they are not native. They may become competitors with native species and serve as pollinators for introduced weeds.</p> <p><a href='/article/Bumblebee'>Read Full Article...</a></p> http://www.eoearth.org/article/Bumblebee Fri, 20 Mar 2009 01:54:36 GMT http://www.eoearth.org/article/Aquifer <a href='/article/Aquifer'><img border='0' src='/upload/thumb/a/a4/Aquifer_USGS.gif/350px-Aquifer_USGS.gif' width='100'/></a> <p>An aquifer is a geologic formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to <a href="/article/Spring">springs</a> and wells. Use of the term is often restricted to those water-bearing formations capable of yielding water in sufficient quantity to constitute a usable supply for people's uses. </p> <p><a href='/article/Aquifer'>Read Full Article...</a></p> http://www.eoearth.org/article/Aquifer Thu, 19 Mar 2009 01:39:49 GMT http://www.eoearth.org/article/Space_weather_(AMS_statement) <a href='/article/Space_weather_(AMS_statement)'><img border='0' src='/upload/thumb/0/06/Spaceweatherstatement.jpg/300px-Spaceweatherstatement.jpg' width='100'/></a> <p><strong><em>This is a Policy Statement of the American Meteorological Society (AMS). It was adopted by AMS Council on 5 May 2008, and first published in </em><em>Bull. Amer. Meteor. Soc., 89. Click <a href="/article/Statements_of_the_American_Meteorological_Society">here</a> to see other AMS statements in the EoE. </em></strong></p> <p><a href='/article/Space_weather_(AMS_statement)'>Read Full Article...</a></p> http://www.eoearth.org/article/Space_weather_(AMS_statement) Wed, 18 Mar 2009 01:59:41 GMT http://www.eoearth.org/article/Greening_of_the_Sahel <a href='/article/Greening_of_the_Sahel'><img border='0' src='/upload/thumb/c/c5/Sahel_region.jpg/180px-Sahel_region.jpg' width='100'/></a> <p>The Sahel region in Africa, spanning the entire continent from the <a href="/article/Ocean">Atlantic Ocean</a> to the Red Sea, receives, in the main, the World’s attention in cases of drought, famine or political crisis. The Sahel is a dynamic <a href="/article/Ecosystem">ecosystem</a> that responds not only to climatic variability bu to human exploitation of biospheric resources. Over the long-term, changes in <a href="/article/Precipitation_and_fog">rainfall</a> may have resulted in <a href="/article/Land-use_and_land-cover_change">changes in land use patterns</a>. While there has been a tendency to refer such changes as the <a href="/article/Desertification">desertification</a> of the Sahel, results from analysis of different types of satellite- and ground-based data have not resulted in consensus on the direction of changes.</p><p>Since the early 1980s, global satellite mapping of the <a href="/article/Biosphere">biosphere</a> has generated long time-series measurements of vegetation that can be used as proxies for understating the dynamics of variability of the Sahel&#39;s <a href="/article/Ecosystem">ecological system</a>. A number of studies using these and other data have shown the close coupling among rainfall, land use and primary production in the Sahel. </p> <p><a href='/article/Greening_of_the_Sahel'>Read Full Article...</a></p> http://www.eoearth.org/article/Greening_of_the_Sahel Tue, 17 Mar 2009 01:54:39 GMT http://www.eoearth.org/article/Alternatives_for_significant_uses_of_lead_in_Massachusetts <a href='/article/Alternatives_for_significant_uses_of_lead_in_Massachusetts'><img border='0' src='/upload/thumb/b/b1/Galena2.jpg/200px-Galena2.jpg' width='100'/></a> <p>In July 2005, the Commonwealth of Massachusetts requested that the Toxics Use Reduction Institute perform an alternatives assessment for five chemicals. For each chemical, the Institute was charged with identifying significant uses in manufacturing, consumer products, and other applications; reviewing health and environmental effects; and evaluating possible alternatives. The results of this study will serve as a guide for those seeking safer substitutes to the five chemicals discussed here. </p><p>Presented here is an executive summary of the findings of for high priority uses of lead in Massachusetts. The full report, the <u>Five Chemicals Alternatives Assessment Study</u> available from the link below, presents extensive factual information on each alternative. </p><p><br /> </p> <p><a href='/article/Alternatives_for_significant_uses_of_lead_in_Massachusetts'>Read Full Article...</a></p> http://www.eoearth.org/article/Alternatives_for_significant_uses_of_lead_in_Massachusetts Mon, 16 Mar 2009 01:48:52 GMT http://www.eoearth.org/article/East_African_trypanosomiasis <a href='/article/East_African_trypanosomiasis'><img border='0' src='/upload/thumb/c/cc/FemaleTsetseFly_USDA.jpg/100px-FemaleTsetseFly_USDA.jpg' width='100'/></a> <p>East African trypanosomiasis is a disease caused by a <a href="/article/Protozoa">protozoan</a> parasite that is carried by the tsetse fly. The Centers for Disease Control and Prevention (CDC) has provided the following answers to questions about the organism and the disease:</p><p>&nbsp;</p> <p><a href='/article/East_African_trypanosomiasis'>Read Full Article...</a></p> http://www.eoearth.org/article/East_African_trypanosomiasis Fri, 13 Mar 2009 08:47:17 GMT http://www.eoearth.org/article/Air_masses <a href='/article/Air_masses'><img border='0' src='/upload/thumb/0/03/Airmasses_1_NOAA.gif/180px-Airmasses_1_NOAA.gif' width='100'/></a> <p>An air mass is a large body of air with generally uniform <a href="/article/Temperature">temperature</a> and humidity. The area from which an air mass originates is called a &quot;source region.&quot;</p> <p>Air mass source regions range from extensive snow covered polar areas to deserts to tropical oceans. The United States is not a favorable source region because of the relatively frequent passage of weather disturbances that disrupt any opportunity for an air mass to stagnate and take on the properties of the underlying region. The longer the air mass stays over its source region, the more likely it will acquire the properties of the surface below.</p> <p>The four principal air mass classifications that influence the continental United States according to their source region are:</p> <ul><li>Polar latitudes - Located poleward of 60° north and south.</li><li>Continental - Located over large land masses between 25°N/S and 60°N/S.</li><li>Maritime - Located over the oceans between 25°N/S and 60°N/S</li><li>Tropical latitudes - Located within about 25° of the equator.</li></ul> <p>As these air masses move around the earth they can begin to acquire additional attributes. For example, in winter an arctic air mass (very cold and dry air) can move over the ocean, picking up some warmth and moisture from the warmer <a href="/article/Ocean">ocean</a> and becoming a maritime polar air mass (mP) - one that is still fairly cold but contains moisture. If that same polar air mass moves south from Canada into the southern U.S. it will pick up some of the warmth of the ground, but due to lack of moisture it remains very dry. This is called a continental polar air mass (cP).</p> <p>The Gulf Coast states and the eastern third of the country commonly experience the tropical air mass in the summer. Continental tropical (cT) air is dry air pumped north, off of the Mexican Plateau. If it becomes stagnant over the Midwest, a drought may result. Maritime tropical (mT) air is air from the tropics which has moved north over cooler water.</p> <p>Air masses can control the weather for a relatively long time period: from a period of days, to months. Most weather occurs along the periphery of these air masses at boundaries called fronts.</p> <p><a href='/article/Air_masses'>Read Full Article...</a></p> http://www.eoearth.org/article/Air_masses Thu, 12 Mar 2009 09:20:59 GMT http://www.eoearth.org/article/Darwin,_Charles <a href='/article/Darwin,_Charles'><img border='0' src='/upload/thumb/6/64/Charlesdarwin.jpg/200px-Charlesdarwin.jpg' width='100'/></a> <p>Charles Darwin (1809-1882) was a British scientist who laid the foundations of the theory of <a href="/article/Evolution">evolution</a> by <a href="/article/Natural_selection">natural selection</a> and transformed the way we think about the natural world. </p><p>Darwin, a naturalist, was born in Shrewsbury, England on Feb. 12, 1809. His father was also a naturalist and a physician. His mother died when he was eight. Darwin was the first of the evolutionary biologists . At age sixteen, Darwin left Shrewsbury to study medicine at the University of Edinbourgh but switched to Cambridge University to study divinity. After he graduated, he went on a five-year scientific expedition to the <a href="/article/Ocean">Pacific</a> coast of South America on the H.M.S. Beagle from 1831-1836. <em><a href="/article/On_the_Origin_of_Species_%28historical_e-book%29">On the Origin of Species</a></em> (1859) described evolution and natural selection, giving a theoretical explanation for the <a href="/article/Biodiversity">diversity</a> among living and fossil beings. His book was not well received among the general population who felt threatened at the notion that humans were descended from ape-like creatures. The scientific community, however, did grasp his theories and today his book forms the basis for many contemporary archaeological theories.</p><p>In 1839 he married his cousin, Emma Wedgewood. Charles Darwin lived with his wife and children at their home at Down House in Kent, England. Darwin&#39;s main works include <em><a href="/article/On_the_Origin_of_Species_%28historical_e-book%29"></em><em>The Origin of Species</a></em> (1859) and <em>The Descent of Man</em> (1871).</p><p>&#160;</p> <h1>Biography <br /></h1><p><br />Charles Darwin (1809-1882) is a towering figure in the history of science.  He was born into a rather wealthy English family–Josiah Wedgwood of Wedgwood pottery and fine china was his grandfather.  He was not a great student as a child: instead of school, he preferred hunting, collecting things, and playing with a chemistry set.  He went to the University of Edinburgh to become a medical doctor, like his father.  Though he hated studying medicine, he began interacting with the natural history scholars there.  After a couple years, Darwin switched to Cambridge University, intending to become a clergyman in the Church of England.  He continued with natural history, collecting beetles, mostly, and thought that becoming a country priest would give him enough spare time to devote to his nature studies.  <br /><br />Darwin sailed on a five-year voyage of the H.M.S. Beagle (1831-1836) mostly to South America, though it did go around the world.  He was invited to be an intellectual companion for the captain, who was not supposed to mingle with the crew, and to contribute to the scientific mission of the voyage.  He was seasick almost the entire time they were at sea.  On land, though, he felt better and mainly collected plants, animals and fossils, and observed the geology.  While on the Galapagos Islands (a group of volcanic islands in the Pacific Ocean, 1200 km west of Ecuador), he was told that locals could tell the difference between tortoises from each island, a fact he didn’t think much about at the time.  While collecting on each island, he did notice differences in some of the bird species, though he didn’t always keep good records of which island each bird came from.  Examining his specimens while crossing the Pacific, it appeared that many of the birds that he thought were of different species were actually finches with significantly different features.  Tortoises were caught on the islands, too, but for food, not science, and their shells were dumped overboard after they were eaten; he unwittingly lost what later would have been useful information for his theory.  </p><p>Back in England after his voyage, Darwin made a name for himself as an explorer and geologist, writing books on his travels, South American geology, and coral reefs.  He also began studying <a href="/article/Evolution">evolution</a>.  There was plenty of talk of evolution of species by scientists trying to understand living things and by non-scientists wishing to disagree with the Church of England. (The Church of England was the established Church and it dominated intellectual life, education and government.  Some felt that Church influence on public affairs was too strong and sought to ‘disestablish’ it.  As an aside, this is the main reason for the separation of church and state in the United States Constitution.  As another aside, one of the longest words in the English language, antidisestablishmentarianism, is the belief of those opposed to disestablishing the Church.) The Church was opposed to evolution, as its official position was that God created species as separate entities as stated in Genesis.  Darwin thought that the Galapagos Islands might shed light on the problem.  <br /><br />Since Darwin’s records for the Galapagos were not in the best order, he borrowed the collections of several others on the Beagle and analyzed them.  With the help of bird specialist John Gould, better known for his bird paintings, he determined that there were twelve distinct species of finch.  Darwin concluded that at some time in the past, one type of finch arrived on the islands and slowly changed into different species.  That evolution occurs was not a new idea to science, though it was quite controversial.  Darwin’s biggest contribution to science was in his explanation for how evolution happens.  He spent a lot of time studying domesticated animals (dogs, pigeons, chickens, etc.) and how breeders get new features.  If people artificially select for certain things, then maybe the environment changes species by “natural selection.”  He was also strongly influenced by Thomas Malthus’s well known essay on human <a href="/article/Population">population</a>, predicting that population growth is faster than growth in the food supply and so in the future people will starve to death in large numbers.  When applied to natural life forms trying to survive with limited resources, this became the concept later called “survival of the fittest.”<br /><br />Darwin concluded that the different species of finch on the Galapagos became distinct because they each had a different food source, depending on which island they lived.  If their food is bugs found in holes in trees, then those with longer and thinner beaks are more likely to survive and since children generally resemble their parents, they too will have long and thin beaks.  The overall change in beaks may be very small in a single generation, but over many generations the beaks take on a new shape on that island.  On another island the food source may be nuts, which have to be cracked open with the beak.  Here, short and fat beaks are selected for and over many generations all the finches on that island will have stubby beaks.  In this way, new species develop.  <br /><br />Over time Darwin gave up the idea of being a priest and devoted himself to science, supporting his family and research on investments.  He developed his theory of evolution by natural selection in the 1830s, but did not publish it.  It was too controversial and as a young scientist he didn’t want to make too many enemies.  So, he put it aside and worked on other projects for twenty years, all the time strengthening his theory with better evidence.  Among other pursuits, he spent ten years working on the physiology and classification of barnacles from around the world and he continued his studies on domesticated animals.  <br /><br />Darwin was sickly most of his adult life, with stomach and other problems.  It was common for him to be unable to work more than a couple hours per day and sometimes he was unable to work at all for months at a time.  In spite of this, he became one of the best known and most respected scientists in England.  <br /><br />In the late 1850s, Darwin was sent a paper outlining the theory of natural selection written by Alfred Russel Wallace, a naturalist working mostly in Asia. Independently, the two had come up with essentially the same theory.  In science, the first to publish generally gets credit for a new idea and Darwin could have used his influence to prevent publication of Wallace’s paper until Darwin’s was published (he was well known, Wallace was not, and Wallace was in Asia).  But he didn’t.  Darwin explained the situation to Wallace and they agreed to publish simultaneously.  Darwin wrote a summary of his theory and the two papers appeared together.  (Not all problems in science are settled this amiably.)  While evolution was still a highly controversial idea and opposed by both the hierarchy of the Church of England and by many scientists, public opinion had changed to the point that many supported the idea.  And by that time Darwin was an influential scientist who could not be dismissed easily.  He then put the theory into book form and On the Origin of Species by Means of Natural Selection was published in 1859.  <br /><br />The Origin of Species was a popular book and stirred quite a controversy.  For reasons of both personality and health, Darwin did not defend it in debates, but he had friends who did, most notably <a href="/article/Huxley%2C_Thomas_Henry">Thomas Henry Huxley</a>.  Some eminent scientists were convinced right away that the theory is correct, some came to believe it over time, and some went to their graves adamant that it is wrong.  The Church of England and the Catholic Church also declared it wrong, though over time both religions have since rejected a literal interpretation of the Bible and support the idea of evolution of new species by natural means.  Virtually all scientists now accept the basic premise of natural selection bringing about new species.  The details are debated, but not the general theory.  Opposition now comes mostly from religious groups who insist that the Bible be interpreted literally.  <br /><br />Darwin spent much of his research time after 1859 more fully developing the ideas in “Origin of Species,” investigating such topics as seed transport across oceans, why orchids look the way they do, and the biology of human facial expressions.  When he died in 1882, he was buried at Westminster Abbey, one of the highest honors his country could bestow.  In terms of influence on scientific thinking, Darwin ranks with such greats as <a href="/article/Galileo">Galileo</a>, Newton, and Einstein.  And like Galileo, Darwin’s theory not only advanced a scientific discipline, but also contributed to changed attitudes about the separation of science and religion.</p><p>&#160;</p><p>(Note: this biography was originally published in <em>Focus on Geography</em>,  v. 47, no. 4 (2004), p. 34-36. and is reprinted here with permission of the American Geographical Society.)  </p> <p><a href='/article/Darwin,_Charles'>Read Full Article...</a></p> http://www.eoearth.org/article/Darwin,_Charles Wed, 11 Mar 2009 09:21:15 GMT http://www.eoearth.org/article/Avalanche <a href='/article/Avalanche'><img border='0' src='/upload/thumb/3/30/Anatomy.jpg/250px-Anatomy.jpg' width='100'/></a> <p>All that is necessary for an avalanche is a mass of snow and a slope for it to slide down. For example, have you ever noticed the snowpack on a car windshield after a <a href="/article/Precipitation_and_fog">snowfall</a>? While the <a href="/article/Temperature">temperature</a> is cold, the snow sticks to the surface and doesn&#39;t slide off. After temperatures warm up a little, however, the snow will &quot;sluff,&quot; or slide, down the front of the windshield, often in small slabs. This is an avalanche on a miniature scale.</p> <p>Of course, <a href="/article/Mountain">mountain</a> avalanches are much larger and the conditions that cause them are more complex. A large avalanche in North America might release 300,000 cubic yards of snow. That&#39;s the equivalent of 20 football fields filled 10 feet deep with snow. However, such large avalanches are often naturally released. Skiers and recreationists are usually caught in smaller, but often more deadly avalanches. </p> <p>Slab avalanches are the most common and most deadly avalanches, where layers of a snowpack fail and slide down the slope. Since 1950, 235 people in the U.S. have been killed in slab avalanches. Hard slab avalanches involve large blocks of snow and debris sliding down a slope. In soft slab avalanches, the snow breaks up in smaller blocks as it falls.</p> <p>An avalanche has three main parts. The <strong>starting zone</strong> is the most volatile area of a slope, where unstable snow can fracture from the surrounding snowcover and begin to slide. Typical starting zones are higher up on slopes, including the areas beneath cornices and &quot;bowls&quot; on mountainsides. However, given the right conditions, snow can fracture at any point on the slope.</p> <p>The <strong>avalanche track</strong> is the path or channel that an avalanche follows as it goes downhill. When crossing terrain, be aware of any slopes that look like avalanche &quot;chutes.&quot; Large vertical swaths of trees missing from a slope or chute-like clearings are often signs that large avalanches run frequently there, creating their own tracks. There may also be a large pile-up of snow and debris at the bottom of the slope, indicating that avalanches have run.</p> <p>The <strong>runout zone</strong> is where the snow and debris finally come to a stop. Similarly, this is also the location of the deposition zone, where the snow and debris pile the highest. Although underlying terrain variations, such as gullies or small boulders, can create conditions that will bury a person further up the slope during an avalanche, the deposition zone is where a victim will most likely be buried.</p> <p><a href='/article/Avalanche'>Read Full Article...</a></p> http://www.eoearth.org/article/Avalanche Tue, 10 Mar 2009 09:10:35 GMT http://www.eoearth.org/article/Anthropocene <a href='/article/Anthropocene'><img border='0' src='/upload/thumb/3/3a/Earth_lights_lrg.jpg/400px-Earth_lights_lrg.jpg' width='100'/></a> <p>The Anthropocene defines Earth&#39;s most recent <a href="/article/Geologic_time">geologic time period</a> as being human-influenced, or anthropogenic, based on overwhelming global evidence that atmospheric, geologic, hydrologic, biospheric and other earth system processes are now altered by humans. The word combines the root &quot;anthropo&quot;, meaning &quot;human&quot; with the root &quot;-cene&quot;, the standard suffix for &quot;epoch&quot; in <a href="/article/Geologic_time">geologic time</a>. The Anthropocene is distinguished as a new period either after or within the &quot;Holocene&quot;, the current <a href="/article/Geologic_time">epoch</a>, which began approximately 10,000 years ago (about 8000 BC) with the end of the last glacial period.</p> <p><a href='/article/Anthropocene'>Read Full Article...</a></p> http://www.eoearth.org/article/Anthropocene Mon, 09 Mar 2009 09:19:14 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Mon, 09 Mar 2009 09:18:29 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Mon, 09 Mar 2009 09:16:40 GMT http://www.eoearth.org/article/Atom <a href='/article/Atom'><img border='0' src='/upload/thumb/c/c9/Gold_phosphorus.jpg/100px-Gold_phosphorus.jpg' width='100'/></a> <p align="left">The atom is the smallest part of the element that retains the chemical characteristics of the element itself. For our purposes, we can think of the atom as a sphere with a diameter of about 10⁻¹⁰ <a href="/article/Meter">meters</a>. This is about a million times smaller than the diameter of the period at the end of this sentence. If the atoms in your body were an inch in diameter, you would have to worry about bumping your head on the moon.</p><p align="left"> </p><p align="justify">Because atoms are so small, there are a tremendous number of them in even a small sample of an element. A ½-carat <a href="/article/Diamond">diamond</a> contains about 5 × 10²¹ atoms of <a href="/article/Carbon">carbon</a>. If these atoms, tiny as they are, were arranged in a straight line with each one touching its neighbors, the line would stretch from here to the sun.</p><p align="justify">If we could look inside the <a href="/article/Gold">gold</a> atom, we would find that it is composed of three types of particles: protons, neutrons, and electrons. (The physicists will tell you that the proton and neutron are themselves composed of simpler particles. Because it is not useful to the chemist to describe atoms in terms of these more fundamental particles, they will not be described here). Every a gold atom in nature, for example, has 79 protons, 79 electrons, and 118 neutrons. Gold is different from phosphorus, because natural phosphorus atoms have 15 protons, 15 electrons, and 16 neutrons.</p><p align="justify">The particles within the atom are extremely tiny. A penny weighs about 2.5 grams, and a neutron, which is the most massive of the particles in the atom, weighs only 1.6750 × 10^-24 grams. The protons have about the same mass as the neutrons, but the electrons have about 2000 times less mass. Because the masses of the particles are so small, a more convenient unit of measurement has been devised for them. An atomic mass unit (also called the unified mass unit) is 1/12 the mass of a <a href="/article/Carbon">carbon</a> atom that has 6 protons, 6 neutrons, and 6 electrons. The modern abbreviation for atomic mass unit is μ, but amu is commonly used.</p><p align="justify">Protons have a positive charge, electrons have a negative charge, and neutrons have no charge. Charge, a fundamental property of <a href="/article/Matter">matter</a>, is difficult to describe. Most definitions focus less on what it is than on what it does. For example, we know that objects of opposite charge attract each other, and objects of the same charge repel each other. An electron has a charge that is opposite but equal in magnitude to the charge of a proton. We arbitrarily assign the electron a charge of -1, so the charge of a proton is considered to be +1.</p><p><strong><big>Further Reading</big></strong></p><ul><li>This article is an exerpt from the preparatory chemistry text <em><a href="http://preparatorychemistry.com/" class='external text' title="http://preparatorychemistry.com/">An Introduction to Chemistry</a></em> by Mark Bishop. </li></ul> <p><a href='/article/Atom'>Read Full Article...</a></p> http://www.eoearth.org/article/Atom Fri, 06 Mar 2009 09:12:28 GMT http://www.eoearth.org/article/Estuary <a href='/article/Estuary'><img border='0' src='/upload/thumb/a/a1/Estuary.jpg/300px-Estuary.jpg' width='100'/></a> <p>Estuaries are found throughout the world in <a href="/article/Coastal_zone">coastal</a> environments. </p><p>An estuary is defined as a semi-enclosed coastal body of water with <a href="/article/Freshwater">freshwater</a> flowing into it and a connection to the open sea.An estuary typically forms at the tidal mouth of a <a href="/article/River">river</a>, and receives sediment or silt carried in from terrestrial <a href="/article/Surface_runoff_of_water">runoff</a>. Types of estuaries include bays and sounds. Large estuaries, like <a href="/article/Chesapeake_Bay_National_Estuarine_Research_Reserve%2C_Maryland">Chesapeake Bay</a> and Puget Sound, may have many rivers flowing into them and have complex shapes. Because of the freshwater input, the salinity of an estuary is lower than that of <a href="/article/Seawater">sea water</a>, and is called brackish. Estuaries are environments whose salinity and water level vary, depending on the freshwater input and the nearby <a href="/article/Ocean">ocean</a> water. </p> <p><a href='/article/Estuary'>Read Full Article...</a></p> http://www.eoearth.org/article/Estuary Thu, 05 Mar 2009 08:52:08 GMT http://www.eoearth.org/article/Anthropogenic_biomes <a href='/article/Anthropogenic_biomes'><img border='0' src='/upload/thumb/9/98/Ellis_1999_07_01_NE_009_300pix.jpg/120px-Ellis_1999_07_01_NE_009_300pix.jpg' width='100'/></a> <p>Anthropogenic <a href="/article/Biome">biomes</a> describe globally-significant ecological patterns within the terrestrial <a href="/article/Biosphere">biosphere</a> caused by sustained direct human interaction with <a href="/article/Ecosystem">ecosystems</a>, including <a href="/article/Agriculture">agriculture</a>, urbanization, <a href="/article/Forestry">forestry</a> and other land uses. Conventional <a href="/article/Biome">biomes</a>, such as tropical rainforests or <a href="/article/Grassland_biome">grasslands</a>, are based on global vegetation patterns related to climate. Now that humans have fundamentally altered global patterns of <a href="/article/Ecosystem">ecosystem</a> form, process, and <a href="/article/Biodiversity">biodiversity</a>, anthropogenic biomes provide a contemporary view of the terrestrial biosphere in its human-altered form. Anthropogenic biomes may also be termed &quot;anthromes&quot; to distinguish them from conventional biome systems, or &quot;human biomes&quot; (a simpler but less precise term).</p> <p><a href='/article/Anthropogenic_biomes'>Read Full Article...</a></p> http://www.eoearth.org/article/Anthropogenic_biomes Wed, 04 Mar 2009 11:07:16 GMT http://www.eoearth.org/article/Hawk_moth <a href='/article/Hawk_moth'><img border='0' src='/upload/thumb/0/0b/Hawk_moth_USFS_JosephScheer.jpg/150px-Hawk_moth_USFS_JosephScheer.jpg' width='100'/></a> <h2>Hawk Moths or Sphinx Moths (<em>Sphingidae</em>)</h2> <p>Moths live in a wide variety of habitats around the world. They usually go unnoticed, except when flying erratically around your porch light, a streetlight, or other source of light during the darkness of night. Perhaps you notice their handiwork when you find small holes in a woolen garment stored in your closet or you find your tomato plants consumed by a hungry tomato hornworm.</p> <p>Most moths work the night shift, unlike their “respectable cousins” the butterflies, which are out during the daytime, and glorified in prose, poetry, and art. Unfortunately, we usually vilify moths because of their association with the dark of night and our innate fear of darkness and things that go bump in the night. Do you remember the monsters under your bed?</p> <p>They get little respect, except from the relatively few scientists and naturalists who are passionate about their study and who study moths and their ways. Moths represent a biological storehouse of interesting, dramatic, and unusual behaviors, some with roles as pollinators, and others as food for other animals. All have interesting stories to tell if we will only take the time to stop, look, listen and smell the hidden world of moths and their flowers. Planting moonlight or a fragrance garden is a sure way to enjoy not only these wonderful blossoms, but also their nocturnal pollinators, especially the giant hawk moths.</p> <p class="img-caption"> </p> <p>Estimated populations of 11,000 moths are known to occur in the United States. Around the world, another 160,000 species of moths have been catalogued. A staggering 200,000 or more species of moths may exist, just waiting to be discovered. The number of moths far outnumbers the number of world’s species of butterflies (17,500 species). Not all moths are a drab brown or white. Many moths come clothed in a myriad of colors and patterns, some brighter than those flashy butterflies, and just as interesting. Like butterflies, minute scales cover the wings of moth, making them slippery to the touch. If you have ever held or tried to catch a butterfly or moth, the “powder” or “dust” that comes off on your fingers is their scales.</p> <p>Some of the largest moths in the world belong to the hawk moth or Sphingid family within the order Lepidoptera (the animal order that includes butterflies and moths). These magnificent animals have long narrow wings and thick bodies. They are fast flyers and often highly aerobatic. Many species can hover in place. Some can briefly fly backwards or dart away. Hawk moths are experts at finding sweet-smelling flowers after dark. They are especially fond of <em>Datura</em> (Jimpson weeds), <em>Mirabilis</em> (Four O’clocks), and <em>Peniocereus</em> (Queen-of-the-night cactus) blossoms. These flowers are highly fragrant with long floral tubes concealing pools of thin but abundant nectar.</p> <p class="img-caption"> </p> <p>Hawk moths have the world’s longest tongues of any other moth or butterfly (some up to 14 inches long). <a href="/article/Darwin%2C_Charles">Charles Darwin</a> knew of the star orchids (<em>Angraecum</em> spp.) from Madagascar that had nectar spurs over a foot in length. Darwin was ridiculed by other scientists of his day for predicting that these orchids would be pollinated by hawk moths. After his death, hawk moths with tongues long enough to sip of the nectar produced by the star orchids were discovered on the island of Madagascar. </p> <p>The caterpillars (larvae) of hawk moths are the familiar green hornworms or tobacco worms, familiar to gardeners who plant tomatoes. Since some hawk moths are minor crop pests, aerial application of <a href="/article/Pesticide">pesticides</a> to protect crops sometimes affects their numbers. With the populations of all the sphinx moths affected by this agricultural practice there are fewer sphinx moths that pollinate rare plants, like the famous Queen-of-the-night cactus or the sacred Datura, which live in northern Mexico and along the border in the desert southwest.</p> <p>Moths pick up pollen on their legs and wings when they visit flowers and deposit pollen (accidentally) on subsequent floral visits. Two kinds of small moths (Yucca moths and the <em>Senita</em> cactus moth) actually pick up pollen and jam a pollen ball onto the stigmas of their flowers in order to assure food, the resulting immature seeds, for their caterpillars. They are some of the only insects to pollinate flowers “purposefully”.</p><p>&nbsp;</p> <p><a href='/article/Hawk_moth'>Read Full Article...</a></p> http://www.eoearth.org/article/Hawk_moth Tue, 03 Mar 2009 01:20:51 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Mon, 02 Mar 2009 06:20:07 GMT http://www.eoearth.org/article/Human_population_explosion <a href='/article/Human_population_explosion'><img border='0' src='/upload/thumb/8/83/Figure_1_long-term_population_growth.JPG/300px-Figure_1_long-term_population_growth.JPG' width='100'/></a> <p>Approximately 6.6 billion humans now inhabit the Earth. By comparison, there might be 20 million mallard ducks and, among a multitude of threatened and endangered species, perhaps 100,000 gorillas, 50,000 polar bears, and less than 10,000 tigers, 2,000 giant pandas and 200 California condors. Notably, the human population has <a href="/article/Population_growth_rate">grown</a> nearly ten-fold over the past three centuries and has increased by a factor of four in the last century. This monumental historical development has profoundly changed the relationship of our species to its natural support systems and has greatly intensified our <a href="/article/IPAT_equation">environmental impact</a>. Equally amazing are the signs that, in our generation, the human population explosion has begun to abate (Figure 1; note that, here and below, many of the values given are estimates and, after the year 2005, projections). Our numbers are expected to rise by another 50% before reaching a peak late in this century; a decline is likely to follow. What caused this population surge; what caused its reversal; where are we headed; and how might the proliferation of our species affect its future well-being? </p> <p><a href='/article/Human_population_explosion'>Read Full Article...</a></p> http://www.eoearth.org/article/Human_population_explosion Fri, 27 Feb 2009 02:06:42 GMT http://www.eoearth.org/article/Human_population_explosion <a href='/article/Human_population_explosion'><img border='0' src='/upload/thumb/8/83/Figure_1_long-term_population_growth.JPG/300px-Figure_1_long-term_population_growth.JPG' width='100'/></a> <p>Approximately 6.6 billion humans now inhabit the Earth. By comparison, there might be 20 million mallard ducks and, among a multitude of threatened and endangered species, perhaps 100,000 gorillas, 50,000 polar bears, and less than 10,000 tigers, 2,000 giant pandas and 200 California condors. Notably, the human population has <a href="/article/Population_growth_rate">grown</a> nearly ten-fold over the past three centuries and has increased by a factor of four in the last century. This monumental historical development has profoundly changed the relationship of our species to its natural support systems and has greatly intensified our <a href="/article/IPAT_equation">environmental impact</a>. Equally amazing are the signs that, in our generation, the human population explosion has begun to abate (Figure 1; note that, here and below, many of the values given are estimates and, after the year 2005, projections). Our numbers are expected to rise by another 50% before reaching a peak late in this century; a decline is likely to follow. What caused this population surge; what caused its reversal; where are we headed; and how might the proliferation of our species affect its future well-being? </p> <p><a href='/article/Human_population_explosion'>Read Full Article...</a></p> http://www.eoearth.org/article/Human_population_explosion Fri, 27 Feb 2009 01:35:51 GMT http://www.eoearth.org/article/Business_strategy_and_climate_change <a href='/article/Business_strategy_and_climate_change'><img border='0' src='/upload/thumb/c/ca/Cars_in_transport.jpg/250px-Cars_in_transport.jpg' width='100'/></a> <p>In many respects, the scientific debate is irrelevant. For the business community, climate change represents an impending market shift – one that will both alter existing <a href="/article/Market">markets</a> and create new ones. It will not be unlike shifts that have occurred in the past, when <a href="/article/Essential_economic_activities">consumer</a> needs changed, or technology advanced, and some companies declined while others rose to take their place. In the 1980s alone, computers eliminated the typewriter industry, compact discs replaced phonograph records, and the Bell System’s demise wrought structural changes in telecommunications. New competitive environments produce both risks and opportunities, as well as winners and losers.</p><p>This market shift will create new <a href="/article/Supply_and_demand">supply and demand</a> for <a href="/article/Air_pollution_emissions">emission</a>-reducing technologies, new financial instruments for emissions trading, new mechanisms for transferring technologies globally (i.e. Joint Implementation and the Clean Development Mechanism), and new pressures to retire historic sources of <a href="/article/Greenhouse_gas">greenhouse gases</a> (GHG). The shift will affect all companies to varying degrees, and all have a managerial and fiduciary obligation to assess their business exposure and decide whether action is prudent. In short, as the market shift of climate change looms on the business horizon, the argument against action is increasingly harder to make.</p><p>For many within the business community, the future is a <a href="/article/Carbon">carbon</a>-constrained world and the time for action is now. Companies with this perspective already have engaged in GHG reductions. Yet other companies (particularly in the United States) continue to resist and deride their proactive competitors with labels such as ‘carbon cartel’ or ‘Kyoto capitalists.’ Such resistance is a very risky strategy, however, in the face of the coming market shift.</p><p>The debate is thus strategic (not scientific) and companies taking voluntary climate action are not practicing philanthropy or pure social responsibility (although many couch their activities in the language of ‘doing the right thing’). In fact, many companies are agnostic about the science of climate change. They engage the climate-change issue as a way to protect their strategic investments and to search for business opportunities in a changing <a href="/article/Market">market</a> landscape.</p><p>This article seeks to explain the current business phenomenon at three different yet closely related levels of response. First, we look at the early warning signs that suggest a market shift is coming. Second, we identify the various business frameworks that can be and are being used to link climate change to business interests. Third, we describe some specific ways in which companies synergistically integrate climate change and business strategy to contribute to the bottom line.</p> <p><a href='/article/Business_strategy_and_climate_change'>Read Full Article...</a></p> http://www.eoearth.org/article/Business_strategy_and_climate_change Thu, 26 Feb 2009 03:21:02 GMT http://www.eoearth.org/article/Biodiversity <a href='/article/Biodiversity'><img border='0' src='/upload/thumb/7/7d/NWHI_reef_fish.jpg/300px-NWHI_reef_fish.jpg' width='100'/></a> <p>The word &quot;biodiversity&quot; is a contracted version of &quot;biological diversity&quot;. The <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> defines biodiversity as:<br /> </p><p>&quot;the variability among living organisms from all sources including, <em>inter alia</em>, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and of ecosystems.&quot;<br /> </p><p>Thus, biodiversity includes genetic variation within species, the variety of species in an area, and the variety of habitat types within a landscape. Perhaps inevitably, such an all-encompassing definition, together with the strong emotive power of the concept, has led to somewhat cavalier use of the term biodiversity, in extreme cases to refer to life or biology itself. But biodiversity properly refers to the variety of living organisms. </p><p>Biological diversity is of fundamental importance to the functioning of all natural and human-engineered ecosystems, and by extension to the ecosystem services that nature provides free of charge to human society. Living organisms play central roles in the cycles of major elements (<a href="/article/Carbon">carbon</a>, <a href="/article/Nitrogen">nitrogen</a>, and so on) and water in the environment, and diversity specifically is important in that these cycles require numerous interacting species. </p><p>General interest in biodiversity has grown rapidly in recent decades, in parallel with the growing concern about nature conservation generally, largely as a result of the accelerating rates of natural habitat loss and degradation, and resulting extinctions of species. The IUCN Red List estimates that 12-52% of species within well-studied higher taxa such as vertebrates and vascular plants are threatened with extinction. Based on data on recorded extinctions of known species over the past century, scientists estimate that current rates of species extinction are about 100 times higher than long-term average rates based on fossil data. More speculative, but also quite plausuble, estimates suggest that extinction rates now and in the near future may reach 1000 to 10,000 times the average over past geologic time. These estimates are the basis of the growing consensus that the Earth is in the midst of the sixth mass extinction event in its history. </p> <p><a href='/article/Biodiversity'>Read Full Article...</a></p> http://www.eoearth.org/article/Biodiversity Thu, 26 Feb 2009 03:18:30 GMT http://www.eoearth.org/article/Biodiversity <a href='/article/Biodiversity'><img border='0' src='/upload/thumb/7/7d/NWHI_reef_fish.jpg/300px-NWHI_reef_fish.jpg' width='100'/></a> <p>The word &quot;biodiversity&quot; is a contracted version of &quot;biological diversity&quot;. The <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> defines biodiversity as:<br /> </p><p>&quot;the variability among living organisms from all sources including, <em>inter alia</em>, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are a part; this includes diversity within species, between species, and of ecosystems.&quot;<br /> </p><p>Thus, biodiversity includes genetic variation within species, the variety of species in an area, and the variety of habitat types within a landscape. Perhaps inevitably, such an all-encompassing definition, together with the strong emotive power of the concept, has led to somewhat cavalier use of the term biodiversity, in extreme cases to refer to life or biology itself. But biodiversity properly refers to the variety of living organisms. </p><p>Biological diversity is of fundamental importance to the functioning of all natural and human-engineered ecosystems, and by extension to the ecosystem services that nature provides free of charge to human society. Living organisms play central roles in the cycles of major elements (<a href="/article/Carbon">carbon</a>, <a href="/article/Nitrogen">nitrogen</a>, and so on) and water in the environment, and diversity specifically is important in that these cycles require numerous interacting species. </p><p>General interest in biodiversity has grown rapidly in recent decades, in parallel with the growing concern about nature conservation generally, largely as a result of the accelerating rates of natural habitat loss and degradation, and resulting extinctions of species. The IUCN Red List estimates that 12-52% of species within well-studied higher taxa such as vertebrates and vascular plants are threatened with extinction. Based on data on recorded extinctions of known species over the past century, scientists estimate that current rates of species extinction are about 100 times higher than long-term average rates based on fossil data. More speculative, but also quite plausuble, estimates suggest that extinction rates now and in the near future may reach 1000 to 10,000 times the average over past geologic time. These estimates are the basis of the growing consensus that the Earth is in the midst of the sixth mass extinction event in its history. </p> <p><a href='/article/Biodiversity'>Read Full Article...</a></p> http://www.eoearth.org/article/Biodiversity Wed, 25 Feb 2009 03:30:19 GMT http://www.eoearth.org/article/Water_governance <a href='/article/Water_governance'><img border='0' src='/upload/thumb/b/be/Fig_1_water_governance.JPG/250px-Fig_1_water_governance.JPG' width='100'/></a> <p>The water sector worldwide is increasingly characterized in terms of a crisis situation. The unique and complex characteristics of the water resource entail complex social, political, and economic implications in its management. The water crisis is mainly a crisis of governance and the management forms under which water has been historically governed. In light of the problems in the water sector, <a href="/article/Support_and_opposition_of_public-private_partnerships">public-private partnerships</a> have been increasingly advocated and adopted throughout the world. Proponents of partnerships have often appealed to the financial gains, cost reductions, efficiency gains, environmental compliance, human resource developments, and increased services which have followed private sector engagement. Opponents of partnerships have appealed to the price increases, imbalance of power, labor disputes, inequities, environmental damage, and increased risks associated with private sector participation in water services. This paper reviews these debates to conclude that evidence can be found in support of either position. The paper argues that this dichotomous debate has lead to inconclusive and unconstructive discussions among interested parties. The paper recommended that focus be re-directed away from ideological positions on privatization towards a focus on the principals and standards which can make private participation work for the public good when it is chosen. </p> <p><a href='/article/Water_governance'>Read Full Article...</a></p> http://www.eoearth.org/article/Water_governance Tue, 24 Feb 2009 05:47:44 GMT http://www.eoearth.org/article/Poaching <a href='/article/Poaching'><img border='0' src='/upload/thumb/a/af/African_lion_in_queen_Elizabeth_NP.jpg/250px-African_lion_in_queen_Elizabeth_NP.jpg' width='100'/></a> <p style="font: normal normal normal 20px/normal Papyrus; margin: 0px"><span style="font-family: Arial; font-size: 12px; line-height: 18px" class="Apple-style-span">Poaching is the illegal hunting, killing or capturing of animals. This can occur in a variety of ways.  Poaching can refer to the failure to comply with regulations for legal harvest, resulting in the illegal taking of wildlife that would otherwise be allowable. Examples include: Taking without a license or permit, use of a prohibited weapon or trap, taking outside of the designated time of day or year, and taking of a prohibited sex or life stage.  Poaching can also refer to the taking of animals from a gazzetted wildlife sanctuary, such as a national park, game reserve, or zoo. Most countries enforce various sanctions on the hunting of wild animals, and international controls, such as bans, restrictions and monitored <a href="/article/Trade_and_the_environment">trade</a>, are all aimed at controlling poaching. However, it is important to note that hunting, under specific regulations, is in fact often permitted in designated game preserves.</span></p> <p><a href='/article/Poaching'>Read Full Article...</a></p> http://www.eoearth.org/article/Poaching Mon, 23 Feb 2009 08:21:08 GMT http://www.eoearth.org/article/Nuclear_fuel_cycle <a href='/article/Nuclear_fuel_cycle'><img border='0' src='/upload/thumb/c/cb/Nuclear_fuel_cycle.gif/200px-Nuclear_fuel_cycle.gif' width='100'/></a> <p>The various activities associated with the production of electricity from nuclear reactions are referred to collectively as the nuclear fuel cycle. The nuclear fuel cycle starts with the mining of <a href="/article/Uranium">uranium</a> and ends with the disposal of nuclear waste. With the reprocessing of used fuel as an option for nuclear energy, the stages form a true cycle. </p> <p><a href='/article/Nuclear_fuel_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Nuclear_fuel_cycle Fri, 20 Feb 2009 06:05:12 GMT http://www.eoearth.org/article/Chemical_properties_of_rivers <a href='/article/Chemical_properties_of_rivers'><img border='0' src='/upload/thumb/8/8b/Green.gif/246px-Green.gif' width='100'/></a> <p>Water chemistry is responsible for many of the characteristics associated with the &quot;quality&quot; of a <a href="/article/River">river</a>. It is a reflection of complex interdependent relationships involving the <a href="/article/River">river</a>, the <a href="/article/Atmospheric_composition">atmosphere</a>, the surrounding <a href="/article/Soil">soil</a> and <a href="/article/Composition_of_rocks">rocks</a>, <a href="/article/Groundwater">groundwater</a>, sediments and living systems. </p><p>Rivers have been called the &quot;gutters down which flow the ruins of continents&quot;. The world&#39;s rivers dump 2.25 x 10¹⁰ metric tons of dissolved and particulate matter from erosion of the land into the seas every year, thus playing a major role in global biogeochemical cycling. The river, however, is more than just a transporter of materials. It is also a processor of materials as the biota it contains take up, convert, use and release materials that come to them. It is useful to think of a river as an active biological system that metabolizes the organic matter contained within it. The water that arrives at the mouth of a river is far different, both quantitatively and qualitatively, from what was present in the waters nearer the source. </p> <p><a href='/article/Chemical_properties_of_rivers'>Read Full Article...</a></p> http://www.eoearth.org/article/Chemical_properties_of_rivers Thu, 19 Feb 2009 02:27:42 GMT http://www.eoearth.org/article/Wind_farm <a href='/article/Wind_farm'><img border='0' src='/upload/thumb/6/65/Wind_farm.jpg/200px-Wind_farm.jpg' width='100'/></a> <p>A wind farm (often also called a wind park) is as a cluster of wind turbines that acts and is connected to the power system as a single electricity producing power station. </p> <p>Generally it is expected that a wind farm consists of more than three wind turbines. Modern wind farms may have capacities in the order of hundreds of <a href="/article/Watt">megawatts</a>, and are installed offshore as well as on land. Modern wind farms generally are connected to the high voltage transmission system, in contrast to the early application of wind energy for electricity production with wind turbines individually connected to the low- to medium-voltage distribution system. Hence, modern wind farms are considered power plants with responsibilities for control, stability, and power balance. Thus, wind farms are required to contribute to the control of voltage, frequency and reactive power needs in the power system and stay on-line during less critical grid faults, and to help maintain the stability of the power system. While wind farm production cannot exceed the power given by the instantaneous <a href="/article/Wind">wind</a> resource, capabilities for regulating the power output at time scales consistent with the power system needs, powering up and down, are also included in order to assist with balancing and stabilizing the power system. </p><p>Most of the other technical issues with wind farms are associated with the close spacing of multiple turbines. The close spacing implies that extraction of energy by wind turbines upwind will reduce the wind speed and increase the turbulence, which may cause reduced efficiency and higher loads on downwind turbines. Another technical issue for large wind farms is the grid connection and the integration into the power system. Large wind farms are very visible, especially at land and in coastal areas and this together with a number of environmental concerns, such as possible disturbance of migrating birds and bats, play an important role in the wind farm planning process and can result in selection of sites with less than optimal wind conditions. However, good wind conditions are essential for the economics viability of any wind project, and methods for accurately predicting wind climates at specific sites worldwide is constantly being improved. </p><p><strong>Further Reading</strong><br /> </p><ul><li>Erik Lundtang Petersen and Peter Hauge Madsen. 2004. Wind farms. In, Cutler J. Cleveland, Editor, <em><a href="http://www.sciencedirect.com/science?_ob=RefWorkSubjClassURL&amp;_refWorkId=222&amp;_acct=C000050221&amp;_version=1&amp;_userid=10&amp;md5=e03eb7de034b25e7e658312ec5bc0a0a|" class='external text' title="http://www.sciencedirect.com/science? ob=RefWorkSubjClassURL&amp; refWorkId=222&amp; acct=C000050221&amp; version=1&amp; userid=10&amp;md5=e03eb7de034b25e7e658312ec5bc0a0a|">The Encyclopedia of Energy</a></em>, vol 6., pp. 449-463. </li></ul> <p><a href='/article/Wind_farm'>Read Full Article...</a></p> http://www.eoearth.org/article/Wind_farm Wed, 18 Feb 2009 01:58:12 GMT http://www.eoearth.org/article/Atom <a href='/article/Atom'><img border='0' src='/upload/thumb/c/c9/Gold_phosphorus.jpg/100px-Gold_phosphorus.jpg' width='100'/></a> <p align="left">The atom is the smallest part of the element that retains the chemical characteristics of the element itself. For our purposes, we can think of the atom as a sphere with a diameter of about 10⁻¹⁰ <a href="/article/Meter">meters</a>. This is about a million times smaller than the diameter of the period at the end of this sentence. If the atoms in your body were an inch in diameter, you would have to worry about bumping your head on the moon.</p><p align="left"> </p><p align="justify">Because atoms are so small, there are a tremendous number of them in even a small sample of an element. A ½-carat <a href="/article/Diamond">diamond</a> contains about 5 × 10²¹ atoms of <a href="/article/Carbon">carbon</a>. If these atoms, tiny as they are, were arranged in a straight line with each one touching its neighbors, the line would stretch from here to the sun.</p><p align="justify">If we could look inside the <a href="/article/Gold">gold</a> atom, we would find that it is composed of three types of particles: protons, neutrons, and electrons. (The physicists will tell you that the proton and neutron are themselves composed of simpler particles. Because it is not useful to the chemist to describe atoms in terms of these more fundamental particles, they will not be described here). Every a gold atom in nature, for example, has 79 protons, 79 electrons, and 118 neutrons. Gold is different from phosphorus, because natural phosphorus atoms have 15 protons, 15 electrons, and 16 neutrons.</p><p align="justify">The particles within the atom are extremely tiny. A penny weighs about 2.5 grams, and a neutron, which is the most massive of the particles in the atom, weighs only 1.6750 × 10^-24 grams. The protons have about the same mass as the neutrons, but the electrons have about 2000 times less mass. Because the masses of the particles are so small, a more convenient unit of measurement has been devised for them. An atomic mass unit (also called the unified mass unit) is 1/12 the mass of a <a href="/article/Carbon">carbon</a> atom that has 6 protons, 6 neutrons, and 6 electrons. The modern abbreviation for atomic mass unit is μ, but amu is commonly used.</p><p align="justify">Protons have a positive charge, electrons have a negative charge, and neutrons have no charge. Charge, a fundamental property of <a href="/article/Matter">matter</a>, is difficult to describe. Most definitions focus less on what it is than on what it does. For example, we know that objects of opposite charge attract each other, and objects of the same charge repel each other. An electron has a charge that is opposite but equal in magnitude to the charge of a proton. We arbitrarily assign the electron a charge of -1, so the charge of a proton is considered to be +1.</p><p><strong><big>Further Reading</big></strong></p><ul><li>This article is an exerpt from the preparatory chemistry text <em><a href="http://preparatorychemistry.com/" class='external text' title="http://preparatorychemistry.com/">An Introduction to Chemistry</a></em> by Mark Bishop. </li></ul> <p><a href='/article/Atom'>Read Full Article...</a></p> http://www.eoearth.org/article/Atom Tue, 17 Feb 2009 02:18:40 GMT http://www.eoearth.org/article/Global_dust_budget <a href='/article/Global_dust_budget'><img border='0' src='/upload/thumb/d/d5/Saharan_dust_traveling_over_Atlantic.gif/300px-Saharan_dust_traveling_over_Atlantic.gif' width='100'/></a> <p>The global dust budget refers to an accounting of the emission, atmospheric loading, and deposition of the mineral dust <a href="/article/Aerosols">aerosol</a> on a global scale. The topic covers the location and strength of sources, transport paths, atmospheric distribution, and deposition of mineral dust aerosol. </p> <p><a href="/article/Soil">Soil</a> particles are entrained into the air by wind erosion caused by strong <a href="/article/Wind">winds</a> over bare ground. While large sand particles quickly fall onto the ground, smaller particles (less than about 10 <a href="/article/Meter">micrometers</a> [&mu;m]) stay suspended in the air as mineral (or soil) dust aerosol. Billions of tons of mineral dust aerosols are released each year from arid and semi-arid <a href="/article/Region">regions</a> to the <a href="/article/Atmospheric_composition">atmosphere</a>. Mineral dust aerosol can be transported long distances, and can influence the air quality far beyond the source region. For example, North African (Saharan) dust is often transported over the <a href="/article/Ocean">Atlantic Ocean</a>, reaching the North or South American continents, and dust from East Asian deserts travels over the <a href="/article/Ocean">Pacific Ocean</a> and occasionally influences air quality in North America. Since these large-scale dust events have been captured by <a href="/article/Remote_sensing">satellite imagery</a>, the issue of mineral dust has been recognized as a global-scale problem. </p><p>The global dust budget has been recognized as an important research topic related to the atmospheric environment and climate. Mineral dust <a href="/article/Aerosols">aerosol</a> can cause air quality hazards such as visibility impairment and respiratory problems, which can pose risks to human health and society. Mineral dust aerosols also play an important role in the Earth&#39;s climate in several ways, including exerting a significant direct and indirect influence on the atmospheric <a href="/article/Earth%27s_energy_balance">radiation balance</a>. They do so directly through scattering and absorbing shortwave and longwave <a href="/article/Solar_radiation">radiation</a>, and indirectly by acting as cloud condensation nuclei or ice nuclei and modifying the optical properties of clouds. In addition, dust aerosol can serve as a reaction surface for reactive gases, thus affecting atmospheric photochemistry. When these aerosols falls onto the <a href="/article/Ocean">ocean</a>, the <a href="/article/Iron">iron</a> content in dust acts as a nutrient for marine <a href="/article/Phytoplankton">phytoplankton</a> and can thus enhance <a href="/article/Photosynthesis">photosynthesis</a>, in turn influencing the global <a href="/article/Carbon_cycle">carbon cycle</a>. </p><p>Quantification of the global dust budget is still a challenging issue because direct observation of dust emission and deposition over a wide area is difficult. Because of the difficulty of estimating the dust budget at the global scale, most of the currently reported dust budget values are based on numerical simulations using global dust transport models. </p> <p><a href='/article/Global_dust_budget'>Read Full Article...</a></p> http://www.eoearth.org/article/Global_dust_budget Tue, 17 Feb 2009 02:14:22 GMT http://www.eoearth.org/article/International_Polar_Year <a href='/article/International_Polar_Year'><img border='0' src='/upload/thumb/1/15/Mcameron_polarbear2.jpg/300px-Mcameron_polarbear2.jpg' width='100'/></a> <p>The International Council for Science (ICSU), in conjunction with the World Meteorological Organization (WMO), has designated 2007-2008 an International Polar Year. Activities are designed to focus the attention of the public and the scientific community on the need for greater understanding of the complex interrelationships between the geophysical and climatological processes that occur in the Earth's high latitudes and their effects on the rest of the globe. Many of the changes seen in the polar regions are more dramatic and sudden than those seen in lower latitudes. They provide, therefore, a wonderful natural laboratory for examining the nature of those changes and the relationship between climate changes and the general <a href="/article/Ecology">ecology</a> of the <a href="/article/Region">region</a>, as well as human social structures. Ceremonies around the world on March 1, 2007, marked the beginning of this multinational and interdisciplinary effort which is uniting over sixty nations in a common goal. </p><p>To gain a precise picture of the state of the polar regions as a benchmark against which changes can be measured, and to quantify past and present environmental and social changes for the purpose of improving projections about the future, are among the goals. </p><p>The United States National Committee for the International Polar Year has a broad vision for America's participation. With the National Science Foundation acting as the lead agency, the goals include: </p> <ul><li> initiating sustained efforts aimed at assessing the large-scale environmental changes that take place; </li><li> beginning new studies of the human-natural systems that impact social, economic and strategic interests; </li><li> designing and implementing polar observational networks that will provide a long-term and multi-disciplinary perspective; and </li><li> encouraging public engagement with the scientific community to increase general scientific literacy in the population, and specifically to build support for continued research into the least densely inhabited lands on Earth. An example is the Census of Antarctic Marine Life which endeavors to catalogue the amount and location of living resources in the <a href="/article/Region">region</a>. </li></ul> <p><a href='/article/International_Polar_Year'>Read Full Article...</a></p> http://www.eoearth.org/article/International_Polar_Year Fri, 13 Feb 2009 02:41:14 GMT http://www.eoearth.org/article/Mauna_Loa_curve <a href='/article/Mauna_Loa_curve'><img border='0' src='/upload/thumb/5/58/Mauna_Loa_map.png/250px-Mauna_Loa_map.png' width='100'/></a> <p>Since 1958, the concentration of <a href="/article/Carbon_dioxide">carbon dioxide</a> (CO₂) in the <a href="/article/Atmospheric_composition">atmosphere</a> has been measured daily at Mauna Loa Observatory, Hawaii (19°32' N, 155°35' W). Mauna Loa Observatory is located on the Island of Hawaii at an elevation of 3,397 meters above mean sea level) on the northern flank of Mauna Loa volcano. Established in 1957, Mauna Lao Observatory has grown to become the premier long-term atmospheric monitoring facility on Earth and is the site where the ever-increasing concentrations of global atmospheric CO₂ were determined. The observatory consists of 10 buildings from which up to 250 different atmospheric parameters are measured by scientists and engineers. </p><p>This air is relatively free from local pollutants, and so is thought to be representative of air in the northern hemisphere. CO₂ measurements at Mauna Loa show two movements. Since 1958, there has been a general increase in the atmospheric concentration of CO₂ due to the <a href="/article/Combustion">combustion</a> of fossil fuels and deforestation. The data also show an annual <a href="/article/Carbon_cycle">cycle</a>. Each year, the concentration of CO₂ rises and falls. The curve is also known as the "Keeling curve", named for <a href="/article/Keeling%2C_Charles_D.">Charles D. Keeling</a> (1928-2005), an American pioneer in the <a href="/article/Monitoring">monitoring</a> of carbon dioxide concentrations in the atmosphere. </p> <p><a href='/article/Mauna_Loa_curve'>Read Full Article...</a></p> http://www.eoearth.org/article/Mauna_Loa_curve Thu, 12 Feb 2009 02:52:19 GMT http://www.eoearth.org/article/Biology_of_early_life_stage_of_tropical_reef_corals <a href='/article/Biology_of_early_life_stage_of_tropical_reef_corals'><img border='0' src='/upload/thumb/b/b6/Healthy_coral_reef_in_Moorea%2C_French_Polynesia.jpg/200px-Healthy_coral_reef_in_Moorea%2C_French_Polynesia.jpg' width='100'/></a> <p style="line-height: 150%" class="MsoNormal"> </p><p style="line-height: 150%" class="MsoNormal">Even the largest <a href="/article/Coral_reef">coral reef</a> (Fig. 1) and the biggest coral colony start life as a diminutive pelagic larva, and the choices that such larvae make with regards to where they settle (Fig. 2) have consequences that cascade through the entire reef ecosystem. A coral reef clearly is more than the sum of the component corals, but without a clear understanding of the biological events affecting the early life stages of coral it is impossible to fully understand the events that maintain coral communities. This article describes what is currently known about these events, and collectively considers coral larvae, recruits and juvenile colonies as early life stages. </p> <p><a href='/article/Biology_of_early_life_stage_of_tropical_reef_corals'>Read Full Article...</a></p> http://www.eoearth.org/article/Biology_of_early_life_stage_of_tropical_reef_corals Wed, 11 Feb 2009 04:30:35 GMT http://www.eoearth.org/article/Transpiration <a href='/article/Transpiration'><img border='0' src='/upload/thumb/e/e3/Transpirationleafsoil.jpg/225px-Transpirationleafsoil.jpg' width='100'/></a> <p>Transpiration is the term used to describe the transport of water through an actual, vegetated plant into the <a href="/article/Atmospheric_composition">atmosphere</a>. Transpiration is an important part of the <a href="/article/Evapotranspiration">evapotranspiration</a> process, and a major mechanism of the water cycle in the atmosphere. Transpiration may also refer to the rate of the water vapor transport through the whole vegetative canopy (that is, through the group of plants). </p><p>Just as you release water vapor when you breathe, plants do, too&mdash;although the term "transpire" is more appropriate than "breath." During this process individual water molecules are released from the surface of the plant body through tiny structures called <a href="/article/Stomata">stomata</a>. There are many more individual water vapor molecules inside the air spaces between the tissues of a plant than in the air surrounding the plant body. Consequently water vapor will always exit the plant along a concentration gradient. As more water vapor molecules exit the plant, the remaining water molecules tug on each other and will pull an entire column of water throughout the plant body through special tissues called xylem during the process of transpiration. One way to visualize transpiration is to put a plastic bag around some plant leaves. As Figure 1 shows, transpired <a href="/article/Physical_properties_of_water">water</a> will condense on the inside of the bag. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also <a href="/article/Evaporation">evaporates</a> from the soil. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year. </p> <p><a href='/article/Transpiration'>Read Full Article...</a></p> http://www.eoearth.org/article/Transpiration Tue, 10 Feb 2009 02:14:29 GMT http://www.eoearth.org/article/Wetland <a href='/article/Wetland'><img border='0' src='/upload/thumb/6/6f/Suisun_Marsh_wetlands.jpg/300px-Suisun_Marsh_wetlands.jpg' width='100'/></a> <p>The following information focuses primarily on freshwater, inland wetlands and provides brief information about tidal, coastal, estuarine wetlands. It is important to note, that whether inland or coastal, there are several federal agencies that have special interest in and jurisdiction over wetlands and therefore it is important to define some terms and phrases throughout this article. Our intent is to provide the reader who might have special interest in wetland delineation, wetland mitigation, wetland biology, etc. with information or references to additional information that will be helpful. </p> <p>The U. S. Army Corps of Engineers and the Environmental Protection Agency (EPA) in the originally published 1987 Corps of Engineers Wetlands Delineation Manual jointly defined wetlands as: “Those areas that are inundated or saturated by surface or <a href="/article/Groundwater">groundwater</a> at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated <a href="/article/Soil">soil</a> conditions.” They continue to describe specifics of the three core components that constitute whether or not an area is a wetland, i.e., Vegetation, Soil, and Hydrology. Page 2 of the Manual states that “This report should be cited as follows: Environmental Laboratory. 1987. “Corps of Engineers Wetlands Delineation Manual”, Technical Report Y-87-1, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.” To access an electronic version, see Further Reading. </p><p>The U.S. Federal Highway Administration has interest in the location, form, and function of wetlands due to highway construction and maintenance. Their policy memoranda from 1994 refers and defers to the Soil Conservation Service (SCS), the Environmental Protection Agency (EPA), and the Corps of Engineers (COE) (see Further Reading). </p><p>State government agencies often have special considerations regarding wetland delineations. The state of Florida, for example, often has public, state, and federal interests that require careful attention to issues that relate to wetlands. Therefore, special definitions for Hydric soils, Delineation of Wetlands, and Hydrophytic vegetation may be found on their website (see Further Reading). </p><p>Numerous books are dedicated to plants and animals found in wetlands. Birds and vegetation, for example, are some of the most recognizable, distinguishable features in a wetland landscape, and therefore books may focus on the identification of such birds and plants. The Audubon Society uses the U.S. Fish and Wildlife Service definition in The Audubon Society Nature Guides “Wetlands” by William A. Niering (see Further Reading). </p><p>From all of these sources, the common elements of wetlands include water on the surface or under (but near) the surface for sufficient lengths of time that the area is dominated by hydric soils and organisms that are sustained by and physiologically adapted to such saturated and/or inundated conditions. Hydrology largely determines how the soil develops and the types of plant and animal communities living in and on the soil. Wetlands may support species ranging from obligate aquatic to obligate terrestrial. </p><p>When the upper part of the soil is saturated with water at growing season <a href="/article/Temperature">temperatures</a>, soil organisms consume the <a href="/article/Oxygen">oxygen</a> in the soil and cause conditions ([anaerobic]) unsuitable for most plants. Such conditions also cause the development of <a href="/article/Soil">soil</a> characteristics (such as color and texture) of so-called &quot;hydric soils.&quot; The plants that can grow in such conditions, such as marsh grasses, are called &quot;hydrophytes.&quot; Together, hydric soils and hydrophytes give clues that a wetland area is present. </p><p>The presence of water by ponding, flooding, or soil saturation is not always a good indicator of wetlands. Except for wetlands flooded by ocean tides, the amount of water present in wetlands fluctuates as a result of rainfall patterns, snow melt, dry seasons and longer droughts. </p><p>Some of the most well-known wetlands, such as the Everglades and Mississippi bottomland hardwood swamps, may have periods of dryness. In contrast, many upland areas are very wet during and shortly after wet weather. Such natural fluctuations must be considered when identifying areas subject to government regulation. Similarly, the effects of upstream dams, drainage ditches, dikes, irrigation, and other modifications must also be considered. </p> <p><a href='/article/Wetland'>Read Full Article...</a></p> http://www.eoearth.org/article/Wetland Mon, 09 Feb 2009 02:51:35 GMT http://www.eoearth.org/article/Crustacea <a href='/article/Crustacea'><img border='0' src='/upload/thumb/5/52/Amphipodintro.jpg/199px-Amphipodintro.jpg' width='100'/></a> <h2>Crustacea <br /></h2> <h3><strong>Subphylum Crustacea</strong></h3><p>Crustaceans are invertebrates belonging to the phylum Arthropoda and include such familiar groups as barnacles, crabs, crayfish, lobster, water fleas and pill bugs. Crustaceans are key players in marine and freshwater <a href="/article/Food_web">food webs</a>. The majority of zooplankton in freshwater is composed of cladocerans and copepods, and in the oceans copepods, who are the major consumers of <a href="/article/Phytoplankton">phytoplankton</a>. Benthic crustaceans are often both scavengers and consumers of plant life found on lake bottoms and the seabed. Collectively, these crustaceans serve as a key food source for fishes, especially during juvenile stages. Aside from their role in food webs, the largest species of crustaceans are of considerable economic importance. Lobster, shrimp and even freshwater crayfish each support important fishing industries. They are also increasingly important in aquaculture. In fact, the value of crustaceans produced in aquaculture is already as great as that of fish! </p><p>Adults of the smallest species are less then 0.1 mm in length and weigh less than 1 mg. By comparison, the heaviest crustacean is the mud crab which reaches a peak weight of 40 kg. The Japanese spider crab is the largest living arthropod, with a leg span of 4 m. </p><p>Most crustaceans employ standard sexual reproduction. Other crustaceans, such as water fleas that live in temporarey ponds, reproduce by cyclic or obligate parthenogenesis, where males are unknown or rare. Females in parthenogenetic species produce eggs which do not require fertilization to develop. Aside from this variation in mating systems, many freshwater crustaceans produce two types of eggs: one which develops immediately, while the other which may diapause for up to several hundred years. </p><p>There are more than 40,000 different species of crustaceans. Some 4,000 of these species occur in freshwater and nearly 200 species are found in the North American Great Lakes. </p><p>Crustaceans show extraordinary diversity in body shape and form, bearing anywhere from 3 to 50 pairs of limbs. However, crustaceans also share common features such as jointed, paired appendages, and two pairs of antennae. All crustaceans are enclosed in a protective exoskeleton made of chitin, which must be shed (or &quot;moulted&quot;) to accommodate growth. </p><p>Most crustaceans are carnivores or scavengers, though herbivores and detritivores are also common, and some crustacean groups (e.g., the bopyrid idopods) are parasites hardly recognizable as crustaceans. In some species cannibalism can occur at high densities, or when individuals have just moulted and are vulnerable to attack. Food is taken into the mouth and passed to the gastric mill where it is ground into small particles. Digestion occurs in the midgut and waste is passed out of the hindgut. </p><p>All crustaceans have an open circulatory system and employ either haemoglobin or haemocyanin as a respiratory pigment. Most crustaceans have a dorsal heart, but some smaller crustaceans simply circulate their hemolymph with body movements. Crustaceans osmoregulate in freshwater by producing copious amount of urine. Most freshwater crustaceans have thoracic and abdominal gills with which they exchange gases while the rest simply diffuse gases across their body integument. </p><p>Crustaceans have developed a complex tripartite brain and paired, ganglionated ventral nerve cords. They often possess both compound eyes and a array of simple eyes. Zooplankton show particular sensitivity to light as they undergo daily migrations up and down the water column to stay in the best light conditions and to avoid visually hunting predators. Chemosensory systems allow them to locate food and mates while avoiding predators. </p> <p><a href='/article/Crustacea'>Read Full Article...</a></p> http://www.eoearth.org/article/Crustacea Fri, 06 Feb 2009 01:47:51 GMT http://www.eoearth.org/article/Global_dust_budget <a href='/article/Global_dust_budget'><img border='0' src='/upload/thumb/d/d5/Saharan_dust_traveling_over_Atlantic.gif/300px-Saharan_dust_traveling_over_Atlantic.gif' width='100'/></a> <p>The global dust budget refers to an accounting of the emission, atmospheric loading, and deposition of the mineral dust <a href="/article/Aerosols">aerosol</a> on a global scale. The topic covers the location and strength of sources, transport paths, atmospheric distribution, and deposition of mineral dust aerosol. </p> <p><a href="/article/Soil">Soil</a> particles are entrained into the air by wind erosion caused by strong <a href="/article/Wind">winds</a> over bare ground. While large sand particles quickly fall onto the ground, smaller particles (less than about 10 <a href="/article/Meter">micrometers</a> [&mu;m]) stay suspended in the air as mineral (or soil) dust aerosol. Billions of tons of mineral dust aerosols are released each year from arid and semi-arid <a href="/article/Region">regions</a> to the <a href="/article/Atmospheric_composition">atmosphere</a>. Mineral dust aerosol can be transported long distances, and can influence the air quality far beyond the source region. For example, North African (Saharan) dust is often transported over the <a href="/article/Ocean">Atlantic Ocean</a>, reaching the North or South American continents, and dust from East Asian deserts travels over the <a href="/article/Ocean">Pacific Ocean</a> and occasionally influences air quality in North America. Since these large-scale dust events have been captured by <a href="/article/Remote_sensing">satellite imagery</a>, the issue of mineral dust has been recognized as a global-scale problem. </p><p>The global dust budget has been recognized as an important research topic related to the atmospheric environment and climate. Mineral dust <a href="/article/Aerosols">aerosol</a> can cause air quality hazards such as visibility impairment and respiratory problems, which can pose risks to human health and society. Mineral dust aerosols also play an important role in the Earth&#39;s climate in several ways, including exerting a significant direct and indirect influence on the atmospheric <a href="/article/Earth%27s_energy_balance">radiation balance</a>. They do so directly through scattering and absorbing shortwave and longwave <a href="/article/Solar_radiation">radiation</a>, and indirectly by acting as cloud condensation nuclei or ice nuclei and modifying the optical properties of clouds. In addition, dust aerosol can serve as a reaction surface for reactive gases, thus affecting atmospheric photochemistry. When these aerosols falls onto the <a href="/article/Ocean">ocean</a>, the <a href="/article/Iron">iron</a> content in dust acts as a nutrient for marine <a href="/article/Phytoplankton">phytoplankton</a> and can thus enhance <a href="/article/Photosynthesis">photosynthesis</a>, in turn influencing the global <a href="/article/Carbon_cycle">carbon cycle</a>. </p><p>Quantification of the global dust budget is still a challenging issue because direct observation of dust emission and deposition over a wide area is difficult. Because of the difficulty of estimating the dust budget at the global scale, most of the currently reported dust budget values are based on numerical simulations using global dust transport models. </p> <p><a href='/article/Global_dust_budget'>Read Full Article...</a></p> http://www.eoearth.org/article/Global_dust_budget Thu, 05 Feb 2009 01:38:25 GMT http://www.eoearth.org/article/Biome <a href='/article/Biome'><img border='0' src='/upload/thumb/e/ec/Konza_Prairie.jpg/229px-Konza_Prairie.jpg' width='100'/></a> <p>Biomes organize the biological communities of the earth based on similarities in the dominant vegetation, climate, geographic location, and other characteristics. Aspects of the physical environment such as precipitation, <a href="/article/Temperature">temperature</a>, and water depth, have a strong influence on the traits of species living in that environment, and thus biological communities experiencing similar environmental conditions often contain species that have evolved similar characteristics. There is no single classification of biomes that is agreed upon by all scientists because different scientists wish to emphasize different characteristics by their definition. Historically however, biomes have been identified and mapped based on general differences in vegetation type associated with regional variations in climate and terrain.</p> <p><a href='/article/Biome'>Read Full Article...</a></p> http://www.eoearth.org/article/Biome Wed, 04 Feb 2009 01:08:50 GMT http://www.eoearth.org/article/Managing_coral_reef_fisheries <a href='/article/Managing_coral_reef_fisheries'><img border='0' src='/upload/thumb/9/9d/Fish_trader_in_Kenya.jpg/200px-Fish_trader_in_Kenya.jpg' width='100'/></a> <p>The management of <a href="/article/Coral_reef">coral reef</a> <a href="/article/Marine_fisheries">fisheries</a> generally involves restricting fishers’ access to marine resources of economic value (food fish, edible invertebrates, fish for the aquarium trade, decorative shells for tourists, etc.) through licensing fishers and fishing vessels, restricting the use of certain fishing gear, setting catch limits, or designating waters as closed to all commercial and artisanal fishing short term or more permanently as is generally the case with marine <a href="/article/Protected_areas">protected areas</a>. Given that coral reefs are of interest to multiple user groups whose interests vary considerably, from commercial and sport fishers to snorkelers, divers, researchers, glass bottom boat operators, and other stakeholders, managers are faced with the challenging task of addressing the needs of stakeholders, while protecting the biological richness of reefs. The establishment of marine protected areas that prioritize research and recreational uses is a widely used approach in the management of coral reef fisheries; such marine protected areas often promote tourism and species conservation but conflict with the livelihood interests of fishers. </p> <p>The majority of the world’s coral reefs are located in poorer, tropical countries, and marine protected areas offer economic benefits via park entry fees and recreational services. Nonetheless, the income generated is rarely sufficient to offset the management costs (patrols, mooring buoys, educational placards, lifeguards, etc.) and an unfortunate reality is that most coral reef-based marine protected areas are undermanaged due to lack of funds and corruption. Managing coral reef fisheries is further complicated by the fact that the benefits from marine parks (jobs and recreational opportunities) tend to accrue to non-local people, whereas the costs in terms of lost livelihood opportunities tend to affect local fishing communities. Finally, many modern approaches to fisheries management do not support the informal management systems historically practiced by indigenous people, potentially fueling local fishers’ discontent with marine protected areas. Local fishing communities receiving few benefits and experiencing notable costs due to the presence of marine protected areas<em> </em>often leads to the illegal extraction of resources, increased law enforcement costs, and ultimately the failure to achieve conservation aims.</p> <p><a href='/article/Managing_coral_reef_fisheries'>Read Full Article...</a></p> http://www.eoearth.org/article/Managing_coral_reef_fisheries Tue, 03 Feb 2009 04:30:29 GMT http://www.eoearth.org/article/Agriculture <a href='/article/Agriculture'><img border='0' src='/upload/thumb/d/d0/Agriculture.jpg/250px-Agriculture.jpg' width='100'/></a> <p>Humans began to cultivate food crops about 10,000 years ago. Prior to that time, hunter-gatherers secured their food as they traveled in the nearby environment. When they observed some of the grains left behind at their campsites sprouting and growing to harvest, they began to cultivate these grains. From these humble beginnings agriculture began. <a href="/article/Slash_and_burn">Slash and burn</a>, an early type of crop culture, remains today a truly sustainable agriculture, one that is independent of fossil fuel energy. In such a system, about 10 hectares of productive land is held in fallow for each planted hectare. With this rotation system, a hectare is planted once every 20 years, allowing the <a href="/article/Soil">soil</a> to reaccumulate vital plant nutrients. Although the practice requires large acreages and large labor inputs, the crop yields are adequate. For example, corn with ample <a href="/article/Precipitation_and_fog">rainfall</a> can yield about 2,000 <a href="/article/Kilogram">kilograms</a> per hectare (kg/ha). </p> <p>Over time, human labor in agriculture has decreased, first because of the use of animals and finally with machinery powered by fossil fuels. Currently, plentiful and economical fossil energy supports an era of machinery and agricultural chemicals. About 1,000 liters of oil equivalent are used to produce a hectare of corn with a yield of 9,000 kg/ha. One-third of this energy is used to replace labor, one-third for <a href="/article/Fertilizer">fertilizers</a>, and one-third for others. </p><p>Worldwide, more than 99.7% of human food (<a href="/article/Calorie">calories</a>) comes from the land. Serious environmental impacts, such as soil erosion, <a href="/article/Surface_runoff_of_water">water runoff</a>, and <a href="/article/Pesticide">pesticide</a> pollution, result from fossil fuel-intensive agriculture. A critical need exists to assess fossil energy limits, the <a href="/article/Sustainability">sustainability</a> of agriculture, and the food needs of a <a href="/article/Human_population_explosion">rapidly growing world population</a>. </p> <p><a href='/article/Agriculture'>Read Full Article...</a></p> http://www.eoearth.org/article/Agriculture Mon, 02 Feb 2009 02:11:04 GMT http://www.eoearth.org/article/Variables_affecting_water_yield <a href='/article/Variables_affecting_water_yield'><img border='0' src='/upload/thumb/5/50/Flood.jpg/300px-Flood.jpg' width='100'/></a> <p>There is a direct relationship between the amount of water available in a <a href="/article/Watershed">watershed</a>, climate, and climate variability. The fraction of precipitation that will reach <a href="/article/Stream">stream</a> channels depends on the amount and type of vegetation cover, the physiography, and <a href="/article/Land-use">land use(s)</a> of the watershed. Climate is responsible for precipitation quantity, intensity, and duration, as well as storm distribution within a watershed, the results of which significantly impact streamflow regimes and the annual hydrograph. As an example, when a relatively large storm occurs in the upper part of a sufficiently large watershed, the resulting hydrograph will exhibit a lower peak flow, longer time base, and a slower rise to peak. Higher elevations also undergo potential snow deposition processes (depending on season), which can also affect the hydrograph by lowering and broadening it. In watersheds having sufficiently cold <a href="/article/Temperature">temperatures</a>, usually in higher altitudes, snowfall accumulates forming snowpack, and no significant overland or subsurface runoff is displayed until snowmelt. In the event of an extreme warming event, rapid climate-induced rain, <a href="/article/Wind">wind</a>, and subsequent snowmelt (rain on snow, ROS) can result in flashfloods with often costly and disastrous consequences for communities located in the <a href="/article/Fluvial_landforms">floodplain</a>. This response is less likely at lower altitudes where temperature and <a href="/article/Atmospheric_humidity">atmospheric humidity</a> are usually warmer, and <a href="/article/Evapotranspiration">evapotranspiration</a> (ET) tends to reduce the <a href="/article/Soil">soil</a> moisture content, resulting in a reduced streamflow and increased storage capacity in the soil reservoir. </p><p>Different species of vegetation will affect water yield differently. For example, the ET of a hardwood forest is considerably less than that of coniferous forest. This is explained by differences in leaf area index (LAI) resulting in varying interception, <a href="/article/Evaporation">evaporation</a> and <a href="/article/Transpiration">transpiration</a> processes. A canopy with a higher LAI will intercept more rainfall and generate greater evaporation. Additionally, canopy density is directly correlated to the amount of water that is drawn from the <a href="/article/Soil">soil</a> and released into the <a href="/article/Atmospheric_composition">atmosphere</a> through plant <a href="/article/Transpiration">transpiration</a>. If, for example, the LAI for a given hardwood is 1 compared to an LAI of 10 for pine, one can expect that the soil water losses via transpiration will be greater for the pine. Similarly, species conversion in a given <a href="/article/Watershed">watershed</a> will affect water yields. Studies have shown that converting hardwood to pine can reduce the annual, seasonal, and monthly water yield. </p><p>Topography can greatly affect streamflow and the shape of a hydrograph through direct impacts on the watershed’s response to precipitation. The shape of the hydrograph is influenced by watershed characteristics such as slope, shape, size, elevation and soil. A steeper slope is usually characterized by shallower soil depth and increased overland <a href="/article/Surface_runoff_of_water">runoff</a> that moves at higher velocities. Some soils allow better <a href="/article/Infiltration_and_soil_water_storage">water infiltration</a>, which can also impact the hydrograph by lowering the peak flow and broadening its time base. The response of smaller <a href="/article/Watershed">watersheds</a> is sensitive to high rainfall intensity while the response of larger watersheds is dominated by soil reservoir storage capacity. The hydrograph of small watersheds usually displays sharp and narrow peaks while larger watersheds have broader peaks with a longer time base. Rainfall to runoff ratios also change depending on the elevation (i.e., quantity of rain to quantity of runoff). For example, low-elevation watersheds have a gentle slope and deeper soil and lower rainfall/runoff ratios relative to high-elevation watersheds with steep slopes and shallow soils, which exhibit much higher rainfall/runoff ratios. </p><p><a href="/article/Land-use">Land use</a> has a direct effect on the portion of precipitation resulting in <a href="/article/Surface_runoff_of_water">runoff</a>. Vegetation cover has a direct influence on the quantity of precipitation that reaches the forest floor and the quantity that is accumulated as snowpack and/or <a href="/article/Soil">soil</a> moisture. Forest cutting usually results in an increase in water yield. As an extreme example, during urban development, trees are often replaced by pavement. In this case there is very little accumulation of water in the soil reservoir, and almost all rainfall results in direct surface runoff. As pavement deteriorates and cracks, or as trees grow back in the years following harvest (afforestation), soil reservoirs gradually recharge, and water yield tends to decrease thereby returning to previous flow levels. </p><p><b>Further Reading</b> </p> <ul><li> Bosch, J.M. and Hewlett, J.D., 1982. A review of catchment experiments to determine the effect of vegetation change on water yield and transpiration. Journal of Hydrology, 55:3-23. </li><li> Chang, M., 2002. Forest hydrology: An introduction to water and forests, CRC Press, 373 pp. </li><li> Cheng, J.D., 1989. Streamflow changes after clear-cut logging of a pine beetle-infested watershed in southern BC, Canada. Water Resources Research, 25(3):449-456. </li><li> Hibbert, A.R., 1967. Forest treatment effects on water yield. In: W.E. Sopper and H.W. Lull (Editors), International Symposium For Hydrology, Pergamon, Oxford, 813 pp. </li><li> Horton, R.E., 1933. The role of infiltration in the hydrologic cycle. Transactions of The American Geophysical Union Fourteenth Annual Meeting, Washington, DC, pp. 446-460. </li><li> Slaymaker, O., 2000. Assessment of the Geomorphic Impacts of Forestry in British Columbia. Ambio, 29(7):381-387. </li><li> Swift, L.W. Jr., Cunningham, G.B., and Douglass, J.E., 1988. Climatology and Hydrology. Forest Hydrology and Ecology at Coweeta. W.T. Swank and D.A. Crossley (eds.). Springer Verlag, New York, pp. 35-55. </li></ul> <p><a href='/article/Variables_affecting_water_yield'>Read Full Article...</a></p> http://www.eoearth.org/article/Variables_affecting_water_yield Fri, 30 Jan 2009 00:41:15 GMT http://www.eoearth.org/article/Gypsum <a href='/article/Gypsum'><img border='0' src='/upload/thumb/f/ff/RockGypsum.jpg/250px-RockGypsum.jpg' width='100'/></a> <p>Gypsum is found in nature in mineral and rock form. As a mineral, it can form very pretty, and sometimes extremely large, crystals. As a rock, gypsum is a sedimentary rock, typically found in thick beds or layers. It forms in lagoons where ocean waters high in calcium and sulfate content can slowly <a href="/article/Evaporation">evaporate</a> and be regularly replenished with new sources of water. The result is the accumulation of large beds of sedimentary gypsum. Because it is deposited in this environment, it is common for gypsum to be associated with rock salt and sulfur deposits. </p><p>Gypsum belongs to a group of minerals called the sulfates, and is the most common of the approximately 150 sulfate minerals. Sulfates are compounds of one or more metals with <a href="/article/Oxygen">oxygen</a> and sulfur. The oxygen and sulfur join together to form the sulfate <a href="/article/Ion">ion</a>, SO₄^-2. Technically, gypsum is <em>hydrous calcium sulfate</em> because it has water in its crystal structure, CaSO₄.2H₂O. </p><p>A secondary, and minor source, of raw calcium sulfate is the mineral <em>anhydrite</em>. Anhydrite is chemically very much like gypsum, but lacks the water molecule in its crystal structure. Its chemical formula is CaSO₄.</p><p>Gypsum is very soft at 2 on <a href="/article/Mohs%2C_Frederick">Mohs&#39; hardness scale</a>. It is so soft that a fingernail can easily scratch it. Gypsum crystals can be a number of attractive colors, ranging from completely colorless to tan and even green. Sedimentary gypsum is nearly always white or gray in color. </p><p>Sedimentary gypsum is the gypsum that is mined as a commodity. </p> <p><a href='/article/Gypsum'>Read Full Article...</a></p> http://www.eoearth.org/article/Gypsum Thu, 29 Jan 2009 00:11:23 GMT http://www.eoearth.org/article/Invasive_species <a href='/article/Invasive_species'><img border='0' src='/upload/thumb/1/1d/Chestnut_blight.gif/90px-Chestnut_blight.gif' width='100'/></a> <p>An invasive species is defined legally in the USA as “An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health…‘Alien species’ means, with respect to a particular <a href="/article/Ecosystem">ecosystem</a>, any species…that is not native to that ecosystem.” Novel species can be added to a community either by natural range extensions or because they are introduced as a result of human activity. Some introduced or alien species are beneficial to humans, for example most of our crops and pets. However many alien species have harmful effects; these are referred to as invasive species. Virtually all ecosystems are at risk from the harmful effects of introduced species ( also see <a href="/article/Exotic_species">exotic species</a>, <a href="/article/Marine_invasive_species">marine invasive species</a>, <a href="/article/Aquatic_invasive_species">aquatic invasive species</a>).</p><p>Invasive species are a major threat to our environment because they (1) can change habitats and alter ecosystem function and ecosystem services, (2) crowd out or replace native species, and (3) damage human activities, costing the economy millions of dollars. For example, costs to <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, <a href="/article/Fisheries_and_aquaculture">fisheries</a>, and other human activities by introduced species are estimated at $137 billion per year to the U.S. economy alone.</p> <p><a href='/article/Invasive_species'>Read Full Article...</a></p> http://www.eoearth.org/article/Invasive_species Wed, 28 Jan 2009 01:52:54 GMT http://www.eoearth.org/article/Atmospheric_humidity <a href='/article/Atmospheric_humidity'><img border='0' src='/upload/thumb/d/d5/Relative_humidity.gif/300px-Relative_humidity.gif' width='100'/></a> <p>The term humidity describes the fact that the <a href="/article/Atmospheric_composition">atmosphere</a> can contain water vapor. The amount of humidity found in air varies because of a number of factors. Two important factors are <a href="/article/Evaporation">evaporation</a> and condensation. At the water/atmosphere interface over our planet's oceans, large amounts of liquid water are evaporated into atmospheric water vapor. This process is mainly caused by absorption of <a href="/article/Solar_radiation">solar radiation</a> and the subsequent generation of heat at the ocean's surface. In our atmosphere, water vapor is converted back into liquid form when air masses lose heat energy and cool. This process is responsible for the development of most <a href="/article/Cloud_formation_processes">clouds</a> and also produces the rain that falls to the Earth's surface. </p> <p>Scientists have developed a number of different measures of atmospheric humidity. We are primarily interested in three of these measures: mixing ratio, saturation mixing ratio, and relative humidity. Mixing ratio is a measure that refers to the mass of a specific gas component relative to the mass of the remaining gaseous components for a sample of air. When used to measure humidity, mixing ratio would measure the mass of water vapor relative to the mass of all of the other gases. In meteorological measurements, mixing ratio is usually expressed in grams of water vapor per kilogram of dry air. Saturation mixing ratio refers to the mass of water vapor that can be held in a kilogram of dry air at saturation. Saturation can be generally defined as the condition where any addition of water vapor to a mass of air leads to the condensation of liquid water or the deposition of ice at a given temperature and pressure. The data in Table 1 indicates that warmer air has a higher saturation mixing ratio than cooler air at a constant atmospheric pressure. It is important to note that this relationship between <a href="/article/Temperature">temperature</a> and water vapor content in the air is not linear but exponential. In other words, for each 10° increase in temperature, saturation mixing ratio increases by a larger quantity. </p><p>The most commonly used measure of humidity is relative humidity. Relative humidity can be simply defined as the amount of water in the air relative to the saturation amount the air can hold at a given temperature multiplied by 100. Air with a relative humidity of 50% contains a half of the water vapor it could hold at a particular <a href="/article/Temperature">temperature</a>. </p><p>Figure 1 illustrates how relative humidity changes in a parcel of air with an increase in air temperature. At 10° Celsius, a parcel of dry air weighing one kilogram can hold a maximum of 7.76 grams of water vapor (see Table 1). In this state, the parcel of air would be at saturation and its relative humidity would be 100%. Increasing the <a href="/article/Temperature">temperature</a> of this parcel, without adding or removing any water, would increase its ability to hold water vapor. According to Table 1, a 10 degree Celsius rise in temperature would increase the saturation mixing ratio of this parcel of air to 14.85 grams. Since no water has been added or removed, the actual amount of water in the parcel would remain 7.76 grams. This quantity is known as the mixing ratio. Dividing the mixing ratio by the saturation mixing ratio and then multiplying this number by 100 determines the relative humidity of the parcel of air (7.76/14.85 x 100 = 52%). At a temperature of 20° Celsius, relative humidity would be 52%. Raising the temperature of the parcel of air by another 10° Celsius would again lower its relative humidity. In this state, the actual mixing ratio would still be 7.76 grams, while the saturation mixing ratio would increase to 27.69 grams. Relative humidity would drop to 28% at a temperature of 30° Celsius (7.76/27.69 x 100 = 28%). </p><p><b>Further Reading</b> </p> <ul><li> <a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Atmospheric_humidity'>Read Full Article...</a></p> http://www.eoearth.org/article/Atmospheric_humidity Tue, 27 Jan 2009 02:15:05 GMT http://www.eoearth.org/article/Bumblebee <a href='/article/Bumblebee'><img border='0' src='/upload/thumb/a/a4/Cuckoo_bumblebee_USFS_DavidInouye.jpg/200px-Cuckoo_bumblebee_USFS_DavidInouye.jpg' width='100'/></a> <h2>Bumblebees (<em>Bombus</em> spp.)</h2> <p class="img-caption"> </p> <p>Bumblebees (of the genus <em>Bombus</em>) are common native bees and important <a href="/article/Pollination">pollinators</a> in most areas of North America. In spring, queens emerge from underground where they have spent the winter, and look for a nest site, often found underground in an old mouse nest or rodent burrow. Bumblebees visit flowers for the nectar and pollen upon which they feed, and once the eggs they lay have hatched, they use those plant resources to feed larval worker bees. Bumblebees can generate heat with their flight muscles, and queens will use this ability to incubate their brood and speed up development of the workers. After the first generation of workers hatches, the empty cocoons may be used for short-term storage of nectar, but bumblebees do not make and store large quantities of honey like honeybees (which need ample supplies of honey to make it through the winter).</p> <p>The bumblebee queen produces a few generations of workers during the summer, which then take over the task of collecting nectar and pollen and help rear the final generation of the colony, queens for the next summer, and males to mate with them. By late fall, the colony has died out except for a few final workers and males, and the new queens burrow into the ground to wait for the following spring.</p> <h2>A Pollinator&#39;s Life<br /> </h2> <p>Bumblebees are important pollinators for many wildflowers. There are 49 species of bumblebees in the United States, which can be separated into three different classes of proboscis (tongue) length: short, medium, and long. This variation in tongue size allows different species of bees to visit different sizes and shapes of flowers. A few of the short-tongued species, however, manage to feed on long-tube flowers by “nectar robbing”. They bite holes in the flowers near the nectaries and extract the nectar through the hole instead of visiting the flowers “legitimately”.</p> <p>Another reason bumble bees are important pollinators is their behavior of buzzing, or sonicating, flowers that require this behavior for pollination. For example, tomatoes and some other flowers in that plant family don’t produce nectar but the bees visit them anyway in order to collect pollen, which they do by vibrating their wing muscles (making a buzzing noise) to shake pollen grains out of the anthers.</p> <p>As one of the few species of commercially developed pollinators, a few species of bumblebees have been shipped to a variety of places around the world where they are not native but are wanted for greenhouse pollination. They typically forage outside of the greenhouses as well. As a result, they have been implicated in transmitting new diseases to wild, native bumblebees. They have also escaped from the greenhouses becoming feral in places where they are not native. They may become competitors with native species and serve as pollinators for introduced weeds.</p> <p><a href='/article/Bumblebee'>Read Full Article...</a></p> http://www.eoearth.org/article/Bumblebee Mon, 26 Jan 2009 00:52:15 GMT http://www.eoearth.org/article/Sea_ice_in_the_Arctic <a href='/article/Sea_ice_in_the_Arctic'><img border='0' src='/upload/thumb/4/47/Figure6.3_mean_sea_ice_conc.JPG/620px-Figure6.3_mean_sea_ice_conc.JPG' width='100'/></a> <p>This is Section 6.3 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a>. <br />Lead Author: John E.Walsh; Contributing Authors: Oleg Anisimov, Jon Ove M. Hagen,Thor Jakobsson, Johannes Oerlemans,Terry D. Prowse,Vladimir Romanovsky, Nina Savelieva,Mark Serreze, Alex Shiklomanov, Igor Shiklomanov, Steven Solomon; Consulting Authors: Anthony Arendt, David Atkinson, Michael N. Demuth, Julian Dowdeswell, Mark Dyurgerov, Andrey Glazovsky, Roy M. Koerner, Mark Meier, Niels Reeh, Oddur Sigur0sson, Konrad Steffen, Martin Truffer</p> <p><a href='/article/Sea_ice_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_ice_in_the_Arctic Fri, 23 Jan 2009 01:06:47 GMT http://www.eoearth.org/article/Watershed <a href='/article/Watershed'><img border='0' src='/upload/thumb/0/02/Watershed_diagram1.gif/250px-Watershed_diagram1.gif' width='100'/></a> <p>The term watershed is used (especially in North America and Europe) to indicate an area of land from which all water falling as <a href="/article/Precipitation_and_fog">rain or snow</a> would flow toward a single point. This includes both surface water flow, such as <a href="/article/Freshwater_biomes">rivers</a>, <a href="/article/Stream">streams</a> and creeks, and the <a href="/article/Groundwater">underground</a> movement of water. The boundaries and the area of such a watershed are determined by first specifying geographic point on land. A line is then drawn which connects all of the points of highest elevation immediately adjacent to that point. The watershed area would be the land area within those boundaries. The watershed of the Amazon River would include all of the tributaries that flow into it so it would actually contain several hundred smaller watersheds. The watershed is thus defined hydrologically, that is, by the specific river or stream. Watershed and <a href="/article/Drainage_basin">drainage basin</a> or catchment are used synonymously and all of them refer to the area of land drained by a river system. Three hydrological types of watershed can be distinguished: </p><ul><li>Exorheic watershed, which empty to the sea and represent the major part of the drainage of all of the continents except Australia. </li><li>Endorheic watershed, which discharge inland, into closed lake basins, and are mainly (but not exclusively) restricted to the arid and semi-arid regions. <br /> </li><li>Arheic regions, which is the region within which no rivers arise (the lower part of the Nile, Oranje and Niger, all in Africa, are a good examples of this category of basin). </li></ul><p>Watershed identification is now a primary tool for environmental planning. Called watershed management areas, these geographic units are utilized to gain an understanding of what happens to the surface or <a href="/article/Groundwater">groundwater</a> in the upper elevations of a watershed because that is imperative for the interpretation of local phenomenon. In some locales, the term &quot;watershed&quot; actually refers to the height of land <em>between</em> two catchment areas.</p> <p><a href='/article/Watershed'>Read Full Article...</a></p> http://www.eoearth.org/article/Watershed Thu, 22 Jan 2009 01:52:21 GMT http://www.eoearth.org/article/Plankton <a href='/article/Plankton'><img border='0' src='/upload/thumb/f/fb/Diatom_Thalassiosira_pseudonana.jpg/200px-Diatom_Thalassiosira_pseudonana.jpg' width='100'/></a> <p>Plankton are drifting organisms in aquatic environments, including <a href="/article/Marine_biomes">marine</a> and <a href="/article/Freshwater_biomes">fresh water</a>. They are the base of the <a href="/article/Food_web">food web</a> in these environments. </p> <p>Plankton can be divided into broad functional (or trophic level) groups:</p> <ul><li class="MsoNormal"><strong><a href="/article/Phytoplankton">Phytoplankton</a></strong> are tiny (usually unicellular) algae that live near the water surface where there is sufficient <a href="/article/Solar_radiation">light</a> to support <a href="/article/Photosynthesis">photosynthesis</a>. Among the more important groups are the diatoms, coccolithophores, cyanobacteria and dinoflagellates.</li><li class="MsoNormal"><strong>Zooplankton</strong> are small protists or metazoans (e.g. crustaceans and other animals) that feed on the phytoplankton. Larval stages of larger animals, such as fish, crustaceans, and annelids are included here. Zooplankton are in turn consumed by small fishes. </li><li class="MsoNormal"><strong>Bacterioplankton</strong> are <a href="/article/Bacteria">bacteria</a> and archaea which play an important role in nutrient cycles in the water column.</li></ul> <p>This classification divides the plankton into broad producer, consumer and recycler groups. In reality, the trophic level of some plankton is not straightforward. For example, although most dinoflagellates are either photosynthetic producers or heterotrophic consumers, some species can do both, depending upon the circumstances.</p> <p>Within the plankton, holoplankton are those that spend their entire life cycle in the plankton, while meroplankton are those organisms that are only planktonic for part of their lives (usually the larval stage), and then move into the nekton or a benthic habitat. Examples of meroplankton include larvae of sea urchins, starfish, clams, crustaceans, worms and most fish.</p><p>Plankton can also be categorized by their size range (e.g., macroplankton, microplankton, nannoplankton, and picoplankton). </p> <p>Some zooplankton can swim up to several hundreds of <a href="/article/Meter">meters</a> vertically in a single day (called diel vertical migration), but their horizontal position is primarily determined by currents in the water. Plankton are unable to swim against <a href="/article/Ocean_circulation">ocean currents</a>, while larger nekton such as fish and squid can swim against the flow of the water. Diel vertical migrations by zooplankton consist of moving up in the water at night and down in the day time. Being in deeper water during the daylight provides protection from <a href="/article/Predation">predators</a> that use vision to capture prey. This behavior is seen in animals from all different phyla that are in the plankton, so it must have enormous survival value. </p> <p>Plankton abundance and distribution are strongly dependent on factors such as nutrient concentrations, the state of the water, and the abundance of other plankton. Their abundance varies horizontally, vertically and seasonally. The primary sources of this variability are the availability of light and nutrients. In temperate climates, springtime brings increased light and higher <a href="/article/Temperature">temperatures</a>, resulting in a spring bloom of phytoplankton, followed by zooplankton. During the summer, dead organisms sink to the bottom where bacteria and fungi break down the tissues in the process of decay. This decomposition restores the nutrients, which concentrate on the bottom, although the phytoplankton that need them are on the top of the water column. Consequently the rate of photosynthesis declines. During the summer, the water column is stratified with warmer water staying on top and cooler water staying on the bottom. Only when water movements can bring the regenerated nutrients up closer to the surface can the phytoplankton bloom again. This happens in the fall, when temperatures fall and the now cooler surface water sinks down and bottom water comes up (upwelling) causing the stratification to break down and another small bloom to occur. Although tropical <a href="/article/Ocean">oceans</a> have abundant light, they have relatively low primary production because of low levels of nutrients such as nitrate and phosphate, due to perpetual stratification of the water column. While plankton are found in the greatest abundance in surface waters, in areas that are too deep for primary production to occur, zooplankton and bacterioplankton can make use of organic material that sinks down from the surface waters above. </p> <p><a href='/article/Plankton'>Read Full Article...</a></p> http://www.eoearth.org/article/Plankton Fri, 16 Jan 2009 03:29:27 GMT http://www.eoearth.org/article/Biodiversity_in_Africa <a href='/article/Biodiversity_in_Africa'><img border='0' src='/upload/thumb/8/84/Distribution_of_biodiversity.JPG/300px-Distribution_of_biodiversity.JPG' width='100'/></a> <p><a href="/article/Biodiversity">Biodiversity</a> offers multiple opportunities for development and improving human well-being. It is the basis for essential environmental services upon which life on Earth depends. Thus, its conservation and sustainable use are of critical importance. </p><p>The opportunities and <a href="/article/Biodiversity_and_development_challenges_in_Africa">challenges associated with biodiversity</a> typically apply over large geographical extents, although one or two issues may be more important at any given location. To avoid repetition, particular issues are highlighted in the sub-regional sections, not because they are restricted to those areas, but because they are best illustrated there. Deforestation is discussed under <a href="/article/Central_Africa_and_biodiversity">Central Africa</a>, while relations between protected areas and adjacent populations are dealt with under <a href="/article/Eastern_Africa_and_biodiversity">Eastern Africa</a>. Riparian biodiversity is discussed in <a href="/article/Northern_Africa_and_biodiversity">Northern Africa</a>, climate change and invasive alien species (IAS) in Southern Africa, desertification in <a href="/article/Western_Africa_and_biodiversity">Western Africa</a>, and endemism in the <a href="/article/Western_Indian_Ocean_Islands_and_biodiversity">Western Indian Ocean (WIO) islands</a>. Habitat degradation and resource overexploitation are discussed in this regional synthesis, because they are overwhelmingly important as drivers of biodiversity loss throughout Africa. </p> <p><a href='/article/Biodiversity_in_Africa'>Read Full Article...</a></p> http://www.eoearth.org/article/Biodiversity_in_Africa Thu, 15 Jan 2009 00:38:53 GMT http://www.eoearth.org/article/Arctic_Ocean <a href='/article/Arctic_Ocean'><img border='0' src='/upload/thumb/3/34/Grease_ice.jpg/250px-Grease_ice.jpg' width='100'/></a> <p>Ice is the dominant feature of <a href="/article/Arctic">Arctic</a> marine <a href="/article/Ecosystem">ecosystems</a>. It continuously sculpts the <a href="/article/Coastal_zone">coastal</a> landscape and acts as a major limiting factor to all biological activity. Two distinct zones are distinguished in the Arctic region based on ice: the Arctic Basin <a href="/article/Marine_biomes">marine</a> region is characterized by the year-round presence of <a href="/article/Sea_ice_in_the_Arctic">sea ice</a>, while the other Arctic subregions have ice-free periods ranging from less than a month to up to four months. The Arctic coast (including islands) encompasses 68% of Canada&#39;s coastline, stretching 165,000 <a href="/article/Meter">kilometers</a> (km) from James Bay and Baffin Island to the Yukon. The region exhibits a wide range of coastal landforms and reliefs fashioned by the processes of volcanism, glaciation, <a href="/article/Folding_and_faulting_in_the_Earth%27s_crust">faulting and folding</a>. The tidal range is generally less than 0.5 <a href="/article/Meter">meter</a> (m) in the northern and western sectors but increases to 1.0-5.0 m in the east and south.</p> <p><a href='/article/Arctic_Ocean'>Read Full Article...</a></p> http://www.eoearth.org/article/Arctic_Ocean Wed, 14 Ja