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/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 photosynthesis, 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/300px-Figure14.3_russia_forest.jpg' width='100'/></a> <h1>Introduction<br /></h1><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 World Conservation Union (IUCN) 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/300px-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 photosynthesis, 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 photosynthesis. 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 Large Marine Ecosystem (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 Northern Hemisphere. 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 photosynthesis 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/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic <a href='/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic'><img border='0' src='/upload/thumb/2/2f/Aciaworlddiag1.JPG/300px-Aciaworlddiag1.JPG' width='100'/></a> <p>The indigenous peoples of the <a href="/article/Arctic">Arctic</a> have adapted to great environmental variability, cold, extended winter darkness, and fluctuations in animal <a href="/article/Population">populations</a>, among many other challenges posed by <a href="/article/Geography">geography</a> and climate. Although the arctic climate has always undergone change, current and projected changes make it timely and important to reflect on the ways that such changes affect arctic residents, particularly the indigenous residents whose way of life is so closely linked to their surroundings. It is also important to consider how these indigenous residents observe and feel about the changes that are occurring. Together, such perspectives can help the global community understand what is at stake in a changing Arctic. </p><p>Much of the Arctic has been inhabited since at least the end of the last ice age, and some areas for far longer<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>. During this time, human groups have come and gone, and <a href="/article/Evolution">evolved</a> and adapted, their patterns of settlement changing, often abruptly, in response not only to climate but also to regional patterns such as resource availability, relations with neighbors, <a href="/article/Land-use_and_land-cover_change">landscape change</a>, hunting and fishing technology, and the rise of reindeer husbandry<span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. In recent centuries and in particular the twentieth century, forces from outside the region have shaped human patterns in the Arctic, as the modern world has extended its reach and influence. Today, the Arctic is home to a large number of indigenous peoples with distinct cultures, languages, traditions, and ways of interacting with their environment<span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span>. They have in common a close connection to their surroundings, an intimate understanding of their environment<span class="reference"><sup id="ref_4" class="plainlinksneverexpand"><a href="#endnote_4" class='external autonumber' title="#endnote 4">[4]</a></sup></span>, complex relationships with national and sub-national governments and non-indigenous migrants to the Arctic<span class="reference"><sup id="ref_5" class="plainlinksneverexpand"><a href="#endnote_5" class='external autonumber' title="#endnote 5">[5]</a></sup></span>, a way of life that mixes modern and traditional activities, and a major stake in the future of the region<span class="reference"><sup id="ref_6" class="plainlinksneverexpand"><a href="#endnote_6" class='external autonumber' title="#endnote 6">[6]</a></sup></span>. An overview of humans in the Arctic is given in the Arctic Climate Impact Assessment (ACIA), Chapter 1. </p><p>This article attempts to show some of the observations of change that indigenous inhabitants of the <a href="/article/Arctic">Arctic</a> consider to be related to climate change. In doing so, the comments and perspective also show what climate change means to them and their communities within the context of the other forces affecting their lives and cultures. Although little material is available concerning indigenous perspectives on <a href="/article/Solar_radiation">ultraviolet (UV) radiation</a> and <a href="/article/Ozone">ozone</a> depletion, this article includes a short summary of some related observations. Other chapters of the ACIA describe impacts on specific components of the environment and areas of human activity and so draw extensively on indigenous knowledge and perspectives, a level of inclusion that is unprecedented in an assessment of the type and scope of the ACIA. </p><p>This chapter addresses the impacts of climate change and variability on those affected most directly: the people whose ways of life are based on their use of the land and waters of the Arctic. This has been achieved using a series of case studies drawn from existing research projects that have been selected to give, through specific examples rather than general summaries, a sense of the variety of indigenous perspectives on climate change in the Arctic. The case studies are idiosyncratic, reflecting differences in the communities they describe as well as differences in the aims and methods of the studies from which they derive. Because they are examples, the case studies cannot reflect all the views held within arctic communities. Some communities, such as those in Greenland that fish for cod, may see benefits from climate change if fish stocks increase, a perspective that may be missing from case studies focusing more on the negative impacts of climate change. Nonetheless, the case studies are intended to give a human face to some of the impacts of weather and climate change observed by arctic residents. </p><p>Although people plan around expectations that reflect the climate of their area, their daily activities are affected more by the day’s weather. Many of the statements and perspectives contained in this chapter reflect perceptions of weather and changes in weather patterns and variability, which are also of interest to climatologists examining the ways that climate change is manifested in the <a href="/article/Arctic">Arctic</a><span class="reference"><sup id="ref_7" class="plainlinksneverexpand"><a href="#endnote_7" class='external autonumber' title="#endnote 7">[7]</a></sup></span>. The distinction between weather change and climate change is not simple, and observations about weather may indicate something significant about the arctic climate. It is also likely that the publicity surrounding climate change has led many people in the Arctic, as elsewhere, to interpret observations in the light of climate, whether or not this is appropriate. This article presents the connections indigenous peoples draw between their own observations and the general phenomenon of climate change. </p><p>In describing the significance of climate change for indigenous peoples, it is important to remember that there are many forms of environmental change in the Arctic, as well as extensive social changes related to modernization and globalization<span class="reference"><sup id="ref_8" class="plainlinksneverexpand"><a href="#endnote_8" class='external autonumber' title="#endnote 8">[8]</a></sup></span>. The challenges these pose often require great attention and effort by indigenous peoples and organizations. From negotiating the creation of Nunavut in Canada to responding to threats from oil and gas development in northern Russia, arctic indigenous peoples have had to organize themselves to articulate and fight for their values and ways of life. In some cases, they have been successful in promoting global action. The Stockholm Convention on Persistent Organic Pollutants was adopted in 2001, in no small part resulting from concerns about contaminants in the Arctic and their impacts on indigenous peoples and cultures<span class="reference"><sup id="ref_9" class="plainlinksneverexpand"><a href="#endnote_9" class='external autonumber' title="#endnote 9">[9]</a></sup></span>. More recently, Inuit leaders have framed climate change as a human rights issue (Sheila Watt-Cloutier as quoted in Brown<span class="reference"><sup id="ref_10" class="plainlinksneverexpand"><a href="#endnote_10" class='external autonumber' title="#endnote 10">[10]</a></sup></span>). Climate change is a topic about which indigenous peoples have a great deal to share with the world. </p> <p><a href='/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic Thu, 26 Mar 2009 02:41:52 GMT http://www.eoearth.org/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic <a href='/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic'><img border='0' src='/upload/thumb/2/2f/Aciaworlddiag1.JPG/300px-Aciaworlddiag1.JPG' width='100'/></a> <p>The indigenous peoples of the <a href="/article/Arctic">Arctic</a> have adapted to great environmental variability, cold, extended winter darkness, and fluctuations in animal <a href="/article/Population">populations</a>, among many other challenges posed by <a href="/article/Geography">geography</a> and climate. Although the arctic climate has always undergone change, current and projected changes make it timely and important to reflect on the ways that such changes affect arctic residents, particularly the indigenous residents whose way of life is so closely linked to their surroundings. It is also important to consider how these indigenous residents observe and feel about the changes that are occurring. Together, such perspectives can help the global community understand what is at stake in a changing Arctic. </p><p>Much of the Arctic has been inhabited since at least the end of the last ice age, and some areas for far longer<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>. During this time, human groups have come and gone, and <a href="/article/Evolution">evolved</a> and adapted, their patterns of settlement changing, often abruptly, in response not only to climate but also to regional patterns such as resource availability, relations with neighbors, <a href="/article/Land-use_and_land-cover_change">landscape change</a>, hunting and fishing technology, and the rise of reindeer husbandry<span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. In recent centuries and in particular the twentieth century, forces from outside the region have shaped human patterns in the Arctic, as the modern world has extended its reach and influence. Today, the Arctic is home to a large number of indigenous peoples with distinct cultures, languages, traditions, and ways of interacting with their environment<span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span>. They have in common a close connection to their surroundings, an intimate understanding of their environment<span class="reference"><sup id="ref_4" class="plainlinksneverexpand"><a href="#endnote_4" class='external autonumber' title="#endnote 4">[4]</a></sup></span>, complex relationships with national and sub-national governments and non-indigenous migrants to the Arctic<span class="reference"><sup id="ref_5" class="plainlinksneverexpand"><a href="#endnote_5" class='external autonumber' title="#endnote 5">[5]</a></sup></span>, a way of life that mixes modern and traditional activities, and a major stake in the future of the region<span class="reference"><sup id="ref_6" class="plainlinksneverexpand"><a href="#endnote_6" class='external autonumber' title="#endnote 6">[6]</a></sup></span>. An overview of humans in the Arctic is given in the Arctic Climate Impact Assessment (ACIA), Chapter 1. </p><p>This article attempts to show some of the observations of change that indigenous inhabitants of the <a href="/article/Arctic">Arctic</a> consider to be related to climate change. In doing so, the comments and perspective also show what climate change means to them and their communities within the context of the other forces affecting their lives and cultures. Although little material is available concerning indigenous perspectives on <a href="/article/Solar_radiation">ultraviolet (UV) radiation</a> and <a href="/article/Ozone">ozone</a> depletion, this article includes a short summary of some related observations. Other chapters of the ACIA describe impacts on specific components of the environment and areas of human activity and so draw extensively on indigenous knowledge and perspectives, a level of inclusion that is unprecedented in an assessment of the type and scope of the ACIA. </p><p>This chapter addresses the impacts of climate change and variability on those affected most directly: the people whose ways of life are based on their use of the land and waters of the Arctic. This has been achieved using a series of case studies drawn from existing research projects that have been selected to give, through specific examples rather than general summaries, a sense of the variety of indigenous perspectives on climate change in the Arctic. The case studies are idiosyncratic, reflecting differences in the communities they describe as well as differences in the aims and methods of the studies from which they derive. Because they are examples, the case studies cannot reflect all the views held within arctic communities. Some communities, such as those in Greenland that fish for cod, may see benefits from climate change if fish stocks increase, a perspective that may be missing from case studies focusing more on the negative impacts of climate change. Nonetheless, the case studies are intended to give a human face to some of the impacts of weather and climate change observed by arctic residents. </p><p>Although people plan around expectations that reflect the climate of their area, their daily activities are affected more by the day’s weather. Many of the statements and perspectives contained in this chapter reflect perceptions of weather and changes in weather patterns and variability, which are also of interest to climatologists examining the ways that climate change is manifested in the <a href="/article/Arctic">Arctic</a><span class="reference"><sup id="ref_7" class="plainlinksneverexpand"><a href="#endnote_7" class='external autonumber' title="#endnote 7">[7]</a></sup></span>. The distinction between weather change and climate change is not simple, and observations about weather may indicate something significant about the arctic climate. It is also likely that the publicity surrounding climate change has led many people in the Arctic, as elsewhere, to interpret observations in the light of climate, whether or not this is appropriate. This article presents the connections indigenous peoples draw between their own observations and the general phenomenon of climate change. </p><p>In describing the significance of climate change for indigenous peoples, it is important to remember that there are many forms of environmental change in the Arctic, as well as extensive social changes related to modernization and globalization<span class="reference"><sup id="ref_8" class="plainlinksneverexpand"><a href="#endnote_8" class='external autonumber' title="#endnote 8">[8]</a></sup></span>. The challenges these pose often require great attention and effort by indigenous peoples and organizations. From negotiating the creation of Nunavut in Canada to responding to threats from oil and gas development in northern Russia, arctic indigenous peoples have had to organize themselves to articulate and fight for their values and ways of life. In some cases, they have been successful in promoting global action. The Stockholm Convention on Persistent Organic Pollutants was adopted in 2001, in no small part resulting from concerns about contaminants in the Arctic and their impacts on indigenous peoples and cultures<span class="reference"><sup id="ref_9" class="plainlinksneverexpand"><a href="#endnote_9" class='external autonumber' title="#endnote 9">[9]</a></sup></span>. More recently, Inuit leaders have framed climate change as a human rights issue (Sheila Watt-Cloutier as quoted in Brown<span class="reference"><sup id="ref_10" class="plainlinksneverexpand"><a href="#endnote_10" class='external autonumber' title="#endnote 10">[10]</a></sup></span>). Climate change is a topic about which indigenous peoples have a great deal to share with the world. </p> <p><a href='/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic Thu, 26 Mar 2009 02:34:39 GMT http://www.eoearth.org/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic <a href='/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic'><img border='0' src='/upload/thumb/2/2f/Aciaworlddiag1.JPG/300px-Aciaworlddiag1.JPG' width='100'/></a> <p>The indigenous peoples of the <a href="/article/Arctic">Arctic</a> have adapted to great environmental variability, cold, extended winter darkness, and fluctuations in animal <a href="/article/Population">populations</a>, among many other challenges posed by <a href="/article/Geography">geography</a> and climate. Although the arctic climate has always undergone change, current and projected changes make it timely and important to reflect on the ways that such changes affect arctic residents, particularly the indigenous residents whose way of life is so closely linked to their surroundings. It is also important to consider how these indigenous residents observe and feel about the changes that are occurring. Together, such perspectives can help the global community understand what is at stake in a changing Arctic. </p><p>Much of the Arctic has been inhabited since at least the end of the last ice age, and some areas for far longer<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>. During this time, human groups have come and gone, and <a href="/article/Evolution">evolved</a> and adapted, their patterns of settlement changing, often abruptly, in response not only to climate but also to regional patterns such as resource availability, relations with neighbors, <a href="/article/Land-use_and_land-cover_change">landscape change</a>, hunting and fishing technology, and the rise of reindeer husbandry<span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. In recent centuries and in particular the twentieth century, forces from outside the region have shaped human patterns in the Arctic, as the modern world has extended its reach and influence. Today, the Arctic is home to a large number of indigenous peoples with distinct cultures, languages, traditions, and ways of interacting with their environment<span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span>. They have in common a close connection to their surroundings, an intimate understanding of their environment<span class="reference"><sup id="ref_4" class="plainlinksneverexpand"><a href="#endnote_4" class='external autonumber' title="#endnote 4">[4]</a></sup></span>, complex relationships with national and sub-national governments and non-indigenous migrants to the Arctic<span class="reference"><sup id="ref_5" class="plainlinksneverexpand"><a href="#endnote_5" class='external autonumber' title="#endnote 5">[5]</a></sup></span>, a way of life that mixes modern and traditional activities, and a major stake in the future of the region<span class="reference"><sup id="ref_6" class="plainlinksneverexpand"><a href="#endnote_6" class='external autonumber' title="#endnote 6">[6]</a></sup></span>. An overview of humans in the Arctic is given in the Arctic Climate Impact Assessment (ACIA), Chapter 1. </p><p>This article attempts to show some of the observations of change that indigenous inhabitants of the <a href="/article/Arctic">Arctic</a> consider to be related to climate change. In doing so, the comments and perspective also show what climate change means to them and their communities within the context of the other forces affecting their lives and cultures. Although little material is available concerning indigenous perspectives on <a href="/article/Solar_radiation">ultraviolet (UV) radiation</a> and <a href="/article/Ozone">ozone</a> depletion, this article includes a short summary of some related observations. Other chapters of the ACIA describe impacts on specific components of the environment and areas of human activity and so draw extensively on indigenous knowledge and perspectives, a level of inclusion that is unprecedented in an assessment of the type and scope of the ACIA. </p><p>This chapter addresses the impacts of climate change and variability on those affected most directly: the people whose ways of life are based on their use of the land and waters of the Arctic. This has been achieved using a series of case studies drawn from existing research projects that have been selected to give, through specific examples rather than general summaries, a sense of the variety of indigenous perspectives on climate change in the Arctic. The case studies are idiosyncratic, reflecting differences in the communities they describe as well as differences in the aims and methods of the studies from which they derive. Because they are examples, the case studies cannot reflect all the views held within arctic communities. Some communities, such as those in Greenland that fish for cod, may see benefits from climate change if fish stocks increase, a perspective that may be missing from case studies focusing more on the negative impacts of climate change. Nonetheless, the case studies are intended to give a human face to some of the impacts of weather and climate change observed by arctic residents. </p><p>Although people plan around expectations that reflect the climate of their area, their daily activities are affected more by the day’s weather. Many of the statements and perspectives contained in this chapter reflect perceptions of weather and changes in weather patterns and variability, which are also of interest to climatologists examining the ways that climate change is manifested in the <a href="/article/Arctic">Arctic</a><span class="reference"><sup id="ref_7" class="plainlinksneverexpand"><a href="#endnote_7" class='external autonumber' title="#endnote 7">[7]</a></sup></span>. The distinction between weather change and climate change is not simple, and observations about weather may indicate something significant about the arctic climate. It is also likely that the publicity surrounding climate change has led many people in the Arctic, as elsewhere, to interpret observations in the light of climate, whether or not this is appropriate. This article presents the connections indigenous peoples draw between their own observations and the general phenomenon of climate change. </p><p>In describing the significance of climate change for indigenous peoples, it is important to remember that there are many forms of environmental change in the Arctic, as well as extensive social changes related to modernization and globalization<span class="reference"><sup id="ref_8" class="plainlinksneverexpand"><a href="#endnote_8" class='external autonumber' title="#endnote 8">[8]</a></sup></span>. The challenges these pose often require great attention and effort by indigenous peoples and organizations. From negotiating the creation of Nunavut in Canada to responding to threats from oil and gas development in northern Russia, arctic indigenous peoples have had to organize themselves to articulate and fight for their values and ways of life. In some cases, they have been successful in promoting global action. The Stockholm Convention on Persistent Organic Pollutants was adopted in 2001, in no small part resulting from concerns about contaminants in the Arctic and their impacts on indigenous peoples and cultures<span class="reference"><sup id="ref_9" class="plainlinksneverexpand"><a href="#endnote_9" class='external autonumber' title="#endnote 9">[9]</a></sup></span>. More recently, Inuit leaders have framed climate change as a human rights issue (Sheila Watt-Cloutier as quoted in Brown<span class="reference"><sup id="ref_10" class="plainlinksneverexpand"><a href="#endnote_10" class='external autonumber' title="#endnote 10">[10]</a></sup></span>). Climate change is a topic about which indigenous peoples have a great deal to share with the world. </p> <p><a href='/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Indigenous_knowledge_and_observations_of_climate_change_in_the_Arctic 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 on Downe, England. It is thought that he may have contracted some kind of illness during his travels in South America. He died on April 19, 1882 and is buried at Westminster Abbey.</p><p>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>&nbsp;</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 Thomas Henry Huxley.  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 in 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>&nbsp;</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 photosynthesis, 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 photosynthesis, 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&g