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/Osmoregulator <a href='/article/Osmoregulator'><img border='0' src='/upload/thumb/a/aa/Osmoregulator1.JPG/300px-Osmoregulator1.JPG' width='100'/></a> <p>An osmoregulator is an organism that can regulate or keep the solutes or salts of its body fluid at a higher or lower concentration than the concentration of solutes in the external medium, although this regulation may be limited at extremely high or extremely low external solute concentrations. If the solutes in the organism&#39;s body fluids are kept at a concentration higher than that of the external medium (e.g., lake water), this organism&#39;s body fluids are said to be hyperosmotic to the external medium and the organism is a hyperosmotic osmoregulator. If the solutes of the organism&#39;s body fluids are kept at a concentration lower than that of the external medium (<a href="/article/Seawater">seawater</a> for example), this organism&#39;s body fluids are said to be hypoosmotic to the external medium and the organism is a hypoosmotic osmoregulator. If the solutes of the organism&#39;s body fluids are the same concentration as that of the external medium, the organism is isoosmotic and is at its isoosmotic point (see the Figure). An organism could be hyperosmotic in an external medium of low solute concentration and be isoosmotic in an external medium of higher solute concentration. Conversely, an organism could be hypoosmotic in an external medium of high solute concentration and be isoosmotic in an external medium of low solute concentration. Both of these situations could happen, for example, in a <a href="/article/Tidal_marsh">tidal marsh</a> or other estuarine habitat because in these environments the solute concentrations of the water change with the <a href="/article/Tide">tides</a>, salinity being lower at low tide and higher at high tide as ocean water floods the estuary. In either case the organism is still an osmoregulator as long as the solute concentration of its body fluids are different than the solute concentration of the external medium. An organism could also be hyperosmotic in both low and high solute concentrations in the external medium. This is the case with sharks. They are always hyperosmotic because of the high concentration of urea in their bodies. </p><p>Organisms that are hyperosmotic tend to lose solutes to the external medium by diffusion and to gain water from the external medium by osmosis. The opposite is true of organisms that are hypoosmotic, which tend to gain solutes from the external medium by diffusion and lose water to the external medium by osmosis. Organisms that are isoosmotic are at equilibrium with the external medium and do not gain or lose solutes or water. </p> <p>Hyperosmotic regulators decrease the loss of solutes from the blood to the external medium via chloride cells that actively take up the chloride <a href="/article/Ion">ions</a> that were lost to the external medium due to diffusion. In animals, chloride cells are located in the gills. Hyperosmotic regulators decrease the osmotic gain of water in the blood from the external medium by excreting urine that is hypoosmotic to the blood. Hyperosmotic regulators decrease the osmotic gain of water in their cells from the blood by joining amino acids into proteins. This decreases the gain of water into the cells because the cells become hypoosmotic to the blood when the solute concentration is decreased by joining many amino acids into fewer proteins, and this makes less water move into the cells from the blood. Although proteins are larger than amino acids, they do not increase the solute concentration as much as the many amino acids needed to make a protein. In these ways, regulators can maintain <a href="/article/Homeostasis">homeostasis</a> in their blood and cells. </p><p>Animals that are hypoosmotic regulators decrease the gain of solutes that diffuse into the blood from the external medium by drinking the external medium and having efficient kidneys that can remove the solutes, pumping them into the urine so that the urine is hyperosmotic to the blood. Hypoosmotic regulators decrease the osmotic loss of water from the blood to the external medium by having body surfaces that are relatively impermeable. Hypoosmotic regulators decrease the osmotic loss of water from their cells to their blood by breaking proteins into amino acids. This decreases the loss of water from cells into the surrounding blood because the resulting high concentration of amino acids in the cells makes them hyperosmotic to the blood. This increases the gain of water into the cells from the blood and maintains homeostasis.</p><p>Almost all aquatic animals are physiological osmoregulators. Exceptions include soft-bodied animals such as worms and <a href="/article/Mollusca">mollusks</a>, which are <a href="/article/Osmoconformer">osmoconformers</a>. Some animals are capable of behavioral osmoregulation --  they behave in certain ways that regulate how fast or slowly they encounter the differing solute concentration of the external medium. For example, certain animals may seek out microhabitats with favorable salinity, and bivalved mollusks such as clams may close their shells when bathed by water with unfavorabale solute concentrations.   </p> <p><a href='/article/Osmoregulator'>Read Full Article...</a></p> http://www.eoearth.org/article/Osmoregulator Fri, 06 Nov 2009 06:40:32 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Fri, 06 Nov 2009 06:40:02 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Fri, 06 Nov 2009 06:39:35 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Fri, 06 Nov 2009 06:39:23 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Tue, 03 Nov 2009 05:56:01 GMT http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication <a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'><img border='0' src='/upload/thumb/7/7d/NOxcycle.gif/250px-NOxcycle.gif' width='100'/></a> <p><a href='/article/Impact_and_abatement_of_acid_deposition_and_eutrophication'>Read Full Article...</a></p> http://www.eoearth.org/article/Impact_and_abatement_of_acid_deposition_and_eutrophication Tue, 03 Nov 2009 05:55:28 GMT http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic <a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'><img border='0' src='/upload/thumb/8/89/Fig9.2_ave_sea_ice_cover.JPG/620px-Fig9.2_ave_sea_ice_cover.JPG' width='100'/></a> <p>This is Section 9.2.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a><br /> Lead Author: Harald Loeng; Contributing Authors: Keith Brander, Eddy Carmack, Stanislav Denisenko, Ken Drinkwater, Bogi Hansen, Kit Kovacs, Pat Livingston, Fiona McLaughlin, Egil Sakshaug;  Consulting Authors: Richard Bellerby, Howard Browman,Tore Furevik, Jacqueline M. Grebmeier, Eystein Jansen, Steingrimur Jónsson, Lis Lindal Jørgensen, Svend-Aage Malmberg, Svein Østerhus, Geir Ottersen, Koji Shimada</p><p>&nbsp;</p><p><a href="/article/Sea_ice_in_the_Arctic">Sea ice</a> controls the exchange of <a href="/article/Heat">heat</a> and other properties between the <a href="/article/Atmosphere_layers">atmosphere</a> and <a href="/article/Ocean">ocean</a> and, together with <a href="/article/Snow_cover_in_the_Arctic">snow cover</a>, determines the penetration of <a href="/article/Solar_radiation">light</a> into the sea. Sea ice also provides a surface for particle and snow deposition, a habitat for <a href="/article/Plankton">plankton</a>, and contributes to stratification through ice melt. The zone seaward of the ice edge is important for plankton production and planktivorous fish. For some <a href="/article/Implications_for_biodiversity_conservation_in_the_Arctic">marine mammals</a> sea ice provides a place for birth and also functions as a nursery area. </p><p>This section describes features of sea ice that are important for physical oceanographic processes and the <a href="/article/Arctic_marine_environments">marine ecosystem</a>. More detailed information about sea ice is given in <a href="/article/Cryosphere_and_Hydrology_in_the_Arctic">Chapter 6</a>. </p> <p><a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic Mon, 02 Nov 2009 07:56:27 GMT http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic <a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'><img border='0' src='/upload/thumb/8/89/Fig9.2_ave_sea_ice_cover.JPG/620px-Fig9.2_ave_sea_ice_cover.JPG' width='100'/></a> <p>This is Section 9.2.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a><br /> Lead Author: Harald Loeng; Contributing Authors: Keith Brander, Eddy Carmack, Stanislav Denisenko, Ken Drinkwater, Bogi Hansen, Kit Kovacs, Pat Livingston, Fiona McLaughlin, Egil Sakshaug;  Consulting Authors: Richard Bellerby, Howard Browman,Tore Furevik, Jacqueline M. Grebmeier, Eystein Jansen, Steingrimur Jónsson, Lis Lindal Jørgensen, Svend-Aage Malmberg, Svein Østerhus, Geir Ottersen, Koji Shimada</p><p>&nbsp;</p><p><a href="/article/Sea_ice_in_the_Arctic">Sea ice</a> controls the exchange of <a href="/article/Heat">heat</a> and other properties between the <a href="/article/Atmosphere_layers">atmosphere</a> and <a href="/article/Ocean">ocean</a> and, together with <a href="/article/Snow_cover_in_the_Arctic">snow cover</a>, determines the penetration of <a href="/article/Solar_radiation">light</a> into the sea. Sea ice also provides a surface for particle and snow deposition, a habitat for <a href="/article/Plankton">plankton</a>, and contributes to stratification through ice melt. The zone seaward of the ice edge is important for plankton production and planktivorous fish. For some <a href="/article/Implications_for_biodiversity_conservation_in_the_Arctic">marine mammals</a> sea ice provides a place for birth and also functions as a nursery area. </p><p>This section describes features of sea ice that are important for physical oceanographic processes and the <a href="/article/Arctic_marine_environments">marine ecosystem</a>. More detailed information about sea ice is given in <a href="/article/Cryosphere_and_Hydrology_in_the_Arctic">Chapter 6</a>. </p> <p><a href='/article/Sea_ice_effect_on_marine_systems_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_ice_effect_on_marine_systems_in_the_Arctic Mon, 02 Nov 2009 07:55:14 GMT http://www.eoearth.org/article/Valuing_environmental_costs_and_benefits <a href='/article/Valuing_environmental_costs_and_benefits'><img border='0' src='/upload/thumb/3/32/Economic_values-environmental_assets.gif/300px-Economic_values-environmental_assets.gif' width='100'/></a> <p>Little and Mirrlees noted that from the mid 1970s to 1990s, there had been a rise and decline of project appraisal in development community<span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>. Our view is that natural resource and environmental issues may be critical for making development more sustainable. Therefore, environmental economic analysis should be pursued, preferably early in the project cycle. Even where the valuation is difficult, techniques like <a href="/article/Multi-criteria_analysis_in_environmental_decision-making">multi-criteria analysis</a> are useful to make decisions. </p><p>The first step in the analysis is to determine the environmental (and social) impacts of the project or policy, by comparing the “with project” and the “without project” scenarios (see "Measuring economic costs and benefits"). Transdisciplinary work is essential (see "<a href="/article/Basic_concepts_and_principles_of_sustainomics">Basic concepts and principles of sustainomics</a>"). The quantification of impacts in non-monetary units is a prerequisite not only for accurate economic valuation, but also for the use of other analytical methods like multi-criteria analysis. Such biophysical impacts are themselves complex and often poorly understood. </p><p>The second step in considering environmental effects involves valuing project impacts. Several practical valuation techniques are described below, based on extensions of the framework discussed in the previous section ("Measuring economic costs and benefits"). </p> <p>Conceptually, the <a href="/article/Total_economic_value">total economic value</a> (TEV) of a resource consists of its (i) <a href="/article/Total_economic_value">use value</a> (UV) and (ii) <a href="/article/Total_economic_value">non use value</a> (NUV). Use values may be broken down further into the direct use value (DUV), the indirect use value (IUV) and the <a href="/article/Total_economic_value">option value</a> (OV) (potential use value). One needs to be careful not to double count both the value of indirect supporting functions and the value of the resulting direct use. We may write: </p> TEV = UV + NUV<br />or<br />TEV = [DUV + IUV + OV] + [NUV] <p>Figure 1 shows this disaggregation of TEV in schematic form. A short description of each valuation concept, and a few typical examples of the underlying environmental resources, are provided: </p> <ul><li> direct use value is the contribution to current <a href="/article/Essential_economic_activities">production</a>/<a href="/article/Essential_economic_activities">consumption</a>; </li><li> indirect use value includes benefits from functional services that the environment provides to support current production/consumption (e.g., ecological functions like nutrient recycling); </li><li> option value is the willingness to pay for an unutilized asset, simply to avoid the risk of not having it available in the future (see "Discount rate, risk, and uncertainty in environmental decision-making"); and </li><li> non-use value is the willingness to pay for perceived benefits not related to use value, e.g., <a href="/article/Total_economic_value">existence value</a>, which is based on the satisfaction of merely knowing that an asset exists, even without intending to use it. </li></ul> <p>Economic theory clearly defines TUV, but there is considerable overlap and ambiguity in the breakdown categories, especially with regard to non use values. Thus, <a href="/article/Total_economic_value">option values</a> and <a href="/article/Total_economic_value">non use values</a> are shaded in the figure. These categories are useful as an indicative guide, but the goal of practical estimation to measure TUV rather than its components. </p><p>The distinction between use and non use values is not always clear. The latter tend to be linked to more altruistic motives<span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. Differing forms of altruism include intergenerational altruism, or the bequest motive; interpersonal altruism or the gift motive; stewardship (which has more ethical than utilitarian origins); and q Altruism, which states that the resource has an intrinsic right to exist. This final definition is outside conventional economic theory, and incorporates the notion that the welfare function should be derived from something more than purely human utility<span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span>. </p><p>For the practitioner, the precise conceptual basis of <a href="/article/Total_economic_value">economic value</a> is less important than the various empirical techniques that permit us to estimate a <a href="/article/Monetary_valuation">monetary value</a> for environmental assets. </p> <p><a href='/article/Valuing_environmental_costs_and_benefits'>Read Full Article...</a></p> http://www.eoearth.org/article/Valuing_environmental_costs_and_benefits Thu, 29 Oct 2009 06:11:55 GMT http://www.eoearth.org/article/Indian_Ricegrass <a href='/article/Indian_Ricegrass'><img border='0' src='/media/approved/a/ab/Indian_Ricegrass_achnatherum_hymenoidesUSFS_GaryMonroe.jpg' width='100'/></a> <p><em>Achnatherum hymenoides</em> (Roemer &amp; J.A. Schultes) Barkworth</p><p>As the common name implies, Native Americans utilized this species of grass in a manner analogous to that of rice by peoples of the Old World and their descendants. The name in Spanish is essentially the same: “<em>arroz indio</em>.” It is also known as Indian Millet or Sand-grass, and Latin synonyms are <em>Oryzopsis h., Stipa h.</em>, and<em> Eriocoma cuspidata</em>.</p> <p><em>Achnatherum hymenoides</em> is a member of the Poaceae, or grass family. It likes to live in sandy soils and is adapted to dry places, but also lives in moist areas within drier environments; look for it where you see sagebrush, juniper, or ponderosa pine. Distinguishing Indian ricegrass from other grasses may sound difficult to someone who has not seen it before, but armed with a good picture and an idea of what to look for, it can be done. Look for a bunchgrass from 1 to 2½ feet tall. The leaves are tightly rolled from the edges, giving each leaf the look of a long, straight, skinny tube. The inflorescence is the easiest feature to distinguish. It is an open, branching panicle, consisting of long, undulating stalks that look like hairs. Each branch terminates in a single seed (or, technically, a single fruit, containing a single seed). The seed itself is covered with short hairs, is black, and is the portion used for food.</p> <p>Because of its importance to native Nevadans, <em>A. hymenoides</em> is honoured as the Nevada state grass. In many cultures it was the principle grain, while in others it was only eaten when other crops or wild food plants failed. When mature, the seeds fall easily from the plant. It may be gathered by beating the inflorescence with a light paddle and collecting the seeds in a shallow basket; the Indians of this area produced exquisite paddles and baskets for this purpose. Some seeds would not fall into the basket, but would fall to the ground and produce more plants. After parching the seeds to remove the hairs, the grain can be ground into meal and baked into bread, eaten as porridge, or made into other logical things to make from meal. Another species, <em>A. speciosum</em> is also used for food in a similar manner, though not as extensively.</p> <p>Besides use as food, Indian ricegrass is also used in restoration, planted to help stop wind erosion. It may be planted as a garden plant, but requires well-drained soil. In the United States and <a href="/article/Mexico">Mexico</a>, it is used as good winter forage for livestock, being cold and drought tolerant; this has led in some situations to overgrazing. The seeds are nutritious for birds.</p> <p><strong>For More Information:</strong><br /><a href="http://plants.usda.gov/java/profile?symbol=ACHY" class='external text' title="http://plants.usda.gov/java/profile?symbol=ACHY">PLANTS Profile - &lt;em&gt;Achnatherum hymenoides&lt;/em&gt;, Indian ricegrass</a></p> <p><a href='/article/Indian_Ricegrass'>Read Full Article...</a></p> http://www.eoearth.org/article/Indian_Ricegrass Wed, 28 Oct 2009 06:10:06 GMT http://www.eoearth.org/article/Kyanite <a href='/article/Kyanite'><img border='0' src='/upload/thumb/f/fe/Kyanite.jpg/250px-Kyanite.jpg' width='100'/></a> <p>Kyanite and its related mineral “cousins,” sillimanite and andalusite, are called <em>polymorphs</em>. This means that they are three distinct minerals, but they all have the same chemical formula, Al₂SiO₅ (aluminum silicate). Because they are chemically the same, they can all be used in the same applications. </p><p>All three form in <a href="/article/Metamorphic_rock">metamorphic rocks</a> (rocks that are changed by intense <a href="/article/Heat">heat</a> and <a href="/article/Pressure">pressure</a>), specifically in schists and gneisses that were formed out of sedimentary rocks with a high <a href="/article/Clay">clay</a> content. Studies have shown that each mineral forms under very specific <a href="/article/Temperature">temperature</a>/pressure (T/P) conditions. Relative to one another, kyanite forms in a lower temperature/higher pressure environment; andalusite forms in a lower temperature/lower pressure environment, and sillimanite forms in a higher temperature/higher pressure environment. </p><p>Kyanite forms bladed crystals. It is generally blue, but can also be green or gray. It has a glassy luster. Kyanite has a unique physical feature in that it has two different hardnesses. When its hardness is measured across the crystal, it is 7; when it is measured down the length of the crystal, it is 5. All other minerals have a single hardness no matter where it is measured on the crystal. </p> <p><a href='/article/Kyanite'>Read Full Article...</a></p> http://www.eoearth.org/article/Kyanite Tue, 27 Oct 2009 07:07:25 GMT http://www.eoearth.org/article/Kilogram <a href='/article/Kilogram'><img border='0' src='/upload/thumb/2/23/Kilogram.jpeg/200px-Kilogram.jpeg' width='100'/></a> <p><span> </p> <p></center> </p> <p><a href='/article/Kilogram'>Read Full Article...</a></p> http://www.eoearth.org/article/Kilogram Tue, 27 Oct 2009 07:05:14 GMT http://www.eoearth.org/article/Kilogram <a href='/article/Kilogram'><img border='0' src='/upload/thumb/2/23/Kilogram.jpeg/200px-Kilogram.jpeg' width='100'/></a> <p><span> </p> <p></center> </p> <p><a href='/article/Kilogram'>Read Full Article...</a></p> http://www.eoearth.org/article/Kilogram Tue, 27 Oct 2009 07:02:58 GMT http://www.eoearth.org/article/Weathering <a href='/article/Weathering'><img border='0' src='/upload/thumb/5/52/Rock_weathering.jpg/300px-Rock_weathering.jpg' width='100'/></a> <p>Weathering is the breakdown and alteration of <a href="/article/Composition_of_rocks">rocks</a> and minerals at or near the Earth's surface into products that are more in equilibrium with the conditions found in this environment. Most rocks and minerals are formed deep within the Earth's crust where <a href="/article/Temperature">temperatures</a> and <a href="/article/Pressure">pressures</a> differ greatly from the surface. The physical and chemical nature of materials formed in the Earth's interior are characteristically in disequilibrium with conditions occurring on the surface. Because of this disequilbrium, these materials are easily attacked, decomposed, and eroded by various chemical and physical surface processes. </p><p>Weathering is the first step for a number of other geomorphic and biogeochemical processes. The products of weathering are a major source of sediments for erosion and deposition. Many types of sedimentary rocks are composed of particles that have been weathered, eroded, transported, and terminally deposited in basins. Weathering also contributes to the formation of soil by providing mineral particles like sand, silt, and clay. Elements and compounds extracted from the rocks and minerals by weathering processes supply nutrients for plant uptake. The fact that the oceans are saline in the result of the release of ion salts from rock and minerals on the continents. Leaching and <a href="/article/Surface_runoff_of_water">runoff</a> transport these ions from land to the ocean basins where they accumulate in seawater. In conclusion, weathering is a process that is fundamental to many other aspects of the hydrosphere, lithosphere, and <a href="/article/Biosphere">biosphere</a>. </p><p>There are three broad categories of mechanisms for weathering: chemical, physical and biological. </p> <p><a href='/article/Weathering'>Read Full Article...</a></p> http://www.eoearth.org/article/Weathering Fri, 23 Oct 2009 06:05:32 GMT http://www.eoearth.org/article/Hawk_moth <a href='/article/Hawk_moth'><img border='0' src='/upload/thumb/0/0b/Hawk_moth_USFS_JosephScheer.jpg/150px-Hawk_moth_USFS_JosephScheer.jpg' width='100'/></a> <h2>Hawk Moths or Sphinx Moths (<em>Sphingidae</em>)</h2> <p>Moths live in a wide variety of habitats around the world. They usually go unnoticed, except when flying erratically around your porch light, a streetlight, or other source of light during the darkness of night. Perhaps you notice their handiwork when you find small holes in a woolen garment stored in your closet or you find your tomato plants consumed by a hungry tomato hornworm.</p> <p>Most moths work the night shift, unlike their “respectable cousins” the butterflies, which are out during the daytime, and glorified in prose, poetry, and art. Unfortunately, we usually vilify moths because of their association with the dark of night and our innate fear of darkness and things that go bump in the night. Do you remember the monsters under your bed?</p> <p>They get little respect, except from the relatively few scientists and naturalists who are passionate about their study and who study moths and their ways. Moths represent a biological storehouse of interesting, dramatic, and unusual behaviors, some with roles as pollinators, and others as food for other animals. All have interesting stories to tell if we will only take the time to stop, look, listen and smell the hidden world of moths and their flowers. Planting moonlight or a fragrance garden is a sure way to enjoy not only these wonderful blossoms, but also their nocturnal pollinators, especially the giant hawk moths.</p> <p class="img-caption"> </p> <p>Estimated populations of 11,000 moths are known to occur in the United States. Around the world, another 160,000 species of moths have been catalogued. A staggering 200,000 or more species of moths may exist, just waiting to be discovered. The number of moths far outnumbers the number of world’s species of butterflies (17,500 species). Not all moths are a drab brown or white. Many moths come clothed in a myriad of colors and patterns, some brighter than those flashy butterflies, and just as interesting. Like butterflies, minute scales cover the wings of moth, making them slippery to the touch. If you have ever held or tried to catch a butterfly or moth, the “powder” or “dust” that comes off on your fingers is their scales.</p> <p>Some of the largest moths in the world belong to the hawk moth or Sphingid family within the order Lepidoptera (the animal order that includes butterflies and moths). These magnificent animals have long narrow wings and thick bodies. They are fast flyers and often highly aerobatic. Many species can hover in place. Some can briefly fly backwards or dart away. Hawk moths are experts at finding sweet-smelling flowers after dark. They are especially fond of <em>Datura</em> (Jimpson weeds), <em>Mirabilis</em> (Four O’clocks), and <em>Peniocereus</em> (Queen-of-the-night cactus) blossoms. These flowers are highly fragrant with long floral tubes concealing pools of thin but abundant nectar.</p> <p class="img-caption"> </p> <p>Hawk moths have the world’s longest tongues of any other moth or butterfly (some up to 14 inches long). <a href="/article/Darwin%2C_Charles">Charles Darwin</a> knew of the star orchids (<em>Angraecum</em> spp.) from Madagascar that had nectar spurs over a foot in length. Darwin was ridiculed by other scientists of his day for predicting that these orchids would be pollinated by hawk moths. After his death, hawk moths with tongues long enough to sip of the nectar produced by the star orchids were discovered on the island of Madagascar. </p> <p>The caterpillars (larvae) of hawk moths are the familiar green hornworms or tobacco worms, familiar to gardeners who plant tomatoes. Since some hawk moths are minor crop pests, aerial application of <a href="/article/Pesticide">pesticides</a> to protect crops sometimes affects their numbers. With the populations of all the sphinx moths affected by this agricultural practice there are fewer sphinx moths that pollinate rare plants, like the famous Queen-of-the-night cactus or the sacred Datura, which live in northern Mexico and along the border in the desert southwest.</p> <p>Moths pick up pollen on their legs and wings when they visit flowers and deposit pollen (accidentally) on subsequent floral visits. Two kinds of small moths (Yucca moths and the <em>Senita</em> cactus moth) actually pick up pollen and jam a pollen ball onto the stigmas of their flowers in order to assure food, the resulting immature seeds, for their caterpillars. They are some of the only insects to pollinate flowers “purposefully”.</p><p>&nbsp;</p> <p><a href='/article/Hawk_moth'>Read Full Article...</a></p> http://www.eoearth.org/article/Hawk_moth Thu, 22 Oct 2009 07:17:34 GMT http://www.eoearth.org/article/Zinn,_Walter <a href='/article/Zinn,_Walter'><img border='0' src='/upload/thumb/f/f5/Zinn.gif/200px-Zinn.gif' width='100'/></a> <p>Walter Zinn (1907 – 2000) a Canadian physicist who, on December 2, 1942, pulled out the emergency control rod from the reactor at the University of Chicago that released the world’s first self-sustaining nuclear reaction. Zinn reinserted it to terminate the chain reaction after 28 minutes of operation. Recruited by Enrico Fermi to work on the Manhattan Project, Zinn supervised all phases of the construction of the first experimental nuclear reactor, or "atomic pile" as it was then called. He also served as the first director of Argonne National Laboratory from 1946-1956. Zinn designed the Experimental Breeder Reactor-I, the first nuclear reactor to produce electric power (Dec. 20, 1951) in Idaho at the National Reactor Testing Site. EBR-I is now a National Historic Landmark. It also was the first nuclear reactor to demonstrate the breeding principle (that reactors can generate more nuclear fuel than they consume). In 1963, the EBR-I was the first nuclear reactor to achieve a chain reaction with plutonium as well as the first to demonstrate the feasibility of using liquid metals at high temperatures as a reactor coolant. </p><p><b>Further Readings</b><br /> <a href="http://www.cns-snc.ca/history/pioneers/zinn/zinn.html" class='external text' title="http://www.cns-snc.ca/history/pioneers/zinn/zinn.html">Walter Zinn 1907-2000</a> (Canadian Nuclear Society)<br /> <a href="http://www.nap.edu/readingroom/books/biomems/wzinn.html" class='external text' title="http://www.nap.edu/readingroom/books/biomems/wzinn.html">Walter Henry Zinn</a> (National Academy of Sciences) </p> <p><a href='/article/Zinn,_Walter'>Read Full Article...</a></p> http://www.eoearth.org/article/Zinn,_Walter Wed, 21 Oct 2009 06:26:29 GMT http://www.eoearth.org/article/Macrophytes <a href='/article/Macrophytes'><img border='0' src='/upload/thumb/9/99/Macrophytes_plants.jpg/300px-Macrophytes_plants.jpg' width='100'/></a> <p>Macrophytes are the conspicuous plants that dominate <a href="/article/Wetland">wetlands</a>, shallow lakes, and <a href="/article/Stream">streams</a>. Macroscopic flora include the aquatic angiosperms (flowering plants), pteridophytes (ferns), and bryophytes (mosses, hornworts, and liverworts). An <a href="/article/Aquatic_plants">aquatic plant</a> can be defined as one that is normally found growing in association with standing water whose level is at or above the surface of the <a href="/article/Soil">soil</a>. Standing water includes ponds, shallow lakes, <a href="/article/Marsh">marshes</a>, ditches, reservoirs, <a href="/article/Swamp">swamps</a>, <a href="/article/Bog">bogs</a>, canals, and sewage lagoons. Aquatic plants, though less frequently, also occur in flowing water, in streams, <a href="/article/River">rivers</a>, and <a href="/article/Spring">springs</a>. </p> <p><a href='/article/Macrophytes'>Read Full Article...</a></p> http://www.eoearth.org/article/Macrophytes Tue, 20 Oct 2009 06:42:25 GMT http://www.eoearth.org/article/Backyard_wetland <a href='/article/Backyard_wetland'><img border='0' src='/upload/thumb/3/3e/Wetland.jpg/350px-Wetland.jpg' width='100'/></a> <p><em><a href="/article/Wetland">Wetlands</a> filter excess pesticides and nutrients. Many plants and animals find a home in wetlands.</em></p> <p><a href='/article/Backyard_wetland'>Read Full Article...</a></p> http://www.eoearth.org/article/Backyard_wetland Thu, 15 Oct 2009 05:43:25 GMT http://www.eoearth.org/article/Amphibian <a href='/article/Amphibian'><img border='0' src='/upload/thumb/4/49/Green_treefrog.jpg/225px-Green_treefrog.jpg' width='100'/></a> <p>The word amphibian comes from the Greek <em>amphibios</em> meaning &quot;both lives&quot;. This is an apt description because most adult amphibians are better adapted to life on land than in water, while their larval phases are entirely aquatic. </p><p>For much of their lives, which may last a couple of months or several years depending on the species, larval amphibians bear little resemblance to their adult forms. Then something miraculous happens. In a matter of weeks or even days, the once fish-like larvae metamorphose into terrestrial, air-breathing quadrupeds! </p><p>There are three extant orders in the Class Amphibia: Anura (frogs and toads), Caudata (salamanders), and Apoda (caecilians). The order Anura has the most living species, with 4000 members worldwide. </p><p>Of 390 salamander species that exist worldwide. The third amphibian group, the caecilians, is smaller still with a total of only 162 species, all of which are restricted to the tropics.</p> <p><a href='/article/Amphibian'>Read Full Article...</a></p> http://www.eoearth.org/article/Amphibian Wed, 14 Oct 2009 05:31:08 GMT http://www.eoearth.org/article/Biosphere <a href='/article/Biosphere'><img border='0' src='/upload/thumb/0/03/Earth_spheres.jpg/300px-Earth_spheres.jpg' width='100'/></a> <p>The<strong> biosphere</strong> is the biological component of earth systems, which also include the lithosphere, hydrosphere, <a href="/article/Atmosphere_layers">atmosphere</a> and other &quot;spheres&quot; (e.g. <a href="/article/Cryosphere">cryosphere</a>, anthrosphere, etc.). The biosphere includes all living organisms on earth, together with the dead organic matter produced by them. </p> <p>The biosphere concept is common to many scientific disciplines including astronomy, geophysics, geology, hydrology, biogeography and <a href="/article/Evolution">evolution</a>, and is a core concept in <a href="/article/Ecology">ecology</a>, earth science and <a href="/article/Physical_geography">physical geography</a>. A key component of earth systems, the biosphere interacts with and exchanges <a href="/article/Matter">matter</a> and energy with the other spheres, helping to drive the global biogeochemical cycling of <a href="/article/Carbon_cycle">carbon</a>, <a href="/article/Nitrogen_cycle">nitrogen</a>, phosphorus, sulfur and other <a href="/article/Elements">elements</a>. From an ecological point of view, the biosphere is the &quot;global <a href="/article/Ecosystem">ecosystem</a>&quot;, comprising the totality of <a href="/article/Biodiversity">biodiversity</a> on earth and performing all manner of biological functions, including <a href="/article/Photosynthesis">photosynthesis</a>, respiration, decomposition, nitrogen fixation and denitrification. </p><p>The biosphere is dynamic, undergoing strong seasonal cycles in primary productivity and the many biological processes driven by the energy captured by photosynthesis. Seasonal cycles in solar irradiation of the hemispheres is the main driver of this dynamic, especially by its strong effect on <a href="/article/Terrestrial_biome">terrestrial</a> primary productivity in the temperate and boreal <a href="/article/Biome">biomes</a>, which essentially cease productivity in the winter time. </p><p>The biosphere has evolved since the first single-celled organisms originated 3.5 billion years ago under atmospheric conditions resembling those of our neighboring planets Mars and Venus, which have atmospheres composed primarily of <a href="/article/Carbon_dioxide">carbon dioxide</a>. Billions of years of primary production by plants released <a href="/article/Oxygen">oxygen</a> from this carbon dioxide and deposited the carbon in sediments, eventually producing the oxygen-rich <a href="/article/Atmospheric_composition">atmosphere</a> we know today. Free oxygen, both for breathing (O₂, respiration) and in the stratospheric <a href="/article/Ozone">ozone</a> (O₃) that protects us from harmful UV radiation, has made possible life as we know it while transforming the chemistry of earth systems forever. </p><p>As a result of long-term interactions between the biosphere and the other earth systems, there is almost no part of the earth&#39;s surface that has not been profoundly altered by living organisms. The earth is a living planet, even in terms of its physics and chemistry. A concept related to, but different from, that of the biosphere, is the <a href="/article/Environmental_ethics_and_the_Gaia_theory">Gaia hypotheses</a>, which posits that living organisms have and continue to transform earth systems for their own benefit. </p> <p><a href='/article/Biosphere'>Read Full Article...</a></p> http://www.eoearth.org/article/Biosphere Tue, 13 Oct 2009 04:28:53 GMT http://www.eoearth.org/article/PCBs <a href='/article/PCBs'><img border='0' src='/upload/thumb/6/60/PCb_structure.gif/200px-PCb_structure.gif' width='100'/></a> <p>Polychlorinated Biphenyls (PCBs) are mixtures of human-made chemicals with similar chemical structures. PCBs can range from oily liquids to waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer, and hydraulic equipment; as plasticizers in paints, plastics and rubber products; in pigments, dyes and carbonless copy paper and many other applications. More than 1.5 billion pounds of PCBs were manufactured in the United States prior to cessation of production in 1977. </p><p>Concern over the <a href="/article/Toxicity"> toxicity</a> and persistence (chemical stability) in the environment of Polychlorinated Biphenyls (PCBs) led Congress in 1976 to enact Section 6(e) of the Toxic Substances Control Act (TSCA) that included among other things, prohibitions on the manufacture, processing, and distribution in commerce of PCBs. Thus, TSCA legislated true "cradle to grave" (i.e., from manufacture to disposal) management of PCBs in the United States. </p><p>Polychlorinated biphenyls (PCBs) are chemically related to organochlorine pesticides. Each PCB molecule consists of chlorine atoms attached to a double <a href="/article/Carbon">carbon</a>-<a href="/article/Hydrogen">hydrogen</a> ring (a "biphenyl" ring). There are actually 209 different PCB "congeners", which differ in the number and location of chlorine atoms. There are three categories of PCBs: 1) PCBs that are chlorinated in two or more ortho positions (ortho positions are closest to the single bond joining the two aromatic rings); 2) those that are chlorinated in only one ortho position (mono-ortho); and 3) PCBs lacking any ortho chlorination, known as non-ortho or co-planar PCBs. Early work on PCBs focused on PCB mixtures such as A1254, 1260 or 1248. Later work focused on individual PCB congeners, with the greatest emphasis on the co-planar PCBs. Many of the adverse effects of these co-planar PCBs are similar to the adverse effects of dioxins, and other dioxin-like chemicals. Most recently the focus is shifting back to PCB mixtures and to congeners other than the co-planars because, although the co-planar PCBs may be the most potent congeners, other congeners may have important toxic effects as well. </p><p>Like <a href="/article/Chlorinated_pesticides">chlorinated pesticides</a>, PCBs remain in the environment for long periods of time, have low water solubility, and accumulate in fat tissues. Unlike pesticides, PCBs were never purposefully released into the environment to kill plants or animals. Rather, these mixtures of chlorinated compounds were used in industry, mostly as lubricants and heat dissipators in electrical transformers and capacitors, entering the environment through careless behavior. </p><p>There are a broad range of health effects caused by PCB exposure. In birds and fish, PCBs are known to impact the immune system, reproductive system, nervous system, and endocrine system. They also cause a variety of adverse health effects in humans. Studies provide supportive evidence for potential carcinogenic and non-carcinogenic effects, and PCBs are considered probable carcinogens. The different health effects of PCBs may be interrelated, as alterations in one system may have significant implications for the other systems of the body. </p> <p>The General Electric Co. discharged between 209,000 and 1.3 million PCBs into the river from two capacitor manufacturing plants located in Hudson Falls and Fort Edward. Since that time, the spread of PCBs throughout the river and its food chain has created an extensive toxic waste problem. About 200 miles of the river is designated as a Superfund site. In 1976, because of the concern over the bioaccumulation of PCBs in fish and other aquatic organisms and their subsequent consumption by people, the State of New York banned fishing in the Upper Hudson River and commercial fishing of striped bass, and several other species, in the Lower Hudson. In August 1995, the Upper Hudson was re-opened to fishing, but only on a catch and release basis. </p><p>Though required by Superfund laws (CERCLA) to clean up the PCBs, GE continually battled the U.S. Environmental Protection Agency (EPA) over the regulations, although an agreement was finally reached in 2005. Much of the PCBs in the lower Hudson originate from toxic "hot spots" upstream, then disperse downstream, causing continued contamination of the entire Hudson River. Cleanup is finally getting started, but in the past 30 years the PCB-contaminated sediments have spread out to cover a much more considerable stretch of the river than they did originally, making the effort both more extensive and expensive. Elevated PCB levels are found all around the New York/New Jersey Harbor, about 40% of which originates from local sources rather than the upper Hudson. The level of PCBs in white perch populations is strongly related to the percent of development in the local watershed; when the level of development of the watershed fills about 20% of the area, PCB levels in the fish begin to exceed the recommended levels safe for food consumption. This indicates that <a href="/article/Land-use">land-use</a> (development) near the estuary has important effects on the PCB levels in white perch. Bluefish, being higher up on the food chain and eating mostly other fish, accumulate high levels of PCBs while living in the contaminated estuaries of the system. </p><p>PCBs have been banned in the US since 1976, but they continue to be redistributed and dispersed. More than 25 years after the prohibition, they are still accumulating in fish tissue to an extent that state agencies recommend that people eat no striped bass or blue crabs from the Newark Bay area, and no more than one meal a week from other areas in the New York Harbor estuary. </p><p>Other PCB-contaminated sites include the Housatonic River in Massachusetts which is undergoing remediation, and New Bedford Harbor, Massaschusetts. Some of the highest concentrations of PCBs measured in the country have been measured in wildlife from the Housatonic River or surrounding areas. New Bedfod Harbor is an 18,000-acre tidal estuary with sediments that are highly contaminated with PCBs and heavy metals. Manufacturers in the area used PCBs while producing electric devices from 1940 to the late 1970s, when PCBs were banned. These facilities discharged wastes with PCBs directly into the harbor and into the city's sewage system, which also led into the harbor. PCB levels in fish and lobsters at the site exceed the Food and Drug Administration's (FDA) limit for PCBs in edible seafood. There is an increased risk of cancer and other diseases for people who regularly eat seafood from the area. </p><p>Fish from several highly contaminated sites such as New Bedford Harbor, Newark Bay, New Jersey and the Hudson River have developed resistance to some of the biochemical changes caused by PCBs. These heritable changes are thought to provide some level of protection against <a href="/article/Toxicity">toxicity</a> caused by PCBs and similar chemicals. </p><p><b>Further Reading</b><br /> </p> <ul><li> <a href="http://www.epa.gov/pcb/index.html" class='external text' title="http://www.epa.gov/pcb/index.html">Polychlorinated Biphenyls (PCBs) page at the Environmental Protection Agency</a> </li></ul> <p><br /> <br style="clear: left" /> <center> </p> <p></center> </p> <p><a href='/article/PCBs'>Read Full Article...</a></p> http://www.eoearth.org/article/PCBs Thu, 08 Oct 2009 05:25:17 GMT http://www.eoearth.org/article/PCBs <a href='/article/PCBs'><img border='0' src='/upload/thumb/6/60/PCb_structure.gif/200px-PCb_structure.gif' width='100'/></a> <p>Polychlorinated Biphenyls (PCBs) are mixtures of human-made chemicals with similar chemical structures. PCBs can range from oily liquids to waxy solids. Due to their non-flammability, chemical stability, high boiling point and electrical insulating properties, PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer, and hydraulic equipment; as plasticizers in paints, plastics and rubber products; in pigments, dyes and carbonless copy paper and many other applications. More than 1.5 billion pounds of PCBs were manufactured in the United States prior to cessation of production in 1977. </p><p>Concern over the <a href="/article/Toxicity"> toxicity</a> and persistence (chemical stability) in the environment of Polychlorinated Biphenyls (PCBs) led Congress in 1976 to enact Section 6(e) of the Toxic Substances Control Act (TSCA) that included among other things, prohibitions on the manufacture, processing, and distribution in commerce of PCBs. Thus, TSCA legislated true "cradle to grave" (i.e., from manufacture to disposal) management of PCBs in the United States. </p><p>Polychlorinated biphenyls (PCBs) are chemically related to organochlorine pesticides. Each PCB molecule consists of chlorine atoms attached to a double <a href="/article/Carbon">carbon</a>-<a href="/article/Hydrogen">hydrogen</a> ring (a "biphenyl" ring). There are actually 209 different PCB "congeners", which differ in the number and location of chlorine atoms. There are three categories of PCBs: 1) PCBs that are chlorinated in two or more ortho positions (ortho positions are closest to the single bond joining the two aromatic rings); 2) those that are chlorinated in only one ortho position (mono-ortho); and 3) PCBs lacking any ortho chlorination, known as non-ortho or co-planar PCBs. Early work on PCBs focused on PCB mixtures such as A1254, 1260 or 1248. Later work focused on individual PCB congeners, with the greatest emphasis on the co-planar PCBs. Many of the adverse effects of these co-planar PCBs are similar to the adverse effects of dioxins, and other dioxin-like chemicals. Most recently the focus is shifting back to PCB mixtures and to congeners other than the co-planars because, although the co-planar PCBs may be the most potent congeners, other congeners may have important toxic effects as well. </p><p>Like <a href="/article/Chlorinated_pesticides">chlorinated pesticides</a>, PCBs remain in the environment for long periods of time, have low water solubility, and accumulate in fat tissues. Unlike pesticides, PCBs were never purposefully released into the environment to kill plants or animals. Rather, these mixtures of chlorinated compounds were used in industry, mostly as lubricants and heat dissipators in electrical transformers and capacitors, entering the environment through careless behavior. </p><p>There are a broad range of health effects caused by PCB exposure. In birds and fish, PCBs are known to impact the immune system, reproductive system, nervous system, and endocrine system. They also cause a variety of adverse health effects in humans. Studies provide supportive evidence for potential carcinogenic and non-carcinogenic effects, and PCBs are considered probable carcinogens. The different health effects of PCBs may be interrelated, as alterations in one system may have significant implications for the other systems of the body. </p> <p>The General Electric Co. discharged between 209,000 and 1.3 million PCBs into the river from two capacitor manufacturing plants located in Hudson Falls and Fort Edward. Since that time, the spread of PCBs throughout the river and its food chain has created an extensive toxic waste problem. About 200 miles of the river is designated as a Superfund site. In 1976, because of the concern over the bioaccumulation of PCBs in fish and other aquatic organisms and their subsequent consumption by people, the State of New York banned fishing in the Upper Hudson River and commercial fishing of striped bass, and several other species, in the Lower Hudson. In August 1995, the Upper Hudson was re-opened to fishing, but only on a catch and release basis. </p><p>Though required by Superfund laws (CERCLA) to clean up the PCBs, GE continually battled the U.S. Environmental Protection Agency (EPA) over the regulations, although an agreement was finally reached in 2005. Much of the PCBs in the lower Hudson originate from toxic "hot spots" upstream, then disperse downstream, causing continued contamination of the entire Hudson River. Cleanup is finally getting started, but in the past 30 years the PCB-contaminated sediments have spread out to cover a much more considerable stretch of the river than they did originally, making the effort both more extensive and expensive. Elevated PCB levels are found all around the New York/New Jersey Harbor, about 40% of which originates from local sources rather than the upper Hudson. The level of PCBs in white perch populations is strongly related to the percent of development in the local watershed; when the level of development of the watershed fills about 20% of the area, PCB levels in the fish begin to exceed the recommended levels safe for food consumption. This indicates that <a href="/article/Land-use">land-use</a> (development) near the estuary has important effects on the PCB levels in white perch. Bluefish, being higher up on the food chain and eating mostly other fish, accumulate high levels of PCBs while living in the contaminated estuaries of the system. </p><p>PCBs have been banned in the US since 1976, but they continue to be redistributed and dispersed. More than 25 years after the prohibition, they are still accumulating in fish tissue to an extent that state agencies recommend that people eat no striped bass or blue crabs from the Newark Bay area, and no more than one meal a week from other areas in the New York Harbor estuary. </p><p>Other PCB-contaminated sites include the Housatonic River in Massachusetts which is undergoing remediation, and New Bedford Harbor, Massaschusetts. Some of the highest concentrations of PCBs measured in the country have been measured in wildlife from the Housatonic River or surrounding areas. New Bedfod Harbor is an 18,000-acre tidal estuary with sediments that are highly contaminated with PCBs and heavy metals. Manufacturers in the area used PCBs while producing electric devices from 1940 to the late 1970s, when PCBs were banned. These facilities discharged wastes with PCBs directly into the harbor and into the city's sewage system, which also led into the harbor. PCB levels in fish and lobsters at the site exceed the Food and Drug Administration's (FDA) limit for PCBs in edible seafood. There is an increased risk of cancer and other diseases for people who regularly eat seafood from the area. </p><p>Fish from several highly contaminated sites such as New Bedford Harbor, Newark Bay, New Jersey and the Hudson River have developed resistance to some of the biochemical changes caused by PCBs. These heritable changes are thought to provide some level of protection against <a href="/article/Toxicity">toxicity</a> caused by PCBs and similar chemicals. </p><p><b>Further Reading</b><br /> </p> <ul><li> <a href="http://www.epa.gov/pcb/index.html" class='external text' title="http://www.epa.gov/pcb/index.html">Polychlorinated Biphenyls (PCBs) page at the Environmental Protection Agency</a> </li></ul> <p><br /> <br style="clear: left" /> <center> </p> <p></center> </p> <p><a href='/article/PCBs'>Read Full Article...</a></p> http://www.eoearth.org/article/PCBs Thu, 08 Oct 2009 05:24:40 GMT http://www.eoearth.org/article/United_Nations_Millennium_Declaration <a href='/article/United_Nations_Millennium_Declaration'><img border='0' src='/upload/thumb/e/ef/Un_signed_declaration.jpg/350px-Un_signed_declaration.jpg' width='100'/></a> <p>In September 2000, 150 heads of state met at the United Nations and ratified the UN Millennium Declaration. In September 2005, the UN hosted a Millennium+5 Summit to evaluate the progress towards the goals spelled out in the document. Leaders also resolved to meet a number of <a href="/article/Millennium_Development_Goals_%28MDGs%29">Millennium Development Goals (MDGs)</a>, which include halving the proportion of people living in poverty and hunger by 2015, ensuring primary schooling for all children, and reversing the spread of HIV/AIDS, malaria and other major diseases. </p><p>The full text of the 2000 Millennium Declaration is given below. </p> <dl><dd><strong>I. Values and principles</strong> </dd></dl> <ol><li> We, heads of State and Government, have gathered at United Nations Headquarters in New York from 6 to 8 September 2000, at the dawn of a new millennium, to reaffirm our faith in the Organization and its Charter as indispensable foundations of a more peaceful, prosperous and just world. </li><li> We recognize that, in addition to our separate responsibilities to our individual societies, we have a collective responsibility to uphold the principles of human dignity, equality and equity at the global level. As leaders we have a duty therefore to all the world’s people, especially the most vulnerable and, in particular, the children of the world, to whom the future belongs. </li><li> We reaffirm our commitment to the purposes and principles of the Charter of the United Nations, which have proved timeless and universal. Indeed, their relevance and capacity to inspire have increased, as nations and peoples have become increasingly interconnected and interdependent. </li><li> We are determined to establish a just and lasting peace all over the world in accordance with the purposes and principles of the Charter. We rededicate ourselves to support all efforts to uphold the sovereign equality of all States, respect for their territorial integrity and political independence, resolution of disputes by peaceful means and in conformity with the principles of justice and international law, the right to self-determination of peoples which remain under colonial domination and foreign occupation, non-interference in the internal affairs of States, respect for human rights and fundamental freedoms, respect for the equal rights of all without distinction as to race, sex, language or religion and international cooperation in solving international problems of an economic, social, cultural or humanitarian character. </li><li> We believe that the central challenge we face today is to ensure that globalization becomes a positive force for all the world’s people. For while globalization offers great opportunities, at present its benefits are very unevenly shared, while its costs are unevenly distributed. We recognize that developing countries and countries with economies in transition face special difficulties in responding to this central challenge. Thus, only through broad and sustained efforts to create a shared future, based upon our common humanity in all its diversity, can globalization be made fully inclusive and equitable. These efforts must include policies and measures, at the global level, which correspond to the needs of developing countries and economies in transition and are formulated and implemented with their effective participation. </li><li> We consider certain fundamental values to be essential to international relations in the twenty-first century. These include: <ul><li> <strong>Freedom.</strong> Men and women have the right to live their lives and raise their children in dignity, free from hunger and from the fear of violence, oppression or injustice. Democratic and participatory governance based on the will of the people best assures these rights. </li><li> <strong>Equality.</strong> No individual and no nation must be denied the opportunity to benefit from development. The equal rights and opportunities of women and men must be assured. </li><li> <strong>Solidarity.</strong> Global challenges must be managed in a way that distributes the costs and burdens fairly in accordance with basic principles of equity and social justice. Those who suffer or who benefit least deserve help from those who benefit most. </li><li> <strong>Tolerance.</strong> Human beings must respect one other, in all their diversity of belief, culture and language. Differences within and between societies should be neither feared nor repressed, but cherished as a precious asset of humanity. A culture of peace and dialogue among all civilizations should be actively promoted. </li><li> <strong>Respect for nature.</strong> Prudence must be shown in the management of all living species and natural resources, in accordance with the precepts of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>. Only in this way can the immeasurable riches provided to us by nature be preserved and passed on to our descendants. The current unsustainable patterns of production and consumption must be changed in the interest of our future welfare and that of our descendants. </li><li> <strong>Shared responsibility.</strong> Responsibility for managing worldwide economic and social development, as well as threats to international peace and security, must be shared among the nations of the world and should be exercised multilaterally. As the most universal and most representative organization in the world, the United Nations must play the central role. </li></ul> </li><li> In order to translate these shared values into actions, we have identified key objectives to which we assign special significance. <dl><dd> <br /> </dd><dd> <strong>II. Peace, security and disarmament</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our peoples from the scourge of war, whether within or between States, which has claimed more than 5 million lives in the past decade. We will also seek to eliminate the dangers posed by weapons of mass destruction. </li><li> We resolve therefore: <ul><li> To strengthen respect for the rule of law in international as in national affairs and, in particular, to ensure compliance by Member States with the decisions of the International Court of Justice, in compliance with the Charter of the United Nations, in cases to which they are parties. </li><li> To make the United Nations more effective in maintaining peace and security by giving it the resources and tools it needs for conflict prevention, peaceful resolution of disputes, peacekeeping, post-conflict peace-building and reconstruction. In this context, we take note of the report of the Panel on United Nations Peace Operations and request the General Assembly to consider its recommendations expeditiously. </li><li> To strengthen cooperation between the United Nations and regional organizations, in accordance with the provisions of Chapter VIII of the Charter. </li><li> To ensure the implementation, by States Parties, of treaties in areas such as arms control and disarmament and of international humanitarian law and human rights law, and call upon all States to consider signing and ratifying the Rome Statute of the International Criminal Court. </li><li> To take concerted action against international terrorism, and to accede as soon as possible to all the relevant international conventions. </li><li> To redouble our efforts to implement our commitment to counter the world drug problem. </li><li> To intensify our efforts to fight transnational crime in all its dimensions, including trafficking as well as smuggling in human beings and money laundering. </li><li> To minimize the adverse effects of United Nations economic sanctions on innocent populations, to subject such sanctions regimes to regular reviews and to eliminate the adverse effects of sanctions on third parties. </li><li> To strive for the elimination of weapons of mass destruction, particularly nuclear weapons, and to keep all options open for achieving this aim, including the possibility of convening an international conference to identify ways of eliminating nuclear dangers. </li><li> To take concerted action to end illicit traffic in small arms and light weapons, especially by making arms transfers more transparent and supporting regional disarmament measures, taking account of all the recommendations of the forthcoming United Nations Conference on Illicit Trade in Small Arms and Light Weapons. </li><li> To call on all States to consider acceding to the Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-personnel Mines and on Their Destruction, as well as the amended mines protocol to the Convention on conventional weapons. </li></ul> </li><li> We urge Member States to observe the Olympic Truce, individually and collectively, now and in the future, and to support the International Olympic Committee in its efforts to promote peace and human understanding through sport and the Olympic Ideal. <dl><dd> <br /> </dd><dd> <strong>III. Development and poverty eradication</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our fellow men, women and children from the abject and dehumanizing conditions of extreme poverty, to which more than a billion of them are currently subjected. We are committed to making the right to development a reality for everyone and to freeing the entire human race from want. </li><li> We resolve therefore to create an environment – at the national and global levels alike – which is conducive to development and to the elimination of poverty. </li><li> Success in meeting these objectives depends, <em>inter alia</em>, on good governance within each country. It also depends on good governance at the international level and on transparency in the financial, monetary and trading systems. We are committed to an open, equitable, rule-based, predictable and non-discriminatory multilateral trading and financial system. </li><li> We are concerned about the obstacles developing countries face in mobilizing the resources needed to finance their <a href="/article/Sustainomics_and_sustainable_development">sustained development</a>. We will therefore make every effort to ensure the success of the High-level International and Intergovernmental Event on Financing for Development, to be held in 2001. </li><li> We also undertake to address the special needs of the least developed countries. In this context, we welcome the Third United Nations Conference on the Least Developed Countries to be held in May 2001 and will endeavour to ensure its success. We call on the industrialized countries: <ul><li> To adopt, preferably by the time of that Conference, a policy of duty- and quota-free access for essentially all exports from the least developed countries; </li><li> To implement the enhanced programme of debt relief for the heavily indebted poor countries without further delay and to agree to cancel all official bilateral debts of those countries in return for their making demonstrable commitments to poverty reduction; and </li><li> To grant more generous development assistance, especially to countries that are genuinely making an effort to apply their resources to poverty reduction. </li></ul> </li><li> We are also determined to deal comprehensively and effectively with the debt problems of low- and middle-income developing countries, through various national and international measures designed to make their debt sustainable in the long term. </li><li> We also resolve to address the special needs of small island developing States, by implementing the Barbados Programme of Action and the outcome of the twenty-second special session of the General Assembly rapidly and in full. We urge the international community to ensure that, in the development of a vulnerability index, the special needs of small island developing States are taken into account. </li><li> We recognize the special needs and problems of the landlocked developing countries, and urge both bilateral and multilateral donors to increase financial and technical assistance to this group of countries to meet their special development needs and to help them overcome the impediments of <a href="/article/Geography">geography</a> by improving their transit transport systems. </li><li> We resolve further: <ul><li> To halve, by the year 2015, the proportion of the world’s people whose income is less than one dollar a day and the proportion of people who suffer from hunger and, by the same date, to halve the proportion of people who are unable to reach or to afford safe drinking <a href="/article/Society_and_water_resources">water</a>. </li><li> To ensure that, by the same date, children everywhere, boys and girls alike, will be able to complete a full course of primary schooling and that girls and boys will have equal access to all levels of education. </li><li> By the same date, to have reduced maternal mortality by three quarters, and under-five child mortality by two thirds, of their current rates. </li><li> To have, by then, halted, and begun to reverse, the spread of HIV/AIDS, the scourge of <a href="/article/Malaria">malaria</a> and other major diseases that afflict humanity. </li><li> To provide special assistance to children orphaned by HIV/AIDS. </li><li> By 2020, to have achieved a significant improvement in the lives of at least 100 million slum dwellers as proposed in the &quot;Cities Without Slums&quot; initiative. </li></ul> </li><li> We also resolve: <ul><li> To promote gender equality and the empowerment of women as effective ways to combat poverty, hunger and disease and to stimulate development that is truly <a href="/article/Sustainomics_and_sustainable_development">sustainable</a>. </li><li> To develop and implement strategies that give young people everywhere a real chance to find decent and productive work. </li><li> To encourage the pharmaceutical industry to make essential drugs more widely available and affordable by all who need them in developing countries. </li><li> To develop strong partnerships with the private sector and with civil society organizations in pursuit of development and poverty eradication. </li><li> To ensure that the benefits of new technologies, especially information and communication technologies, in conformity with recommendations contained in the United Nations Economic and Social Council (ECOSOC) 2000 Ministerial Declaration, are available to all. </li></ul> <dl><dd> <br /> </dd><dd> <strong>IV. Protecting our common environment</strong> </dd><dd> </dd></dl> </li><li> We must spare no effort to free all of humanity, and above all our children and grandchildren, from the threat of living on a planet irredeemably spoilt by human activities, and whose resources would no longer be sufficient for their needs. </li><li> We reaffirm our support for the principles of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, including those set out in Agenda 21, agreed upon at the United Nations Conference on Environment and Development. </li><li> We resolve therefore to adopt in all our environmental actions a new ethic of conservation and stewardship and, as first steps, we resolve: <ul><li> To make every effort to ensure the entry into force of the <a href="/article/Kyoto_Protocol">Kyoto Protocol</a>, preferably by the tenth anniversary of the United Nations Conference on Environment and Development in 2002, and to embark on the required reduction in emissions of greenhouse gases. </li><li> To intensify our collective efforts for the <a href="/article/Forestry">management</a>, conservation and sustainable development of all types of forests. </li><li> To press for the full implementation of the <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> and the Convention to Combat Desertification in those Countries Experiencing Serious Drought and/or Desertification, particularly in Africa. </li><li> To stop the unsustainable exploitation of <a href="/article/Water_resources">water resources</a> by developing <a href="/article/Water_governance">water management</a> strategies at the regional, national and local levels, which promote both equitable access and adequate supplies. </li><li> To intensify cooperation to reduce the number and effects of natural and man-made disasters. </li><li> To ensure free access to information on the human genome sequence. </li></ul> <dl><dd> <br /> </dd><dd> <strong>V. Human rights, democracy and good governance</strong></dd></dl> </li><li> We will spare no effort to promote democracy and strengthen the rule of law, as well as respect for all internationally recognized human rights and fundamental freedoms, including the right to development. </li><li> We resolve therefore: <br /> <ul><li>To respect fully and uphold the Universal Declaration of Human Rights. </li><li> To strive for the full protection and promotion in all our countries of civil, political, economic, social and cultural rights for all. </li><li> To strengthen the capacity of all our countries to implement the principles and practices of democracy and respect for human rights, including minority rights. <dl><dd> </dd></dl> </li><li> To combat all forms of violence against women and to implement the Convention on the Elimination of All Forms of Discrimination against Women. </li><li> To take measures to ensure respect for and protection of the human rights of migrants, migrant workers and their families, to eliminate the increasing acts of racism and xenophobia in many societies and to promote greater harmony and tolerance in all societies. </li><li> To work collectively for more inclusive political processes, allowing genuine <a href="/article/Global_citizens_movement">participation by all citizens</a> in all our countries. </li><li> To ensure the freedom of the media to perform their essential role and the right of the public to have access to information. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VI. Protecting the vulnerable</strong> </dd></dl> </li><li> We will spare no effort to ensure that children and all civilian populations that suffer disproportionately the consequences of natural disasters, genocide, armed conflicts and other humanitarian emergencies are given every assistance and protection so that they can resume normal life as soon as possible. We resolve therefore: <ul><li> To expand and strengthen the protection of civilians in complex emergencies, in conformity with international humanitarian law. </li><li> To strengthen international cooperation, including burden sharing in, and the coordination of humanitarian assistance to, countries hosting refugees and to help all refugees and displaced persons to return voluntarily to their homes, in safety and dignity and to be smoothly reintegrated into their societies. </li><li> To encourage the ratification and full implementation of the Convention on the Rights of the Child and its optional protocols on the involvement of children in armed conflict and on the sale of children, child prostitution and child pornography. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VII. Meeting the special needs of Africa</strong> </dd></dl> </li><li> We will support the consolidation of democracy in Africa and assist Africans in their struggle for lasting peace, poverty eradication and <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, thereby bringing Africa into the mainstream of the world economy. </li><li> We resolve therefore: <ul><li> To give full support to the political and institutional structures of emerging democracies in Africa. </li><li> To encourage and sustain regional and subregional mechanisms for preventing conflict and promoting political stability, and to ensure a reliable flow of resources for peacekeeping operations on the continent. </li><li> To take special measures to address the challenges of poverty eradication and sustainable development in Africa, including debt cancellation, improved market access, enhanced Official Development Assistance and increased flows of Foreign Direct Investment, as well as transfers of technology. </li><li> To help Africa build up its capacity to tackle the spread of the HIV/AIDS pandemic and other infectious diseases. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VIII. Strengthening the United Nations</strong> </dd></dl> </li><li> We will spare no effort to make the United Nations a more effective instrument for pursuing all of these priorities: the fight for development for all the peoples of the world, the fight against poverty, ignorance and disease; the fight against injustice; the fight against violence, terror and crime; and the fight against the degradation and destruction of our common home. </li><li> We resolve therefore: <ul><li> To reaffirm the central position of the General Assembly as the chief deliberative, policy-making and representative organ of the United Nations, and to enable it to play that role effectively. </li><li> To intensify our efforts to achieve a comprehensive reform of the Security Council in all its aspects. </li><li> To strengthen further the Economic and Social Council, building on its recent achievements, to help it fulfil the role ascribed to it in the Charter. <dl><dd> </dd></dl> </li><li> To strengthen the International Court of Justice, in order to ensure justice and the rule of law in international affairs. </li><li> To encourage regular consultations and coordination among the principal organs of the United Nations in pursuit of their functions. </li><li> To ensure that the Organization is provided on a timely and predictable basis with the resources it needs to carry out its mandates. </li><li> To urge the Secretariat to make the best use of those resources, in accordance with clear rules and procedures agreed by the General Assembly, in the interests of all Member States, by adopting the best management practices and technologies available and by concentrating on those tasks that reflect the agreed priorities of Member States. </li><li> To promote adherence to the Convention on the Safety of United Nations and Associated Personnel. </li><li> To ensure greater policy coherence and better cooperation between the United Nations, its agencies, the Bretton Woods Institutions and the World Trade Organization, as well as other multilateral bodies, with a view to achieving a fully coordinated approach to the problems of peace and development. </li><li> To strengthen further cooperation between the United Nations and national parliaments through their world organization, the Inter-Parliamentary Union, in various fields, including peace and security, economic and social development, international law and human rights and democracy and gender issues. </li><li> To give greater opportunities to the private sector, non-governmental organizations and civil society, in general, to contribute to the realization of the Organization’s goals and programmes. </li></ul> </li><li> We request the General Assembly to review on a regular basis the progress made in implementing the provisions of this Declaration, and ask the Secretary-General to issue periodic reports for consideration by the General Assembly and as a basis for further action. </li><li> We solemnly reaffirm, on this historic occasion, that the United Nations is the indispensable common house of the entire human family, through which we will seek to realize our universal aspirations for peace, cooperation and development. We therefore pledge our unstinting support for these common objectives and our determination to achieve them. </li></ol> <p><strong>Further Reading</strong> </p> <ul><li> <a href="http://www.un.org/" class='external text' title="http://www.un.org/">United Nations Homepage</a> </li><li> <a href="http://www.un.org/millennium/" class='external text' title="http://www.un.org/millennium/">United Nations Millennium Assembly</a> </li></ul> <p><br /> <p><br style="clear: left" /> <center> </p> </center> </p> <p><a href='/article/United_Nations_Millennium_Declaration'>Read Full Article...</a></p> http://www.eoearth.org/article/United_Nations_Millennium_Declaration Wed, 07 Oct 2009 06:38:39 GMT http://www.eoearth.org/article/United_Nations_Millennium_Declaration <a href='/article/United_Nations_Millennium_Declaration'><img border='0' src='/upload/thumb/e/ef/Un_signed_declaration.jpg/350px-Un_signed_declaration.jpg' width='100'/></a> <p>In September 2000, 150 heads of state met at the United Nations and ratified the UN Millennium Declaration. In September 2005, the UN hosted a Millennium+5 Summit to evaluate the progress towards the goals spelled out in the document. Leaders also resolved to meet a number of <a href="/article/Millennium_Development_Goals_%28MDGs%29">Millennium Development Goals (MDGs)</a>, which include halving the proportion of people living in poverty and hunger by 2015, ensuring primary schooling for all children, and reversing the spread of HIV/AIDS, malaria and other major diseases. </p><p>The full text of the 2000 Millennium Declaration is given below. </p> <dl><dd><strong>I. Values and principles</strong> </dd></dl> <ol><li> We, heads of State and Government, have gathered at United Nations Headquarters in New York from 6 to 8 September 2000, at the dawn of a new millennium, to reaffirm our faith in the Organization and its Charter as indispensable foundations of a more peaceful, prosperous and just world. </li><li> We recognize that, in addition to our separate responsibilities to our individual societies, we have a collective responsibility to uphold the principles of human dignity, equality and equity at the global level. As leaders we have a duty therefore to all the world’s people, especially the most vulnerable and, in particular, the children of the world, to whom the future belongs. </li><li> We reaffirm our commitment to the purposes and principles of the Charter of the United Nations, which have proved timeless and universal. Indeed, their relevance and capacity to inspire have increased, as nations and peoples have become increasingly interconnected and interdependent. </li><li> We are determined to establish a just and lasting peace all over the world in accordance with the purposes and principles of the Charter. We rededicate ourselves to support all efforts to uphold the sovereign equality of all States, respect for their territorial integrity and political independence, resolution of disputes by peaceful means and in conformity with the principles of justice and international law, the right to self-determination of peoples which remain under colonial domination and foreign occupation, non-interference in the internal affairs of States, respect for human rights and fundamental freedoms, respect for the equal rights of all without distinction as to race, sex, language or religion and international cooperation in solving international problems of an economic, social, cultural or humanitarian character. </li><li> We believe that the central challenge we face today is to ensure that globalization becomes a positive force for all the world’s people. For while globalization offers great opportunities, at present its benefits are very unevenly shared, while its costs are unevenly distributed. We recognize that developing countries and countries with economies in transition face special difficulties in responding to this central challenge. Thus, only through broad and sustained efforts to create a shared future, based upon our common humanity in all its diversity, can globalization be made fully inclusive and equitable. These efforts must include policies and measures, at the global level, which correspond to the needs of developing countries and economies in transition and are formulated and implemented with their effective participation. </li><li> We consider certain fundamental values to be essential to international relations in the twenty-first century. These include: <ul><li> <strong>Freedom.</strong> Men and women have the right to live their lives and raise their children in dignity, free from hunger and from the fear of violence, oppression or injustice. Democratic and participatory governance based on the will of the people best assures these rights. </li><li> <strong>Equality.</strong> No individual and no nation must be denied the opportunity to benefit from development. The equal rights and opportunities of women and men must be assured. </li><li> <strong>Solidarity.</strong> Global challenges must be managed in a way that distributes the costs and burdens fairly in accordance with basic principles of equity and social justice. Those who suffer or who benefit least deserve help from those who benefit most. </li><li> <strong>Tolerance.</strong> Human beings must respect one other, in all their diversity of belief, culture and language. Differences within and between societies should be neither feared nor repressed, but cherished as a precious asset of humanity. A culture of peace and dialogue among all civilizations should be actively promoted. </li><li> <strong>Respect for nature.</strong> Prudence must be shown in the management of all living species and natural resources, in accordance with the precepts of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>. Only in this way can the immeasurable riches provided to us by nature be preserved and passed on to our descendants. The current unsustainable patterns of production and consumption must be changed in the interest of our future welfare and that of our descendants. </li><li> <strong>Shared responsibility.</strong> Responsibility for managing worldwide economic and social development, as well as threats to international peace and security, must be shared among the nations of the world and should be exercised multilaterally. As the most universal and most representative organization in the world, the United Nations must play the central role. </li></ul> </li><li> In order to translate these shared values into actions, we have identified key objectives to which we assign special significance. <dl><dd> <br /> </dd><dd> <strong>II. Peace, security and disarmament</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our peoples from the scourge of war, whether within or between States, which has claimed more than 5 million lives in the past decade. We will also seek to eliminate the dangers posed by weapons of mass destruction. </li><li> We resolve therefore: <ul><li> To strengthen respect for the rule of law in international as in national affairs and, in particular, to ensure compliance by Member States with the decisions of the International Court of Justice, in compliance with the Charter of the United Nations, in cases to which they are parties. </li><li> To make the United Nations more effective in maintaining peace and security by giving it the resources and tools it needs for conflict prevention, peaceful resolution of disputes, peacekeeping, post-conflict peace-building and reconstruction. In this context, we take note of the report of the Panel on United Nations Peace Operations and request the General Assembly to consider its recommendations expeditiously. </li><li> To strengthen cooperation between the United Nations and regional organizations, in accordance with the provisions of Chapter VIII of the Charter. </li><li> To ensure the implementation, by States Parties, of treaties in areas such as arms control and disarmament and of international humanitarian law and human rights law, and call upon all States to consider signing and ratifying the Rome Statute of the International Criminal Court. </li><li> To take concerted action against international terrorism, and to accede as soon as possible to all the relevant international conventions. </li><li> To redouble our efforts to implement our commitment to counter the world drug problem. </li><li> To intensify our efforts to fight transnational crime in all its dimensions, including trafficking as well as smuggling in human beings and money laundering. </li><li> To minimize the adverse effects of United Nations economic sanctions on innocent populations, to subject such sanctions regimes to regular reviews and to eliminate the adverse effects of sanctions on third parties. </li><li> To strive for the elimination of weapons of mass destruction, particularly nuclear weapons, and to keep all options open for achieving this aim, including the possibility of convening an international conference to identify ways of eliminating nuclear dangers. </li><li> To take concerted action to end illicit traffic in small arms and light weapons, especially by making arms transfers more transparent and supporting regional disarmament measures, taking account of all the recommendations of the forthcoming United Nations Conference on Illicit Trade in Small Arms and Light Weapons. </li><li> To call on all States to consider acceding to the Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-personnel Mines and on Their Destruction, as well as the amended mines protocol to the Convention on conventional weapons. </li></ul> </li><li> We urge Member States to observe the Olympic Truce, individually and collectively, now and in the future, and to support the International Olympic Committee in its efforts to promote peace and human understanding through sport and the Olympic Ideal. <dl><dd> <br /> </dd><dd> <strong>III. Development and poverty eradication</strong> </dd><dd> </dd></dl> </li><li> We will spare no effort to free our fellow men, women and children from the abject and dehumanizing conditions of extreme poverty, to which more than a billion of them are currently subjected. We are committed to making the right to development a reality for everyone and to freeing the entire human race from want. </li><li> We resolve therefore to create an environment – at the national and global levels alike – which is conducive to development and to the elimination of poverty. </li><li> Success in meeting these objectives depends, <em>inter alia</em>, on good governance within each country. It also depends on good governance at the international level and on transparency in the financial, monetary and trading systems. We are committed to an open, equitable, rule-based, predictable and non-discriminatory multilateral trading and financial system. </li><li> We are concerned about the obstacles developing countries face in mobilizing the resources needed to finance their <a href="/article/Sustainomics_and_sustainable_development">sustained development</a>. We will therefore make every effort to ensure the success of the High-level International and Intergovernmental Event on Financing for Development, to be held in 2001. </li><li> We also undertake to address the special needs of the least developed countries. In this context, we welcome the Third United Nations Conference on the Least Developed Countries to be held in May 2001 and will endeavour to ensure its success. We call on the industrialized countries: <ul><li> To adopt, preferably by the time of that Conference, a policy of duty- and quota-free access for essentially all exports from the least developed countries; </li><li> To implement the enhanced programme of debt relief for the heavily indebted poor countries without further delay and to agree to cancel all official bilateral debts of those countries in return for their making demonstrable commitments to poverty reduction; and </li><li> To grant more generous development assistance, especially to countries that are genuinely making an effort to apply their resources to poverty reduction. </li></ul> </li><li> We are also determined to deal comprehensively and effectively with the debt problems of low- and middle-income developing countries, through various national and international measures designed to make their debt sustainable in the long term. </li><li> We also resolve to address the special needs of small island developing States, by implementing the Barbados Programme of Action and the outcome of the twenty-second special session of the General Assembly rapidly and in full. We urge the international community to ensure that, in the development of a vulnerability index, the special needs of small island developing States are taken into account. </li><li> We recognize the special needs and problems of the landlocked developing countries, and urge both bilateral and multilateral donors to increase financial and technical assistance to this group of countries to meet their special development needs and to help them overcome the impediments of <a href="/article/Geography">geography</a> by improving their transit transport systems. </li><li> We resolve further: <ul><li> To halve, by the year 2015, the proportion of the world’s people whose income is less than one dollar a day and the proportion of people who suffer from hunger and, by the same date, to halve the proportion of people who are unable to reach or to afford safe drinking <a href="/article/Society_and_water_resources">water</a>. </li><li> To ensure that, by the same date, children everywhere, boys and girls alike, will be able to complete a full course of primary schooling and that girls and boys will have equal access to all levels of education. </li><li> By the same date, to have reduced maternal mortality by three quarters, and under-five child mortality by two thirds, of their current rates. </li><li> To have, by then, halted, and begun to reverse, the spread of HIV/AIDS, the scourge of <a href="/article/Malaria">malaria</a> and other major diseases that afflict humanity. </li><li> To provide special assistance to children orphaned by HIV/AIDS. </li><li> By 2020, to have achieved a significant improvement in the lives of at least 100 million slum dwellers as proposed in the &quot;Cities Without Slums&quot; initiative. </li></ul> </li><li> We also resolve: <ul><li> To promote gender equality and the empowerment of women as effective ways to combat poverty, hunger and disease and to stimulate development that is truly <a href="/article/Sustainomics_and_sustainable_development">sustainable</a>. </li><li> To develop and implement strategies that give young people everywhere a real chance to find decent and productive work. </li><li> To encourage the pharmaceutical industry to make essential drugs more widely available and affordable by all who need them in developing countries. </li><li> To develop strong partnerships with the private sector and with civil society organizations in pursuit of development and poverty eradication. </li><li> To ensure that the benefits of new technologies, especially information and communication technologies, in conformity with recommendations contained in the United Nations Economic and Social Council (ECOSOC) 2000 Ministerial Declaration, are available to all. </li></ul> <dl><dd> <br /> </dd><dd> <strong>IV. Protecting our common environment</strong> </dd><dd> </dd></dl> </li><li> We must spare no effort to free all of humanity, and above all our children and grandchildren, from the threat of living on a planet irredeemably spoilt by human activities, and whose resources would no longer be sufficient for their needs. </li><li> We reaffirm our support for the principles of <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, including those set out in Agenda 21, agreed upon at the United Nations Conference on Environment and Development. </li><li> We resolve therefore to adopt in all our environmental actions a new ethic of conservation and stewardship and, as first steps, we resolve: <ul><li> To make every effort to ensure the entry into force of the <a href="/article/Kyoto_Protocol">Kyoto Protocol</a>, preferably by the tenth anniversary of the United Nations Conference on Environment and Development in 2002, and to embark on the required reduction in emissions of greenhouse gases. </li><li> To intensify our collective efforts for the <a href="/article/Forestry">management</a>, conservation and sustainable development of all types of forests. </li><li> To press for the full implementation of the <a href="/article/Convention_on_Biological_Diversity">Convention on Biological Diversity</a> and the Convention to Combat Desertification in those Countries Experiencing Serious Drought and/or Desertification, particularly in Africa. </li><li> To stop the unsustainable exploitation of <a href="/article/Water_resources">water resources</a> by developing <a href="/article/Water_governance">water management</a> strategies at the regional, national and local levels, which promote both equitable access and adequate supplies. </li><li> To intensify cooperation to reduce the number and effects of natural and man-made disasters. </li><li> To ensure free access to information on the human genome sequence. </li></ul> <dl><dd> <br /> </dd><dd> <strong>V. Human rights, democracy and good governance</strong></dd></dl> </li><li> We will spare no effort to promote democracy and strengthen the rule of law, as well as respect for all internationally recognized human rights and fundamental freedoms, including the right to development. </li><li> We resolve therefore: <br /> <ul><li>To respect fully and uphold the Universal Declaration of Human Rights. </li><li> To strive for the full protection and promotion in all our countries of civil, political, economic, social and cultural rights for all. </li><li> To strengthen the capacity of all our countries to implement the principles and practices of democracy and respect for human rights, including minority rights. <dl><dd> </dd></dl> </li><li> To combat all forms of violence against women and to implement the Convention on the Elimination of All Forms of Discrimination against Women. </li><li> To take measures to ensure respect for and protection of the human rights of migrants, migrant workers and their families, to eliminate the increasing acts of racism and xenophobia in many societies and to promote greater harmony and tolerance in all societies. </li><li> To work collectively for more inclusive political processes, allowing genuine <a href="/article/Global_citizens_movement">participation by all citizens</a> in all our countries. </li><li> To ensure the freedom of the media to perform their essential role and the right of the public to have access to information. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VI. Protecting the vulnerable</strong> </dd></dl> </li><li> We will spare no effort to ensure that children and all civilian populations that suffer disproportionately the consequences of natural disasters, genocide, armed conflicts and other humanitarian emergencies are given every assistance and protection so that they can resume normal life as soon as possible. We resolve therefore: <ul><li> To expand and strengthen the protection of civilians in complex emergencies, in conformity with international humanitarian law. </li><li> To strengthen international cooperation, including burden sharing in, and the coordination of humanitarian assistance to, countries hosting refugees and to help all refugees and displaced persons to return voluntarily to their homes, in safety and dignity and to be smoothly reintegrated into their societies. </li><li> To encourage the ratification and full implementation of the Convention on the Rights of the Child and its optional protocols on the involvement of children in armed conflict and on the sale of children, child prostitution and child pornography. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VII. Meeting the special needs of Africa</strong> </dd></dl> </li><li> We will support the consolidation of democracy in Africa and assist Africans in their struggle for lasting peace, poverty eradication and <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a>, thereby bringing Africa into the mainstream of the world economy. </li><li> We resolve therefore: <ul><li> To give full support to the political and institutional structures of emerging democracies in Africa. </li><li> To encourage and sustain regional and subregional mechanisms for preventing conflict and promoting political stability, and to ensure a reliable flow of resources for peacekeeping operations on the continent. </li><li> To take special measures to address the challenges of poverty eradication and sustainable development in Africa, including debt cancellation, improved market access, enhanced Official Development Assistance and increased flows of Foreign Direct Investment, as well as transfers of technology. </li><li> To help Africa build up its capacity to tackle the spread of the HIV/AIDS pandemic and other infectious diseases. </li></ul> <dl><dd> <br /> </dd><dd> <strong>VIII. Strengthening the United Nations</strong> </dd></dl> </li><li> We will spare no effort to make the United Nations a more effective instrument for pursuing all of these priorities: the fight for development for all the peoples of the world, the fight against poverty, ignorance and disease; the fight against injustice; the fight against violence, terror and crime; and the fight against the degradation and destruction of our common home. </li><li> We resolve therefore: <ul><li> To reaffirm the central position of the General Assembly as the chief deliberative, policy-making and representative organ of the United Nations, and to enable it to play that role effectively. </li><li> To intensify our efforts to achieve a comprehensive reform of the Security Council in all its aspects. </li><li> To strengthen further the Economic and Social Council, building on its recent achievements, to help it fulfil the role ascribed to it in the Charter. <dl><dd> </dd></dl> </li><li> To strengthen the International Court of Justice, in order to ensure justice and the rule of law in international affairs. </li><li> To encourage regular consultations and coordination among the principal organs of the United Nations in pursuit of their functions. </li><li> To ensure that the Organization is provided on a timely and predictable basis with the resources it needs to carry out its mandates. </li><li> To urge the Secretariat to make the best use of those resources, in accordance with clear rules and procedures agreed by the General Assembly, in the interests of all Member States, by adopting the best management practices and technologies available and by concentrating on those tasks that reflect the agreed priorities of Member States. </li><li> To promote adherence to the Convention on the Safety of United Nations and Associated Personnel. </li><li> To ensure greater policy coherence and better cooperation between the United Nations, its agencies, the Bretton Woods Institutions and the World Trade Organization, as well as other multilateral bodies, with a view to achieving a fully coordinated approach to the problems of peace and development. </li><li> To strengthen further cooperation between the United Nations and national parliaments through their world organization, the Inter-Parliamentary Union, in various fields, including peace and security, economic and social development, international law and human rights and democracy and gender issues. </li><li> To give greater opportunities to the private sector, non-governmental organizations and civil society, in general, to contribute to the realization of the Organization’s goals and programmes. </li></ul> </li><li> We request the General Assembly to review on a regular basis the progress made in implementing the provisions of this Declaration, and ask the Secretary-General to issue periodic reports for consideration by the General Assembly and as a basis for further action. </li><li> We solemnly reaffirm, on this historic occasion, that the United Nations is the indispensable common house of the entire human family, through which we will seek to realize our universal aspirations for peace, cooperation and development. We therefore pledge our unstinting support for these common objectives and our determination to achieve them. </li></ol> <p><strong>Further Reading</strong> </p> <ul><li> <a href="http://www.un.org/" class='external text' title="http://www.un.org/">United Nations Homepage</a> </li><li> <a href="http://www.un.org/millennium/" class='external text' title="http://www.un.org/millennium/">United Nations Millennium Assembly</a> </li></ul> <p><br /> <p><br style="clear: left" /> <center> </p> </center> </p> <p><a href='/article/United_Nations_Millennium_Declaration'>Read Full Article...</a></p> http://www.eoearth.org/article/United_Nations_Millennium_Declaration Wed, 07 Oct 2009 06:38:11 GMT http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics <a href='/article/Rachel_Carson's_environmental_ethics'><img border='0' src='/upload/thumb/f/fd/Rachel_Carson.jpg/180px-Rachel_Carson.jpg' width='100'/></a> <p><a href="/article/Carson%2C_Rachel_Louise">Rachel Carson</a> has been called the founder of the U.S. environmental movement, which some date, plausibly, to the publication of <em>Silent Spring</em> in 1962. That best-selling book focused public attention on the problem of <a href="/article/Pesticide">pesticide</a> and other chemical pollution, and led to such landmark legislation as the U.S. Clean Water Act and the banning of <a href="/article/DDT">DDT</a> in many countries throughout the world. Whatever Carson&#39;s arguments were in <em>Silent Spring</em>, they succeeded. Yet she has received little attention from environmental ethicists.</p><p>I believe Rachel Carson was not just a successful polemicist, but an important environmental thinker. With the recent publication of a definitive biography, <a href="/contributor/Linda.lear">Linda Lear&#39;s</a> <em>Rachel Carson: Witness for Nature</em>, we can better understand her environmental philosophy, for Carson lived that philosophy as well as wrote about it. Meeting Carson the scientist and naturalist clarifies her understanding of the role knowledge can play in a larger relationship to nature. Studying her fifteen-year career as a <a href="/article/United_States_Fish_and_Wildlife_Service">U.S. Fish and Wildlife Service</a> biologist gives valuable insight into her views on practical conservation issues. Carson&#39;s personal story teaches us much about humility and courage, as she triumphed over various setbacks and achieved great literary success, while faithfully discharging her many responsibilities to family, friends, and nature. Still, in order to best understand Carson&#39;s environmental ethics, the place to start is with her final work, <em>Silent Spring</em>. </p> <p><a href='/article/Rachel_Carson's_environmental_ethics'>Read Full Article...</a></p> http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics Wed, 07 Oct 2009 06:33:05 GMT http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics <a href='/article/Rachel_Carson's_environmental_ethics'><img border='0' src='/upload/thumb/f/fd/Rachel_Carson.jpg/180px-Rachel_Carson.jpg' width='100'/></a> <p><a href="/article/Carson%2C_Rachel_Louise">Rachel Carson</a> has been called the founder of the U.S. environmental movement, which some date, plausibly, to the publication of <em>Silent Spring</em> in 1962. That best-selling book focused public attention on the problem of <a href="/article/Pesticide">pesticide</a> and other chemical pollution, and led to such landmark legislation as the U.S. Clean Water Act and the banning of <a href="/article/DDT">DDT</a> in many countries throughout the world. Whatever Carson&#39;s arguments were in <em>Silent Spring</em>, they succeeded. Yet she has received little attention from environmental ethicists.</p><p>I believe Rachel Carson was not just a successful polemicist, but an important environmental thinker. With the recent publication of a definitive biography, <a href="/contributor/Linda.lear">Linda Lear&#39;s</a> <em>Rachel Carson: Witness for Nature</em>, we can better understand her environmental philosophy, for Carson lived that philosophy as well as wrote about it. Meeting Carson the scientist and naturalist clarifies her understanding of the role knowledge can play in a larger relationship to nature. Studying her fifteen-year career as a <a href="/article/United_States_Fish_and_Wildlife_Service">U.S. Fish and Wildlife Service</a> biologist gives valuable insight into her views on practical conservation issues. Carson&#39;s personal story teaches us much about humility and courage, as she triumphed over various setbacks and achieved great literary success, while faithfully discharging her many responsibilities to family, friends, and nature. Still, in order to best understand Carson&#39;s environmental ethics, the place to start is with her final work, <em>Silent Spring</em>. </p> <p><a href='/article/Rachel_Carson's_environmental_ethics'>Read Full Article...</a></p> http://www.eoearth.org/article/Rachel_Carson's_environmental_ethics Tue, 06 Oct 2009 06:32:48 GMT http://www.eoearth.org/article/Yosemite_National_Park,_United_States <a href='/article/Yosemite_National_Park,_United_States'><img border='0' src='/upload/thumb/4/45/Yosemite2.jpg/300px-Yosemite2.jpg' width='100'/></a> <p>Yosemite National Park, (37°30&#39;-38°11&#39;N, 119°12&#39;-119°53&#39;W) is a World Heritage Site located in the heart of California, United States. </p> <p><a href='/article/Yosemite_National_Park,_United_States'>Read Full Article...</a></p> http://www.eoearth.org/article/Yosemite_National_Park,_United_States Fri, 02 Oct 2009 05:46:27 GMT http://www.eoearth.org/article/Yosemite_National_Park,_United_States <a href='/article/Yosemite_National_Park,_United_States'><img border='0' src='/upload/thumb/4/45/Yosemite2.jpg/300px-Yosemite2.jpg' width='100'/></a> <p>Yosemite National Park, (37°30&#39;-38°11&#39;N, 119°12&#39;-119°53&#39;W) is a World Heritage Site located in the heart of California, United States. </p> <p><a href='/article/Yosemite_National_Park,_United_States'>Read Full Article...</a></p> http://www.eoearth.org/article/Yosemite_National_Park,_United_States Fri, 02 Oct 2009 05:45:48 GMT http://www.eoearth.org/article/Whaling_for_scientific_research_purposes <a href='/article/Whaling_for_scientific_research_purposes'><img border='0' src='/upload/thumb/9/99/8janphotobig1.jpg/250px-8janphotobig1.jpg' width='100'/></a> <p>A major area of controversy within the international community has been the issuing of permits by States parties to the 1946 International Convention for the Regulation of Whaling (ICRW) for the killing of whales for scientific research purposes. </p> <p>Article VIII of the ICRW provides that: </p> <dl><dd>…any Contracting Government may grant to any of its nationals a special permit authorizing that national to kill, take and treat whales for purposes of scientific research subject to such restrictions as to number and subject to such other conditions as the Contracting Government thinks fit, and the killing, taking, and treating of whales in accordance with the provisions of this Article shall be exempt from the operation of this Convention. Each Contracting Government shall report at once to the Commission all such authorizations which it has granted. Each Contracting Government may at any time revoke any such special permit which it has granted.<br /><br />Any whales taken under these special permits shall so far as practicable be processed and the proceeds shall be dealt with in accordance with directions issued by the Government by which the permit was granted (...) </dd></dl> <p>Before 1982, when it was decided that a moratorium on commercial whaling would come into effect in 1986, more than 100 permits for scientific research purposes were issued by a number of governments including Canada, USA, USSR, South Africa and Japan. Since the beginning of the moratorium, Japan, Norway and Iceland have issued scientific research permits. Currently, Iceland and Japan are the two countries that are engaged in whaling for “scientific purposes”. </p><p>The applications for the permits are reviewed by the Scientific Committee which has to follow a set of guidelines established by the International Whaling Commission (IWC). One of the most recent guidelines states that: </p> <blockquote> (the IWC) requests the Scientific Committee, with respect to all Special Permit Research Programmes, to provide advice to the Commission, on the research to be undertaken pursuant to any proposed Special Permit or that has been undertaken in respect of any Special Permit, as to whether the information sought in the research programme under each Special Permit is: required for the purposes of management of the species or stock being researched; and whether the information sought could be obtained by non-lethal means. (<i>Report of the International Whaling Commission 45: 82ff.</i>)</blockquote> <p>While plenty of information can be obtained by using non-lethal research methods such as biopsy sampling and photo-identification, according to the Scientific Committee of the IWC, data such as the age of an animal (obtained from earplugs) and the reproductive status and history of females (obtained from ovaries) can be obtained only by lethal methods. The question is whether these data are really ‘essential’, ‘reliable enough’ or ‘critical’ to justify the taking of the whales that are studied. Since 1987, a number of IWC Resolutions have expressed concern over the fact that the "provision permitting special permit whaling enables countries to conduct whaling for commercial purposes despite the moratorium on commercial whaling" (IWC Resolution 2003-2), including the notion that non-lethal techniques usually provide better data at less cost to both animals and budget. In 2006, Japan has responded that its research - including the use of lethal techniques - is" consistent with the unanimous decision of the IWC in 2001 to make the study of interactions between whales and fisheries a priority" (The Government of Japan’s Position for the 58th Annual Meeting of the IWC). </p> <p><a href='/article/Whaling_for_scientific_research_purposes'>Read Full Article...</a></p> http://www.eoearth.org/article/Whaling_for_scientific_research_purposes Thu, 01 Oct 2009 08:12:21 GMT http://www.eoearth.org/article/Whaling_for_scientific_research_purposes <a href='/article/Whaling_for_scientific_research_purposes'><img border='0' src='/upload/thumb/9/99/8janphotobig1.jpg/250px-8janphotobig1.jpg' width='100'/></a> <p>A major area of controversy within the international community has been the issuing of permits by States parties to the 1946 International Convention for the Regulation of Whaling (ICRW) for the killing of whales for scientific research purposes. </p> <p>Article VIII of the ICRW provides that: </p> <dl><dd>…any Contracting Government may grant to any of its nationals a special permit authorizing that national to kill, take and treat whales for purposes of scientific research subject to such restrictions as to number and subject to such other conditions as the Contracting Government thinks fit, and the killing, taking, and treating of whales in accordance with the provisions of this Article shall be exempt from the operation of this Convention. Each Contracting Government shall report at once to the Commission all such authorizations which it has granted. Each Contracting Government may at any time revoke any such special permit which it has granted.<br /><br />Any whales taken under these special permits shall so far as practicable be processed and the proceeds shall be dealt with in accordance with directions issued by the Government by which the permit was granted (...) </dd></dl> <p>Before 1982, when it was decided that a moratorium on commercial whaling would come into effect in 1986, more than 100 permits for scientific research purposes were issued by a number of governments including Canada, USA, USSR, South Africa and Japan. Since the beginning of the moratorium, Japan, Norway and Iceland have issued scientific research permits. Currently, Iceland and Japan are the two countries that are engaged in whaling for “scientific purposes”. </p><p>The applications for the permits are reviewed by the Scientific Committee which has to follow a set of guidelines established by the International Whaling Commission (IWC). One of the most recent guidelines states that: </p> <blockquote> (the IWC) requests the Scientific Committee, with respect to all Special Permit Research Programmes, to provide advice to the Commission, on the research to be undertaken pursuant to any proposed Special Permit or that has been undertaken in respect of any Special Permit, as to whether the information sought in the research programme under each Special Permit is: required for the purposes of management of the species or stock being researched; and whether the information sought could be obtained by non-lethal means. (<i>Report of the International Whaling Commission 45: 82ff.</i>)</blockquote> <p>While plenty of information can be obtained by using non-lethal research methods such as biopsy sampling and photo-identification, according to the Scientific Committee of the IWC, data such as the age of an animal (obtained from earplugs) and the reproductive status and history of females (obtained from ovaries) can be obtained only by lethal methods. The question is whether these data are really ‘essential’, ‘reliable enough’ or ‘critical’ to justify the taking of the whales that are studied. Since 1987, a number of IWC Resolutions have expressed concern over the fact that the "provision permitting special permit whaling enables countries to conduct whaling for commercial purposes despite the moratorium on commercial whaling" (IWC Resolution 2003-2), including the notion that non-lethal techniques usually provide better data at less cost to both animals and budget. In 2006, Japan has responded that its research - including the use of lethal techniques - is" consistent with the unanimous decision of the IWC in 2001 to make the study of interactions between whales and fisheries a priority" (The Government of Japan’s Position for the 58th Annual Meeting of the IWC). </p> <p><a href='/article/Whaling_for_scientific_research_purposes'>Read Full Article...</a></p> http://www.eoearth.org/article/Whaling_for_scientific_research_purposes Thu, 01 Oct 2009 08:12:02 GMT http://www.eoearth.org/article/Latin_America_and_the_Caribbean_(collection) <a href='/article/Latin_America_and_the_Caribbean_(collection)'><img border='0' src='/media/approved/6/6f/LAC_Collection_header_2.jpg' width='100'/></a> </p><p>Welcome to the Latin America and the Caribbean Collection! This collection focuses on environmental and social issues in a diverse political, cultural, and environmental framework. As one of the highest biodiversity hotspots of the world, this collection attempts to address this complexity through three main geographic regions (Mexico and Central America, the Caribbean, and South America) by profiling each country and ecosystem. This collection is a work in progress, so please visit often to learn more about what is being done in the LAC. </p> <p><a href='/article/Latin_America_and_the_Caribbean_(collection)'>Read Full Article...</a></p> http://www.eoearth.org/article/Latin_America_and_the_Caribbean_(collection) Wed, 30 Sep 2009 07:24:59 GMT http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic <a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'><img border='0' src='/upload/thumb/0/03/Figure11.1_management_forces.JPG/320px-Figure11.1_management_forces.JPG' width='100'/></a> <p>This is Section 11.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a> <br />Lead Author: David R. Klein; Contributing Authors: Leonid M. Baskin, Lyudmila S. Bogoslovskaya, Kjell Danell, Anne Gunn, David B. Irons, Gary P. Kofinas, Kit M. Kovacs, Margarita Magomedova, Rosa H. Meehan, Don E. Russell, Patrick Valkenburg </p> <p><a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic Tue, 29 Sep 2009 07:51:06 GMT http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic <a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'><img border='0' src='/upload/thumb/0/03/Figure11.1_management_forces.JPG/320px-Figure11.1_management_forces.JPG' width='100'/></a> <p>This is Section 11.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a> <br />Lead Author: David R. Klein; Contributing Authors: Leonid M. Baskin, Lyudmila S. Bogoslovskaya, Kjell Danell, Anne Gunn, David B. Irons, Gary P. Kofinas, Kit M. Kovacs, Margarita Magomedova, Rosa H. Meehan, Don E. Russell, Patrick Valkenburg </p> <p><a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic Tue, 29 Sep 2009 07:38:27 GMT http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic <a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'><img border='0' src='/upload/thumb/0/03/Figure11.1_management_forces.JPG/320px-Figure11.1_management_forces.JPG' width='100'/></a> <p>This is Section 11.2 of the <a href="/article/Arctic_Climate_Impact_Assessment_%28full_report%29">Arctic Climate Impact Assessment</a> <br />Lead Author: David R. Klein; Contributing Authors: Leonid M. Baskin, Lyudmila S. Bogoslovskaya, Kjell Danell, Anne Gunn, David B. Irons, Gary P. Kofinas, Kit M. Kovacs, Margarita Magomedova, Rosa H. Meehan, Don E. Russell, Patrick Valkenburg </p> <p><a href='/article/Management_and_conservation_of_wildlife_in_the_Arctic'>Read Full Article...</a></p> http://www.eoearth.org/article/Management_and_conservation_of_wildlife_in_the_Arctic Tue, 29 Sep 2009 05:48:18 GMT http://www.eoearth.org <p><a href=''>Read Full Article...</a></p> http://www.eoearth.org Tue, 29 Sep 2009 05:47:23 GMT http://www.eoearth.org/article/Origin_and_age_of_lakes <a href='/article/Origin_and_age_of_lakes'><img border='0' src='/upload/thumb/2/2a/Intro.gif/200px-Intro.gif' width='100'/></a> <p>Lakes are formed by geological, climatological, biological, and extraterrestrial (meteorites) mechanisms. While most lakes are formed by catastrophic events, others are created more gradually.</p> <p><a href='/article/Origin_and_age_of_lakes'>Read Full Article...</a></p> http://www.eoearth.org/article/Origin_and_age_of_lakes Mon, 28 Sep 2009 07:08:54 GMT http://www.eoearth.org/article/Carbon <a href='/article/Carbon'><img border='0' src='/upload/thumb/1/1f/Carbon_atom.gif/200px-Carbon_atom.gif' width='100'/></a> <p><a href='/article/Carbon'>Read Full Article...</a></p> http://www.eoearth.org/article/Carbon Fri, 25 Sep 2009 05:47:55 GMT http://www.eoearth.org/article/Carbon <a href='/article/Carbon'><img border='0' src='/upload/thumb/1/1f/Carbon_atom.gif/200px-Carbon_atom.gif' width='100'/></a> <p><a href='/article/Carbon'>Read Full Article...</a></p> http://www.eoearth.org/article/Carbon Fri, 25 Sep 2009 05:47:38 GMT http://www.eoearth.org/article/Lake_effect_snow <a href='/article/Lake_effect_snow'><img border='0' src='/upload/thumb/a/ae/Lakeeffect_seawifs_big.jpg/300px-Lakeeffect_seawifs_big.jpg' width='100'/></a> <p>During the fall and winter, many areas of the eastern United States and Canada experience tremendous amounts of <a href="/article/Precipitation_and_fog">snowfall</a>. This snow, known as "lake-effect snow," is generated from the <a href="/article/Temperature">temperature</a> contrast between the cold arctic air moving over the relatively warm waters of the Great Lakes (or other large body of water). Unlike most winter storms, lake effect snows do not build their foundation upon strong areas of low <a href="/article/Pressure">pressure</a>. Instead, they are fueled by the same dry arctic air that is responsible for clearing skies over land in other parts of the country. Specifically, cold arctic air passing over the Great Lakes picks up moisture and deposits it as snow inland from the downwind shore. So while other parts of the northeastern United States are clearing up after a recent cold frontal passage, communities near the Great Lakes wait for the lake effect snow machine to fire up! Barny Wiggin, former Meteorologist-In-Charge at the NWS Office in Buffalo, said it best when he claimed that the ‘weather often "clears up stormy" to the lee of the Great Lakes during the winter.' </p><p>Lake effect snow <a href="/article/Cloud_formation_processes">cloud</a> bands are remarkably persistent and have been known to cause continuous snowfall for as long as 48 hours over a sharply defined <a href="/article/Region">region</a>—an amount that often exceeds that of a typical winter storm (i.e., one associated with a low pressure). Lake effect snows yielding as much as 193 <a href="/article/Meter">centimeters</a> (cm) (76 inches) of light-density snow in 24 hours and fall rates as high as 15 cm (6 inches) per hour have been reported. Furthermore, because <a href="/article/Wind">winds</a> accompanying arctic air masses generally originate from a southwest to northwest direction, lake effect snow typically falls on the east or southeast sides of the <a href="/article/Freshwater_biomes">lakes</a>. In general, lake effect snowfall contributes between 30 and 60 percent of the annual winter snowfall on the eastern and southern shores of the Great Lakes. </p> <p><a href='/article/Lake_effect_snow'>Read Full Article...</a></p> http://www.eoearth.org/article/Lake_effect_snow Thu, 24 Sep 2009 05:41:48 GMT http://www.eoearth.org/article/Perlite <a href='/article/Perlite'><img border='0' src='/upload/thumb/2/23/Perlite2.jpg/250px-Perlite2.jpg' width='100'/></a> <p>Perlite is a type of volcanic glass that expands and becomes porous when it is <a href="/article/Heat">heated</a>. When heated, it can expand to as much as twenty times its original volume. This expansion is the result of heated water: when the glassy lava rock is heated to 1,600 degrees Fahrenheit (871 degrees Celsius), the water molecules trapped in the rock turn into vapor which causes the rock to expand. (This is the same principle as the water in pop corn that causes the kernel to pop when it is heated.) Before it is expanded, perlite is commonly gray, but can also be green, brown, blue or red. After it has been heated, perlite is typically light gray to white. </p><p>Volcanic glass forms when molten rock (lava) pours out of a <a href="/article/Volcano">volcano</a> and cools very, very quickly. Because is cools so quickly, there is no time for crystals to form or for water to escape. Instead, the lava hardens immediately into this glass-like material containing 2-5% water. It is a silicate rock, which means that it has a high percentage of silica (<a href="/article/Silicon">Si</a>). </p><p>Perlite is known in industry in two forms. <em>Crude perlite</em> is prepared by the crushing and screening of perlite into various size fractions. <em>Expanded perlite</em> is perlite after it has been heated.</p> <p><a href='/article/Perlite'>Read Full Article...</a></p> http://www.eoearth.org/article/Perlite Wed, 23 Sep 2009 05:38:11 GMT http://www.eoearth.org/article/Food_web <a href='/article/Food_web'><img border='0' src='/upload/thumb/4/4a/Alaska_food_web.jpg/300px-Alaska_food_web.jpg' width='100'/></a> <p>A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom (Fig. 1). It is also a means of showing how energy and materials (e.g., <a href="/article/Carbon">carbon</a>) flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called &quot;links&quot;, and the species are sometimes referred to as &quot;nodes&quot; in food web diagrams. </p><p>The pioneering animal ecologist <a href="/article/Elton%2C_Charles">Charles Elton</a> (1927) introduced the concept of the food web (which he called food cycle) to general <a href="/article/Ecology">ecological science</a>. As he described it: &quot;The herbivores are usually preyed upon by carnivores, which get the energy of the <a href="/article/Solar_radiation">sunlight</a> at third-hand, and these again may be preyed upon by other carnivores, and so on, until we reach an animal which has no enemies, and which forms, as it were, a terminus on this food cycle. There are, in fact, chains of animals linked together by food, and all dependent in the long run upon plants. We refer to these as &#39;food-chains&#39;, and to all the food chains in a community as the &#39;food-cycle.&#39;&quot; </p><p>A food web differs from a food chain in that the latter shows only a portion of the food web involving a simple, linear series of species (e.g., predator, herbivore, plant) connected by feeding links. A food web aims to depict a more complete picture of the feeding relationships, and can be considered a bundle of many interconnected food chains occurring within the community. All species occupying the same position within a food chain comprise a trophic level within the food web. For instance, all of the plants in the foodweb comprise the first or &quot;primary producer&quot; tropic level, all herbivores comprise the second or &quot;primary consumer&quot; trophic level, and carnivores that eat herbivores comprise the third or &quot;secondary consumer&quot; trophic level. Additional levels, in which carnivores eat other carnivores, comprise a tertiary trophic level.</p><p>Elton emphasized early on that food chains tend to show characteristic patterns of increasing body size as one moves up the food chain, for example from <a href="/article/Phytoplankton">phytoplankton</a> to invertebrate grazers to fishes, or from insects to rodents to larger carnivores like foxes. Because individuals of small-bodied species require less energy and food than individuals of larger-bodied species, a given amount of energy can support a greater number of individuals of the smaller-bodied species. Hence, ecological communities typically show what Elton called a pyramid of numbers (later dubbed the Eltonian pyramid), in which the species at lower trophic levels in the food web tend to be more numerous than those at higher trophic levels. </p> <p>A second reason for the pyramid of numbers is low ecological efficiency: some energy is lost at each transfer between consumer and prey, such that the energy that reaches top predators is a very small fraction of that available in the plants at the base of the food web. Although there is wide variation among types of organisms and types of <a href="/article/Ecosystem">ecosystems</a>, a general rule of thumb is that available energy decreases by about an order of magnitude at each step in the food chain. That is, only about 10% of the energy harvested by plants is consumed and converted into herbivore biomass, only 10% of that makes it into biomass of primary carnivores, and so on. Thus, the structure of food webs is dictated in part by basic constraints set by <a href="/article/Thermodynamics">thermodynamics</a>. The predictable dissipation of energy at each step in food chains is one of the factors thought to limit the length of most food chains to a maximum of four or five steps. Cohen et al. (2003) emphasized that the correlations among body size, abundance, and trophic level produce a characteristic trivariate structure to (pelagic) food webs (Fig. 2). </p><p>The pyramid of numbers is less obvious at the most basal levels in terrestrial communities based on trees, which are typically much larger than the herbivores that feed on them. Pyramids of numbers or biomass may even be inverted in cases where the microscopic plants that support the web show very rapid turnover, that is, where they grow and are eaten so rapidly that there is less plant biomass than herbivore biomass present at a given time. </p><p>Decomposers are an assemblage of small organisms, including invertebrates, fungi, and <a href="/article/Bacteria">bacteria</a>, that do not fit neatly into any trophic level because they consume dead biomass of organisms from all trophic levels. Decomposers are a critical component of the food web, however, because they recycle nutrients that otherwise would become sequestered in accumulating detritus.</p><p><strong>References and further reading</strong></p><ul><li>Cohen, J., T. Jonsson, and S.R. Carpenter. 2003. Ecological community description using the food web, species abundance, and body size. Proceedings of the National Academy of Sciences USA. 100: 1781–1786. </li><li>Elton, C. 1927. Animal ecology. Sidgwick and Jackson Ltd, London, UK. </li><li>Hardy, A.C. 1924. The herring in relation to its animate environment, Part I. Ministry of Agriculture and Fisheries, Fishery Investigations, Series 2, Volume 7, number 3. </li><li>Lindemann, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23: 399-418. </li><li>May, R.M. 1973. Stability and complexity in model food webs. Princeton University Press, Princeton, NJ. </li><li>Morin, P.J. 1999. Community ecology. Blackwell Science, Oxford, UK. </li><li>Paine, R.T. 1980. Food Webs: Linkage, Interaction Strength and Community Infrastructure. Journal of Animal Ecology 49:666-685. </li><li>Pimm, S.L. 1982. Food webs. Chapman and Hall, London. </li></ul> <p><a href='/article/Food_web'>Read Full Article...</a></p> http://www.eoearth.org/article/Food_web Tue, 22 Sep 2009 06:12:50 GMT http://www.eoearth.org/article/Food_web <a href='/article/Food_web'><img border='0' src='/upload/thumb/4/4a/Alaska_food_web.jpg/300px-Alaska_food_web.jpg' width='100'/></a> <p>A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom (Fig. 1). It is also a means of showing how energy and materials (e.g., <a href="/article/Carbon">carbon</a>) flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called &quot;links&quot;, and the species are sometimes referred to as &quot;nodes&quot; in food web diagrams. </p><p>The pioneering animal ecologist <a href="/article/Elton%2C_Charles">Charles Elton</a> (1927) introduced the concept of the food web (which he called food cycle) to general <a href="/article/Ecology">ecological science</a>. As he described it: &quot;The herbivores are usually preyed upon by carnivores, which get the energy of the <a href="/article/Solar_radiation">sunlight</a> at third-hand, and these again may be preyed upon by other carnivores, and so on, until we reach an animal which has no enemies, and which forms, as it were, a terminus on this food cycle. There are, in fact, chains of animals linked together by food, and all dependent in the long run upon plants. We refer to these as &#39;food-chains&#39;, and to all the food chains in a community as the &#39;food-cycle.&#39;&quot; </p><p>A food web differs from a food chain in that the latter shows only a portion of the food web involving a simple, linear series of species (e.g., predator, herbivore, plant) connected by feeding links. A food web aims to depict a more complete picture of the feeding relationships, and can be considered a bundle of many interconnected food chains occurring within the community. All species occupying the same position within a food chain comprise a trophic level within the food web. For instance, all of the plants in the foodweb comprise the first or &quot;primary producer&quot; tropic level, all herbivores comprise the second or &quot;primary consumer&quot; trophic level, and carnivores that eat herbivores comprise the third or &quot;secondary consumer&quot; trophic level. Additional levels, in which carnivores eat other carnivores, comprise a tertiary trophic level.</p><p>Elton emphasized early on that food chains tend to show characteristic patterns of increasing body size as one moves up the food chain, for example from <a href="/article/Phytoplankton">phytoplankton</a> to invertebrate grazers to fishes, or from insects to rodents to larger carnivores like foxes. Because individuals of small-bodied species require less energy and food than individuals of larger-bodied species, a given amount of energy can support a greater number of individuals of the smaller-bodied species. Hence, ecological communities typically show what Elton called a pyramid of numbers (later dubbed the Eltonian pyramid), in which the species at lower trophic levels in the food web tend to be more numerous than those at higher trophic levels. </p> <p>A second reason for the pyramid of numbers is low ecological efficiency: some energy is lost at each transfer between consumer and prey, such that the energy that reaches top predators is a very small fraction of that available in the plants at the base of the food web. Although there is wide variation among types of organisms and types of <a href="/article/Ecosystem">ecosystems</a>, a general rule of thumb is that available energy decreases by about an order of magnitude at each step in the food chain. That is, only about 10% of the energy harvested by plants is consumed and converted into herbivore biomass, only 10% of that makes it into biomass of primary carnivores, and so on. Thus, the structure of food webs is dictated in part by basic constraints set by <a href="/article/Thermodynamics">thermodynamics</a>. The predictable dissipation of energy at each step in food chains is one of the factors thought to limit the length of most food chains to a maximum of four or five steps. Cohen et al. (2003) emphasized that the correlations among body size, abundance, and trophic level produce a characteristic trivariate structure to (pelagic) food webs (Fig. 2). </p><p>The pyramid of numbers is less obvious at the most basal levels in terrestrial communities based on trees, which are typically much larger than the herbivores that feed on them. Pyramids of numbers or biomass may even be inverted in cases where the microscopic plants that support the web show very rapid turnover, that is, where they grow and are eaten so rapidly that there is less plant biomass than herbivore biomass present at a given time. </p><p>Decomposers are an assemblage of small organisms, including invertebrates, fungi, and <a href="/article/Bacteria">bacteria</a>, that do not fit neatly into any trophic level because they consume dead biomass of organisms from all trophic levels. Decomposers are a critical component of the food web, however, because they recycle nutrients that otherwise would become sequestered in accumulating detritus.</p><p><strong>References and further reading</strong></p><ul><li>Cohen, J., T. Jonsson, and S.R. Carpenter. 2003. Ecological community description using the food web, species abundance, and body size. Proceedings of the National Academy of Sciences USA. 100: 1781–1786. </li><li>Elton, C. 1927. Animal ecology. Sidgwick and Jackson Ltd, London, UK. </li><li>Hardy, A.C. 1924. The herring in relation to its animate environment, Part I. Ministry of Agriculture and Fisheries, Fishery Investigations, Series 2, Volume 7, number 3. </li><li>Lindemann, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23: 399-418. </li><li>May, R.M. 1973. Stability and complexity in model food webs. Princeton University Press, Princeton, NJ. </li><li>Morin, P.J. 1999. Community ecology. Blackwell Science, Oxford, UK. </li><li>Paine, R.T. 1980. Food Webs: Linkage, Interaction Strength and Community Infrastructure. Journal of Animal Ecology 49:666-685. </li><li>Pimm, S.L. 1982. Food webs. Chapman and Hall, London. </li></ul> <p><a href='/article/Food_web'>Read Full Article...</a></p> http://www.eoearth.org/article/Food_web Tue, 22 Sep 2009 06:12:32 GMT http://www.eoearth.org/article/Food_web <a href='/article/Food_web'><img border='0' src='/upload/thumb/4/4a/Alaska_food_web.jpg/300px-Alaska_food_web.jpg' width='100'/></a> <p>A food web is a graphical description of feeding relationships among species in an ecological community, that is, of who eats whom (Fig. 1). It is also a means of showing how energy and materials (e.g., <a href="/article/Carbon">carbon</a>) flow through a community of species as a result of these feeding relationships. Typically, species are connected by lines or arrows called &quot;links&quot;, and the species are sometimes referred to as &quot;nodes&quot; in food web diagrams. </p><p>The pioneering animal ecologist <a href="/article/Elton%2C_Charles">Charles Elton</a> (1927) introduced the concept of the food web (which he called food cycle) to general <a href="/article/Ecology">ecological science</a>. As he described it: &quot;The herbivores are usually preyed upon by carnivores, which get the energy of the <a href="/article/Solar_radiation">sunlight</a> at third-hand, and these again may be preyed upon by other carnivores, and so on, until we reach an animal which has no enemies, and which forms, as it were, a terminus on this food cycle. There are, in fact, chains of animals linked together by food, and all dependent in the long run upon plants. We refer to these as &#39;food-chains&#39;, and to all the food chains in a community as the &#39;food-cycle.&#39;&quot; </p><p>A food web differs from a food chain in that the latter shows only a portion of the food web involving a simple, linear series of species (e.g., predator, herbivore, plant) connected by feeding links. A food web aims to depict a more complete picture of the feeding relationships, and can be considered a bundle of many interconnected food chains occurring within the community. All species occupying the same position within a food chain comprise a trophic level within the food web. For instance, all of the plants in the foodweb comprise the first or &quot;primary producer&quot; tropic level, all herbivores comprise the second or &quot;primary consumer&quot; trophic level, and carnivores that eat herbivores comprise the third or &quot;secondary consumer&quot; trophic level. Additional levels, in which carnivores eat other carnivores, comprise a tertiary trophic level.</p><p>Elton emphasized early on that food chains tend to show characteristic patterns of increasing body size as one moves up the food chain, for example from <a href="/article/Phytoplankton">phytoplankton</a> to invertebrate grazers to fishes, or from insects to rodents to larger carnivores like foxes. Because individuals of small-bodied species require less energy and food than individuals of larger-bodied species, a given amount of energy can support a greater number of individuals of the smaller-bodied species. Hence, ecological communities typically show what Elton called a pyramid of numbers (later dubbed the Eltonian pyramid), in which the species at lower trophic levels in the food web tend to be more numerous than those at higher trophic levels. </p> <p>A second reason for the pyramid of numbers is low ecological efficiency: some energy is lost at each transfer between consumer and prey, such that the energy that reaches top predators is a very small fraction of that available in the plants at the base of the food web. Although there is wide variation among types of organisms and types of <a href="/article/Ecosystem">ecosystems</a>, a general rule of thumb is that available energy decreases by about an order of magnitude at each step in the food chain. That is, only about 10% of the energy harvested by plants is consumed and converted into herbivore biomass, only 10% of that makes it into biomass of primary carnivores, and so on. Thus, the structure of food webs is dictated in part by basic constraints set by <a href="/article/Thermodynamics">thermodynamics</a>. The predictable dissipation of energy at each step in food chains is one of the factors thought to limit the length of most food chains to a maximum of four or five steps. Cohen et al. (2003) emphasized that the correlations among body size, abundance, and trophic level produce a characteristic trivariate structure to (pelagic) food webs (Fig. 2). </p><p>The pyramid of numbers is less obvious at the most basal levels in terrestrial communities based on trees, which are typically much larger than the herbivores that feed on them. Pyramids of numbers or biomass may even be inverted in cases where the microscopic plants that support the web show very rapid turnover, that is, where they grow and are eaten so rapidly that there is less plant biomass than herbivore biomass present at a given time. </p><p>Decomposers are an assemblage of small organisms, including invertebrates, fungi, and <a href="/article/Bacteria">bacteria</a>, that do not fit neatly into any trophic level because they consume dead biomass of organisms from all trophic levels. Decomposers are a critical component of the food web, however, because they recycle nutrients that otherwise would become sequestered in accumulating detritus.</p><p><strong>References and further reading</strong></p><ul><li>Cohen, J., T. Jonsson, and S.R. Carpenter. 2003. Ecological community description using the food web, species abundance, and body size. Proceedings of the National Academy of Sciences USA. 100: 1781–1786. </li><li>Elton, C. 1927. Animal ecology. Sidgwick and Jackson Ltd, London, UK. </li><li>Hardy, A.C. 1924. The herring in relation to its animate environment, Part I. Ministry of Agriculture and Fisheries, Fishery Investigations, Series 2, Volume 7, number 3. </li><li>Lindemann, R.L. 1942. The trophic-dynamic aspect of ecology. Ecology 23: 399-418. </li><li>May, R.M. 1973. Stability and complexity in model food webs. Princeton University Press, Princeton, NJ. </li><li>Morin, P.J. 1999. Community ecology. Blackwell Science, Oxford, UK. </li><li>Paine, R.T. 1980. Food Webs: Linkage, Interaction Strength and Community Infrastructure. Journal of Animal Ecology 49:666-685. </li><li>Pimm, S.L. 1982. Food webs. Chapman and Hall, London. </li></ul> <p><a href='/article/Food_web'>Read Full Article...</a></p> http://www.eoearth.org/article/Food_web Tue, 22 Sep 2009 06:12:16 GMT http://www.eoearth.org/article/Glacier <a href='/article/Glacier'><img border='0' src='/upload/thumb/a/af/Antarctica_glacier.gif/250px-Antarctica_glacier.gif' width='100'/></a> <p>Various types of paleoclimatic evidence suggest that the climate of the Earth has <a href="/article/Earth%27s_climatic_history">varied over time</a>. The data suggest that during most of the Earth&#39;s history, global <a href="/article/Temperature">temperatures</a> were probably 8 to 15° Celsius warmer than they are today. However, there were periods of times when the Earth&#39;s average global temperature became cold; cold enough for the formation of alpine glaciers and continental glaciers that extended in to the higher, middle and sometimes lower latitudes. In the last billion years of Earth&#39;s history, glacial periods have started at roughly 925, 800, 680, 450, 330, and 2 million years before present (B.P.). Of these ice ages, the most severe occurred at 800 million years ago when glaciers came within 5 degrees of the equator. </p><p>The last major glacial period began about 2,000,000 years B.P. and is commonly known as the Pleistocene or Ice Age. During this glacial period, large glacial ice sheets covered much of North America, Europe, and Asia for long periods of time. The extent of the glacier ice during the Pleistocene, however, was not static. The Pleistocene had periods when the glaciers retreated (interglacial) because of mild temperatures, and advanced because of colder temperatures (glacial). Average global temperatures were probably 4 to 5° Celsius colder than they are today at the peak of the Pleistocene. The most recent glacial retreat began about 14,000 years B.P. and is still going on. We call this period the Holocene epoch. </p><p>In North America, the Pleistocene glaciers began their formation in the higher altitudes of the Rocky Mountains, and high-latitude locations in Greenland and north-central Canada. From these locations, the ice spread in all directions following the topography of the landscape. In North America, the glaciers from the Rocky Mountains and north-central Canada met each other in the center of the continent creating an ice sheet that stretched from the <a href="/article/Ocean">Pacific</a> to the <a href="/article/Ocean">Atlantic Ocean</a>. At their greatest extent, the ice sheets of North America covered most of Canada and extended into the United States to a latitude of about 40° North. </p><p>A similar pattern of glaciation has also been scientifically documented in Europe and Asia. In Eurasia, ice sheets had their birth place in the Alps Mountains, Scandinavia, northern British Isles, and northern Siberia. The ice sheets of Eurasia, however, did not form a single ice sheet through convergence and their furthest extent south was limited to a latitude of about 45° North. </p> <p><a href='/article/Glacier'>Read Full Article...</a></p> http://www.eoearth.org/article/Glacier Fri, 18 Sep 2009 07:46:12 GMT http://www.eoearth.org/article/Glacier <a href='/article/Glacier'><img border='0' src='/upload/thumb/a/af/Antarctica_glacier.gif/250px-Antarctica_glacier.gif' width='100'/></a> <p>Various types of paleoclimatic evidence suggest that the climate of the Earth has <a href="/article/Earth%27s_climatic_history">varied over time</a>. The data suggest that during most of the Earth&#39;s history, global <a href="/article/Temperature">temperatures</a> were probably 8 to 15° Celsius warmer than they are today. However, there were periods of times when the Earth&#39;s average global temperature became cold; cold enough for the formation of alpine glaciers and continental glaciers that extended in to the higher, middle and sometimes lower latitudes. In the last billion years of Earth&#39;s history, glacial periods have started at roughly 925, 800, 680, 450, 330, and 2 million years before present (B.P.). Of these ice ages, the most severe occurred at 800 million years ago when glaciers came within 5 degrees of the equator. </p><p>The last major glacial period began about 2,000,000 years B.P. and is commonly known as the Pleistocene or Ice Age. During this glacial period, large glacial ice sheets covered much of North America, Europe, and Asia for long periods of time. The extent of the glacier ice during the Pleistocene, however, was not static. The Pleistocene had periods when the glaciers retreated (interglacial) because of mild temperatures, and advanced because of colder temperatures (glacial). Average global temperatures were probably 4 to 5° Celsius colder than they are today at the peak of the Pleistocene. The most recent glacial retreat began about 14,000 years B.P. and is still going on. We call this period the Holocene epoch. </p><p>In North America, the Pleistocene glaciers began their formation in the higher altitudes of the Rocky Mountains, and high-latitude locations in Greenland and north-central Canada. From these locations, the ice spread in all directions following the topography of the landscape. In North America, the glaciers from the Rocky Mountains and north-central Canada met each other in the center of the continent creating an ice sheet that stretched from the <a href="/article/Ocean">Pacific</a> to the <a href="/article/Ocean">Atlantic Ocean</a>. At their greatest extent, the ice sheets of North America covered most of Canada and extended into the United States to a latitude of about 40° North. </p><p>A similar pattern of glaciation has also been scientifically documented in Europe and Asia. In Eurasia, ice sheets had their birth place in the Alps Mountains, Scandinavia, northern British Isles, and northern Siberia. The ice sheets of Eurasia, however, did not form a single ice sheet through convergence and their furthest extent south was limited to a latitude of about 45° North. </p> <p><a href='/article/Glacier'>Read Full Article...</a></p> http://www.eoearth.org/article/Glacier Fri, 18 Sep 2009 07:44:25 GMT http://www.eoearth.org/article/Fossil_fuel_power_plant <a href='/article/Fossil_fuel_power_plant'><img border='0' src='/upload/thumb/0/0a/CF_powerplantbyriver.jpg/199px-CF_powerplantbyriver.jpg' width='100'/></a> <p>A fossil fuel power plant is a system of devices for the conversion of fossil fuel energy to mechanical work or electric energy. The main systems are the steam cycle and the gas turbine cycle. The steam cycle relies on the Rankine cycle in which high pressure and high temperature steam raised in a boiler is expanded through a steam turbine that drives an electric generator. The steam gives up its <a href="/article/Heat">heat</a> of condensation in a condenser to a heat sink such as water from a river or a lake, and the condensate can then be pumped back into the boiler to repeat the cycle. The heat taken up by the cooling water in the condenser is dissipated mostly through cooling towers into the atmosphere. </p><p>The gas turbine cycle relies on the Brayton cycle in which air compressed to high pressure, and heated to high temperature by the combustion of natural gas or light fuel oil, is the working fluid that expands in the turbine to provide the torque for driving both a compressor and the electric generator. The gas turbine demands clean fuels such as natural gas or light fuel oil. <a href="/article/Combustion">Combustion</a> is the prevailing fuel utilization technology in both the above cycles. <a href="/article/Coal">Coal</a> is the preferred fuel for the steam cycle because of its low cost and broad and secure availability worldwide. </p><p><a href="/article/Combustion">Combustion</a>-generated pollutants, such as oxides of nitrogen (NO,_x), of sulfur (SO_x), and particulates, if uncontrolled and emitted into the atmosphere represent environmental and health hazards, such as <a href="/article/Acid_rain">acid rain</a>. Environmental regulations supported by intensive research and developments have reduced pollutant emissions significantly. Improvements in efficiency and emissions come by increasing steam pressure and temperature in the steam cycle, and by increased turbine inlet temperature in the gas turbine cycle. Coal gasification produces a fuel gas that is capable of being used in the gas turbine. By integrating coal gasification with gas turbine and steam cycles, advantage can be taken of high efficiency and low pollutant emission while using <a href="/article/Coal">coal</a>, an inexpensive, secure and indigenous fuel in many countries throughout the world. A potential additional advantage of the Integrated Gasification Combined Cycle (IGCC) is the capability of capturing carbon dioxide (CO₂) from the fuel gas and making it ready for high-pressure pipeline transportation to a carbon sequestration site. This will be key to the commercial and clean co-production of electricity and hydrogen from coal. </p><p><strong>Further reading</strong> <a href="http://www.tva.com/power/fossil.htm" class='external text' title="http://www.tva.com/power/fossil.htm">Fossil-Fuel Generation</a>, Tennessee Valley Authority. </p> <p><a href='/article/Fossil_fuel_power_plant'>Read Full Article...</a></p> http://www.eoearth.org/article/Fossil_fuel_power_plant Thu, 17 Sep 2009 07:15:03 GMT http://www.eoearth.org/article/Water_governance <a href='/article/Water_governance'><img border='0' src='/upload/thumb/b/be/Fig_1_water_governance.JPG/250px-Fig_1_water_governance.JPG' width='100'/></a> <p>The water sector worldwide is increasingly characterized in terms of a crisis situation. The unique and complex characteristics of the water resource entail complex social, political, and economic implications in its management. The water crisis is mainly a crisis of governance and the management forms under which water has been historically governed. In light of the problems in the water sector, <a href="/article/Support_and_opposition_of_public-private_partnerships">public-private partnerships</a> have been increasingly advocated and adopted throughout the world. Proponents of partnerships have often appealed to the financial gains, cost reductions, efficiency gains, environmental compliance, human resource developments, and increased services which have followed private sector engagement. Opponents of partnerships have appealed to the price increases, imbalance of power, labor disputes, inequities, environmental damage, and increased risks associated with private sector participation in water services. This paper reviews these debates to conclude that evidence can be found in support of either position. The paper argues that this dichotomous debate has lead to inconclusive and unconstructive discussions among interested parties. The paper recommended that focus be re-directed away from ideological positions on privatization towards a focus on the principals and standards which can make private participation work for the public good when it is chosen. </p> <p><a href='/article/Water_governance'>Read Full Article...</a></p> http://www.eoearth.org/article/Water_governance Wed, 16 Sep 2009 06:18:47 GMT http://www.eoearth.org/article/Marine_reserves <a href='/article/Marine_reserves'><img border='0' src='/upload/thumb/1/16/MarineReserves_pub_rate.gif/300px-MarineReserves_pub_rate.gif' width='100'/></a> <p>Marine reserves are areas in the <a href="/article/Ocean">ocean</a> where no extractive activities are allowed. They are also often called ‘no-take zones’, since the killing, harming, or harassing of any plants or animals within the reserve boundaries is not allowed, and they are part of a broader spectrum of marine spatial management tools that fit under the umbrella term ‘Marine Protected Areas’, or MPAs. </p><p>The idea of setting aside fully protected regions of the oceans has been around for a long time, but it is only in the past decade or two that marine reserves have become a common tool for managing and protecting marine resources. Most commonly reserves are established for conservation purposes, but strong interest also exists in using them as a <a href="/article/Marine_fisheries">fisheries</a> management tool. Even so, a relatively small portion of the world’s oceans to date have been set aside in marine reserves – less that 1%. </p> <p><a href='/article/Marine_reserves'>Read Full Article...</a></p> http://www.eoearth.org/article/Marine_reserves Tue, 15 Sep 2009 06:26:44 GMT http://www.eoearth.org/article/Transpiration <a href='/article/Transpiration'><img border='0' src='/upload/thumb/e/e3/Transpirationleafsoil.jpg/225px-Transpirationleafsoil.jpg' width='100'/></a> <p>Transpiration is the term used to describe the transport of water through an actual, vegetated plant into the <a href="/article/Atmospheric_composition">atmosphere</a>. Transpiration is an important part of the <a href="/article/Evapotranspiration">evapotranspiration</a> process, and a major mechanism of the water cycle in the atmosphere. Transpiration may also refer to the rate of the water vapor transport through the whole vegetative canopy (that is, through the group of plants). </p><p>Just as you release water vapor when you breathe, plants do, too&mdash;although the term "transpire" is more appropriate than "breath." During this process individual water molecules are released from the surface of the plant body through tiny structures called <a href="/article/Stomata">stomata</a>. There are many more individual water vapor molecules inside the air spaces between the tissues of a plant than in the air surrounding the plant body. Consequently water vapor will always exit the plant along a concentration gradient. As more water vapor molecules exit the plant, the remaining water molecules tug on each other and will pull an entire column of water throughout the plant body through special tissues called xylem during the process of transpiration. One way to visualize transpiration is to put a plastic bag around some plant leaves. As Figure 1 shows, transpired <a href="/article/Physical_properties_of_water">water</a> will condense on the inside of the bag. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also <a href="/article/Evaporation">evaporates</a> from the soil. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year. </p> <p><a href='/article/Transpiration'>Read Full Article...</a></p> http://www.eoearth.org/article/Transpiration Tue, 15 Sep 2009 06:25:13 GMT http://www.eoearth.org/article/Transpiration <a href='/article/Transpiration'><img border='0' src='/upload/thumb/e/e3/Transpirationleafsoil.jpg/225px-Transpirationleafsoil.jpg' width='100'/></a> <p>Transpiration is the term used to describe the transport of water through an actual, vegetated plant into the <a href="/article/Atmospheric_composition">atmosphere</a>. Transpiration is an important part of the <a href="/article/Evapotranspiration">evapotranspiration</a> process, and a major mechanism of the water cycle in the atmosphere. Transpiration may also refer to the rate of the water vapor transport through the whole vegetative canopy (that is, through the group of plants). </p><p>Just as you release water vapor when you breathe, plants do, too&mdash;although the term "transpire" is more appropriate than "breath." During this process individual water molecules are released from the surface of the plant body through tiny structures called <a href="/article/Stomata">stomata</a>. There are many more individual water vapor molecules inside the air spaces between the tissues of a plant than in the air surrounding the plant body. Consequently water vapor will always exit the plant along a concentration gradient. As more water vapor molecules exit the plant, the remaining water molecules tug on each other and will pull an entire column of water throughout the plant body through special tissues called xylem during the process of transpiration. One way to visualize transpiration is to put a plastic bag around some plant leaves. As Figure 1 shows, transpired <a href="/article/Physical_properties_of_water">water</a> will condense on the inside of the bag. If the bag had been wrapped around the soil below it, too, then even more water vapor would have been released, as water also <a href="/article/Evaporation">evaporates</a> from the soil. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year. </p> <p><a href='/article/Transpiration'>Read Full Article...</a></p> http://www.eoearth.org/article/Transpiration Mon, 14 Sep 2009 07:26:24 GMT http://www.eoearth.org/article/Oil_spill <a href='/article/Oil_spill'><img border='0' src='/upload/thumb/7/7d/Exxon_valdez_aground.jpg/250px-Exxon_valdez_aground.jpg' width='100'/></a> <p>An oil spill is the accidental petroleum release into the environment. On land, oil spills are usually localized and thus their impact can be eliminated relatively easily. In contrast, marine oil spills may result in oil pollution over large areas and present serious environmental hazards. The primary source of accidental oil input into seas is associated with oil transportation by tankers and pipelines (about 70%), whereas the contribution of offshore drilling and production activities is minimal (less than 1%). Large and catastrophic spills releasing more than 30,000 tons of oil are relatively rare events and their frequency in recent decades has decreased perceptibly. Yet, such episodes have the potential to cause the most serious ecological risk (primarily for sea birds and mammals) and result in long-term environmental disturbances (mainly in <a href="/article/Coastal_zone">coastal zones</a>) and economic impact on coastal activities (especially on <a href="/article/Marine_fisheries">fisheries</a> and mariculture). </p><p>Public concern over marine oil spills has been clearly augmented since the 1967 Torrey Canyon <a href="/article/Supertanker">supertanker</a> accident off the UK coast, when 100,000 tonnes of spilled oil caused heavy pollution of the French and British shores with serious ecological and fisheries consequences. More recently, the highly publicized 1989 spill of the <em>Exxon Valdez</em> in <a href="/article/Prince_William_Sound%2C_Alaska">Prince William Sound, Alaska</a> caused unprecedented damage to the fragile <a href="/article/Arctic">Arctic</a> system. Since then, impressive technical, political, and legal experience in managing the problem has been gained in many countries and at the international level, mainly through a number of Conventions initiated by the International Maritime Organization (IMO). As a result of the <a href="/article/Exxon_Valdez_oil_spill">Exxon Valdez oil spill</a>, the U.S. passed legislation requiring all newly built tankers to have a double hull. </p><p>When the oil reaches the shoreline, on rocky shores some components of the oil evaporate, leaving behind the heaviest components and turning the oil into tar. On rocky shores with surf, the tar will erode away from the wave action, and biological communities will return rather quickly. In <a href="/article/Marsh">marshes</a>, however, oil can sink down below the surface and remain for many years. Oil accumulated in marsh sediments undergoes some microbial breakdown, but it is slow. Low-energy environments like marshes are the most vulnerable and show the slowest rates of recovery from oil spills. Effects of a rather small oil spill in Falmouth, MA in the late 1960s were seen to last for a decade by a team of scientists from the nearby Woods Hole Oceanographic Institute. It is seldom that a spill occurs right in an area that has been intensively studied prior to the spill. Fiddler crabs were particularly sensitive, and were still affected after seven years. The oil affected their burrow construction – the burrows did not go straight down, but leveled off to a horizontal plane. While this was not a problem during the summer, when winter came the crabs were not below the freezing zone of the marsh as they should have been and froze to death. Benthic communities took about a decade to return to normal. After 30 years, some abnormalities still are noted in fiddler crab burrows in the oiled areas. </p><p>Marshes and sediments in <a href="/article/Prince_William_Sound%2C_Alaska">Prince William Sound</a> in Alaska retained oil from the massive oil spill of the <em>Exxon Valdez</em> in 1989 for many years, affecting the development of fish embryos on the bottom. After ten years, pockets of oil remained in these <a href="/article/Marsh">marshes</a>, and mussels, clams, ducks and sea otters showed evidence of harm in some localized areas. Remedial actions after oil spills are controversial, and some of the cures (e.g. aggressive cleaning with large heavy equipment) may be worse than the original problem, as was seen in the attempted clean up after the <a href="/article/Exxon_Valdez_oil_spill">Exxon Valdez oil spill</a>. </p><p><strong>Further Reading</strong></p><ul><li>Patin, Stanislav and Elena Cascio (Translator), 1999. <a href="http://www.offshore-environment.com/index.html" class='external text' title="http://www.offshore-environment.com/index.html">Environmental impact of the offshore oil and gas industry</a>. EcoMonitor Pub, East North Port, N.Y. <a href="http://www.amazon.com/dp/0-9671836-0-X/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0-9671836-0-X/?tag=encycofearth-20">ISBN: 0-9671836-0-X</a> </li><li>Patin, Stanislav, 2004. <a href="http://www.sciencedirect.com/science?_ob=ArticleURL&amp;_udi=B7GGD-4CM9GC0-7X&amp;_rdoc=1&amp;_hierId=40165&amp;_refWorkId=222&amp;_explode=39816,40165&amp;_alpha=P&amp;_fmt=summary&amp;_orig=na&amp;_docanchor=&amp;_idxType=AU&amp;view=c&amp;_acct=C000050221&amp;_version=1&amp;_urlVersion=0&amp;_userid=10&amp;md5=363d97b258fc147442d4870d7fa85763" class='external text' title="http://www.sciencedirect.com/science? ob=ArticleURL&amp; udi=B7GGD-4CM9GC0-7X&amp; rdoc=1&amp; hierId=40165&amp; refWorkId=222&amp; explode=39816,40165&amp; alpha=P&amp; fmt=summary&amp; orig=na&amp; docanchor=&amp; idxType=AU&amp;view=c&amp; acct=C000050221&amp; version=1&amp; urlVersion=0&amp; userid=10&amp;md5=363d97b258fc147442d4870d7fa85763">Crude Oil Spills, Environmental Impact of,</a> In: Cutler J. Cleveland (Editor), <em>The Encyclopedia of Energy</em>. Elsevier Science, Oxford, pp. 737-748. </li></ul> <p><a href='/article/Oil_spill'>Read Full Article...</a></p> http://www.eoearth.org/article/Oil_spill Fri, 11 Sep 2009 05:51:10 GMT http://www.eoearth.org/article/Top-down_control <a href='/article/Top-down_control'><img border='0' src='/upload/thumb/c/c6/Topdown.JPG/450px-Topdown.JPG' width='100'/></a> <p>All organisms require energy and nutrients in some form to survive and grow. Thus, the existence and total biomass of ecosystems are ultimately regulated from the &quot;bottom up&quot;, that is, by availability of resources such as light, inorganic nutrients, and water. Nevertheless, on more localized scales, the abundances of organisms at lower trophic levels can be strongly affected by their own predation, that is, by &quot;top-down&quot; control. <a href="/article/Ecosystem">Ecosystems</a> often have been assumed to be controlled from the bottom-up, wherein nutrients and <a href="/article/Solar_radiation">light</a> stimulate primary production by plants, and the greater primary production in turn supports more animal production at higher trophic levels. But this is not the whole story. A simple way to envision top-down control is as follows: because the predator eats prey, the prey population is reduced, so when predators are removed, the prey species can become more abundant. For example, evidence of such top-down control of prey populations was seen when large predators like wolves were extirpated from much of the US and deer became very abundant, indeed a pest, in many areas. Even in <a href="/article/Yosemite_National_Park%2C_United_States">Yosemite National Park</a>, reduced numbers of bobcats, cougars and coyotes led to increased numbers of mule deer, which then led to declines in evening primrose and young black oaks, which are grazed by deer. </p> <h1>Trophic cascades <br /></h1><p>Some other clear examples of strong top-down control are seen in the <a href="/article/Marine_biomes">marine</a> environment. In the Pacific Coast of North America there are “kelp forests” of very large brown algae. These are grazed by sea urchins, which are, in turn, eaten by sea otters. When sea otter populations are reduced (as they were a century ago because of hunting, and again lately due to killer whale <a href="/article/Predation">predation</a>) the sea urchin populations can grow out of control and graze down most the kelp, creating “urchin barrens.” Unchecked by otters, they can bloom and basically destroy the kelp forest by eating huge amounts of kelp. When population control of prey by their predators (as in the sea otter/sea urchin interaction) then affects the next level down, the kelp, it is referred to as a “trophic cascade.” Trophic cascades are now known from a wide range of marine, freshwater, and terrestrial ecosystems.</p> <p>Other systems have been affected by the loss of filter feeders such as oysters. It has been suggested that the populations of oysters in Chesapeake Bay used to be enough to filter all the water (including its <a href="/article/Phytoplankton">phytoplankton</a> residents) in the bay in about one week. Although this has since been considered an overestimate, it is clear that filter-feeding aimals can have strong impacts on water quality. as As a result of overfishing and several devastating diseases, the oyster population is currently only a tiny fraction of what it used to be, and algal blooms are more common, as the phytoplankton can no longer be controlled by the filter feeders (increased levels of nutrients exacerbate this effect). Top-down <a href="/article/Ecology">ecology</a> is also seen in <a href="/article/Freshwater_biomes">lakes</a>, <a href="/article/Composition_of_rocks">rocky</a> shores, <a href="/article/Terrestrial_biome">terrestrial</a>, and many other ecosystems.</p> <h1>Top-down control and behavior: &quot;The ecology of fear&quot; <br /></h1> <p>Top-down control of lower trophic levels as a result of direct consumption and reduction of prey population size is referred to as “density-mediated” control, because predators reduce density of prey. However, predators can affect populations of their prey without actually eating them but in a more indirect ways, for example by influencing their behavior, physiology, or morphology. For example, water-borne chemicals (“risk cues”) released by predators can cause changes in prey behavior such as feeding rates, thereby altering the impact of the prey species on their own resources. When prey species detect the presence of predators they often alter their behavior by spending more time hiding and generally being inconspicuous, thus reducing the amount of time they spend feeding. The reduced food intake by these prey animals can result in slower growth and reproduction, and ultimately result in population reductions. The reduced feeding rates by the prey then cascade down to release the prey&#39;s own food (e.g., plants) from top-down control, causing a trophic cascade based not on changes in prey abundance but by changes in prey behavior. This more subtle mechanism is called “trait-mediated” control. Trait-mediated interactions represent the nonlethal effects of predators, and contrast with the more traditional emphasis on lethal effects. An example of this from the intertidal zones is the effect of risk cues from green crabs that reduce feeding by snails and consequently allow increases in the snails’ food, barnacles and algae. Carnivorous snails exposed to cues from green crabs consumed fewer barnacles, and herbivorous snails exposed to risk cues from crabs consumed far less algae. Both species of snails spent more time in refuges and grew less, while <a href="/article/Population">populations</a> of the barnacles and algae increased as a result of reduced top-down control. </p> <p>Trait-mediated cascades are not restricted to aquatic organisms or environments. Spiders eat grasshoppers, and have direct density-mediated effects on their populations. However, when spiders’ mouths were experimentally glued shut, grasshoppers still showed elevated mortality even though they weren’t being eaten; in the presence of spiders they switched from eating <a href="/article/Grasses">grasses</a> to eating safer, but less nutritious plants, and the reduced energy input led to higher grasshopper mortality. Another way that trait-mediated effects can happen is if the behavioral changes in response to one <a href="/article/Predation">predator</a> make the prey more vulnerable to another. In <a href="/article/Freshwater_biomes">fresh water</a> systems, bass eat darters, and have direct density-mediated effects. To avoid bass, however, the darters tend to hide in rocky shelters, which makes them more susceptible to predation by crayfish that also live in those habitats. Trait-mediated interactions are very common in predator/prey interactions. Some research suggests that the effects of predators on behavior is as important, if not more important, than the direct lethal effects through predation.</p> <h1>Top-down control and inducible defenses <br /></h1><p>Trait-mediated effects can occur through mechanisms other than behavior. For example, pea aphids, which do not generally have wings, produce winged offspring in response to the presence of ladybird predators or other enemies. This trait modification allows the winged aphids to disperse to new habitats. Water fleas (Daphnia) develop defensive spines when exposed to chemical cues from fish. This makes them more difficult to eat, but developing this structure has energetic costs and reduces lifetime fitness. Snails often develop a thicker shell upon exposure to predacious crabs, which affords the snail greater protection and therefore a greater chance of survival. However, it must expend more energy to carry around a heavier shell. Frog tadpoles in the presence of predators reduce their feeding behavior, but also change their morphology to have a relatively larger tail, which allows them to swim faster and escape predators more effectively. This defense comes at the expense of slower growth. Some of these morphological changes are reversible, but others are not. Crucian carp, when exposed to cues from predatory pike become deeper-bodied, and thus harder for a predator to grab. This body change is reversible.</p> <p>Plants can also alter their morphology or chemistry in response to herbivores. They may manufacture toxins or noxious chemicals to deter grazing (a number of these chemicals have been shown to have pharmaceutical value). Plants have developed many secondary metabolites involved in defense, which are collectively known as antiherbivory compounds. Defenses in some systems are very complex. For example, <em>Phaseolus</em> plants infested by spider mites emit specific volatile substances which attract predatory mites that eat the spider mites. In addition to chemical defenses, plants may have many external structural defenses that discourage herbivory. A plant&#39;s leaves and stem may be covered with sharp spines or hairs, often with barbs, sometimes containing irritants or <a href="/article/Poison">poisons</a>. After considerable grazing or defoliation, plants can produce a new set of leaves with increased silica and other characteristics that make them tougher and more difficult and less palatable for herbivores to consume. </p> <p>These altered traits in the presence of predators are referred to as “inducible defenses” or “phenotypic plasticity.” Behavioral, physiological, and morphological plasticity in response to predators can stabilize populations, but the changes can come at a cost. The ultimate effects of top-down processes on the abundance, morphology, behavior, and evolution of populations and communities can be far-reaching. </p><p><strong><big>References</big></strong></p> <ul><li>Borer E.T., Seabloom E.W., Shurin J.B., Anderson K.E., Blanchette C.A., Broitman B., Cooper S.D. &amp; Halpern B.S. 2005. What determines the strength of a trophic cascade? <em>Ecology</em> 86:528-537.</li><li>Miner, B.G., S.E. Sultan, S.G. Morgan, D.K. Padilla and R.A. Relyea 2005. Ecological consequences of phenotypic plasticity. <em>Trends in Ecology and Evolution</em> 20:685-692.</li><li>Pace M.L., Cole J.J., Carpenter S.R. &amp; Kitchell J.F. 1999. Trophic cascades revealed in diverse ecosystems. <em>Trends in Ecology and Evolution</em> 14:483-488.</li><li> Preisser, E.L., D. Bolnick and M.F. Benard 2005. Scared to death? The effects of intimidation and consumption in predator-prey interactions. <em>Ecology</em> 86:501-509.</li><li> Rahel, F. and R. Stein 1988, Complex predator/prey interactions and predator intimidation among crayfish, piscivorous fish, and small benthic fish. <em>Oecologia</em> 75:94-98.</li><li>Schmitz, O. 1998. Direct and indirect effects of predation and predation risk in old-field interaction webs. <em>American Naturalist</em> 151:327-342.</li><li>Schmitz O.J., Krivan V. &amp; Ovadia O. 2004. Trophic cascades: the primacy of trait-mediated indirect interactions. <em>Ecology Letters</em> 7:153-163.</li></ul> <p><a href='/article/Top-down_control'>Read Full Article...</a></p> http://www.eoearth.org/article/Top-down_control Wed, 09 Sep 2009 06:08:09 GMT http://www.eoearth.org/article/Resource_curse <a href='/article/Resource_curse'><img border='0' src='/upload/thumb/b/bd/Saudi_Arabia_map.gif/199px-Saudi_Arabia_map.gif' width='100'/></a> <p>The term &#39;resource curse&#39; refers to the observation that nations with rich endowments of natural resources (oil, metals, timber) often dramatically underperform economically relative to what one would expect. Common sense and simple economics suggest that countries blessed with an abundance of natural resources should live long and prosper. Yet over many years, it has been observed that nations rich in oil, gas, or mineral resources have been disadvantaged in the drive for <a href="/article/Economic_growth">economic progress</a>. In the 1950&#39;s and 1960&#39;s, concern was based upon deteriorating terms of <a href="/article/Trade_and_the_environment">trade</a> between industrialized and developing countries. In the 1970&#39;s, it was driven by the impact of the oil price shocks on the oil exporters where windfall revenues seemed to introduce serious distortions to the economies. In the 1980&#39;s, the phenomenon of &quot;Dutch Disease&quot;—an overvaluation of the real exchange rate and the contraction of <a href="/article/Agriculture">agriculture</a> and industry —attracted attention. In the 1990&#39;s, it was the impact on government behavior—rent seeking and corruption—that dominated discussions. More recently, a revival of interest follows the World Bank&#39;s &quot;Extractive Industry Review&quot; and growing concern over corporate social responsibility. Existence of the &quot;curse&quot; is controversial in the literature and there is growing evidence that its occurrence is far from inevitable. In many countries, natural resource revenues can produce tangible benefits. Where a &quot;curse&quot; has occurred, the main explanation lies in the way large windfall resource revenues affect government behavior. Thus avoidance implies political reform to encourage good governance. Increasingly, analysis addresses how the various players in natural resource projects—international financial institutions, multinational corporations and non-governmental organizations (NGOs)—can assist governments at risk to create capacity to manage the problem. </p><p><strong>Further Reading</strong></p><ul><li>Auty, Richard M. <a href="http://www.wider.unu.edu/research/pr9899d2/pr9899d2s.htm" class='external text' title="http://www.wider.unu.edu/research/pr9899d2/pr9899d2s.htm">The Resource Curse in Developing Countries can be Avoided</a>.</li><li>Sachs, Jeffrey D. &amp; Warner, Andrew M., 1995. &quot;<a href="http://www.nber.org/papers/w5398.pdf" class='external text' title="http://www.nber.org/papers/w5398.pdf">Natural Resource Abundance and Economic Growth</a>&quot;, NBER Working Papers 5398, National Bureau of Economic Research, Inc.</li><li>Sachs, Jeffrey D. &amp; Warner, Andrew M., 2001. &quot;<a href="http://www.elsevier.com/wps/find/journaldescription.cws_home/505541/description#description" class='external text' title="http://www.elsevier.com/wps/find/journaldescription.cws home/505541/description#description">The curse of natural resources</a>&quot;, European Economic Review, Elsevier, vol. 45(4-6), pages 827-838, May. </li></ul> <p><a href='/article/Resource_curse'>Read Full Article...</a></p> http://www.eoearth.org/article/Resource_curse Tue, 08 Sep 2009 05:46:34 GMT http://www.eoearth.org/article/Ross_Ice_Shelf <a href='/article/Ross_Ice_Shelf'><img border='0' src='/upload/thumb/d/d5/Moa_iceshelves.jpg/330px-Moa_iceshelves.jpg' width='100'/></a> <p>See also Ice Shelf and Climate change and ice shelves</p> <p>The Ross Ice Shelf is the largest ice shelf in the world with an area of roughly 182,000 square miles (472,000 km²) - about the size of Spain. It is bordered by the Ross Sea to the north,  the Transantarctic Mountains to the west and south, and by the King Edward the VII Peninsula to the east.</p><p>Facing the Ross Sea, it presents a nearly vertical ice cliff of between 50  and 200 feet (15 and 60 meters) above the water surface and 500 miles (800 km) long between Ross Island and the King Edward the VII Peninsula. The interior of the Shelf entends from 400 to nearly 600 miles.</p><p>Most of the Ross Ice Shelf is located within the Ross Dependency claimed by New Zealand. However, the claim is not recognized by most countries or under the <a href="/article/Antarctic_Treaty_System">Antarctic Treaty System</a>.</p><p>The ice shelf was named after Captain James Clark Ross who discovered it on 28 January 1841. It was originally named the &quot;Great Ice Barrier&quot; or the &quot;Ice Barrier&quot; or the &quot;Barrier.&quot; Ross mapped the ice front eastward to 160°W. </p> <p><a href='/article/Ross_Ice_Shelf'>Read Full Article...</a></p> http://www.eoearth.org/article/Ross_Ice_Shelf Thu, 03 Sep 2009 07:32:06 GMT http://www.eoearth.org/article/Soil_compaction <a href='/article/Soil_compaction'><img border='0' src='/upload/thumb/a/a7/Critical_depth_for_harmful_soil_compaction.jpg/250px-Critical_depth_for_harmful_soil_compaction.jpg' width='100'/></a> <p>Soil compaction in <a href="/article/Agriculture">agriculture</a> and <a href="/article/Forestry">forestry</a> is of growing concern. Heavy wheel loads have the potential to impair soil health by soil compaction. In order to maintain soil functions on a sustainable basis, strategies against further compaction are necessary. Technical solutions of best management practices in agriculture have been developed to minimize soil compaction. But they may not be sufficient to safeguard against damage to soil structure, since they do not compare the compressive forces of farm implements with the soils physical resistance against compaction. The effectiveness of practical means against soil compaction needs to be validated by physical <a href="/article/Soil">soil</a> assessment methods. Soil mechanical research has developed models to predict soil stress propagation below a running tire. Stress sensors have been developed to validate model predictions. Soil physical research has identified the parameters that characterize soil bearing capacity during wheeling. With the help of a bearing capacity model it is possible to assess, for given loading conditions, whether soil compaction in the subsoil will occur. If soil compaction is likely to occur, indicators are needed to assess harmful changes in the soil structure. Soil physical research has identified soil parameters that indicate harmful soil compaction and proposed an indicator set for the protection of soils against compaction integrating practical, mechanical, and soil physical aspects into one unique strategy. </p> <p><a href='/article/Soil_compaction'>Read Full Article...</a></p> http://www.eoearth.org/article/Soil_compaction Wed, 02 Sep 2009 05:57:10 GMT http://www.eoearth.org/article/Agriculture <a href='/article/Agriculture'><img border='0' src='/upload/thumb/d/d0/Agriculture.jpg/250px-Agriculture.jpg' width='100'/></a> <p>Humans began to cultivate food crops about 10,000 years ago. Prior to that time, hunter-gatherers secured their food as they traveled in the nearby environment. When they observed some of the grains left behind at their campsites sprouting and growing to harvest, they began to cultivate these grains. From these humble beginnings agriculture began. <a href="/article/Slash_and_burn">Slash and burn</a>, an early type of crop culture, remains today a truly sustainable agriculture, one that is independent of fossil fuel energy. In such a system, about 10 hectares of productive land is held in fallow for each planted hectare. With this rotation system, a hectare is planted once every 20 years, allowing the <a href="/article/Soil">soil</a> to reaccumulate vital plant nutrients. Although the practice requires large acreages and large labor inputs, the crop yields are adequate. For example, corn with ample <a href="/article/Precipitation_and_fog">rainfall</a> can yield about 2,000 <a href="/article/Kilogram">kilograms</a> per hectare (kg/ha). </p> <p>Over time, human labor in agriculture has decreased, first because of the use of animals and finally with machinery powered by fossil fuels. Currently, plentiful and economical fossil energy supports an era of machinery and agricultural chemicals. About 1,000 liters of oil equivalent are used to produce a hectare of corn with a yield of 9,000 kg/ha. One-third of this energy is used to replace labor, one-third for <a href="/article/Fertilizer">fertilizers</a>, and one-third for others. </p><p>Worldwide, more than 99.7% of human food (<a href="/article/Calorie">calories</a>) comes from the land. Serious environmental impacts, such as soil erosion, <a href="/article/Surface_runoff_of_water">water runoff</a>, and <a href="/article/Pesticide">pesticide</a> pollution, result from fossil fuel-intensive agriculture. A critical need exists to assess fossil energy limits, the <a href="/article/Sustainability">sustainability</a> of agriculture, and the food needs of a <a href="/article/Human_population_explosion">rapidly growing world population</a>. </p> <p><a href='/article/Agriculture'>Read Full Article...</a></p> http://www.eoearth.org/article/Agriculture Tue, 01 Sep 2009 06:55:15 GMT http://www.eoearth.org/article/Coral_reef <a href='/article/Coral_reef'><img border='0' src='/upload/thumb/c/c1/Reefs_vs_sst.jpg/350px-Reefs_vs_sst.jpg' width='100'/></a> <p>The term &quot;coral reef&quot; generally refers to a marine <a href="/article/Ecosystem">ecosystem</a> in which the main organisms are corals that house algal symbionts within their tissues. These ecosystems require: 1) fully marine waters; 2) warm <a href="/article/Temperature">temperatures</a>; and 3) ample <a href="/article/Solar_radiation">sunlight</a>. They are therefore restricted to shallow waters of tropical and subtropical regions. </p> <p>Corals that do not have algal symbionts can also form significant reef communities in deeper, darker, and colder waters, but these communities are distinguished as cold-water coral bioherms. </p><p>The more technical definition of &quot;coral reef&quot; includes an additional geological requirement that the reef organisms produce enough calcium carbonate to build the physical reef structure. The coral reef community lives only on the surface veneer of the reef, on top of already existing skeletal material left behind by previous reef-builders. Many processes act to break down the skeletal material and reef as soon it is laid down by organisms. These include mechanical processes such as waves and currents, and a wide array of biological processes (e.g., bioerosion). Some of the best known bioeroders are large organisms such as parrotfish and sponges, but much of the bioerosion occurs at the microscopic scale by organisms such as algae and fungi. A coral reef is produced only if the coral reef community produces more calcium carbonate than is removed. Indeed, some coral reef communities grow too slowly to build a reef. </p> <p><a href='/article/Coral_reef'>Read Full Article...</a></p> http://www.eoearth.org/article/Coral_reef Mon, 31 Aug 2009 06:04:35 GMT http://www.eoearth.org/article/Human_population_explosion <a href='/article/Human_population_explosion'><img border='0' src='/upload/thumb/8/83/Figure_1_long-term_population_growth.JPG/300px-Figure_1_long-term_population_growth.JPG' width='100'/></a> <p>Approximately 6.6 billion humans now inhabit the Earth. By comparison, there might be 20 million mallard ducks and, among a multitude of threatened and endangered species, perhaps 100,000 gorillas, 50,000 polar bears, and less than 10,000 tigers, 2,000 giant pandas and 200 California condors. Notably, the human population has <a href="/article/Population_growth_rate">grown</a> nearly ten-fold over the past three centuries and has increased by a factor of four in the last century. This monumental historical development has profoundly changed the relationship of our species to its natural support systems and has greatly intensified our <a href="/article/IPAT_equation">environmental impact</a>. Equally amazing are the signs that, in our generation, the human population explosion has begun to abate (Figure 1; note that, here and below, many of the values given are estimates and, after the year 2005, projections). Our numbers are expected to rise by another 50% before reaching a peak late in this century; a decline is likely to follow. What caused this population surge; what caused its reversal; where are we headed; and how might the proliferation of our species affect its future well-being? </p> <p><a href='/article/Human_population_explosion'>Read Full Article...</a></p> http://www.eoearth.org/article/Human_population_explosion Fri, 28 Aug 2009 06:21:46 GMT http://www.eoearth.org/article/Human_population_explosion <a href='/article/Human_population_explosion'><img border='0' src='/upload/thumb/8/83/Figure_1_long-term_population_growth.JPG/300px-Figure_1_long-term_population_growth.JPG' width='100'/></a> <p>Approximately 6.6 billion humans now inhabit the Earth. By comparison, there might be 20 million mallard ducks and, among a multitude of threatened and endangered species, perhaps 100,000 gorillas, 50,000 polar bears, and less than 10,000 tigers, 2,000 giant pandas and 200 California condors. Notably, the human population has <a href="/article/Population_growth_rate">grown</a> nearly ten-fold over the past three centuries and has increased by a factor of four in the last century. This monumental historical development has profoundly changed the relationship of our species to its natural support systems and has greatly intensified our <a href="/article/IPAT_equation">environmental impact</a>. Equally amazing are the signs that, in our generation, the human population explosion has begun to abate (Figure 1; note that, here and below, many of the values given are estimates and, after the year 2005, projections). Our numbers are expected to rise by another 50% before reaching a peak late in this century; a decline is likely to follow. What caused this population surge; what caused its reversal; where are we headed; and how might the proliferation of our species affect its future well-being? </p> <p><a href='/article/Human_population_explosion'>Read Full Article...</a></p> http://www.eoearth.org/article/Human_population_explosion Fri, 28 Aug 2009 06:20:01 GMT http://www.eoearth.org/article/Scabies <a href='/article/Scabies'><img border='0' src='/upload/thumb/0/0f/Sarcoptes_scabei_WHO.jpg/175px-Sarcoptes_scabei_WHO.jpg' width='100'/></a> <p><a href="http://www.cdc.gov/ncidod/dpd/parasites/scabies/factsht_scabies_spanish.htm" class='external text' title="http://www.cdc.gov/ncidod/dpd/parasites/scabies/factsht scabies spanish.htm">En Español</a></p> <p><a href='/article/Scabies'>Read Full Article...</a></p> http://www.eoearth.org/article/Scabies Thu, 27 Aug 2009 06:02:44 GMT http://www.eoearth.org/article/Gallium <a href='/article/Gallium'><img border='0' src='/upload/thumb/5/52/Gallium.jpg/250px-Gallium.jpg' width='100'/></a> <p>Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875. Its existence was predicted in 1871 by a chemist named <a href="/article/Mendeleev%2C_Dimitri_Ivanovich">Mendeleev</a> who said that gallium would be very much like <a href="/article/Aluminum">aluminum</a> in its physical properties, which proved to be quite accurate. In 1875, de Boisbaudran also isolated gallium by electrolysis of a solution of gallium hydroxide Ga(OH)₃ in potassium hydroxide (KOH).</p><p>Gallium has some physical properties that are worth noting. Like water, gallium expands as it freezes which means it becomes less dense. Solid gallium has such a low melting temperature (85.6° F, 29.8° C) it will turn to liquid when held in the hand! It is a liquid over a wider range of <a href="/article/Temperature">temperatures</a> than any other element. By contrast, the boiling point of gallium is unusually high (3999° F, 2204° C).</p><p>Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be <a href="/article/Toxicity">toxic</a>.</p> <p><a href='/article/Gallium'>Read Full Article...</a></p> http://www.eoearth.org/article/Gallium Wed, 26 Aug 2009 06:27:57 GMT http://www.eoearth.org/article/Gallium <a href='/article/Gallium'><img border='0' src='/upload/thumb/5/52/Gallium.jpg/250px-Gallium.jpg' width='100'/></a> <p>Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875. Its existence was predicted in 1871 by a chemist named <a href="/article/Mendeleev%2C_Dimitri_Ivanovich">Mendeleev</a> who said that gallium would be very much like <a href="/article/Aluminum">aluminum</a> in its physical properties, which proved to be quite accurate. In 1875, de Boisbaudran also isolated gallium by electrolysis of a solution of gallium hydroxide Ga(OH)₃ in potassium hydroxide (KOH).</p><p>Gallium has some physical properties that are worth noting. Like water, gallium expands as it freezes which means it becomes less dense. Solid gallium has such a low melting temperature (85.6° F, 29.8° C) it will turn to liquid when held in the hand! It is a liquid over a wider range of <a href="/article/Temperature">temperatures</a> than any other element. By contrast, the boiling point of gallium is unusually high (3999° F, 2204° C).</p><p>Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be <a href="/article/Toxicity">toxic</a>.</p> <p><a href='/article/Gallium'>Read Full Article...</a></p> http://www.eoearth.org/article/Gallium Wed, 26 Aug 2009 06:27:00 GMT http://www.eoearth.org/article/Gallium <a href='/article/Gallium'><img border='0' src='/upload/thumb/5/52/Gallium.jpg/250px-Gallium.jpg' width='100'/></a> <p>Gallium is a soft, silvery metallic element, with an atomic number of 31 and a symbol of Ga. The French chemist Paul-Emile Lecoq de Boisbaudran discovered gallium in 1875. Its existence was predicted in 1871 by a chemist named <a href="/article/Mendeleev%2C_Dimitri_Ivanovich">Mendeleev</a> who said that gallium would be very much like <a href="/article/Aluminum">aluminum</a> in its physical properties, which proved to be quite accurate. In 1875, de Boisbaudran also isolated gallium by electrolysis of a solution of gallium hydroxide Ga(OH)₃ in potassium hydroxide (KOH).</p><p>Gallium has some physical properties that are worth noting. Like water, gallium expands as it freezes which means it becomes less dense. Solid gallium has such a low melting temperature (85.6° F, 29.8° C) it will turn to liquid when held in the hand! It is a liquid over a wider range of <a href="/article/Temperature">temperatures</a> than any other element. By contrast, the boiling point of gallium is unusually high (3999° F, 2204° C).</p><p>Studies have shown that gallium is not useful to living organisms, although gallium and gallium compounds do not appear to be <a href="/article/Toxicity">toxic</a>.</p> <p><a href='/article/Gallium'>Read Full Article...</a></p> http://www.eoearth.org/article/Gallium Wed, 26 Aug 2009 06:26:50 GMT http://www.eoearth.org/article/Synroc <a href='/article/Synroc'><img border='0' src='/upload/thumb/c/ca/Synrocsample_m.jpg/250px-Synrocsample_m.jpg' width='100'/></a> <p>Synroc is a particular kind of &quot;Synthetic Rock&quot;, invented in 1978 by the late Professor Ted Ringwood of the Australian National University. It is an advanced ceramic comprising geochemically stable natural titanate minerals that have immobilized <a href="/article/Uranium">uranium</a> and <a href="/article/Thorium">thorium</a> for billions of years. They can incorporate into their crystal structures nearly all of the elements present in high-level radioactive waste (HLW) and thus immobilize them. Originally, some 57% of Synroc was titanium dioxide (rutile, TiO₂). </p><p>Synroc can take various forms depending on its specific use and can be tailored to immobilize particular components in the <a href="/article/Nuclear_waste_management"> high level nuclear waste (HLW).</a> The original form, Synroc-C, was intended mainly for the immobilization of liquid HLW arising from the reprocessing of light water reactor fuel. However, by 1980 those reprocessing used fuel had chosen borosilicate glass as the medium for immobilization because it was the most technically mature technology. </p><p>The main minerals in Synroc-C are hollandite (BaAl₂Ti₆O₁₆), zirconolite (CaZrTi₂O₇) and perovskite (CaTiO₃). Zirconolite and perovskite are the major hosts for long-lived actinides such as <a href="/article/Plutonium">plutonium</a> (Pu), though perovskite is principally for strontium (Sr) and barium (Ba). Hollandite principally immobilises caesium (Cs), along with potassium (K), rubidium (Rb) and barium. Synroc-C can hold up to 30% HLW by weight. </p><p>Over the past few years, different forms of Synroc have been developed to deal with military <a href="/article/Nuclear_waste_management"> radioactive wastes</a>, including a substantial amount of <a href="/article/Plutonium">plutonium</a>. Other applications have been developed related to the partitioning and transmutation of wastes. This involves partitioning HLW into separate components, some of which can then be transmuted, or changed, into different forms that are less radioactive or shorter-lived (usually by neutron bombardment in a reactor or accelerator). Those not suitable for transmutation can then be immobilized in Synroc. </p><p>The waste form is the key component of the immobilization process, as it determines both waste loading (concentration), which directly impacts cost, as well as the chemical durability, which determines environmental risk. To achieve maximum cost savings and optimum performance, the Synroc waste forms are tailored to suit the particular characteristics of [[<a href="/article/Nuclear_waste_management"> nuclear waste</a> to be immobilized rather than adopting a single one-size fits all approach. </p> <p><a href='/article/Synroc'>Read Full Article...</a></p> http://www.eoearth.org/article/Synroc Tue, 25 Aug 2009 05:43:49 GMT http://www.eoearth.org/article/Synroc <a href='/article/Synroc'><img border='0' src='/upload/thumb/c/ca/Synrocsample_m.jpg/250px-Synrocsample_m.jpg' width='100'/></a> <p>Synroc is a particular kind of &quot;Synthetic Rock&quot;, invented in 1978 by the late Professor Ted Ringwood of the Australian National University. It is an advanced ceramic comprising geochemically stable natural titanate minerals that have immobilized <a href="/article/Uranium">uranium</a> and <a href="/article/Thorium">thorium</a> for billions of years. They can incorporate into their crystal structures nearly all of the elements present in high-level radioactive waste (HLW) and thus immobilize them. Originally, some 57% of Synroc was titanium dioxide (rutile, TiO₂). </p><p>Synroc can take various forms depending on its specific use and can be tailored to immobilize particular components in the <a href="/article/Nuclear_waste_management"> high level nuclear waste (HLW).</a> The original form, Synroc-C, was intended mainly for the immobilization of liquid HLW arising from the reprocessing of light water reactor fuel. However, by 1980 those reprocessing used fuel had chosen borosilicate glass as the medium for immobilization because it was the most technically mature technology. </p><p>The main minerals in Synroc-C are hollandite (BaAl₂Ti₆O₁₆), zirconolite (CaZrTi₂O₇) and perovskite (CaTiO₃). Zirconolite and perovskite are the major hosts for long-lived actinides such as <a href="/article/Plutonium">plutonium</a> (Pu), though perovskite is principally for strontium (Sr) and barium (Ba). Hollandite principally immobilises caesium (Cs), along with potassium (K), rubidium (Rb) and barium. Synroc-C can hold up to 30% HLW by weight. </p><p>Over the past few years, different forms of Synroc have been developed to deal with military <a href="/article/Nuclear_waste_management"> radioactive wastes</a>, including a substantial amount of <a href="/article/Plutonium">plutonium</a>. Other applications have been developed related to the partitioning and transmutation of wastes. This involves partitioning HLW into separate components, some of which can then be transmuted, or changed, into different forms that are less radioactive or shorter-lived (usually by neutron bombardment in a reactor or accelerator). Those not suitable for transmutation can then be immobilized in Synroc. </p><p>The waste form is the key component of the immobilization process, as it determines both waste loading (concentration), which directly impacts cost, as well as the chemical durability, which determines environmental risk. To achieve maximum cost savings and optimum performance, the Synroc waste forms are tailored to suit the particular characteristics of [[<a href="/article/Nuclear_waste_management"> nuclear waste</a> to be immobilized rather than adopting a single one-size fits all approach. </p> <p><a href='/article/Synroc'>Read Full Article...</a></p> http://www.eoearth.org/article/Synroc Tue, 25 Aug 2009 05:42:10 GMT http://www.eoearth.org/article/Wetland <a href='/article/Wetland'><img border='0' src='/upload/thumb/6/6f/Suisun_Marsh_wetlands.jpg/300px-Suisun_Marsh_wetlands.jpg' width='100'/></a> <p>The following information focuses primarily on freshwater, inland wetlands and provides brief information about tidal, coastal, estuarine wetlands. It is important to note, that whether inland or coastal, there are several federal agencies that have special interest in and jurisdiction over wetlands and therefore it is important to define some terms and phrases throughout this article. Our intent is to provide the reader who might have special interest in wetland delineation, wetland mitigation, wetland biology, etc. with information or references to additional information that will be helpful. </p> <p>The U. S. Army Corps of Engineers and the Environmental Protection Agency (EPA) in the originally published 1987 Corps of Engineers Wetlands Delineation Manual jointly defined wetlands as: “Those areas that are inundated or saturated by surface or <a href="/article/Groundwater">groundwater</a> at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated <a href="/article/Soil">soil</a> conditions.” They continue to describe specifics of the three core components that constitute whether or not an area is a wetland, i.e., Vegetation, Soil, and Hydrology. Page 2 of the Manual states that “This report should be cited as follows: Environmental Laboratory. 1987. “Corps of Engineers Wetlands Delineation Manual”, Technical Report Y-87-1, US Army Engineer Waterways Experiment Station, Vicksburg, Miss.” To access an electronic version, see Further Reading. </p><p>The U.S. Federal Highway Administration has interest in the location, form, and function of wetlands due to highway construction and maintenance. Their policy memoranda from 1994 refers and defers to the Soil Conservation Service (SCS), the Environmental Protection Agency (EPA), and the Corps of Engineers (COE) (see Further Reading). </p><p>State government agencies often have special considerations regarding wetland delineations. The state of Florida, for example, often has public, state, and federal interests that require careful attention to issues that relate to wetlands. Therefore, special definitions for Hydric soils, Delineation of Wetlands, and Hydrophytic vegetation may be found on their website (see Further Reading). </p><p>Numerous books are dedicated to plants and animals found in wetlands. Birds and vegetation, for example, are some of the most recognizable, distinguishable features in a wetland landscape, and therefore books may focus on the identification of such birds and plants. The Audubon Society uses the U.S. Fish and Wildlife Service definition in The Audubon Society Nature Guides “Wetlands” by William A. Niering (see Further Reading). </p><p>From all of these sources, the common elements of wetlands include water on the surface or under (but near) the surface for sufficient lengths of time that the area is dominated by hydric soils and organisms that are sustained by and physiologically adapted to such saturated and/or inundated conditions. Hydrology largely determines how the soil develops and the types of plant and animal communities living in and on the soil. Wetlands may support species ranging from obligate aquatic to obligate terrestrial. </p><p>When the upper part of the soil is saturated with water at growing season <a href="/article/Temperature">temperatures</a>, soil organisms consume the <a href="/article/Oxygen">oxygen</a> in the soil and cause conditions ([anaerobic]) unsuitable for most plants. Such conditions also cause the development of <a href="/article/Soil">soil</a> characteristics (such as color and texture) of so-called &quot;hydric soils.&quot; The plants that can grow in such conditions, such as marsh grasses, are called &quot;hydrophytes.&quot; Together, hydric soils and hydrophytes give clues that a wetland area is present. </p><p>The presence of water by ponding, flooding, or soil saturation is not always a good indicator of wetlands. Except for wetlands flooded by ocean tides, the amount of water present in wetlands fluctuates as a result of rainfall patterns, snow melt, dry seasons and longer droughts. </p><p>Some of the most well-known wetlands, such as the Everglades and Mississippi bottomland hardwood swamps, may have periods of dryness. In contrast, many upland areas are very wet during and shortly after wet weather. Such natural fluctuations must be considered when identifying areas subject to government regulation. Similarly, the effects of upstream dams, drainage ditches, dikes, irrigation, and other modifications must also be considered. </p> <p><a href='/article/Wetland'>Read Full Article...</a></p> http://www.eoearth.org/article/Wetland Mon, 24 Aug 2009 06:02:23 GMT http://www.eoearth.org/article/Swamp <a href='/article/Swamp'><img border='0' src='/upload/thumb/d/db/Skunk_cabbage.jpg/150px-Skunk_cabbage.jpg' width='100'/></a> <p>A swamp is any <a href="/article/Wetland">wetland</a> dominated by woody plants. There are many different kinds of swamps, ranging from the forested red maple, (<i>Acer rubrum</i>), swamps of the Northeast, to the extensive bottomland hardwood forests found along the sluggish rivers of the Southeast. Swamps are characterized by saturated soils during the growing season, and standing water during certain times of the year. The highly organic soils of swamps form a thick, black, nutrient-rich environment for the growth of water-tolerant trees such as cypress (<i>Taxodium spp.</i>), Atlantic white cedar (<i>Chamaecyparis thyoides</i>), and tupelo (<i>Nyssa aquatica</i>). Some swamps are dominated by shrubs, such as buttonbush or smooth alder. Plants, birds, fish, and invertebrates such as freshwater shrimp, crayfish, and clams require the habitats provided by swamps. Many rare species, such as the endangered American crocodile depend on these ecosystems as well. Swamps may be divided into two major classes, depending on the type of vegetation present: shrub swamps, and forested swamps. </p> <p><a href='/article/Swamp'>Read Full Article...</a></p> http://www.eoearth.org/article/Swamp Fri, 21 Aug 2009 05:41:52 GMT http://www.eoearth.org/article/Lady_Fern <a href='/article/Lady_Fern'><img border='0' src='/upload/thumb/c/cf/Lady_Fern_USFS.jpg/190px-Lady_Fern_USFS.jpg' width='100'/></a> <p><strong><big>Lady Fern (<em>Athyrium filix-femina</em> (L.) Roth)</big></strong></p> <p>Lady Fern is a native perennial upright fern that can reach 2-5 feet in height. The leaves are a bright green, with a fine-textured lacy appearance, and single fronds can measure up to 1’ wide and 3’ in length. The frond stalks are green to purple or red in color. Lady Fern is native to the continental US and Alaska.</p> <p>This graceful fern is a lovely addition to any moist shade gardens. The lacy light green foliage provides a striking contrast to other wide, dark-leaved shade-tolerant plants. Lady Fern is best introduced into a garden using a containerized plant or by propagating the rhizome. The Lady Fern is easy to grow and maintain as it colonizes through rhizomes but growth is slow. It often forms clumps or groups of upright fern leaves, maintaining a compact appearance, although if left unchecked over a long period, it will spread from 3-7 feet in diameter. This is a deciduous fern. It will drop its leaves with the first frost. Lady Fern is relatively tolerant of sun and dry <a href="/article/Soil">soil</a>, compared to other ferns. The best growth will occur in full to partial shade and a rich, moist soil. This hardy fern also makes a nice ground cover plant on the north or east side of buildings.</p> <p>In the wild, Lady Fern grows in moist woods, moist meadows, and <a href="/article/Swamp">swamps</a> and along <a href="/article/Stream">streams</a>, from lowlands to mid-elevations. Because of its easy maintenance, there are several cultivated varieties, in various shades. This deciduous fern is a very low maintenance plant that adds a lot of esthetic value to the landscape.</p> <p><a href='/article/Lady_Fern'>Read Full Article...</a></p> http://www.eoearth.org/article/Lady_Fern Thu, 20 Aug 2009 05:47:26 GMT http://www.eoearth.org/article/Lady_Fern <a href='/article/Lady_Fern'><img border='0' src='/upload/thumb/c/cf/Lady_Fern_USFS.jpg/190px-Lady_Fern_USFS.jpg' width='100'/></a> <p><strong><big>Lady Fern (<em>Athyrium filix-femina</em> (L.) Roth)</big></strong></p> <p>Lady Fern is a native perennial upright fern that can reach 2-5 feet in height. The leaves are a bright green, with a fine-textured lacy appearance, and single fronds can measure up to 1’ wide and 3’ in length. The frond stalks are green to purple or red in color. Lady Fern is native to the continental US and Alaska.</p> <p>This graceful fern is a lovely addition to any moist shade gardens. The lacy light green foliage provides a striking contrast to other wide, dark-leaved shade-tolerant plants. Lady Fern is best introduced into a garden using a containerized plant or by propagating the rhizome. The Lady Fern is easy to grow and maintain as it colonizes through rhizomes but growth is slow. It often forms clumps or groups of upright fern leaves, maintaining a compact appearance, although if left unchecked over a long period, it will spread from 3-7 feet in diameter. This is a deciduous fern. It will drop its leaves with the first frost. Lady Fern is relatively tolerant of sun and dry <a href="/article/Soil">soil</a>, compared to other ferns. The best growth will occur in full to partial shade and a rich, moist soil. This hardy fern also makes a nice ground cover plant on the north or east side of buildings.</p> <p>In the wild, Lady Fern grows in moist woods, moist meadows, and <a href="/article/Swamp">swamps</a> and along <a href="/article/Stream">streams</a>, from lowlands to mid-elevations. Because of its easy maintenance, there are several cultivated varieties, in various shades. This deciduous fern is a very low maintenance plant that adds a lot of esthetic value to the landscape.</p> <p><a href='/article/Lady_Fern'>Read Full Article...</a></p> http://www.eoearth.org/article/Lady_Fern Thu, 20 Aug 2009 05:47:03 GMT http://www.eoearth.org/article/Maps <a href='/article/Maps'><img border='0' src='/upload/thumb/6/6d/Weather_map_pressure_centers.jpg/250px-Weather_map_pressure_centers.jpg' width='100'/></a> <p>A map can be simply defined as a graphic representation of the real world. This representation is always an abstraction of reality. Because of the infinite nature of our Universe it is impossible to capture all of the complexity found in the real world. For example, <a href="/article/Topographic_maps">topographic maps</a> abstract the three-dimensional real world at a reduced scale on a two-dimensional plane of paper. </p><p>Maps are used to display both cultural and physical features of the environment. Standard topographic maps show a variety of information including roads, <a href="/article/Land-use">land-use</a> classification, elevation, rivers and other water bodies, political boundaries, and the identification of houses and other types of buildings. Some maps are created with very specific goals in mind. Figure 1 displays a weather map showing the location of low and high <a href="/article/Atmospheric_pressure">pressure</a> centers and fronts over most of North America. The intended purpose of this map is considerably more specialized than a topographic map. </p><p>The art of map construction is called cartography. People who work in this field of knowledge are called cartographers. The construction and use of maps has a long history. Some academics believe that the earliest maps date back to the fifth or sixth century BC. Even in these early maps, the main goal of this tool was to communicate information. Early maps were quite subjective in their presentation of spatial information. Maps became more objective with the dawn of Western science. The application of scientific method into cartography made maps more ordered and accurate. Today, the art of map making is quite a sophisticated science employing methods from cartography, engineering, computer science, mathematics, and psychology. </p><p>Cartographers classify maps into two broad categories: reference maps and thematic maps. Reference maps normally show natural and human-made objects from the geographical environment with an emphasis on location. Examples of general reference maps include maps found in atlases and <a href="/article/Topographic_maps">topographic maps</a>. Thematic maps are used to display the geographical distribution of one phenomenon or the spatial associations that occur between a number of phenomena. </p> <p><a href='/article/Maps'>Read Full Article...</a></p> http://www.eoearth.org/article/Maps Wed, 19 Aug 2009 06:26:26 GMT http://www.eoearth.org/article/Maps <a href='/article/Maps'><img border='0' src='/upload/thumb/6/6d/Weather_map_pressure_centers.jpg/250px-Weather_map_pressure_centers.jpg' width='100'/></a> <p>A map can be simply defined as a graphic representation of the real world. This representation is always an abstraction of reality. Because of the infinite nature of our Universe it is impossible to capture all of the complexity found in the real world. For example, <a href="/article/Topographic_maps">topographic maps</a> abstract the three-dimensional real world at a reduced scale on a two-dimensional plane of paper. </p><p>Maps are used to display both cultural and physical features of the environment. Standard topographic maps show a variety of information including roads, <a href="/article/Land-use">land-use</a> classification, elevation, rivers and other water bodies, political boundaries, and the identification of houses and other types of buildings. Some maps are created with very specific goals in mind. Figure 1 displays a weather map showing the location of low and high <a href="/article/Atmospheric_pressure">pressure</a> centers and fronts over most of North America. The intended purpose of this map is considerably more specialized than a topographic map. </p><p>The art of map construction is called cartography. People who work in this field of knowledge are called cartographers. The construction and use of maps has a long history. Some academics believe that the earliest maps date back to the fifth or sixth century BC. Even in these early maps, the main goal of this tool was to communicate information. Early maps were quite subjective in their presentation of spatial information. Maps became more objective with the dawn of Western science. The application of scientific method into cartography made maps more ordered and accurate. Today, the art of map making is quite a sophisticated science employing methods from cartography, engineering, computer science, mathematics, and psychology. </p><p>Cartographers classify maps into two broad categories: reference maps and thematic maps. Reference maps normally show natural and human-made objects from the geographical environment with an emphasis on location. Examples of general reference maps include maps found in atlases and <a href="/article/Topographic_maps">topographic maps</a>. Thematic maps are used to display the geographical distribution of one phenomenon or the spatial associations that occur between a number of phenomena. </p> <p><a href='/article/Maps'>Read Full Article...</a></p> http://www.eoearth.org/article/Maps Wed, 19 Aug 2009 06:26:06 GMT http://www.eoearth.org/article/Ozone <a href='/article/Ozone'><img border='0' src='/upload/thumb/e/eb/OHradicalformation.gif/250px-OHradicalformation.gif' width='100'/></a> <p>Ozone is a gas made up of three <a href="/article/Oxygen">oxygen</a> atoms (O₃). It occurs naturally in small (trace) amounts in the upper <a href="/article/Atmosphere_layers">atmosphere</a> (the stratosphere). Ozone protects life on Earth from the Sun’s ultraviolet (UV) <a href="/article/Solar_radiation">radiation</a>. In the lower atmosphere (the troposphere) near the Earth’s surface, ozone is created by chemical reactions between <a href="/article/Air_pollution_emissions">air pollutants</a> from vehicle exhaust, motor gasoline vapors, and other emissions. At ground level, high concentrations of ozone are <a href="/article/Impact_of_ozone_on_health_and_vegetation">toxic to people and plants.</a> </p><p>Ozone comes from the Greek &quot;ozein&quot; meaning &quot;to smell&quot;, and ozone has a characteristic odor that you can detect around high-voltage discharges. A few examples are a photocopy machine, a television, or during a thunderstorm. </p> <p><a href='/article/Ozone'>Read Full Article...</a></p> http://www.eoearth.org/article/Ozone Tue, 18 Aug 2009 06:01:33 GMT http://www.eoearth.org/article/Ozone <a href='/article/Ozone'><img border='0' src='/upload/thumb/e/eb/OHradicalformation.gif/250px-OHradicalformation.gif' width='100'/></a> <p>Ozone is a gas made up of three <a href="/article/Oxygen">oxygen</a> atoms (O₃). It occurs naturally in small (trace) amounts in the upper <a href="/article/Atmosphere_layers">atmosphere</a> (the stratosphere). Ozone protects life on Earth from the Sun’s ultraviolet (UV) <a href="/article/Solar_radiation">radiation</a>. In the lower atmosphere (the troposphere) near the Earth’s surface, ozone is created by chemical reactions between <a href="/article/Air_pollution_emissions">air pollutants</a> from vehicle exhaust, motor gasoline vapors, and other emissions. At ground level, high concentrations of ozone are <a href="/article/Impact_of_ozone_on_health_and_vegetation">toxic to people and plants.</a> </p><p>Ozone comes from the Greek &quot;ozein&quot; meaning &quot;to smell&quot;, and ozone has a characteristic odor that you can detect around high-voltage discharges. A few examples are a photocopy machine, a television, or during a thunderstorm. </p> <p><a href='/article/Ozone'>Read Full Article...</a></p> http://www.eoearth.org/article/Ozone Tue, 18 Aug 2009 06:00:19 GMT http://www.eoearth.org/article/Research_reactors <a href='/article/Research_reactors'><img border='0' src='/upload/thumb/9/92/Kyoto_University_Research_Reactor.jpg/200px-Kyoto_University_Research_Reactor.jpg' width='100'/></a> <p><a href='/article/Research_reactors'>Read Full Article...</a></p> http://www.eoearth.org/article/Research_reactors Mon, 17 Aug 2009 10:56:46 GMT http://www.eoearth.org/article/Research_reactors <a href='/article/Research_reactors'><img border='0' src='/upload/thumb/9/92/Kyoto_University_Research_Reactor.jpg/200px-Kyoto_University_Research_Reactor.jpg' width='100'/></a> <p><a href='/article/Research_reactors'>Read Full Article...</a></p> http://www.eoearth.org/article/Research_reactors Mon, 17 Aug 2009 10:55:45 GMT http://www.eoearth.org/article/Research_reactors <a href='/article/Research_reactors'><img border='0' src='/upload/thumb/9/92/Kyoto_University_Research_Reactor.jpg/200px-Kyoto_University_Research_Reactor.jpg' width='100'/></a> <p><a href='/article/Research_reactors'>Read Full Article...</a></p> http://www.eoearth.org/article/Research_reactors Mon, 17 Aug 2009 10:55:22 GMT http://www.eoearth.org/article/Sea_ice <a href='/article/Sea_ice'><img border='0' src='/upload/thumb/2/25/Intro.jpg/250px-Intro.jpg' width='100'/></a> <h1><strong>What is sea ice?</strong></h1> <p>Sea ice is simply frozen <a href="/article/Sea_water">ocean water</a>. It forms, grows, and melts in the ocean. In contrast, icebergs, <a href="/article/Glacier">glaciers</a>, ice sheets, and ice shelves all originate on land. Sea ice occurs in both the <a href="/article/Arctic">Arctic</a> and Antarctic. In the <a href="/article/Northern_Hemisphere">Northern Hemisphere</a>, it can currently exist as far south as Bohai Bay, China (approximately 38 degrees north latitude), which is actually about 700 <a href="/article/Meter">kilometers</a> (km) (435 miles) closer to the Equator than it is to the North Pole. In the <a href="/article/Southern_Hemisphere">Southern Hemisphere</a>, sea ice only develops around <a href="/article/Antarctica">Antarctica</a>, occurring as far north as 55 degrees south latitude. </p> <p>Sea ice grows during the winter months and melts during the summer months, but some sea ice remains all year in certain <a href="/article/Region">regions</a>. About 15 percent of the world&#39;s oceans are covered by sea ice during part of the year.</p> <h2><strong>Why is sea ice so important, and why do scientists study it?</strong></h2> <p>Even though sea ice occurs primarily in the polar regions, it influences our global climate. Sea ice has a bright surface, so much of the <a href="/article/Solar_radiation">sunlight</a> that strikes it is reflected back into space. As a result, areas covered by sea ice don&#39;t absorb much solar energy, so <a href="/article/Temperature">temperatures</a> in the polar regions remain relatively cool. If gradually <a href="/article/Global_warming">warming</a> temperatures melt sea ice over time, fewer bright surfaces are available to reflect sunlight back into space, more solar energy is absorbed at the surface, and temperatures rise further. This chain of events starts a cycle of warming and melting. This cycle is temporarily halted when the dark days of the polar winter return, but it starts again in the following spring. Even a small increase in temperature can lead to greater warming over time, making the polar regions the most sensitive areas to climate change on Earth. </p> <p>Sea ice also affects the movement of <a href="/article/Ocean">ocean</a> waters. When sea ice forms, most of the salt is pushed into the ocean water below the ice, although some salt may become trapped in small pockets between ice crystals. Water below sea ice has a higher concentration of salt and is more dense than surrounding ocean water, and so it sinks. In this way, sea ice contributes to the ocean&#39;s global &quot;conveyor-belt&quot; <a href="/article/Ocean_circulation">circulation</a>. Cold, dense, polar water sinks and moves along the ocean bottom toward the equator, while warm water from mid-depth to the surface travels from the equator toward the poles. Changes in the amount of sea ice can disrupt normal ocean circulation, thereby leading to changes in global climate. </p> <p>Too much or too little sea ice can be a problem for wildlife and people who hunt and travel in polar regions. In the <a href="/article/Arctic">Arctic</a>, sea ice can be an obstacle to normal shipping routes through the Northern Sea route and Northwest Passage. </p> <h2><strong>What is the difference between sea ice and icebergs, glaciers, and lake ice?</strong></h2> <p>The most basic difference is that sea ice forms from salty <a href="/article/Seawater">ocean water</a>, whereas icebergs, <a href="/article/Glacier">glaciers</a>, and <a href="/article/Freshwater_biomes">lake</a> ice form from <a href="/article/Freshwater">fresh water</a> or snow. Sea ice grows, forms, and melts strictly in the ocean. Glaciers are considered land ice, and icebergs are chunks of ice that break off of glaciers and fall into the <a href="/article/Ocean">ocean</a>. Lake ice is made from fresh water and freezes as a smooth layer, unlike sea ice, which develops into various forms and shapes because of the constant turbulence of ocean water. </p> <p> The process by which sea ice forms is also different from that of lake or <a href="/article/River">river</a> ice. Fresh water is unlike most substances because it becomes less dense as it nears the freezing point. This difference in density explains why ice cubes float in a glass of water. Very cold, low-density fresh water stays at the surface of lakes and rivers, forming an ice layer on the top.</p> <p>In contrast to fresh water, the salt in ocean water causes the density of the water to increase as it nears the freezing point, and very cold ocean water tends to sink. As a result, sea ice forms slowly, compared to freshwater ice, because salt water sinks away from the cold surface before it cools enough to freeze. Furthermore, other factors cause the formation of sea ice to be a slow process. The freezing temperature of <a href="/article/Seawater">salt water</a> is lower than fresh water; ocean <a href="/article/Temperature">temperatures</a> must reach -1.8 degrees Celsius (28.8 degrees Fahrenheit) to freeze. Because oceans are so deep, it takes longer to reach the freezing point, and generally, the top 100 to 150 <a href="/article/Meter">meters</a> (m) (300 to 450 feet) of water must be cooled to the freezing temperature for ice to form. <br /> </p> <h2><strong>Can you drink melted sea ice?</strong></h2> <p>New ice is usually very salty because it contains concentrated droplets called brine that are trapped in pockets between the ice crystals, and so it would not make good drinking water. As ice ages, the brine eventually drains through the ice, and by the time it becomes multiyear ice, nearly all of the brine is gone. Most multiyear ice is fresh enough that someone could drink its melted water. In fact, multiyear ice often supplies the <a href="/article/Freshwater">fresh water</a> needed for polar expeditions. See Salinity and Brine in the Characteristics section for more information</p> <p><a href='/article/Sea_ice'>Read Full Article...</a></p> http://www.eoearth.org/article/Sea_ice Fri, 14 Aug 2009 05:28:26 GMT http://www.eoearth.org/article/Watershed <a href='/article/Watershed'><img border='0' src='/upload/thumb/0/02/Watershed_diagram1.gif/250px-Watershed_diagram1.gif' width='100'/></a> <p>The term watershed is used (especially in North America and Europe) to indicate an area of land from which all water falling as <a href="/article/Precipitation_and_fog">rain or snow</a> would flow toward a single point. This includes both surface water flow, such as <a href="/article/Freshwater_biomes">rivers</a>, <a href="/article/Stream">streams</a> and creeks, and the <a href="/article/Groundwater">underground</a> movement of water. The boundaries and the area of such a watershed are determined by first specifying geographic point on land. A line is then drawn which connects all of the points of highest elevation immediately adjacent to that point. The watershed area would be the land area within those boundaries. The watershed of the Amazon River would include all of the tributaries that flow into it so it would actually contain several hundred smaller watersheds. The watershed is thus defined hydrologically, that is, by the specific river or stream. Watershed and <a href="/article/Drainage_basin">drainage basin</a> or catchment are used synonymously and all of them refer to the area of land drained by a river system. Three hydrological types of watershed can be distinguished: </p><ul><li>Exorheic watershed, which empty to the sea and represent the major part of the drainage of all of the continents except Australia. </li><li>Endorheic watershed, which discharge inland, into closed lake basins, and are mainly (but not exclusively) restricted to the arid and semi-arid regions. <br /> </li><li>Arheic regions, which is the region within which no rivers arise (the lower part of the Nile, Oranje and Niger, all in Africa, are a good examples of this category of basin). </li></ul><p>Watershed identification is now a primary tool for environmental planning. Called watershed management areas, these geographic units are utilized to gain an understanding of what happens to the surface or <a href="/article/Groundwater">groundwater</a> in the upper elevations of a watershed because that is imperative for the interpretation of local phenomenon. In some locales, the term &quot;watershed&quot; actually refers to the height of land <em>between</em> two catchment areas.</p> <p><a href='/article/Watershed'>Read Full Article...</a></p> http://www.eoearth.org/article/Watershed Thu, 13 Aug 2009 05:50:19 GMT http://www.eoearth.org/article/Heat_island <a href='/article/Heat_island'><img border='0' src='/upload/thumb/b/bf/Heat_island_profile.gif/250px-Heat_island_profile.gif' width='100'/></a> <p>The term &quot;heat island&quot; refers to urban air and surface <a href="/article/Temperature">temperatures</a> that are higher than nearby rural areas. Many cities and suburbs have air temperatures that are 2 to 10°F (1 to 6°C) warmer than the surrounding natural <a href="/article/Land-cover">land cover</a>. Figure 1 shows a city&#39;s heat island profile. It demonstrates how urban temperatures are typically lower at the urban-rural border than in dense downtown areas. The graphic also show how parks, open land, and bodies of water can create cooler areas. Elevated temperatures can impact communities in a number of ways. Elevated temperatures can impact communities by increasing peak energy demand, air conditioning costs, <a href="/article/Air_pollution_emissions">air pollution</a> levels, and <a href="/article/Heat">heat</a>-related illness and mortality. </p> <p>The remotely sensed image of Sacramento, CA in Figure 2 illustrates the heat island phenomenon. In the aerial photo (left), the white areas, mostly rooftops, are about 140 degrees Fahrenheit (60 degrees Celsius) and the dark areas, primarily vegetative areas or water, are approximately 85-96 degree Fahrenheit (29-36 degrees Celsius). The hottest spots are the buildings, seen as white rectangles of various sizes. In the thermal image (right), Sacramento&#39;s rail yard is the orange area east of the Sacramento River, which flows from top to bottom. Red and yellow areas indicate hot spots and generally correspond with urban development, while blue and green areas are cool and generally correspond to the natural environment. </p><p>Cities in cold climates may actually benefit from the wintertime warming effect of heat islands. Warmer <a href="/article/Temperature">temperatures</a> can reduce heating energy needs and may help melt ice and snow on roads. In the summertime, however, the same city may experience the negative effects of heat islands. </p> <p><a href='/article/Heat_island'>Read Full Article...</a></p> http://www.eoearth.org/article/Heat_island Wed, 12 Aug 2009 05:44:39 GMT http://www.eoearth.org/article/Tide <a href='/article/Tide'><img border='0' src='/upload/thumb/b/b6/Earth_moon_system.jpg/300px-Earth_moon_system.jpg' width='100'/></a> <p>An ocean tide refers to the cyclic rise and fall of seawater. Tides are caused by slight variations in gravitational attraction between the Earth, the moon and the sun in geometric relationship with locations on the Earth's surface. Tides are periodic primarily because of the cyclical influence of the Earth's rotation. </p><p>The moon is the primary factor controlling the temporal rhythm and height of tides (Figure 1). The moon produces two tidal bulges somewhere on the Earth through the effects of gravitational attraction. The height of these tidal bulges is controlled by the moon's gravitational force and the Earth's gravity pulling the water back toward the Earth. At the location on the Earth closest to the moon, seawater is drawn toward the moon because of the greater strength of gravitational attraction. On the opposite side of the Earth, another tidal bulge is produced away from the moon. However, this bulge is due to the fact that at this point on the Earth the force of the moon's gravity is at its weakest. Considering this information, any given point on the Earth's surface should experience two tidal crests and two tidal troughs during each tidal period. </p> <p>The timing of tidal events is related to the Earth's rotation and the revolution of the moon around the Earth. If the moon was stationary in space, the tidal cycle would be 24 hours long. However, the moon is in motion revolving around the Earth. One revolution takes about 27 days and adds about 50 minutes to the tidal cycle. As a result, the tidal period is 24 hours and 50 minutes in length. </p> <p>The second factor controlling tides on the Earth's surface is the sun's gravity. The height of the average solar tide is about 50% the average lunar tide. At certain times during the moon's revolution around the Earth, the direction of its gravitational attraction is aligned with the sun's (Figure 2). During these times the two tide producing bodies act together to create the highest and lowest tides of the year. These spring tides occur every 14-15 days during full and new moons. </p><p>When the gravitational pull of the moon and sun are at right angles to each other, the daily tidal variations on the Earth are at their least (Figure 3). These events are called neap tides and they occur during the first and last quarter of the moon. </p> <p><a href='/article/Tide'>Read Full Article...</a></p> http://www.eoearth.org/article/Tide Tue, 11 Aug 2009 05:22:54 GMT http://www.eoearth.org/article/Lithium <a href='/article/Lithium'><img border='0' src='/upload/thumb/9/9b/Spodume.jpg/200px-Spodume.jpg' width='100'/></a> <p>Lithium, the lightest metal, is in a group of elements called alkali metals or <em>Group I elements </em>and is silvery-white in color<em>.</em> It has the atomic number of 3. The alkali metals group includes lithium (Li), potassium (K), and sodium (Na). The three alkali metals are highly reactive with <a href="/article/Oxygen">oxygen</a> and water, so they are stored in oil. Although lithium will react dramatically when put in water, it is the least reactive alkali metal. When it reacts with water it bounces on the top of the water because it is less dense than water. </p><p>Johan A. Arfvedson, of Stockholm, Sweden, first discovered lithium in 1817. It was first isolated by W.T. Brande and <a href="/article/Davy%2C_Humphry">Humphry Davy</a> in the 19th century, but it was not commercially <a href="/article/Essential_economic_activities">produced</a> until 1923. </p> <p><a href='/article/Lithium'>Read Full Article...</a></p> http://www.eoearth.org/article/Lithium Mon, 10 Aug 2009 05:06:58 GMT http://www.eoearth.org/article/Landslide <a href='/article/Landslide'><img border='0' src='/upload/thumb/c/c7/La_conchita_Village.JPG/175px-La_conchita_Village.JPG' width='100'/></a> <p>Landslides in the United States occur in all 50 States. The primary <a href="/article/Region">regions</a> of landslide occurrence and potential are the coastal and <a href="/article/Mountain">mountainous</a> areas of California, Oregon, and Washington, the States comprising the intermountain west, and the mountainous and hilly regions of the Eastern United States. Alaska and Hawaii also experience all types of landslides. </p><p>Landslides in the United States cause approximately $3.5 billion (year 2001 dollars) in damage, and kill between 25 and 50 people annually. Casualties in the United States are primarily caused by rockfalls, rock slides, and debris flows. Worldwide, landslides occur and cause thousands of casualties and billions in monetary losses annually. </p><p>The information in this publication provides an introductory primer on understanding basic scientific facts about landslides—the different types of landslides, how they are initiated, and some basic information about how they can begin to be managed as a hazard. </p> <p><a href='/article/Landslide'>Read Full Article...</a></p> http://www.eoearth.org/article/Landslide Fri, 07 Aug 2009 05:55:59 GMT http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa <a href='/article/Impacts_of_tourism_and_recreation_in_Africa'><img border='0' src='/upload/thumb/d/d5/Great_Zimbabwe.JPG/350px-Great_Zimbabwe.JPG' width='100'/></a> <p>Land-based tourism is a major economic activity in Africa, drawing millions of visitors to different sites across the region every year and generating millions of dollars in foreign exchange earnings. Sites such as the pyramids of Egypt, the Great Rift Valley of Eastern and Southern Africa, Great Zimbabwe, Table Mountain in South Africa, Mount Kenya in Kenya and Mount Kilimanjaro in Tanzania are some of the major attractions. Mountains, wildlife, wetlands and <a href="/article/Coastal_zone">coastal areas</a> are also major tourist attractions. These and other attractions contributed to the arrival of a total of about 124 million international tourists in the five years of 1990, 1995, 2000, 2002 and 2003. The visitors spent a total of US$52 891 million in those five years. In 2003 and 2004 the region attracted 78.1 million international tourists. In 2004, international tourist arrivals grew at 10 percent worldwide and 14 percent in Africa – to 41.6 million, up from 36.5 million in 2003. However, the region shared only 7.4 percent of the global increase of 69 million tourists, and almost all the increase was concentrated in Northern Africa. </p><p>Ecotourism accounted for 20 percent of total international tourism. In recognition of ecotourism’s growth potential, particularly for developing countries, the United Nations Economic and Social Council (ECOSOC) declared 2002 the International Year of Ecotourism. Many countries in Africa, such as Kenya and South Africa, have invested heavily in ecotourism. </p><p>Tourism in Africa varies widely, from viewing gorillas in the Great Lakes Region to lemurs in Madagascar, from trekking in Ethiopia to birdwatching in Botswana, from looking at rock paintings in South Africa to visiting rainforests in Ghana, from <a href="/article/Mountain">mountain</a>-climbing in Eastern Africa (Mt Kilimanjaro and Mt Kenya, for example) to scuba-diving in the Seychelles and to photographic safaris in Eastern and Southern Africa. In the Great Lakes Region, for example, revenue from tourism based on gorilla viewing and other activities brings in about US$20 million to the region annually. Tourism in the area is certain to be boosted with the news in 2004 that the first census since 1989 revealed that the population of the apes in the Virunga Mountains has grown by 17 percent, increasing from 324 in 1989 to 380 by the end of 2003. </p> <p>Tourism can serve as a powerful incentive to protect natural resources. In Madagascar, where tourism is the country’s second largest foreign exchange earner, the country had by 1998 established 40 new protected areas, covering roughly 2 percent of the country’s <a href="/article/Land_resources_in_Africa">land</a> area. In Southern and Eastern Africa, privately-owned protected areas that support tourism and hunting enterprises are also growing. </p><p>Tourism not only generates revenue to support conservation and management of natural environments but also generates many jobs. For example, hundreds of people live off the Bwindi Impenetrable Forest in Uganda, where foreign tourists trek to view gorillas. It has been argued that tourism has larger multiplier effects, with revenue spreading from hotel accommodation, food and beverages, shopping, entertainment and transport to income of hotel staff, taxi operators, shopkeepers and suppliers of goods and services. </p><p>Despite the growth of tourism, the region still only accounts for less than 4 percent of world tourism, with its revenue share at only 2.5 percent – about US$16,000 million in 2002 of the annual sales of about US$4.5 million million. Therefore, opportunities for further investment and development are vast in the region. In Kenya, for example, new regulations that will allow sport bird shooting are expected to attract up to 2,000 sport hunters annually, boosting revenues by US$5 million each year. New Kenya Wildlife Service (KWS) rules provide for private landowners to obtain special authorization to manage their own game bird populations, including breeding, as well as determine open and closed seasons. </p> <p>Several African countries including Ethiopia, South Africa, Kenya and Benin have significant palaeontology sites. In Ethiopia, the government is using these sites to promote &quot;palaeo-tourism,&quot; and to generate revenue. Ethiopia is home to some of the most famous prehistoric remains ever found, including some of the world’s oldest human remains: Ethiopia’s discoveries chart man’s prehistory from more than 6 million years ago to modern ancestors. Tourism officials in Afar believe that &quot;palaeo-tourism&quot; could generate an additional US$2 million in revenue annually for this region alone. The Ethiopian Tourism Commission has reported that the sector generated more than US$77 million in 2003. This revenue is important in the fight against poverty and plays a key role in the government’s poverty reduction strategy paper (PRSP). South Africa has also made palaeontology and other cultural heritage sites a focus of their tourism industry. </p><p>The tourism industry in Africa also has human and environmental costs, contributing to the displacement of communities and thus undermining rights and livelihoods, the generation of waste and pollution, and the unsustainable use of water. In Africa, for example, tourism’s effects on indigenous peoples have been profound, with the eviction of communities from their <a href="/article/Land_resources_in_Africa">lands</a>, in addition to economic dislocation, breakdown of traditional values, and environmental degradation. Pastoralism has been attacked as primitive and destructive. The massive influx of tourists and their vehicles in the Masai Mara National Park in Kenya and in the Ngorongoro Conservation Area in Tanzania has destroyed grass cover, affecting plant and animal species in the area. Hotels have dumped their sewage in Masai settlement areas while campsites have polluted adjacent rivers. One emerging approach is to focus on promoting community conservation areas and also collaborative tourism initiatives in order to ensure greater benefits to communities. There are different levels of community participation, varying from passive participation to interactive decision making to community empowerment initiatives. </p><p>The challenge facing policymakers in this industry and other land-based activities is to critically assess the costs and benefits to ensure that all options are fully weighed and that the policy responses contribute to <a href="/article/Sustainomics_and_sustainable_development">sustainable development</a> and minimize overexploitation. </p><p>Additionally, measures need to be adopted to ensure that the benefits associated with tourism are spread across society, and that those who are directly involved in conservation are rewarded. </p><p><strong>Further Reading</strong> </p> <ul><li>African Environmental News Services, 2003. <a href="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026" class='external text' title="http://www.aens.org/news/newsdetails.asp?newsId=2003050210026">Kenya Hopes to Boost Tourism Revenue by Sport Bird Shooting.</a> </li><li>Chavez, R., 1999. <a href="http://www.twnside.org.sg/title/chavez-cn.htm" class='external text' title="http://www.twnside.org.sg/title/chavez-cn.htm">Globalisation and tourism: Deadly mix for indigenous peoples.</a> Third World Resurgence, 103. Third World Network. </li><li>ECA, 2005. <a href="http://www.uneca.org/era2005/front.pdf" class='external text' title="http://www.uneca.org/era2005/front.pdf">Economic Report on Africa 2005: Meeting the Challenges of Unemployment and Poverty in Africa.</a> Economic Commission for Africa, Addis Ababa. </li><li>IRIN, 2004. <a href="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn_of_Africa" class='external text' title="http://www.irinnews.org/report.asp?ReportID=38868&amp;SelectRegion=Horn of Africa">Ethiopia: Archaeology and palaeontology to boost tourism revenue.</a> United Nations Integrated Regional Information Networks. </li><li>Pickrell, J., 2004. <a href="http://news.nationalgeographic.com/news/2004/01/0127_040127_gorillas.html#main" class='external text' title="http://news.nationalgeographic.com/news/2004/01/0127 040127 gorillas.html#main">Africa’s Mountain Gorillas Rebound, Says New Census.</a> National Geographic News, January 27, 2004. </li><li>Saunders, D. J. (undated). <a href="http://www.africaata.org/trade_2.htm" class='external text' title="http://www.africaata.org/trade 2.htm">Africa Needs More Liberalized Trade Initiatives for the Continued Growth and Sustainability of its Travel and Tourism Industry.</a> Africa Travel Magazine. </li><li>UN (undated). <a href="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm" class='external text' title="http://www.un.org/esa/agenda21/natlinfo/niau/kenyanp.htm">Sustainable tourism in Kenya</a>. United Nations Division for Economic and Social Affairs, New York. </li><li>UNEP, 2006. <a href="http://www.unep.org/dewa/africa/aeo2_launch/index.asp" class='external text' title="http://www.unep.org/dewa/africa/aeo2 launch/index.asp">Africa Environment Outlook 2</a> </li><li>Vieta, F. E., 1999. <a href="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm" class='external text' title="http://www.un.org/ecosocdev/geninfo/afrec/subjindx/131envir.htm">Ecotourism propels development: But social acceptance depends on economic opportunities for local communities.</a> Africa Recovery, 13(1). </li><li>World Tourism Organization, 2005. <a href="http://www.world-tourism.org/facts/menu.html" class='external text' title="http://www.world-tourism.org/facts/menu.html">International Tourist Arrivals &amp;amp; Tourism Receipts by Country.</a> </li></ul> <p><br /> </center> </p><p> <p>[[category:|Impacts of tourism and recreation in Africa]] </p> </p> <p><a href='/article/Impacts_of_tourism_and_recreation_in_Africa'>Read Full Article...</a></p> http://www.eoearth.org/article/Impacts_of_tourism_and_recreation_in_Africa Thu, 06 Aug 2009 05:17:06 GMT http://www.eoearth.org/article/Groundwater <a href='/article/Groundwater'><img border='0' src='/upload/thumb/d/d9/Fresh_water_storage_on_earth.gif/400px-Fresh_water_storage_on_earth.gif' width='100'/></a> <p>In the broadest sense, groundwater refers to all subsurface water. The term more commonly refers to water beneath the surface of the earth which saturates the pores and fractures of sand, gravel, and <a href="/article/Composition_of_rocks">rock</a> formations. Groundwater is a major source of water for <a href="/article/Agriculture">agricultural</a> and industrial purposes, and is an important source of drinking water for many people around the world. </p><p>Some water underlies the Earth&#39;s surface almost everywhere, beneath hills, mountains, plains, and deserts. It is not always accessible, or fresh enough for use without treatment, and it&#39;s sometimes difficult to locate or to measure and describe. This water may occur close to the land surface, as in a <a href="/article/Wetland">wetland</a>, or it may lie many hundreds of feet below the surface, as in some arid regions. Water at very shallow depths might be just a few hours old; at moderate depth, it may be hundreds of years old; and at great depth or after having flowed long distances from places of entry, water may be several thousands of years old. </p> <p>Groundwater is stored in, and moves slowly through, moderately to highly permeable rocks called <a href="/article/Aquifer">aquifers</a>. The word aquifer comes from the two Latin words, <em>aqua</em>, or water, and <em>ferre</em>, to bear or carry. Aquifers literally carry water underground. An aquifer may be a layer of gravel or sand, a layer of sandstone or cavernous limestone, a rubbly top or base of lava flows, or even a large body of massive rock, such as fractured granite, that has sizable cracks and fissures. In terms of storage at any one instant in time, groundwater is the largest single supply of fresh water available for use by humans. </p><p>Groundwater has been known to humans for thousands of years. Scripture (Genesis 7:11) on the Biblical Flood states that &quot;the fountains of the great deep (were) broken up,&quot; and Exodus, among its many references to water and to wells, refers (20:4) to &quot;water under the Earth.&quot; Many other ancient chronicles show that humans have long known that much water is contained underground, but it is only within recent decades that scientists and engineers have learned to estimate how much groundwater is stored underground and have begun to document its vast potential for use. An estimated one million cubic miles of the world&#39;s groundwater is stored within one-half mile of the land surface. Only a fraction of this groundwater, however, can be practicably tapped and made available on a perennial basis through wells and <a href="/article/Spring">springs</a>. The amount of groundwater in storage is more than 30 times greater than the nearly 30,000 cubic-miles volume in all the fresh-water lakes and more than the 300 cubic miles of water in all the world&#39;s streams at any given time (<strong>Figure 1</strong>). </p> <p><a href='/article/Groundwater'>Read Full Article...</a></p> http://www.eoearth.org/article/Groundwater Wed, 05 Aug 2009 06:17:13 GMT http://www.eoearth.org/article/Invasive_species <a href='/article/Invasive_species'><img border='0' src='/upload/thumb/1/1d/Chestnut_blight.gif/90px-Chestnut_blight.gif' width='100'/></a> <p>An invasive species is defined legally in the USA as “An alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health…‘Alien species’ means, with respect to a particular <a href="/article/Ecosystem">ecosystem</a>, any species…that is not native to that ecosystem.” Novel species can be added to a community either by natural range extensions or because they are introduced as a result of human activity. Some introduced or alien species are beneficial to humans, for example most of our crops and pets. However many alien species have harmful effects; these are referred to as invasive species. Virtually all ecosystems are at risk from the harmful effects of introduced species ( also see <a href="/article/Exotic_species">exotic species</a>, <a href="/article/Marine_invasive_species">marine invasive species</a>, <a href="/article/Aquatic_invasive_species">aquatic invasive species</a>).</p><p>Invasive species are a major threat to our environment because they (1) can change habitats and alter ecosystem function and ecosystem services, (2) crowd out or replace native species, and (3) damage human activities, costing the economy millions of dollars. For example, costs to <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, <a href="/article/Fisheries_and_aquaculture">fisheries</a>, and other human activities by introduced species are estimated at $137 billion per year to the U.S. economy alone.</p> <p><a href='/article/Invasive_species'>Read Full Article...</a></p> http://www.eoearth.org/article/Invasive_species Wed, 05 Aug 2009 06:14:51 GMT http://www.eoearth.org/article/Local_and_regional_wind_systems <a href='/article/Local_and_regional_wind_systems'><img border='0' src='/upload/thumb/2/2e/Uniform_atm_pressure.gif/250px-Uniform_atm_pressure.gif' width='100'/></a> <p><a href="/article/Wind">Winds</a> blow because of differences in <a href="/article/Atmospheric_pressure">atmospheric pressure</a>. Pressure gradients may develop on a local to a global scale because of differences in the heating and cooling of the Earth&#39;s surface. Heating and cooling cycles that develop daily or annually can create several common local or regional thermal wind systems. The basic circulation system that develops is described in the Figure 1. </p> <p>In this first diagram (Figure 1), there is no horizontal temperature or pressure gradient and therefore no <a href="/article/Wind">wind</a>. Atmospheric pressure decreases with altitude as depicted by the drawn isobars (1000 to 980 millibars). In the second diagram (Figure 2), the potential for solar heating is added which creates contrasting surface areas of temperature and atmospheric pressure. The area to the right receives more <a href="/article/Solar_radiation">solar radiation</a> and the air begins to warm from heat energy transferred from the ground through conduction and convection. The vertical distance between the isobars becomes greater as the air rises. To the far left, less radiation is received because of the presence of cloud, and this area becomes relatively cooler than the area to the right. In the upper atmosphere, a pressure gradient begins to form because of the rising air and upward spreading of the isobars. The air then begins to flow in the upper atmosphere from high pressure to low pressure.</p><p>&nbsp;</p><p>Figure 3 shows the full circulation system in action. Beneath the upper atmosphere high is a thermal low pressure center created from the heating of the ground surface. Below the upper atmosphere low is a thermal high created by the relatively cooler air temperatures and the descend air from above. Surface air temperatures are cooler here because of the obstruction of shortwave radiation absorption at the Earth&#39;s surface by the cloud. At the surface, the <a href="/article/Wind">wind</a> blows from the high to the low pressure. Once at the low, the wind rises up to the upper air high pressure system because of thermal buoyancy and outflow in the upper atmosphere. From the upper high, the air then travels to the upper air low, and then back down to the surface high to complete the circulation cell. The circulation cell is a closed system that redistributes air in an equitable manner. It is driven by the greater heating of the surface air in the right of the diagram. </p> <p><a href='/article/Local_and_regional_wind_systems'>Read Full Article...</a></p> http://www.eoearth.org/article/Local_and_regional_wind_systems Tue, 04 Aug 2009 05:41:47 GMT http://www.eoearth.org/article/Local_and_regional_wind_systems <a href='/article/Local_and_regional_wind_systems'><img border='0' src='/upload/thumb/2/2e/Uniform_atm_pressure.gif/250px-Uniform_atm_pressure.gif' width='100'/></a> <p><a href="/article/Wind">Winds</a> blow because of differences in <a href="/article/Atmospheric_pressure">atmospheric pressure</a>. Pressure gradients may develop on a local to a global scale because of differences in the heating and cooling of the Earth&#39;s surface. Heating and cooling cycles that develop daily or annually can create several common local or regional thermal wind systems. The basic circulation system that develops is described in the Figure 1. </p> <p>In this first diagram (Figure 1), there is no horizontal temperature or pressure gradient and therefore no <a href="/article/Wind">wind</a>. Atmospheric pressure decreases with altitude as depicted by the drawn isobars (1000 to 980 millibars). In the second diagram (Figure 2), the potential for solar heating is added which creates contrasting surface areas of temperature and atmospheric pressure. The area to the right receives more <a href="/article/Solar_radiation">solar radiation</a> and the air begins to warm from heat energy transferred from the ground through conduction and convection. The vertical distance between the isobars becomes greater as the air rises. To the far left, less radiation is received because of the presence of cloud, and this area becomes relatively cooler than the area to the right. In the upper atmosphere, a pressure gradient begins to form because of the rising air and upward spreading of the isobars. The air then begins to flow in the upper atmosphere from high pressure to low pressure.</p><p>&nbsp;</p><p>Figure 3 shows the full circulation system in action. Beneath the upper atmosphere high is a thermal low pressure center created from the heating of the ground surface. Below the upper atmosphere low is a thermal high created by the relatively cooler air temperatures and the descend air from above. Surface air temperatures are cooler here because of the obstruction of shortwave radiation absorption at the Earth&#39;s surface by the cloud. At the surface, the <a href="/article/Wind">wind</a> blows from the high to the low pressure. Once at the low, the wind rises up to the upper air high pressure system because of thermal buoyancy and outflow in the upper atmosphere. From the upper high, the air then travels to the upper air low, and then back down to the surface high to complete the circulation cell. The circulation cell is a closed system that redistributes air in an equitable manner. It is driven by the greater heating of the surface air in the right of the diagram. </p> <p><a href='/article/Local_and_regional_wind_systems'>Read Full Article...</a></p> http://www.eoearth.org/article/Local_and_regional_wind_systems Tue, 04 Aug 2009 05:41:25 GMT http://www.eoearth.org/article/River <a href='/article/River'><img border='0' src='/upload/thumb/7/73/Confl2.gif/250px-Confl2.gif' width='100'/></a> <p>Rivers are of immense importance geologically, biologically, historically and culturally. Although they contain only about 0.0001% of the total amount of water in the world at any given time, rivers are vital carriers of water and nutrients to areas all around the earth. They are critical components of the hydrological cycle, acting as <a href="/article/Drainage_basin">drainage channels</a> for surface water – the world&#39;s rivers drain nearly 75% of the earth&#39;s land surface. They provide habitat, nourishment and means of transport to countless organisms; their powerful forces create majestic scenery; they provide travel routes for exploration, commerce and recreation; they leave valuable deposits of sediments, such as sand and gravel; they form vast floodplains where many of our cities are built; and their power provides much of the electrical energy we use in our everyday lives. Rivers are central to many of the environmental issues that concern society, and they are studied by a wide range of specialists including hydrologists, engineers, <a href="/article/Ecology">ecologists</a> and geomorphologists.</p> <p><a href='/article/River'>Read Full Article...</a></p> http://www.eoearth.org/article/River Mon, 03 Aug 2009 05:19:58 GMT http://www.eoearth.org/article/Evolution <a href='/article/Evolution'><img border='0' src='/upload/thumb/3/37/Figure1_evolution.jpg/300px-Figure1_evolution.jpg' width='100'/></a> <h1><strong>Introduction<br /></strong></h1> <p class="MsoNormal">Evolution is most commonly defined as a change in allelic (varieties of genes) frequencies in a <a href="/article/Population">population</a> over time. In other words, evolution encompasses a series of mechanisms that lead to changes in the relative proportion of different types of genes contained in a population where these changes persist from one generation to another. The primary mechanisms that result in such changes are <a href="/article/Natural_selection">selection</a>, genetic drift, mutation, and gene flow. </p> <p class="MsoNormal"> It is a common misconception that evolution occurs only through selection, but all four mechanisms often co-occur and selection is not necessarily the dominant force of evolutionary change. As <a href="/article/Darwin%2C_Charles">Charles Darwin</a> is recognized as the preeminent scientist to write formally about evolution by selection, this mechanism is often termed Darwinian selection. In fact, many scientists were synthesizing their ideas about evolution at the same time as Darwin and the first formal presentation of evolution by <a href="/article/Natural_selection">natural selection</a> was jointly authored by Alfred Russell Wallace and Charles Darwin. However, Darwin’s seminal book entitled <a href="/article/On_the_Origin_of_Species_%28historical_e-book%29"><em>On The Origin of Species by Means of Natural Selection</em></a> is often cited as the genesis of evolutionary theory as it contains a litany of evidence indicating how selection operates and how species are descended from common ancestors. </p> <p class="MsoNormal"> Darwin’s theories on evolution lacked any knowledge of genetic change and it was not until Gregor Mendel’s work on the genetic heritability of pea plant characteristics were incorporated into evolutionary thinking that the new synthesis of evolutionary theory was born. This new synthesis led to a flurry of research in the 1920s to 1960s that described and formalized the genetic mechanisms of evolution. Evolutionary theory has changed substantially since the initial days of Darwin and Wallace. </p> <p class="MsoNormal"> As there are now tens of thousands of scientific studies that demonstrate how evolution works, its characterization as a “theory” is somewhat misleading, and many scientists feel the term theory misrepresents the overwhelming weight of evidence that supports the modern conception of evolution and how it works. </p> <h1><strong>Mechanisms of evolution</strong></h1> <p><a href='/article/Evolution'>Read Full Article...</a></p> http://www.eoearth.org/article/Evolution Fri, 31 Jul 2009 06:09:29 GMT http://www.eoearth.org/article/London_smog_disaster,_England <a href='/article/London_smog_disaster,_England'><img border='0' src='/upload/thumb/b/b7/London_Smog.jpg/300px-London_Smog.jpg' width='100'/></a> <p><strong>London, England</strong> ( 51°29&#39;51.75&quot;N, 0° 7&#39;47.65&quot;W) was the site of a dense <a href="/article/Smog">smog</a> caused by heavy coal <a href="/article/Combustion">combustion</a> during the winter of 1952, which killed approximately 12,000 people. </p> <p><a href='/article/London_smog_disaster,_England'>Read Full Article...</a></p> http://www.eoearth.org/article/London_smog_disaster,_England Wed, 29 Jul 2009 06:15:31 GMT http://www.eoearth.org/article/Deception_Island <a href='/article/Deception_Island'><img border='0' src='/upload/thumb/0/0c/AntDotMap_Livingston.png/150px-AntDotMap_Livingston.png' width='100'/></a> <p>Deception Island is one of the <a href="/article/South_Shetland_Islands">South Shetland Islands</a> of <a href="/article/Antarctica">Antarctica</a>, lying about 60 miles (150 km) north of the <a href="/article/Antarctic_Peninsula">Antarctic Peninsula</a> across the Bransfield Strait. </p><p>The island is ring-shaped (roughly circular with with a flooded interior), from 7-10 miles across. The island is an active <a href="/article/Volcano">volcano</a> with a drowned breached crater which provides a sheltered harbor, named Port Foster (an oval 5x3 miles, 8x5 km). This harbor was popular in the early nineteenth century with seal hunters. It was known as Williams Harbor among British sealers and Yankee Harbor among American sealers (not to be confused with today&#39;s Yankee Harbor on nearby Greenwich Island). The narrow entrance to the harbor (feet, meter wide) is known as Neptune&#39;s Bellows.</p> <p>The island covers 38 miles² (98.5 km²), of which just over half is glaciated. The highest point on the island is Mount Pond at 1,890 feet (550 meters) high. It is also known as Monte Cambell and Monte Estanque <span class="reference"><sup id="ref_1" class="plainlinksneverexpand"><a href="#endnote_1" class='external autonumber' title="#endnote 1">[1]</a></sup></span>.</p><p>Eruptions have occurred frequently in the past; most recently in 1970. Volcanic vents (Maars) exist at various places on the island <span class="reference"><sup id="ref_2" class="plainlinksneverexpand"><a href="#endnote_2" class='external autonumber' title="#endnote 2">[2]</a></sup></span>. </p> <p>The climate is &#39;&#39;polar maritime&quot; with temperatures ranging from +11°C to -28°C. However, because of volcanic activity and numerous vents, the island exhibits several &quot;microclimates&quot; where far higher temperatures have been measured.</p><p>The island&#39;s plant life is rich in comparison to most of <a href="/article/Antarctica">Antarctica</a>, with 18 species of moss or <a href="/article/Lichen">lichens</a> not found elsewhere on the continent.</p><p>The first known sighting of the island occurred in January, 1820 by a British expedition led by Edward Bransfield and piloted by William Smith. </p><p>It is thought that American seal hunter Nathaniel Palmer was the first to discover the harbor in late 1820 as a haven for seal hunters. Later it was also used by whaling ships and as the site for a whaling station. Whaler&#39;s Cove, just inside the harbor entrance is the site of an abandoned whaling station<span class="reference"><sup id="ref_3" class="plainlinksneverexpand"><a href="#endnote_3" class='external autonumber' title="#endnote 3">[3]</a></sup></span>.</p><p>The ice near to the whaling station was used as a landing strip by Hubert Wilkins for the first flights over <a href="/article/Antarctica">antarctica</a> in 1928.</p> <p>While the Island has been claimed by the United Kingdom, <a href="/article/Chile">Chile</a> and <a href="/article/Argentina">Argentina</a>, it comes under the jurisdiction of the <a href="/article/Antarctic_Treaty_System">Antarctic Treaty System</a> (1959). Sovereignty is neither recognized nor disputed by the signatories. The <a href="/article/Antarctic_Treaty_System">Antarctic Treaty System</a> limits military activity and promotes environmental protection and scientific and other peaceful activities. Alternative names include Yaraslav Island (Russia - It was named by the Bellinghausen expedition in 1821), Teil Island, and Isla Decepción.</p><p>Permanent research stations on the islands established by the British in the 1940s and 1960s were abandoned because of the volcanic eruptions. Today, summer research stations are maintained by Spain (Gabriel De Castilla<span class="reference"><sup id="ref_5" class="plainlinksneverexpand"><a href="#endnote_5" class='external autonumber' title="#endnote 5">[4]</a></sup></span>) and <a href="/article/Argentina">Argentina</a> (Decepción station), both at at Fumerole Bay {ref|4}}.</p><p>Because of the high risks associated with volcanic eruptions, there is no permanent human presence on the island, but the hot springs make it an increasingly popular tourist stop during the austral summer.</p><p><strong>References</strong></p><ol><li><cite id="endnote_1" style="font-style: normal"><a href="#ref_1"><strong>^</strong></a></cite><a href="http://www.volcano.si.edu/world/volcano.cfm?vnum=1900-03%3D" class='external text' title="http://www.volcano.si.edu/world/volcano.cfm?vnum=1900-03=">Deception Island, Glabal Volcanism Program, Smithsonian Institute</a> accessed December 4, 2008.</li><li><cite id="endnote_2" style="font-style: normal"><a href="#ref_2"><strong>^</strong></a></cite><a href="http://geonames.usgs.gov/pls/gnispublic/f?p=106:3:788274225708607::NO::P3_ANTAR_ID:11942" class='external text' title="http://geonames.usgs.gov/pls/gnispublic/f?p=106:3:788274225708607::NO::P3 ANTAR ID:11942">USGS Geographic Name Information Service</a></li><li><cite id="endnote_3" style="font-style: normal"><a href="#ref_3"><strong>^</strong></a></cite><a href="http://tryfan.ucsd.edu/antpics/deception_island.htm" class='external text' title="http://tryfan.ucsd.edu/antpics/deception island.htm">Deception Island</a>, Teresa K. Chereskin, Scripps Istitute of Oceanography] accessed December 4, 2008</li><li><cite id="endnote_4" style="font-style: normal"><a href="#ref_4"><strong>^</strong></a></cite><a href="http://tryfan.ucsd.edu/antpics/deception_island.htm" class='external text' title="http://tryfan.ucsd.edu/antpics/deception island.htm">Deception Island</a>, Teresa K. Chereskin, Scripps Istitute of Oceanography] accessed December 4, 2008</li><li><cite id="endnote_5" style="font-style: normal"><a href="#ref_5"><strong>^</strong></a></cite><a href="http://www.newzeal.com/theme/bases/Spain/gabrieldecastilla.htm" class='external text' title="http://www.newzeal.com/theme/bases/Spain/gabrieldecastilla.htm">Gabriel De Castilla</a> accessed December 4, 2008</li></ol><p><strong>Further Reading</strong></p><ul><li><a href="http://www.deceptionisland.aq/" class='external text' title="http://www.deceptionisland.aq/">Deception Island</a></li><li><a href="http://www.amazon.com/Antarctica-Exploring-Extreme-Years-Adventure/dp/1556524285/ref=sr_1_5?ie=UTF8&amp;s=books&amp;qid=1226240236&amp;sr=8-5" class='external text' title="http://www.amazon.com/Antarctica-Exploring-Extreme-Years-Adventure/dp/1556524285/ref=sr 1 5?ie=UTF8&amp;s=books&amp;qid=1226240236&amp;sr=8-5">Antarctica: Exploring the Extreme: 400 Years of Adventure</a>, Marilyn J. Landis, Chicago Review Press, 2001</li><li><a href="http://www.amazon.com/exec/obidos/tg/detail/-/0393039498/ref=pd_luc_mri?%5Fencoding=UTF8&amp;v=glance" class='external text' title="http://www.amazon.com/exec/obidos/tg/detail/-/0393039498/ref=pd luc mri? encoding=UTF8&amp;v=glance">Below the Convergence: Voyages Towards Antarctica, 1699-1839</a>, Alan Gurney, W.W. Norton and Company, 1997</li><li><a href="http://www.amazon.com/Discovery-South-Shetland-Islands-1819-1820/dp/B000PS7EYW/ref=sr_1_2?ie=UTF8&amp;s=books&amp;qid=1226252739&amp;sr=1-2" class='external text' title="http://www.amazon.com/Discovery-South-Shetland-Islands-1819-1820/dp/B000PS7EYW/ref=sr 1 2?ie=UTF8&amp;s=books&amp;qid=1226252739&amp;sr=1-2">The Discovery of the South Shetland Islands, 1819-1820&nbsp;: The Journal of Midshipman C. W. Poynter</a>, R. J. Campbell (editor), Hakluyt Society, 2001</li><li><a href="http://www.amazon.com/exec/obidos/tg/detail/-/0905355253/ref=pd_luc_mri?%5Fencoding=UTF8&amp;v=glance" class='external text' title="http://www.amazon.com/exec/obidos/tg/detail/-/0905355253/ref=pd luc mri? encoding=UTF8&amp;v=glance">Antarctica Observed</a>, A.G.E. Jones, Caedmon of Whitby, 1982</li><li><a href="http://www.gpsvisualizer.com/map?lat1=-62.95&amp;lon1=-60.6&amp;location=&amp;radius=60+miles&amp;format=google&amp;radius_segments=&amp;google_wpt_sym=circleGPS" class='external text' title="http://www.gpsvisualizer.com/map?lat1=-62.95&amp;lon1=-60.6&amp;location=&amp;radius=60 miles&amp;format=google&amp;radius segments=&amp;google wpt sym=circleGPS">Visualizer</a></li><li><a href="http://geonames.usgs.gov/" class='external text' title="http://geonames.usgs.gov/">USGS Geographic Name Information Service</a></li></ul> <p>[[category:|Deception Island]] </p> <p><a href='/article/Deception_Island'>Read Full Article...</a></p> http://www.eoearth.org/article/Deception_Island Tue, 28 Jul 2009 05:46:30 GMT http://www.eoearth.org/article/Adaptations_of_marsh_plants <a href='/article/Adaptations_of_marsh_plants'><img border='0' src='/upload/thumb/7/74/Typha7.jpg/150px-Typha7.jpg' width='100'/></a> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Introduction </h1><p><a href="/article/Marsh">Marshes</a> are permanently or periodically covered with nutrient-rich water. Marshes are characterized by emergent vegetation that is adapted to saturated <a href="/article/Soil">soils</a> and by submerged vegetation that lives at deeper depths. Plants living in marshes are exposed to three environmental stresses: (1) they are frequently covered by water so they must be able to cope with low <a href="/article/Oxygen">oxygen</a> content, (2) they are often exposed to the <a href="/article/Atmospheric_composition">atmosphere</a> so they can be exposed to factors such terrestrial herbivores and fire, and (3) they are sometimes exposed to the effects of wave action or water movement. Thus, these factors have selected for the herbaceous plants with well developed root systems (that provide anchorage and storage). <a href="/article/Salt_marsh">Salt marshes</a> are found in <a href="/article/Estuary">estuarine</a> areas with high (and fluctuating) salt content. Thus, <a href="/article/Salt_marsh">salt marsh</a> plants must have adaptations for dealing with high salt content in the water that surrounds them, a fourth type of stress.</p> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Low soil oxygen content</h1><p><span> </span></p><p><a href="/article/Wetland">Wetland</a> soils have been affected by the permanent cover of water. One problem faced by plants living in marshes is the lack of <a href="/article/Oxygen">oxygen</a> in the <a href="/article/Soil">soil</a>. Oxygen is used by plants (and most other organisms) in the process of cellular respiration in which the energy from glucose (produced by <a href="/article/Photosynthesis">photosynthesis</a>) is released so that the organisms can use the energy to do “biological work.” When glucose is broken down in the presence of oxygen, aerobic respiration occurs and the organisms are able to use a great deal of the stored energy in the glucose. In situations where oxygen is lacking, glucose is broken down by the process of anaerobic respiration which does not release as much energy from each molecule of glucose (aerobic respiration releases about 18 times more energy than anaearobic respiration). Not only is anaerobic much less energy efficient than aerobic respiration, but by products of anaerobic respiration, are toxic.</p><p>Plants lack a circulatory system, so plants are not able to “pump” oxygen from air (where the oxygen concentration is about 21%) below ground to the roots. Thus, the roots of terrestrial plants rely on oxygen in air spaces between soil particles. Oxygen is hard to get in hydrated soils for two reasons. First, water fills the space between soil particles that are typically filled with air in terrestrial soils. Second, because the rate of diffusion of oxygen is much slower in water than in air the rate of movement from the water surface to the root zone is extremely slow, so most hydric soils are either low in oxygen (hypoxic) or lack oxygen (anoxic) because the oxygen in the water in the soil is used up, often by the activity of decomposers (<a href="/article/Bacteria">bacteria</a>).</p><p>So how do the roots of <a href="/article/Marsh">marsh</a> plants get the oxygen that they need to survive? Marsh plants have evolved air spaces (&quot;aerenchyma tissue&quot;) in their stems that allow oxygen to move from the leaves (where oxygen is produced in the process of photosynthesis) to the roots by either diffusion or in some cases, by <a href="/article/Pressure">pressure</a> differences between the leaves and the roots.</p> <p>Other marsh plants are able to survive in low <a href="/article/Oxygen">oxygen</a> conditions by relying on anaerobic respiration. These species apparently have altered their biochemical pathways to allow them to avoid the build-up of high concentrations of toxic ethanol (a waste product of anaerobic respiration).</p> <h1><span>Herbivory</span></h1> <p><span>Because of the high availability of light, water, and nutrients, <a href="/article/Marsh">marshes</a> are among the most productive <a href="/article/Ecosystem">ecosystems</a> on earth (i.e., a lot of sugar is produced by the process of <a href="/article/Photosynthesis">photosynthesis</a>). The production of biomass in <a href="/article/Wetland">wetland</a> systems can be over three times higher than in a terrestrial ecosystem. Because biomass production in marsh ecosystems, there is high there is a lot of potential food for herbivores.<span> However, </span>most emergent macrophytes are of low food quality because they have a relatively high content of structural <a href="/article/Carbon">carbon</a> relative to the amount of <a href="/article/Nitrogen">nitrogen</a> and phosphorus they contain. Thus, a relatively large percentage of the plant biomass is not eaten and when the plants die they become detritus, and enter into detritus-based food webs.  </span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Fire</span></h1></span><p><span>Some <a href="/article/Marsh">marshes</a> become dry enough seasonally or during drought periods that they are potentially burned by fire. The extensive root system of most emergent marsh vegetation allows them to resprout following a fire.</span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Salinity</h1></span><p><span><span>Plants living in <a href="/article/Salt_marsh">salt marshes</a> are exposed to high salinity environments. Plants adapted to living in saline environments are known as halophytes (&quot;salt lovers&quot;). Halophytes have evolved physiological, structural, and biochemical means of dealing with a saline environment. Some halophytes are able to secrete salt through salt glands, whereas other plants have mechanisms for dealing with higher cellular concentrations of salt, or can reduce of the uptake of salt through their roots.</span></span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Further Reading</span></h1></span><ul><li><span>Georgia Conservency, </span><span><a href="http://www.gaconservancy.org/education/ED_saltmarshes.asp" class='external text' title="http://www.gaconservancy.org/education/ED saltmarshes.asp">Coastal Salt Marshes</a>. <br /></span></li><li><span>Ofwell Woodland and Wildlife Trust, </span><span><a href="http://www.countrysideinfo.co.uk/wetland_survey/adaptns.htm" class='external text' title="http://www.countrysideinfo.co.uk/wetland survey/adaptns.htm">Plant Adaptations to Aquatic Life</a>. <br /></span></li></ul> <p><a href='/article/Adaptations_of_marsh_plants'>Read Full Article...</a></p> http://www.eoearth.org/article/Adaptations_of_marsh_plants Tue, 28 Jul 2009 05:45:19 GMT http://www.eoearth.org/article/Adaptations_of_marsh_plants <a href='/article/Adaptations_of_marsh_plants'><img border='0' src='/upload/thumb/7/74/Typha7.jpg/150px-Typha7.jpg' width='100'/></a> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Introduction </h1><p><a href="/article/Marsh">Marshes</a> are permanently or periodically covered with nutrient-rich water. Marshes are characterized by emergent vegetation that is adapted to saturated <a href="/article/Soil">soils</a> and by submerged vegetation that lives at deeper depths. Plants living in marshes are exposed to three environmental stresses: (1) they are frequently covered by water so they must be able to cope with low <a href="/article/Oxygen">oxygen</a> content, (2) they are often exposed to the <a href="/article/Atmospheric_composition">atmosphere</a> so they can be exposed to factors such terrestrial herbivores and fire, and (3) they are sometimes exposed to the effects of wave action or water movement. Thus, these factors have selected for the herbaceous plants with well developed root systems (that provide anchorage and storage). <a href="/article/Salt_marsh">Salt marshes</a> are found in <a href="/article/Estuary">estuarine</a> areas with high (and fluctuating) salt content. Thus, <a href="/article/Salt_marsh">salt marsh</a> plants must have adaptations for dealing with high salt content in the water that surrounds them, a fourth type of stress.</p> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Low soil oxygen content</h1><p><span> </span></p><p><a href="/article/Wetland">Wetland</a> soils have been affected by the permanent cover of water. One problem faced by plants living in marshes is the lack of <a href="/article/Oxygen">oxygen</a> in the <a href="/article/Soil">soil</a>. Oxygen is used by plants (and most other organisms) in the process of cellular respiration in which the energy from glucose (produced by <a href="/article/Photosynthesis">photosynthesis</a>) is released so that the organisms can use the energy to do “biological work.” When glucose is broken down in the presence of oxygen, aerobic respiration occurs and the organisms are able to use a great deal of the stored energy in the glucose. In situations where oxygen is lacking, glucose is broken down by the process of anaerobic respiration which does not release as much energy from each molecule of glucose (aerobic respiration releases about 18 times more energy than anaearobic respiration). Not only is anaerobic much less energy efficient than aerobic respiration, but by products of anaerobic respiration, are toxic.</p><p>Plants lack a circulatory system, so plants are not able to “pump” oxygen from air (where the oxygen concentration is about 21%) below ground to the roots. Thus, the roots of terrestrial plants rely on oxygen in air spaces between soil particles. Oxygen is hard to get in hydrated soils for two reasons. First, water fills the space between soil particles that are typically filled with air in terrestrial soils. Second, because the rate of diffusion of oxygen is much slower in water than in air the rate of movement from the water surface to the root zone is extremely slow, so most hydric soils are either low in oxygen (hypoxic) or lack oxygen (anoxic) because the oxygen in the water in the soil is used up, often by the activity of decomposers (<a href="/article/Bacteria">bacteria</a>).</p><p>So how do the roots of <a href="/article/Marsh">marsh</a> plants get the oxygen that they need to survive? Marsh plants have evolved air spaces (&quot;aerenchyma tissue&quot;) in their stems that allow oxygen to move from the leaves (where oxygen is produced in the process of photosynthesis) to the roots by either diffusion or in some cases, by <a href="/article/Pressure">pressure</a> differences between the leaves and the roots.</p> <p>Other marsh plants are able to survive in low <a href="/article/Oxygen">oxygen</a> conditions by relying on anaerobic respiration. These species apparently have altered their biochemical pathways to allow them to avoid the build-up of high concentrations of toxic ethanol (a waste product of anaerobic respiration).</p> <h1><span>Herbivory</span></h1> <p><span>Because of the high availability of light, water, and nutrients, <a href="/article/Marsh">marshes</a> are among the most productive <a href="/article/Ecosystem">ecosystems</a> on earth (i.e., a lot of sugar is produced by the process of <a href="/article/Photosynthesis">photosynthesis</a>). The production of biomass in <a href="/article/Wetland">wetland</a> systems can be over three times higher than in a terrestrial ecosystem. Because biomass production in marsh ecosystems, there is high there is a lot of potential food for herbivores.<span> However, </span>most emergent macrophytes are of low food quality because they have a relatively high content of structural <a href="/article/Carbon">carbon</a> relative to the amount of <a href="/article/Nitrogen">nitrogen</a> and phosphorus they contain. Thus, a relatively large percentage of the plant biomass is not eaten and when the plants die they become detritus, and enter into detritus-based food webs.  </span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Fire</span></h1></span><p><span>Some <a href="/article/Marsh">marshes</a> become dry enough seasonally or during drought periods that they are potentially burned by fire. The extensive root system of most emergent marsh vegetation allows them to resprout following a fire.</span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal">Salinity</h1></span><p><span><span>Plants living in <a href="/article/Salt_marsh">salt marshes</a> are exposed to high salinity environments. Plants adapted to living in saline environments are known as halophytes (&quot;salt lovers&quot;). Halophytes have evolved physiological, structural, and biochemical means of dealing with a saline environment. Some halophytes are able to secrete salt through salt glands, whereas other plants have mechanisms for dealing with higher cellular concentrations of salt, or can reduce of the uptake of salt through their roots.</span></span></p><span> <h1 style="margin: 0in 0in 0pt; line-height: 200%" class="MsoNormal"><span>Further Reading</span></h1></span><ul><li><span>Georgia Conservency, </span><span><a href="http://www.gaconservancy.org/education/ED_saltmarshes.asp" class='external text' title="http://www.gaconservancy.org/education/ED saltmarshes.asp">Coastal Salt Marshes</a>. <br /></span></li><li><span>Ofwell Woodland and Wildlife Trust, </span><span><a href="http://www.countrysideinfo.co.uk/wetland_survey/adaptns.htm" class='external text' title="http://www.countrysideinfo.co.uk/wetland survey/adaptns.htm">Plant Adaptations to Aquatic Life</a>. <br /></span></li></ul> <p><a href='/article/Adaptations_of_marsh_plants'>Read Full Article...</a></p> http://www.eoearth.org/article/Adaptations_of_marsh_plants Tue, 28 Jul 2009 05:44:10 GMT http://www.eoearth.org/article/Tellegen,_Bernard_D.H. <a href='/article/Tellegen,_Bernard_D.H.'><img border='0' src='/upload/thumb/b/bd/Tellegen.jpg/150px-Tellegen.jpg' width='100'/></a> <p>Bernard Tellegen was born 24 June 1900 in the Netherlands. He attended Delft University, where he obtained his degree in electrical engineering in 1923. In 1924 he entered into the service of the Philips Research Laboratories. These laboratories had been founded in 1914 by Holst and Oosterhuis. Tellegen belonged to a fairly small nucleus (van der Pol, de Groot, Penning, Druyvestein, Bouwers) around which one of the largest research centers in the world would grow. As a scientific adviser, he later became a member of its board of directors. </p><p>Tellegen&#39;s first studies concerned vacuum tubes. He became interested in electron motions in triodes and multigrid tubes. In 1926 he invented the penthode, which was patented in a number of countries. It was the first in a series of about 57 patents, which he received either alone or in cooperation with others. </p><p>In the following years Tellegen became interested in electrical circuits on which he published already in 1928, 1933 and 1934. </p><p>In 1932 it was noticed, that the programs of some Italian transmitters, when received in the Netherlands, seemed to carry also the program of Radio Luxemburg and crossmodulation in the receiver tubes was suspected. Tellegen showed that this was really a nonlinear effect in the ionosphere, caused by the powerful Luxemburg transmitter. </p><p>During his further studies in electrical networks, he became more interested in fundamental problems such as duality and geometric configurations and network synthesis in particular of resistanceless four poles. During his basic study of the classical passive network elements, Tellegen arrived at the conclusion that a further element &quot;the gyrator&quot; could complete the series in an elegant way. This new element does not comply with the reciprocity relations, and is antisymmetrical. Tellegen studied the properties of circuits with the &quot;gyrator&quot;. Its first realization came in the microwave field with the use of premagnetized ferrites. The circulator was a further result of this idea. When the miniaturization of electronic circuits led to new possibilities, the gyrator soon became an important building block for selective circuits at low frequencies. In 1952 Dr. Tellegen published an important paper on a general network theorem with applications. Fundamentally &quot;Tellegen&#39;s theorem&quot; gives a simple relation between magnitudes that satisfy the Kirchhoff laws. Many treatises and a book on the application of this theorem were published. A paper on &quot;Synthesis of 2n- poles by networks consisting of a minimum number of elements&quot; proved his interest in economy. He also discussed the ideal amplifier or &quot;nullor&quot;. When he was the guest of honor at the International Symposium on Circuit Theory, London 1970, he gave a paper on circuits with negative resistance elements. </p><p>In the period 1946-1966 Tellegen was professor extraordinary of circuit theory at the University of Delft. Adams, Bordewijk and Duinker were among those who received their doctor&#39;s degree working with him. </p><p>From 1942 to 1952 he was president of the Dutch Electronics and Radio Society, which made him a honorary member at the end of this period. From 1948 to 1960 he was chairman of the Dutch Committee of the International Scientific Radio Union (U.R.S.I.) He was vice-president of U.R.S.I. from 1952 to 1957. From 1957 to 1960 he was vice-chairman of its commission VI, especially charged with circuit theory. </p><p>The Australian Institute of Radio Engineers made Tellegen a honorary life member in 1953. He received the Research Prize of the Royal Dutch Institute of Engineers in 1954, the Fellow Award of the <a href="/contributor/IEEE">IEEE</a> in 1955, and the IEEE Edison Medal in 1973 &quot;For a creative career of significant achievement in electrical circuit theory, including the gyrator&quot;. Tellegen was elected a member of the Royal Academy of Sciences of the Netherlands in 1960. In 1970 the University of Delft conferred on him the degree of doctor honoris causa in technical sciences. </p><p>Tellegen and his wife, the former Gertrud J. van der Lee, reside at the Geulberg in Nuenen, near Eindhoven. They have three children, Ben D. H., Jr., an engineer in computer sciences, John, a physician and Clara, married to a physicist. There are eight grandchildren. The Tellegen&#39;s live amidst the <a href="/article/Forest_biome">woods</a> and fens of the beautiful North Brabant countryside. In long walks they learned to know every part of it. In connection with his international conferences they visited many countries and made a world trip in 1952.</p><p>Dr. Tellegen passed away on 30 August 1990. </p><p><br /> <p><br style="clear: left" /> <center> </p> </center></p> <p><a href='/article/Tellegen,_Bernard_D.H.'>Read Full Article...</a></p> http://www.eoearth.org/article/Tellegen,_Bernard_D.H. Mon, 27 Jul 2009 05:27:36 GMT http://www.eoearth.org/article/Ten_fundamental_principles_of_net_energy <a href='/article/Ten_fundamental_principles_of_net_energy'><img border='0' src='/upload/thumb/c/c9/Snow_geese.jpg/250px-Snow_geese.jpg' width='100'/></a> <p><strong>Introduction</strong><br /><br /> <strong><a href="/article/Energy_return_on_investment_%28EROI%29">Energy return on investment (EROI)</a></strong> is the ratio of the energy extracted or delivered by a process to the energy used directly and indirectly in that process. A common related term is <strong>energy surplus</strong>, which is the gross amount of energy extracted or delivered, minus the energy used directly and indirectly in that process. EROI is a dimensionless number, while energy surplus refers to an actual physical quantity of energy. Suppose an energy delivery system delivers 10 <a href="/article/Joule">joules</a> of energy, but in the processes consumes 2 joules. The EROI for that process is 5 (10 divided by 2), while the energy surplus delivered is 8 joules (10 minus 2). </p><p>EROI is a tool of <a href="/article/Net_energy_analysis">net energy analysis</a>, a methodology that seeks to compare the amount of energy delivered to society by a technology to the total energy required to find, extract, process, deliver, and otherwise upgrade that energy to a socially useful form. Net energy analysis was developed in response to the emergence of energy as an important economic, technological and geopolitical force following the energy price increases of 1973-74 and 1980-81. Interest in net energy analysis was rekindled in recent years following another round of energy price increases, growing concern about energy&#39;s role in climate change, and the debate surrounding the remaining lifetime of conventional fossil fuels, especially crude oil. </p><p><strong>The principles</strong><br /> </p> <p><strong>1. <a href="/article/Net_energy_analysis">Net energy</a> and <a href="/article/Net_energy_analysis">energy surplus</a> are important driving forces in <a href="/article/Ecology">ecology</a> and economic systems</strong><br /><br /> The efficiency and effectiveness of energy capture is a central organizing principle in ecology. Living organisms must capture energy and allocate it among a number of life-sustaining tasks (growth, reproduction, energy storage, defense, competition). A larger surplus produced by a system of energy capture compared to competing strategies gives an organism a competitive advantage. Ecologists have used the principle of net energy to explain a wide range of phenomena, including habitat switching, long distance migration by birds, vertical migration by marine organisms, optimal foraging strategy, the pattern of the distribution and abundance of species, reproductive behavior in bats, and the effects of human disturbance on organisms. </p><p>Biologists such as <a href="/article/Lotka%2C_Alfred_James">Alred Lotka</a> and <a href="/article/Odum%2C_Howard_T.">Howard Odum</a> elevated the concept to the driving force behind <a href="/article/Natural_selection">natural selection</a> itself, where, in the struggle for existence, the advantage goes to those organisms whose energy-capturing devices are more effective in directing available energies into channels favorable to the preservation of the species. </p><p>Scholars from a number of disciplines have applied the same concept of <a href="/article/Net_energy_analysis">net energy</a> to social systems, with widely varying assumptions about the extent to which net energy influences the trajectory of the evolution of culture. The analogy to natural systems is straightforward: societies with access to energy sources with a higher <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a> and a large net energy surplus have an economic and military advantage over societies that use lower <a href="/article/Energy_quality">quality energy sources</a>. A low EROI means that more of a society’s productive resources must be devoted to energy delivery, and thus cannot be used to produce non-energy goods and services, support a powerful military, expand the arts, or be consumed as leisure time. </p><p>Net energy has been used to explain major <a href="/article/Energy_transitions">energy transitions</a>, including the industrial revolution and the emergence of the affluent society, the rise and fall of great civilizations, the pattern of resource depletion, and the impact of technological change on energy technologies. Net energy has been used as a methodological tool to assess and compare energy systems, as a tool to assess the climate impact of energy technologies, and it plays a central role in the longstanding debate on the viability of alternative energy technologies such as ethanol. </p><p><strong>2. The size and rate of delivery of surplus energy is just as important as EROI</strong><br /><br /> The net amount of energy delivered from the energy sector to the non-energy sectors is the energy available to generate non-energy goods and services. The size of that surplus sets broad but distinct limits on human economic aspirations. Falling water, for example, can deliver a large EROI in a specific location, but the total energy surplus available to a society from falling water is limited by the relatively sparse spatial distribution of the resource. The amount of energy surplus potentially available from diffuse energy sources such as solar and wind power is just as important as their EROI. </p> <p>Contrary to popular belief, <a href="/article/Agriculture">agriculture</a> did not supplant hunting and gathering as the major food production technology because it has a higher <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a>. Indeed, hunting and gathering often produced a very high EROI in specific locations and around specific resources. For example, the harvesting of energy-dense biomass in coastal whaling had an EROI in the neighborhood of 2000:1. Some hunting and gathering societies developed sophisticated social and civil institutions, and often consumed their energy surplus in the form of leisure time. But hunting and gathering ultimately is limited by the distribution of edible net primary production in the <a href="/article/Biosphere">biosphere</a>, which limits population densities to about one person per square <a href="/article/Meter">kilometer</a>. </p><p>The advantage of agriculture derives from the large net energy surplus delivered per unit land area and per person compared to hunting and gathering. Agriculture thus erased the energetic limits to <a href="/article/Carrying_capacity">carrying capacity</a> inherent in hunting and gathering, and released human labor and other productive resources from the farm. The latter was a necessary condition for the industrialization of society. </p><p><strong>3. The unprecedented expansion of the human population, the <a href="/article/Global_economy">global economy</a>, and per capita living standards of the last 200 years was powered by high EROI, high energy surplus fossil fuels</strong><br /><br /> The penultimate position of fossil fuels in the energy hierarchy stems from the fact that they have a high EROI and a very large energy surplus. The largest oil and gas fields, which are found early in the exploration process due to their sheer physical size, delivered energy surpluses that dwarfed any previous source (and any source developed since then). That surplus, in combination with other attributes, is what makes conventional fossil fuels unique. The long run challenge society faces is to replace the current system with a combination of alternatives will similar attributes and a much lower carbon intensity. </p> <br /><p><strong>4. The principal economic impact of a shift to a lower EROI energy system is the increased opportunity cost of energy delivery</strong></p><p><br /> A shift to a lower EROI energy system means that more of society&#39;s productive resources are devoted--directly and indirectly-- to delivering the same amount of energy. That energy thus cannot be used for other purposes, notably consumption goods. Energy used to make a drilling rig or wind turbine cannot be used to manufacture iPods or provide medical care. </p> <p><strong>5. <a href="/article/Energy_quality">Energy quality</a> matters</strong><br /><br /> <a href="/article/Net_energy_analysis">Net energy</a> is only one attribute of an energy system that determines it usefulness to society. The usefulness of an energy system is determined by a complex combination of physical, technical, economic, and social attributes. These include gravimetric and volumetric energy density, power density, emissions, cost and efficiency of conversion, financial risk, amenability to storage, risk to human health, and ease of transport. These attributes combine to determine <strong><a href="/article/Energy_quality">energy quality</a>:</strong> differences in the ability of a unit of a fuel to perform useful services for people. No single metric of an energy system captures all such attributes, including EROI. It stands to reason, therefore, that a comprehensive and balanced comparison of energy technologies should employ a range of metrics, with their strengths and weaknesses duly noted. </p><p>Since all forms of energy can be completely converted to <a href="/article/Heat">heat</a>, heat units (Btus, <a href="/article/Joule">joules</a>, <a href="/article/Calorie">calories</a>, <a href="/article/Watt-hour">kilowatt-hours</a>) provide an easy way to aggregate different forms of energy. For example, the world uses about 450x10¹⁵ Btu, or 450 &quot;quads&quot; of energy each year. That quantity is the aggregation of dozens of different energy types added together by multiplying their mass or volume used times their heat content per unit mass or volume. But this approach implicitly assumes that &quot;all Btus are equal,&quot; i.e., that people value a heat unit of electricity the same as a heat unit of <a href="/article/Coal">coal</a>. Of course, this is not the case. Electricity performs important tasks that coal cannot, or it performs them more effectively. People are willing to pay 15 times more for a heat unit of electricity (in the U.S.) because of these differences. Accounting for differences in energy quality can <a href="/article/Energy_quality">dramatically alter the results of net energy analyses</a>. </p> <p><strong>6. <a href="/article/Market_failure">Market imperfections</a> that distort prices and cost also affect <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a></strong><br /><br /> Dollar-based assessments of energy systems are distorted by market imperfections such as <a href="/article/Externality">externalities</a>, <a href="/article/Subsidies_and_market_interventions">subsidies</a>, and government policies. The result is that the full social cost of energy is unaccounted for. However, EROI is plagued by many of the same problems. For example, there is no established methodology to incorporate the ecological and human health impacts of energy production and use in the calculation of EROI, so it too overstates benefits to society. In fact, economic analysis has better developed tools to estimate and aggregate external costs than energy analysis. </p><p>The calculation of <a href="/article/Economic_energy_cost">indirect costs</a> in energy analysis (e.g., the energy used to manufacture a wind turbine) often is based on economic data. Subsidies and other government policies affect decisions made in the <a href="/article/Market">market</a>, and thus affect the economic data often used as inputs to energy analysis, including the pattern of capital investment. A good example of this was government regulation of the natural gas industry in the U.S. in the 1970s. Deep, new, and presumably lower EROI natural gas was assigned a higher price than shallow, old, and presumably higher EROI gas in an attempt to stimulate overall exploration. Any change in the overall EROI for gas extraction caused by this policy had little to do with “resource depletion” per se. </p><p><strong>7. The methodologies to perform <a href="/article/Net_energy_analysis">net energy analysis</a> are well established</strong><br /><br /> Conventional wisdom in the blogsphere and other Internet communities is that there are no guidelines for performing net energy analysis. In fact, there is a rich, well-established literature on the subject, most of which was developed in the first wave of energy research in the 1970s and 1980s. This body of work includes not only methodological detail, but also discussions about how to deal with intractable problems such as joint costs and outputs, the energy cost of human labor, choosing appropriate system boundaries, among many others. The record also has a rich history of debate about the virtues of net energy analysis, particularly in regards to what it adds, if anything, to a discussion that already includes a thorough economic assessment. The current discussion surrounding net energy analysis would be significantly enhanced if participants were better informed by previous work. </p><p><strong>8. The relation between “peak oil” and the EROI for world oil production is unknown</strong><br /><br /> This statement is true for two reasons. The first and most obvious reason is that we do not know when world oil production will peak, and won’t know definitively until sometime afterwards. Second, and more importantly, there is no comprehensive and reliable assessment of the historic <a href="/article/Energy_return_on_investment_%28EROI%29">EROI</a> for world oil production. There is a distinct lack of reliable public data on the direct and indirect costs associated with oil production in many regions of the world. </p><p>The lower 48 U.S. is the only region for which we can compare the trends in EROI and oil production. There we see a remarkable convergence: crude oil production peaks in 1970 and then declines, and the EROI for that production peaks at about the same time. The timing of both peaks is consistent with a change in the underlying cost structure of the resource, when the cost-increasing effects of depletion began to outweigh the cost-decreasing effects of technological change. If such as connection holds at the global level, then the timing and impact of “peak oil” takes on added significance. </p> <p><strong>9. Technological change affects EROI just as it affects price and cost</strong><br /><br /> There is a widely held assumption that the EROI for a nonrenewable energy resource such as crude oil or a renewable resource such as wind inexorably decline once the physical quality of the resource base begins to decline (e.g., smaller and deeper fields, or less windy sites). This is not necessarily the case. Technological change that lowers the dollar cost of extraction can also lower the energy cost of extraction. For example, developing the ability to drill multiple and directional wells from a single platform lowered the dollar cost per well, and it may well have lowered the indirect energy embodied in the materials required to extract oil. The well-documented technical improvements in that have lowered the dollar cost of emerging technologies such as wind and solar undoubtedly exert at least some downward pressure on energy costs as well. </p><p>Technological change exogenous to the energy industry also affects the EROI. For example, the development of more efficient combustion engines would, <em>ceteris paribus</em>, improve the EROI for oil extraction that relies on such engines to lift oil to the surface. Similarly, a decrease in the quantity of energy required to produce a <a href="/article/Kilogram">kilogram</a> of steel will, <em>ceteris paribus,</em> improve the EROI by reducing the energy embodied in oil field equipment. </p> <p><strong>10. Alternatives to the dominant energy and power systems show a wide range in EROI</strong><br /><br /> Most alternatives to conventional liquid fuels have very low or unknown EROIs. The EROI for ethanol derived from corn grown in the U.S. is about 1.5:1, well below that for conventional motor gasoline. Ethanol from sugarcane grown in <a href="/article/Brazil">Brazil</a> apparently has a higher EROI, perhaps as high as 8:1, due to higher yields of sugarcane compared to corn, the use of bagasse as an energy input, and significant cost reductions in ethanol production technology. Shale oil and coal liquefaction have low EROIs and high carbon intensities, although little work has been done in this area in more than 20 years. The <a href="/article/Athabasca%2C_Alberta">Alberta oil sands</a> remain an enigma from a net energy perspective. Anecdotal evidence suggests an EROI of 3:1, but these reports lack veracity. Certainly oil sands will have a lower EROI than conventional crude oil due to the more diffuse nature of the resource base and associated increase in direct and indirect processing energy costs. </p><p>On the power generation side, <a href="/article/Coal">coal</a>, and hydropower have the highest EROI among conventional power systems, although the latter has very limited potential for further expansion in most regions of the world. Nuclear power appears to have a lower EROI, but there are very few credible studies that are thorough and unbiased. We do not know what the EROI will be from the new generation of <a href="/article/Nuclear_power_reactor">nuclear reactors</a> that would be built if demand for them returns. <a href="/article/Energy_return_on_investment_%28EROI%29_for_wind_energy">Wind</a> has a very favorable EROI in the right conditions, while solar thermal and photovoltaic systems have lower EROIs compared to <a href="/article/Coal">coal</a> and hydropower. As outlined above, a key issue is the size of the surplus that can realistically be delivered by those renewable power technologies. </p><p>A final point for consideration: <em>Carbon may trump EROI</em>. The growing concern that climate change may impose swift and large costs on society may drive the next major <a href="/article/Energy_transitions">energy transition</a>. It is plausible that carbon intensity, as opposed to net energy, may be the principal attribute of future energy systems that determines the timing and pace of their adoption. Society may choose to forgo the benefits of a larger energy surplus to reduce its exposure to climate-related risks. </p><p><strong>Further Reading</strong><br /> </p> <ul><li>Biopact. 2006. <a href="http://biopact.com/2006/10/brazilian-ethanol-is-sustainable-and.html" class='external text' title="http://biopact.com/2006/10/brazilian-ethanol-is-sustainable-and.html">Brazilian ethanol is sustainable and has a very positive energy balance - IEA report</a><br /> </li><li>Bullard, Clark W., Peter S. Penner and David A. Pilati. 1978. <a href="http://dx.doi.org/10.1016/0165-0572(78)90008-7" class='external text' title="http://dx.doi.org/10.1016/0165-0572(78)90008-7">Net energy analysis: Handbook for combining process and input-output analysis.</a> Resources and Energy, 1978, vol. 1, issue 3, pages 267-313.<br /> </li><li>Cleveland, Cutler J. 2005. <a href="http://www.digitaluniverse.net/portal/net_energy_analysis" class='external text' title="http://www.digitaluniverse.net/portal/net energy analysis">Net energy from oil and gas extraction in the United States, 1954-1997.</a> <em>Energy</em>, 30: 769-782.<br /> </li><li>Cleveland, Cutler J., and Robert Herendeen. Solar Parabolic Troughs: Succeeding Generations Are Better Net Energy Producers. <em>Energy Systems and Policy</em> 13: 63-77 (1989)<br /> </li><li>Cleveland, Cutler J., Robert Costanza, Charles A.S. Hall, and Robert Kaufmann. Energy and the U.S. Economy: A Biophysical Perspective. <em>Science</em> 225: 890-897 (1984). <br /> </li><li>Farrell,, Alexander E. Richard J. Plevin, Brian T. Turner, Andrew D. Jones, Michael O’Hare, Daniel M. Kammen. <a href="http://www.sciencemag.org/cgi/content/short/311/5760/506" class='external text' title="http://www.sciencemag.org/cgi/content/short/311/5760/506">Ethanol Can Contribute to Energy and Environmental Goals.</a> 27 JANUARY 2006 VOL 311 <em>SCIENCE</em> <br /> </li><li>Gever, John, Robert Kaufmann, David Skole, Charles Vorosmarty. 1986. <em><a href="http://www.bu.edu/cees/research/publications/beyond_oil/beyond_oil_title/beyond_oil.html" class='external text' title="http://www.bu.edu/cees/research/publications/beyond oil/beyond oil title/beyond oil.html">Beyond Oil: The Threat to Food and Fuel in the Coming Decades</a></em>. </li><li>Hall, C.A.S., J.A. Stanford and R. Hauer. 1992. The distribution and abundance of organisms as a consequence of energy balances along multiple environmental gradients. <em>Oikos</em> 65: 377-390.<br /> </li><li>Hall, Charles A.S., Cutler J. Cleveland, and Robert K. Kaufmann. <em><a href="http://www.bu.edu/cees/research/publications/energy_rq/book_intro/Energy_Resource_Quality.html" class='external text' title="http://www.bu.edu/cees/research/publications/energy rq/book intro/Energy Resource Quality.html">Energy and Resource Quality: The Ecology of the Economic Process</a></em>. (Wiley Interscience: New York, 1986). (Reprinted by the University of Colorado Press, Niwot, CO 1992).<br /> </li><li>Lenzen, M. and J. Munksgaard. 2002. <a href="http://dx.doi.org/10.1016/S0960-1481(01)00145-8" class='external text' title="http://dx.doi.org/10.1016/S0960-1481(01)00145-8">Energy and CO2 life-cycle analyses of wind turbines-review and applications</a>. <em>Renewable Energy</em>, 26: 3, pp. 339-362. </li><li>Odum, H. T., 1971. <em>Environment, Power and Society.</em> Wiley-Interscience, New York. <a href="http://www.amazon.com/dp/047165275X/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/047165275X/?tag=encycofearth-20">ISBN: 047165275X</a><br /> </li><li>Smil, V. 1991. <a href="http://home.cc.umanitoba.ca/~vsmil/complete_booklist.html" class='external text' title="http://home.cc.umanitoba.ca/~vsmil/complete booklist.html">General Energetics: Energy in the Biosphere and Civilization.</a> John Wiley, New York. <a href="http://www.amazon.com/dp/0471629057/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0471629057/?tag=encycofearth-20">ISBN: 0471629057</a><br /> </li><li>Spreng, Daniel T. 1988. <em>Net Energy Analysis and the Energy Requirements of Energy Systems</em> (Praeger). <a href="http://www.amazon.com/dp/0-275-92796-2/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0-275-92796-2/?tag=encycofearth-20">ISBN: 0-275-92796-2</a><br /> </li><li>Tainter, Joseph A. (1990). <em>The Collapse of Complex Societies</em> (1st paperback ed.). Cambridge: Cambridge University Press. <a href="http://www.amazon.com/dp/0-521-38673-X/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0-521-38673-X/?tag=encycofearth-20">ISBN: 0-521-38673-X</a> </li></ul> <p><a href='/article/Ten_fundamental_principles_of_net_energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Ten_fundamental_principles_of_net_energy Fri, 24 Jul 2009 07:26:13 GMT http://www.eoearth.org/article/Landform_development <a href='/article/Landform_development'><img border='0' src='/upload/thumb/9/94/Landform_development_model.gif/350px-Landform_development_model.gif' width='100'/></a> <p>The landforms that are found on the surface of the Earth can be grouped into 4 categories: </p> <ol><li> <b>Structural Landforms</b> - landforms that are created by massive earth movements due to <a href="/article/Plate_tectonics">plate tectonics</a>. This includes landforms with some of the following geomorphic features: fold mountains, rift valleys, and volcanoes. </li><li> <b>Weathering Landforms</b> - landforms that are created by the physical or chemical decomposition of rock through <a href="/article/Weathering">weathering</a>. Weathering produces landforms where rocks and sediments are decomposed and disintegrated. This includes landforms with some of the following geomorphic features: karst, patterned ground, and <a href="/article/Soil">soil</a> profiles. </li><li> <b>Erosional Landforms</b> - landforms formed from the removal of weathered and eroded surface materials by <a href="/article/Wind">wind</a>, water, <a href="/article/Glacier">glaciers</a>, and gravity. This includes landforms with some of the following geomorphic features: river valleys, glacial valleys, and coastal cliffs. </li><li> <b>Depositional Landforms</b> - landforms formed from the deposition of weathered and eroded surface materials. On occasion, these deposits can be compressed, altered by <a href="/article/Pressure">pressure</a>, <a href="/article/Heat">heat</a> and chemical processes to become sedimentary rocks. This includes landforms with some of the following geomorphic features: beaches, deltas, flood plains, and glacial moraines. </li></ol> <p>Many landforms show the influence of several of the above processes. We call these landforms polygenetic. Processes acting on landforms can also change over time, and a single landscape can undergo several cycles of development. We call this type landscape development polycyclic. </p><p>The graphical model in Figure 1 describes the relationship between geomorphic processes and landform types. </p><p><b>Further Reading</b> </p> <ul><li> <a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Landform_development'>Read Full Article...</a></p> http://www.eoearth.org/article/Landform_development Thu, 23 Jul 2009 05:32:41 GMT http://www.eoearth.org/article/Petroleum_refining <a href='/article/Petroleum_refining'><img border='0' src='/upload/thumb/1/1f/Crude_oil_distillation_column.gif/250px-Crude_oil_distillation_column.gif' width='100'/></a> <p>A petroleum refinery is an installation that manufactures finished petroleum products from crude oil, unfinished oils, natural gas liquids, other hydrocarbons, and alcohol. Refined petroleum products include but are not limited to gasolines, kerosene, distillate fuel oils (including No. 2 fuel oil), liquefied petroleum gas, <a href="/article/Asphalt">asphalt</a>, lubricating oils, diesel fuels, and residual fuels. </p> <p><a href='/article/Petroleum_refining'>Read Full Article...</a></p> http://www.eoearth.org/article/Petroleum_refining Wed, 22 Jul 2009 05:40:07 GMT http://www.eoearth.org/article/Regional_climate_change_assessment <a href='/article/Regional_climate_change_assessment'><img border='0' src='/upload/thumb/9/91/Mt2m.jpg/300px-Mt2m.jpg' width='100'/></a> <p>Our climate varies regionally, and the <a href="/article/Temperature">temperature</a> and <a href="/article/Precipitation_and_fog">precipitation</a> tend to be influenced by local geographical characters such as latitude, altitude, distance from the <a href="/article/Coastal_zone">coast</a>, nearby <a href="/article/Ocean_circulation">ocean currents</a>, prevailing <a href="/article/Wind">winds</a>, <a href="/article/Mountain">mountain</a> ranges and vegetation. Different local and regional climate characteristics were classified by Köppen in the early 20^th Century.  The regional climate has a key role in determining soil type, ecosystem type distibution, hydology, erosion processes etc.  Changes in regional climate alter the fabric of our physical environment.</p><p>A global climate change will have various implications for the local weather statistics (local climate characteristics), but the local climate response will differ from place to place. The local information is important when one wants to study the impacts of a climate change or implement an adaption strategy. How will the <a href="/article/Precipitation_and_fog">rainfall</a> statistics be affected where I live? Is the drainage system adequate? Do the reservoir dams have sufficiently large capacity to buffer droughts? Will the drainage system be able to cope with future rainfall extremes? How much will the local temperature rise? Will high winter temperatures have any implications for the snow conditions? Is the <a href="/article/Tropical_weather_and_hurricanes">storm</a> statistics going to change along the coast? These are but some questions that only can be answered with detailed local climate information. </p> <p>Global Climate models (GCMs) can be used to make projections for large-scale aspects of the climate, but they alone are not yet able to provide accurate and detailed description of the <em>local</em> characters. The reason why the GCMs are not able to provide an accurate description of the local climate is that the planet is represented by a coarse mesh of grid-point values with ~100-300 <a href="/article/Meter">kilometers</a> (km) between each point (varies with the latitude). The computer resources (memory and speed) are still not sufficient for using global coupled climate models with high spatial resolution to capture a high degree of spatial details. Thus the spatial resolution is about ~100-300 km. In addition, the models represent small-scale phenomena by simpler statistical models and solve the dynamics equations discretely though various numerical methods, both which may lead to biases on the smallest grid-box scales. </p><p>Despite the GCMs&#39; inability to give a detailed picture when it comes to local scales, it is possible to infer likely local response to a change on larger scales over the same area. It is well known that the local climate is influenced by the nearby <a href="/article/Geography">geography</a> (&#39;physiography&#39;) and the large-scale climatic conditions in which it is embedded (spatial scales of ~1,000 km). </p><p>The procedure of estimating the response at local scales from larger scales is known as &#39;downscaling&#39;</p> <p>There are two main methods for deriving information about the local climate: (i) <em>dynamical downscaling</em> (also referred to as &#39;nested modeling&#39; using &#39;regional climate models&#39; or &#39;limited area models&#39;) and (ii) <em>statistical downscaling</em> (also referred to as &#39;empirical&#39; or &#39;statistical-empirical&#39; downscaling). </p><p>Dynamical downscaling involves a regional atmospheric model in a similar fashion to ordinary day-to-day numerical weather forecasting. These models are built on laws of physics (Navier-Stokes equations, thermodynamics, ideal gas law, etc). The main difference is that a regional climate model (RCM) is more concerned about slow changes in the boundary conditions (changes in the <a href="/article/Atmospheric_composition">atmospheric composition</a>, e.g. <a href="/article/Carbon_dioxide">CO₂</a>) than the exact description of the initial conditions used for the simulations. </p><p>Dynamical downscaling can in principle yield a wide range of climate elements over a large region, but these data are merely the product of a model and are not perfect. It is therefore important to validate the model against real observations. </p><p>Caveats associated with RCMs include inconsistency between the driving GCM and RCM in terms of describing small-scale processes, differences in representing the coupling between the atmosphere and <a href="/article/Ocean">ocean</a>/land surface, spurious effects related to lateral boundaries (numerical waves or ill-conditioned solutions to the mathematical equations), or inconsistencies in how improved representation of small scale phenomena affect the ambient climate (e.g. <a href="/article/Tropical_weather_and_hurricanes">cyclones</a> play a role in <a href="/article/Heat">heat</a> transport, both vertically and laterally, and improved realism may alter the heat transport). Thus, it is important to compare results from RCMs with independent methods whenever possible (e.g. statistical downscaling).</p><p>Statistical downscaling involve statistical models that have been trained on empirical data. Data representing large-scale atmospheric conditions (<em>predictors</em>) represent one side of the equation and data representing the local parameter (<em>predictand</em>) the other. When these models are developed (or &#39;trained or &#39;calibrated&#39;), then a statistical relationship is sought between the predictors and the predictands for the past. These may involve regression, canonical correlation analysis (CCA), analogs, neural nets, and may involve everything from simple indices to advanced multivariate methods (linear algebra). </p> <p>It is important that the predictors can be reproduced skilfully by the GCMs, so that the statistical models can be &#39;ported&#39; to climate model results. It is also important that the a climate change can be seen in the predictor (i.e. the predictor captures the climate signal), and that the relationship between the predictor and predictand is constant for the future. These assumptions are not guaranteed. Furthermore, the statistical models do not provide a perfect reproduction of the local element. Thus, it is important to compare these results with other independent downscaled results whenever possible (e.g. dynamical downscaling or other types of statistical downscaling). </p><p>Empirical data are important both for calibrating the models and for validating them. The validation of the models involves comparing the model output to independent data not used for the model construction. Note, there are many ways to apply statistical models to data, but many may be inappropriate for the case in question. Therefore, it is important to have a thorough understanding of the problem and the models (their limitations) when using these to study local climate changes.</p><p>Often RCMs do not provide data that are close to the observed values. The RCMs provide a mean value for a box (e.g. 25 km by 25 km by 10 <a href="/article/Meter">meters</a>) whereas the observations are point measurements. Furthermore, the climatic elements may vary strongly over short distances in regions with complex terrain. Thus, it is common to apply a statistical correction to RCM data before using these for impact studies. Sometimes, the correction may resemble simple statistical downscaling in the sense that both involve a statistical model with a set of limitations. </p><p>Statistical downscaling typically yields results for a single site, but it is possible to assemble the information from several sites in order to make maps (e.g. using so-called Geographical Information Systems, or GIS). </p><p><big><strong>Further Reading</strong></big></p><ul><li><a href="http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter11.pdf" class='external text' title="http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter11.pdf">IPCC 2007, Chapter 11</a>.</li><li><a href="http://www.ipcc.ch/ipccreports/tar/wg1/373.htm" class='external text' title="http://www.ipcc.ch/ipccreports/tar/wg1/373.htm">IPCC 2001, Chapter 10</a>. </li><li><a href="http://www.realclimate.org/index.php/archives/2007/05/climate-models-local-climate/" class='external text' title="http://www.realclimate.org/index.php/archives/2007/05/climate-models-local-climate/">Why global climate models do not give a realistic description of the local climate</a>. </li><li><a href="http://www.realclimate.org/index.php/archives/2007/08/regional-climate-projections/" class='external text' title="http://www.realclimate.org/index.php/archives/2007/08/regional-climate-projections/">Regional Climate Projections</a> RealClimate.org.</li><li><a href="http://www.gvc2.gu.se/ngeo/rcg/edu/esd.pdf" class='external text' title="http://www.gvc2.gu.se/ngeo/rcg/edu/esd.pdf">Compendium on Empirical-Statistical Downscaling</a> used at the STATME summerschool in Lodz, Poland, June 2007. </li></ul> <p><a href='/article/Regional_climate_change_assessment'>Read Full Article...</a></p> http://www.eoearth.org/article/Regional_climate_change_assessment Tue, 21 Jul 2009 05:31:49 GMT http://www.eoearth.org/article/Public_Health_Statement_for_Lead <a href='/article/Public_Health_Statement_for_Lead'><img border='0' src='/upload/thumb/f/f9/Lead.jpg/300px-Lead.jpg' width='100'/></a> <p><em>This article is a <u>verbatim</u> version of the original and is not available for edits or additions by </em>EoE<em> editors or authors. Companion articles on the same topic that are editable may exist within the </em>EoE<em>.</em> </p><p><strong>September 2005</strong></p><p><a href="http://www.atsdr.cdc.gov/es/phs/es_phs13.html" class='external text' title="http://www.atsdr.cdc.gov/es/phs/es phs13.html">En Español</a> </p> <p><a href='/article/Public_Health_Statement_for_Lead'>Read Full Article...</a></p> http://www.eoearth.org/article/Public_Health_Statement_for_Lead Mon, 20 Jul 2009 05:28:04 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Mon, 20 Jul 2009 05:27:47 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Mon, 20 Jul 2009 05:26:48 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Mon, 20 Jul 2009 05:26:34 GMT http://www.eoearth.org/article/Pesticide <a href='/article/Pesticide'><img border='0' src='/upload/thumb/4/4d/Boll_Weevil_USDA_Flynn.jpg/200px-Boll_Weevil_USDA_Flynn.jpg' width='100'/></a> <p><a href='/article/Pesticide'>Read Full Article...</a></p> http://www.eoearth.org/article/Pesticide Fri, 17 Jul 2009 06:26:06 GMT http://www.eoearth.org/article/Subsidies_and_market_interventions <a href='/article/Subsidies_and_market_interventions'><img border='0' src='/upload/thumb/a/a6/Oil_drilling.jpg/250px-Oil_drilling.jpg' width='100'/></a> <p>Government interventions encompass a wide range of regulatory, fiscal, <a href="/article/Taxation_in_the_United_States"> tax,</a> indemnification, and legal actions that modify the rights and responsibilities of various parties in society. Interventions can increase or decrease costs to particular groups, effectively acting either as a subsidy or as a <a href="/article/Taxation_in_the_United_States"> tax.</a> Some of these policies increase societal welfare, while others subsidize powerful groups in society, sometimes making societal imbalances worse. This article provides a general overview of many types of subsidy policies, and describes how to calculate net subsidies to a particular sector.</p> <p><a href='/article/Subsidies_and_market_interventions'>Read Full Article...</a></p> http://www.eoearth.org/article/Subsidies_and_market_interventions Thu, 16 Jul 2009 05:41:27 GMT http://www.eoearth.org/article/Subsidies_and_market_interventions <a href='/article/Subsidies_and_market_interventions'><img border='0' src='/upload/thumb/a/a6/Oil_drilling.jpg/250px-Oil_drilling.jpg' width='100'/></a> <p>Government interventions encompass a wide range of regulatory, fiscal, <a href="/article/Taxation_in_the_United_States"> tax,</a> indemnification, and legal actions that modify the rights and responsibilities of various parties in society. Interventions can increase or decrease costs to particular groups, effectively acting either as a subsidy or as a <a href="/article/Taxation_in_the_United_States"> tax.</a> Some of these policies increase societal welfare, while others subsidize powerful groups in society, sometimes making societal imbalances worse. This article provides a general overview of many types of subsidy policies, and describes how to calculate net subsidies to a particular sector.</p> <p><a href='/article/Subsidies_and_market_interventions'>Read Full Article...</a></p> http://www.eoearth.org/article/Subsidies_and_market_interventions Thu, 16 Jul 2009 05:40:01 GMT http://www.eoearth.org/article/Tax_subsidies <a href='/article/Tax_subsidies'><img border='0' src='/upload/thumb/0/07/Kalinin_nuclear_plant.jpg/300px-Kalinin_nuclear_plant.jpg' width='100'/></a> <p>Tax subsidies are the result of selective <a href="/article/Taxation_in_the_United_States">tax legislation</a> that benefit particular groups of people or industries in the economy. In effect, they share the costs of certain actions between the private sector and the government and impact investment decisions by increasing the expected returns associated with a particular pattern of <a href="/article/Essential_economic_activities">economic activity</a>. Tax subsidies may be applied in a number of ways to any one or a combination of economic variables (land, labor, <a href="/article/Capital">capital</a>). </p><p>While some provisions (e.g., the general investment tax credits) may be available to an entire class of economic activity, such provisions may still be viewed as subsidies because other classes of economic activity are placed at a relative economic disadvantage. In this case, for example, the government has made a decision to favor <a href="/article/Capital">capital</a>-based productive methods rather than alternatives (such as labor). Similarly, subsidies to new investment favor <a href="/article/Supply_and_demand">supply</a> expansions (such as new power plants) over improved efficiency in the use of existing capacity (such as many demand-side management approaches) and constitute a de facto governmental choice of the method by which to meet <a href="/article/Market">market</a> <a href="/article/Supply_and_demand">demand</a>. </p><p>Tax subsidies are generally measured in reference to a normative or baseline <a href="/article/Taxation_in_the_United_States">tax system</a>, and estimates assume no other changes in the tax code. Each tax expenditure is calculated assuming that there is no interaction with other provisions. As a result, the estimates can&#39;t be added directly together without errors. As it is very difficult to estimate the potential interactions from simultaneous removal of multiple subsidies, though, most analyses do add the tax expenditure values together anyway. </p><p>Since the government forgoes revenue that would have been collected had there been no special legislation and must make up those revenues through higher taxes on other economic activities, these policies have real costs. These costs are classified as &quot;tax expenditures.&quot; Within the United States, we are lucky in that two separate groups (the U.S. Treasury and the Joint Committee on Taxation) both independently estimate tax expenditures associate with current and proposed legislation. Many states and countries have no information at all about these special tax rulings. As a general rule of thumb, where there is no light the largest mushrooms grow. However, even within the U.S., the estimates for tax losses for the same provision by the two bodies can differ by hundreds of millions of dollars. The estimation methods or assumptions are not made public, so improving the accuracy of these estimates is not clear-cut. </p><p>The stated goal of tax subsidies, according to the U.S. General Accounting Office, is to promote some policy objective such as &quot;<a href="/article/Economic_growth">economic growth</a> or a desirable expenditure pattern by taxpayers.&quot; However, there is a great deal of disagreement over whether particular tax benefits typically encourage &quot;socially desirable&quot; economic behavior. Further, even if the policies are effective, they are static and may become ineffective or counterproductive as circumstances (be they demographic, technological, or economic) change. For example, percentage depletion allowances were significantly expanded when crucial minerals were needed for war efforts. As these initial conditions changed, the policies did not necessarily evolve with them. </p><p>In summary, tax subsidies are neither inherently right or wrong. They are inherently distortionary, however, in that they alter patterns of <a href="/article/Essential_economic_activities">economic activity</a> to promote particular areas (targeted by Congress) that would not necessarily have received investment or consumer <a href="/article/Supply_and_demand">demand</a> in the absence of the <a href="/article/Subsidies_and_market_interventions">government intervention</a>. The subsidies need to be considered as a real cost when evaluating alternative long-term energy options. These costs include the direct cost of increased <a href="/article/Taxation_in_the_United_States">taxes</a> in other areas to individual taxpayers, and the indirect costs to the economy as a whole through the distortionary effect of the subsidies on R&amp;D, investment, and <a href="/article/Consumption_and_consumer_sovereignty">consumption</a> patterns. </p><p>There are a few issues to keep in mind regarding our net tax expenditure estimates. First, special taxes on energy have been treated as negative subsidies if they are used for general revenue purposes. If they are earmarked for specific energy-related uses, such as <a href="/article/Oil_spill">oil spill</a> cleanup, they are considered user fees and are netted from the total government cost of dealing with the particular energy-related problem. Second, energy-payments such as royalties reflect a return to the resource-owner for selling the oil or minerals in question, and are not a tax. Finally, given the fact that the data regarding Treasury losses from tax provisions are somewhat crude and that interactions between the various tax preferences are not incorporated into these data, our quantification of the tax subsidy magnitude should be viewed as an estimate. </p> <p><a href='/article/Tax_subsidies'>Read Full Article...</a></p> http://www.eoearth.org/article/Tax_subsidies Thu, 16 Jul 2009 05:38:18 GMT http://www.eoearth.org/article/Subsidies_and_market_interventions <a href='/article/Subsidies_and_market_interventions'><img border='0' src='/upload/thumb/a/a6/Oil_drilling.jpg/250px-Oil_drilling.jpg' width='100'/></a> <p>Government interventions encompass a wide range of regulatory, fiscal, <a href="/article/Taxation_in_the_United_States"> tax,</a> indemnification, and legal actions that modify the rights and responsibilities of various parties in society. Interventions can increase or decrease costs to particular groups, effectively acting either as a subsidy or as a <a href="/article/Taxation_in_the_United_States"> tax.</a> Some of these policies increase societal welfare, while others subsidize powerful groups in society, sometimes making societal imbalances worse. This article provides a general overview of many types of subsidy policies, and describes how to calculate net subsidies to a particular sector.</p> <p><a href='/article/Subsidies_and_market_interventions'>Read Full Article...</a></p> http://www.eoearth.org/article/Subsidies_and_market_interventions Thu, 16 Jul 2009 05:36:53 GMT http://www.eoearth.org/article/Folding_and_faulting_in_the_Earth's_crust <a href='/article/Folding_and_faulting_in_the_Earth's_crust'><img border='0' src='/upload/thumb/d/d8/Earth_relief_map.jpg/250px-Earth_relief_map.jpg' width='100'/></a> <p>The topographic map illustrated in Figure 1 suggests that the Earth's surface has been deformed. This deformation is the result of forces that are strong enough to move ocean sediments to an elevation many thousands <a href="/article/Meter">meters</a> above sea level. This displacement of rock can be caused by <a href="/article/Plate_tectonics">tectonic plate</a> movement and subduction, volcanic activity, and intrusive <a href="/article/Formation_of_the_Earth%27s_crust">igneous activity</a>. </p><p>Deformation of rock involves changes in the shape and/or volume of these substances. Changes in shape and volume occur when stress and strain causes rock to buckle and fracture or crumple into folds. A fold can be defined as a bend in rock that is the response to compressional forces. Folds are most visible in rocks that contain layering. For plastic deformation of rock to occur a number of conditions must be met, including: </p> <ul><li> The rock material must have the ability to deform under <a href="/article/Pressure">pressure</a> and <a href="/article/Heat">heat</a>. </li><li> The higher the <a href="/article/Temperature">temperature</a> of the rock the more plastic it becomes. </li><li> Pressure must not exceed the internal strength of the rock. If it does, fracturing occurs. </li><li> Deformation must be applied slowly. </li></ul> <p>A number of different folds have been recognized and classified by geologists. The simplest type of fold is called a monocline (Figure 2). This fold involves a slight bend in otherwise parallel layers of rock. </p><p>An anticline is a convex up fold in rock that resembles an arch-like structure with the rock beds (or limbs) dipping way from the center of the structure (Figure 3). </p> <p><br style="clear: left" /> </p><p>A syncline is a fold where the rock layers are warped downward (Figure 4 and 5). Both anticlines and synclines are the result of compressional stress. </p> <p><br style="clear: left" /> </p><p>More complex fold types can develop in situations where lateral pressures become greater. The greater <a href="/article/Pressure">pressure</a> results in anticlines and synclines that are inclined and asymmetrical (Figure 6). </p><p>A recumbent fold develops if the center of the fold moves from being once vertical to a horizontal position (Figure 7). Recumbent folds are commonly found in the core of <a href="/article/Mountain">mountain</a> ranges and indicate that compression and/or shear forces were stronger in one direction. Extreme stress and <a href="/article/Pressure">pressure</a> can sometimes cause the rocks to shear along a plane of weakness creating a fault. We call the combination of a fault and a fold in a rock an overthrust fault. </p><p>Faults form in rocks when the stresses overcome the internal strength of the rock resulting in a fracture. A fault can be defined as the displacement of once connected blocks of rock along a fault plane. This can occur in any direction with the blocks moving away from each other. Faults occur from both tensional and compressional forces. Figure 8 shows the location of some of the major faults located on the Earth. </p> <p><br style="clear: left" /> There are several different kinds of faults. These faults are named according to the type of stress that acts on the rock and by the nature of the movement of the rock blocks either side of the fault plane. Normal faults occur when tensional forces act in opposite directions and cause one slab of the rock to be displaced up and the other slab down (Figure 9). </p><p>Reverse faults develop when compressional forces exist (Figure 10). Compression causes one block to be pushed up and over the other block. </p> <p><br style="clear: left" /> A graben fault is produced when tensional stresses result in the subsidence of a block of rock. On a large scale these features are known as Rift Valleys (Figure 11). </p><p>A horst fault is the development of two reverse faults causing a block of rock to be pushed up (Figure 12). </p> <p><br style="clear: left" /> </p><p>The final major type of fault is the strike-slip or transform fault. These faults are vertical in nature and are produced where the stresses are exerted parallel to each other (Figure 13). A well-known example of this type of fault is the San Andreas Fault in California. </p><p>Folds and faults have an economic importance. Anticlines and horsts are good sites for oil accumulation forming oil reservoirs whereas synclines and grabens are suitable for water accumulation forming <a href="/article/Aquifer">aquifers</a> or <a href="/article/Groundwater">groundwater</a> basins. </p><p>Faults represent a weak zone so they should be avoided or put in mind in any civil constructions. Also, faults as a weak zone are suitable for upward leakage of either lava forming sills or dykes or <a href="/article/Groundwater">groundwater</a> forming <a href="/article/Spring">springs</a>. </p><p>Folding and faulting reflect the effect of the internal energy of the earth. Consequently, the criteria of folding and faulting represent a kind of eath's ability for stability. </p><p><b>Further Reading</b> </p> <ul><li> <a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Folding_and_faulting_in_the_Earth's_crust'>Read Full Article...</a></p> http://www.eoearth.org/article/Folding_and_faulting_in_the_Earth's_crust Thu, 16 Jul 2009 05:33:02 GMT http://www.eoearth.org/article/Environmental_justice <a href='/article/Environmental_justice'><img border='0' src='/upload/thumb/6/66/Environmental_justice_protest.jpg/300px-Environmental_justice_protest.jpg' width='100'/></a> <p>The concept of environmental justice has surfaced and taken shape over the last thirty years. The first time environmental justice hit the radar screen was in 1976 at a conference entitled: “Working for Environmental and Economic Justice and Jobs" sponsored by the United Automobile Workers of America (UAW) and several other organizations. This conference was held at the Walter May Reuther Family Education Center located at Black Lake near Onaway, Michigan. Over the years, people of color and low-income groups, through struggle to protect their communities from environmental insults, have brought meaning to the concept of environmental justice. Although <a href="/article/Love_Canal%2C_New_York">Love Canal, New York</a> was not the first or the worst of contaminated sites, the struggle that took place there did raise the nation’s consciousness of health impacts of chemical and industrial waste long-buried in a mostly white neighborhood near <a href="/article/Niagara_Falls">Niagara Falls</a>, New York. The Warren County, North Carolina struggle to prevent the burial of <a href="/article/PCBs">PCBs</a> in a landfill in predominantly black area was the first time the connection was made between civil rights and environmental protection. As people struggled in communities across the country for safer and cleaner environments, the Environmental Protection Agency (EPA) was propelled to define environmental justice as follows: </p> <blockquote> <i>The fair treatment and meaningful involvement of people of all races, cultures, incomes and educational levels with respect to the development and enforcement of environmental laws, regulations, and policies. Fair treatment means that no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies. Meaningful involvement means that: (1) people have an opportunity to participate in decisions about activities that may affect their environment and/or health; (2) the publics contribution can influence the regulatory agency's decision; (3) their concerns will be considered in the decision making process; and (4) the decision makers seek out and facilitate the involvement of those potentially affected.</i> </blockquote> <p>The EPA definition can be analyzed from the taxonomy of distributive, procedural, corrective, and social justice. <b>Distributive</b> justice in practice has not meant a redistribution of pollutants equally to all communities, but the enforcement of the equal protection of the law or pollution preventions strategies so that pollutions will not be distributive to any community. The Agency places considerable emphasis upon <b>procedural</b> justice to make rules and regulations transparent in order for communities to access the decision-making process. We can also see that <b>corrective</b> justice is one of the main thrusts of the Agency where it uses legislation, rules and regulations, or lawsuits to reward, compensate, or punish guilty parties for damages done. <b>Social justice</b> attempts to bring about a more just and humane society as a whole, which would put this beyond the scope of EPA policy. Although EPA policy seems to be strongest in support of procedural and corrective justice, it is weakest in support of distributive and social justice. The EPA definition and the taxonomy of definitions, except perhaps for social justice, take a short-term approach to environmental justice. </p><p>Policies to address short-term problems are not the solution. To implement such policies is like fighting a rear guard action. Therefore, we must be visionary and be willing to plan for the future or we will blunder into it with all the alphabet soup of social and environmental problems that have been intensified over the years. The following definition of environmental justice is more visionary and broader in scope: </p> <blockquote> <i>Environmental justice are those cultural norms and values, rules, regulations, behaviors policies, and decisions that support sustainable development, so that people can interact with confidence that their environment is safe, nurturing, and productive. Environmental justice is served when people can realize their highest potential, without experiencing the “isms”. Environmental justice is supported by decent-paying and safe jobs; quality schools and recreation; decent housing and adequate health care; democratic decision-making and personal empowerment; and communities free of violence, drugs, and poverty. Environmental justice communities are where both cultural and biological diversity are respected and highly revered and where distributive justice prevails.</i> </blockquote> <p>This definition makes environmental justice much boarder than the EPA definition. It is not only concerned about short-term policies, but long-term policies that will affect people and the communities they live in. It gives a vision of what an environmentally just community would look like; it reads like a community of the future. To realize this vision of the future will require us to develop cities and systems that mimic nature. In nature there is virtually no waste in that the waste for one life-form becomes the food for another one. Therefore we must build cities and production systems where the waste from one system becomes the raw materials for the other. We must build cities that mimic nature where there will no longer be a need to drill for oil or to mine for <a href="/article/Coal">coal</a>. Although systems that mimic nature will go a long way to eliminate sickness, death, and environmental degradation, such systems fail to address the issue of equity, justice, and fairness, which are critical to an environmentally just society. Without equity and fairness there can be no justice. </p> <p><a href='/article/Environmental_justice'>Read Full Article...</a></p> http://www.eoearth.org/article/Environmental_justice Wed, 15 Jul 2009 05:41:47 GMT http://www.eoearth.org/article/Environmental_justice <a href='/article/Environmental_justice'><img border='0' src='/upload/thumb/6/66/Environmental_justice_protest.jpg/300px-Environmental_justice_protest.jpg' width='100'/></a> <p>The concept of environmental justice has surfaced and taken shape over the last thirty years. The first time environmental justice hit the radar screen was in 1976 at a conference entitled: “Working for Environmental and Economic Justice and Jobs" sponsored by the United Automobile Workers of America (UAW) and several other organizations. This conference was held at the Walter May Reuther Family Education Center located at Black Lake near Onaway, Michigan. Over the years, people of color and low-income groups, through struggle to protect their communities from environmental insults, have brought meaning to the concept of environmental justice. Although <a href="/article/Love_Canal%2C_New_York">Love Canal, New York</a> was not the first or the worst of contaminated sites, the struggle that took place there did raise the nation’s consciousness of health impacts of chemical and industrial waste long-buried in a mostly white neighborhood near <a href="/article/Niagara_Falls">Niagara Falls</a>, New York. The Warren County, North Carolina struggle to prevent the burial of <a href="/article/PCBs">PCBs</a> in a landfill in predominantly black area was the first time the connection was made between civil rights and environmental protection. As people struggled in communities across the country for safer and cleaner environments, the Environmental Protection Agency (EPA) was propelled to define environmental justice as follows: </p> <blockquote> <i>The fair treatment and meaningful involvement of people of all races, cultures, incomes and educational levels with respect to the development and enforcement of environmental laws, regulations, and policies. Fair treatment means that no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies. Meaningful involvement means that: (1) people have an opportunity to participate in decisions about activities that may affect their environment and/or health; (2) the publics contribution can influence the regulatory agency's decision; (3) their concerns will be considered in the decision making process; and (4) the decision makers seek out and facilitate the involvement of those potentially affected.</i> </blockquote> <p>The EPA definition can be analyzed from the taxonomy of distributive, procedural, corrective, and social justice. <b>Distributive</b> justice in practice has not meant a redistribution of pollutants equally to all communities, but the enforcement of the equal protection of the law or pollution preventions strategies so that pollutions will not be distributive to any community. The Agency places considerable emphasis upon <b>procedural</b> justice to make rules and regulations transparent in order for communities to access the decision-making process. We can also see that <b>corrective</b> justice is one of the main thrusts of the Agency where it uses legislation, rules and regulations, or lawsuits to reward, compensate, or punish guilty parties for damages done. <b>Social justice</b> attempts to bring about a more just and humane society as a whole, which would put this beyond the scope of EPA policy. Although EPA policy seems to be strongest in support of procedural and corrective justice, it is weakest in support of distributive and social justice. The EPA definition and the taxonomy of definitions, except perhaps for social justice, take a short-term approach to environmental justice. </p><p>Policies to address short-term problems are not the solution. To implement such policies is like fighting a rear guard action. Therefore, we must be visionary and be willing to plan for the future or we will blunder into it with all the alphabet soup of social and environmental problems that have been intensified over the years. The following definition of environmental justice is more visionary and broader in scope: </p> <blockquote> <i>Environmental justice are those cultural norms and values, rules, regulations, behaviors policies, and decisions that support sustainable development, so that people can interact with confidence that their environment is safe, nurturing, and productive. Environmental justice is served when people can realize their highest potential, without experiencing the “isms”. Environmental justice is supported by decent-paying and safe jobs; quality schools and recreation; decent housing and adequate health care; democratic decision-making and personal empowerment; and communities free of violence, drugs, and poverty. Environmental justice communities are where both cultural and biological diversity are respected and highly revered and where distributive justice prevails.</i> </blockquote> <p>This definition makes environmental justice much boarder than the EPA definition. It is not only concerned about short-term policies, but long-term policies that will affect people and the communities they live in. It gives a vision of what an environmentally just community would look like; it reads like a community of the future. To realize this vision of the future will require us to develop cities and systems that mimic nature. In nature there is virtually no waste in that the waste for one life-form becomes the food for another one. Therefore we must build cities and production systems where the waste from one system becomes the raw materials for the other. We must build cities that mimic nature where there will no longer be a need to drill for oil or to mine for <a href="/article/Coal">coal</a>. Although systems that mimic nature will go a long way to eliminate sickness, death, and environmental degradation, such systems fail to address the issue of equity, justice, and fairness, which are critical to an environmentally just society. Without equity and fairness there can be no justice. </p> <p><a href='/article/Environmental_justice'>Read Full Article...</a></p> http://www.eoearth.org/article/Environmental_justice Wed, 15 Jul 2009 05:40:05 GMT http://www.eoearth.org/article/Environmental_justice <a href='/article/Environmental_justice'><img border='0' src='/upload/thumb/6/66/Environmental_justice_protest.jpg/300px-Environmental_justice_protest.jpg' width='100'/></a> <p>The concept of environmental justice has surfaced and taken shape over the last thirty years. The first time environmental justice hit the radar screen was in 1976 at a conference entitled: “Working for Environmental and Economic Justice and Jobs" sponsored by the United Automobile Workers of America (UAW) and several other organizations. This conference was held at the Walter May Reuther Family Education Center located at Black Lake near Onaway, Michigan. Over the years, people of color and low-income groups, through struggle to protect their communities from environmental insults, have brought meaning to the concept of environmental justice. Although <a href="/article/Love_Canal%2C_New_York">Love Canal, New York</a> was not the first or the worst of contaminated sites, the struggle that took place there did raise the nation’s consciousness of health impacts of chemical and industrial waste long-buried in a mostly white neighborhood near <a href="/article/Niagara_Falls">Niagara Falls</a>, New York. The Warren County, North Carolina struggle to prevent the burial of <a href="/article/PCBs">PCBs</a> in a landfill in predominantly black area was the first time the connection was made between civil rights and environmental protection. As people struggled in communities across the country for safer and cleaner environments, the Environmental Protection Agency (EPA) was propelled to define environmental justice as follows: </p> <blockquote> <i>The fair treatment and meaningful involvement of people of all races, cultures, incomes and educational levels with respect to the development and enforcement of environmental laws, regulations, and policies. Fair treatment means that no group of people should bear a disproportionate share of the negative environmental consequences resulting from industrial, governmental and commercial operations or policies. Meaningful involvement means that: (1) people have an opportunity to participate in decisions about activities that may affect their environment and/or health; (2) the publics contribution can influence the regulatory agency's decision; (3) their concerns will be considered in the decision making process; and (4) the decision makers seek out and facilitate the involvement of those potentially affected.</i> </blockquote> <p>The EPA definition can be analyzed from the taxonomy of distributive, procedural, corrective, and social justice. <b>Distributive</b> justice in practice has not meant a redistribution of pollutants equally to all communities, but the enforcement of the equal protection of the law or pollution preventions strategies so that pollutions will not be distributive to any community. The Agency places considerable emphasis upon <b>procedural</b> justice to make rules and regulations transparent in order for communities to access the decision-making process. We can also see that <b>corrective</b> justice is one of the main thrusts of the Agency where it uses legislation, rules and regulations, or lawsuits to reward, compensate, or punish guilty parties for damages done. <b>Social justice</b> attempts to bring about a more just and humane society as a whole, which would put this beyond the scope of EPA policy. Although EPA policy seems to be strongest in support of procedural and corrective justice, it is weakest in support of distributive and social justice. The EPA definition and the taxonomy of definitions, except perhaps for social justice, take a short-term approach to environmental justice. </p><p>Policies to address short-term problems are not the solution. To implement such policies is like fighting a rear guard action. Therefore, we must be visionary and be willing to plan for the future or we will blunder into it with all the alphabet soup of social and environmental problems that have been intensified over the years. The following definition of environmental justice is more visionary and broader in scope: </p> <blockquote> <i>Environmental justice are those cultural norms and values, rules, regulations, behaviors policies, and decisions that support sustainable development, so that people can interact with confidence that their environment is safe, nurturing, and productive. Environmental justice is served when people can realize their highest potential, without experiencing the “isms”. Environmental justice is supported by decent-paying and safe jobs; quality schools and recreation; decent housing and adequate health care; democratic decision-making and personal empowerment; and communities free of violence, drugs, and poverty. Environmental justice communities are where both cultural and biological diversity are respected and highly revered and where distributive justice prevails.</i> </blockquote> <p>This definition makes environmental justice much boarder than the EPA definition. It is not only concerned about short-term policies, but long-term policies that will affect people and the communities they live in. It gives a vision of what an environmentally just community would look like; it reads like a community of the future. To realize this vision of the future will require us to develop cities and systems that mimic nature. In nature there is virtually no waste in that the waste for one life-form becomes the food for another one. Therefore we must build cities and production systems where the waste from one system becomes the raw materials for the other. We must build cities that mimic nature where there will no longer be a need to drill for oil or to mine for <a href="/article/Coal">coal</a>. Although systems that mimic nature will go a long way to eliminate sickness, death, and environmental degradation, such systems fail to address the issue of equity, justice, and fairness, which are critical to an environmentally just society. Without equity and fairness there can be no justice. </p> <p><a href='/article/Environmental_justice'>Read Full Article...</a></p> http://www.eoearth.org/article/Environmental_justice Wed, 15 Jul 2009 05:39:22 GMT http://www.eoearth.org/article/Patterns_of_economic_growth_and_development <a href='/article/Patterns_of_economic_growth_and_development'><img border='0' src='/upload/thumb/6/6c/World_Economic_Growth_1961-2004_graph.gif/250px-World_Economic_Growth_1961-2004_graph.gif' width='100'/></a> <p>The <a href="/article/Industrial_Revolution">Industrial Revolution</a>, which began in the British Isles and Western Europe, dramatically changed the nature of <a href="/article/Essential_economic_activities">economic production</a>. It is important not just as a historical episode, but because the pattern of economic development that it established has become in many ways a model for development worldwide. Although, as we will discuss later, there are criticisms of the applicability of this model to current development issues, its strong influence on standard views of <a href="/article/Economic_growth">economic growth</a> makes it an important starting point for understanding development. </p><p>Several elements were critical in creating the Industrial Revolution. First, new agricultural techniques, along with new kinds of tools and machines, made <a href="/article/Agriculture">agriculture</a> more productive. That meant that more agricultural output could be produced per worker and per acre of land. These productivity increases, continuing and eventually spreading across the globe, meant that human populations could grow dramatically – as, indeed they have done, reaching a first billion around 1810, and continuing to increase to the present global numbers of well over six billion. Because of the great increase in agricultural labor productivity, the number of workers needed to produce food for the rest of the population was shrinking even while the population as a whole was growing. </p><p>A second outstanding characteristic of the <a href="/article/Industrial_Revolution">Industrial Revolution</a> was the invention and application of technologies using inanimate sources of power (increasingly, fossil fuels) and machinery for <a href="/article/Essential_economic_activities">production</a> of goods. Mechanization created jobs in factories, largely replacing the previous patterns of producing goods at home. Railroads and other advances in transportation, as well as the new kinds of work organization, made it possible to assemble large numbers of workers in factories, resulting in huge urban agglomerations. </p><p>Another important factor in England’s increasing industrialization was its ability to rely on other countries, including its extensive network of colonies, for supplies of raw materials and as markets for its goods. England imported cotton fiber from India, for example. It discouraged the further development of cotton manufacturing within India by putting high import tariffs on Indian-made cloth, while requiring that India let in British-made cloth tariff-free. </p><p>An ever-increasing variety of things were produced in the emerging industrial sector. Some of these were items never seen before, such as bicycles, flushing toilets, machine-loomed cloth, communication by telegraph, early cameras, and steamships. Other products of industry were household goods, such as china dishes and cotton cloth, which had previously been used only by a small, rich elite. Others were, of course, the various kinds of machinery that were used to produce consumer items. These included the cotton gin, steam-powered textile machines, a steam-powered printing press that could turn out tens of thousands of copies of a page per day, and rotary mixers to make bread in commercial bakeries. </p><p>While the <a href="/article/Industrial_Revolution">Industrial Revolution</a> began in England, by the nineteenth and early twentieth century it was well along in much of Western Europe and other &quot;early industrializing&quot; countries such as the United States, Canada, and Australia. It is important not just as a historical episode, but because the pattern of economic development that it established has become, in many people&#39;s minds, the model for how development should proceed worldwide. The vocabulary of referring to rich countries as &quot;developed&quot; and poorer countries as &quot;developing,&quot; for example, involves an implicit assumption that poorer countries are on a path of industrialization, on the road to perhaps eventually &quot;catching up&quot; to rich country lifestyles and levels of wealth. </p> <p><a href='/article/Patterns_of_economic_growth_and_development'>Read Full Article...</a></p> http://www.eoearth.org/article/Patterns_of_economic_growth_and_development Tue, 14 Jul 2009 05:15:09 GMT http://www.eoearth.org/article/Cell_phone_recycling <a href='/article/Cell_phone_recycling'><img border='0' src='/upload/thumb/c/c7/US_cell_phone_subscribers%2C1985-2004.gif/250px-US_cell_phone_subscribers%2C1985-2004.gif' width='100'/></a> <p>Recycling, a significant factor in the supply of many of the metals used in our society, provides environmental benefits, such as energy savings, reduced volumes of waste, and reduced emissions associated with energy savings. In addition, <a href="/article/Recycling">recycling</a> reduces the amount of virgin metals that must be mined to support our lifestyle. </p><p>Cell phones are ubiquitous in much of the world. There were approximately 1 billion cell phones in use worldwide in 2002. In the United States (Fig. 1), the number of cell phone subscribers increased from 340,000 in 1985 to 180 million in 2004.</p> <p>Worldwide, cell phone sales (Fig. 2) have increased from slightly more than 100 million units per year in 1997 to an estimated 779 million units per year in 2005. As shown in Figure 2, sales increased from 1997 through 2000 and then leveled off through 2002. In 2003, sales began to increase again. Cell phone sales are projected to exceed 1 billion units per year in 2009, with an estimated 2.6 billion cell phones in use by the end of that year. Sales are driven by new subscribers signing up for services, by subscribers purchasing additional phones, and by subscribers replacing obsolete cell phones.</p><p>The <a href="/article/Environmental_Protection_Agency%2C_United_States">U.S. Environmental Protection Agency</a> estimated that, by 2005, as many as 130 million cell phones would be retired annually in the United States. The nonprofit organization INFORM, Inc., anticipated that, by 2005, a total of 500 million obsolete cell phones would have accumulated in <a href="/article/Essential_economic_activities">consumers’</a> desk drawers, store rooms, or other storage, awaiting disposal. Typically, cell phones are used for only 1½ years before being replaced. These unused (or obsolete) cell phones usually are replaced because they do not have desired features, they are not compatible with a new provider, or they no longer function.</p><p>Less than 1 percent of the millions of cell phones retired and discarded annually are <a href="/article/Recycling">recycled</a>. Of this small percentage recovered, most are refurbished and put into use or used for replacement parts. If these options are not possible, core elements (such as <a href="/article/Copper">copper</a>) are recycled.</p><p>When discarded cell phones are not recycled, most eventually end up in municipal solid waste facilities. Although there are cell phone collection and recycling programs, they have had little impact on this waste stream. According to INFORM, Inc., the lack of impact results from an inefficient recycling infrastructure, insufficient publicity for the programs, small-scale collection sites, and few or insufficient financial incentives. Figure 3 shows the cell phone life cycle, including the recycling option.</p> <p><a href='/article/Cell_phone_recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Cell_phone_recycling Mon, 13 Jul 2009 05:32:01 GMT http://www.eoearth.org/article/Nitrogen_cycle <a href='/article/Nitrogen_cycle'><img border='0' src='/upload/thumb/b/b9/Nitrogencycle.jpg/600px-Nitrogencycle.jpg' width='100'/></a> <p>The nitrogen cycle represents one of the most important nutrient cycles found in ecosystems. (Figure 1). <a href="/article/Nitrogen">Nitrogen</a> is a required nutrient for all living organisms to produce a number of complex organic molecules like amino acids, the building blocks of proteins, and nucleic acids, including DNA and RNA. The ultimate store of nitrogen is in the atmosphere, where it exists as nitrogen gas (N₂). This store is about one million times larger than the total nitrogen contained in living organisms. Other major stores of nitrogen include organic matter in <a href="/article/Soil">soil</a> and the oceans. Despite its abundance in the atmosphere, nitrogen is often the most limiting nutrient for plant growth. This problem occurs N₂ gas is not biochemically usable by plants. Plants can only take up nitrogen in the form of ammonium ion (NH₄⁺), nitrate ion (NO₃^-), or, less common, as amino acids. Animals receive the <a href="/article/Nitrogen">nitrogen</a> they need for metabolism, growth, and reproduction by the consumption of living or dead organic matter containing molecules composed partially of nitrogen. <br /> </p> <p><br /> In most ecosystems <a href="/article/Nitrogen">nitrogen</a> is primarily stored in living and dead organic matter. This organic nitrogen is converted into inorganic forms when it re-enters the biogeochemical cycle via decomposition. Decomposers chemically modify the nitrogen found in organic matter to ammonium ion (NH₄⁺). This process is known as mineralization and it is carried out by a variety of <a href="/article/Bacteria">bacteria</a> and fungi. </p><p><a href="/article/Nitrogen">Nitrogen</a> in the form of ammonium can be absorbed onto the surfaces of <a href="/article/Clay">clay</a> particles in the soil. The ammonium ion has a positive molecular charge and is normally held by negatively charged soil colloids. This process is sometimes called micelle fixation (see Figure 1). Ammonium is released from the colloids by way of cation exchange. When released, most of the ammonium is often chemically altered by a specific type of autotrophic <a href="/article/Bacteria">bacteria</a> (bacteria that belong to the genus Nitrosomonas) into nitrite (NO₂^-). Further modification by another type of bacteria (belonging to the genus Nitrobacter) converts the nitrite to nitrate (NO₃-). Both of these processes involve chemical oxidation and are known collectively as nitrification. However, nitrate is very soluble and it is easily lost from the soil system by leaching. Some of this leached nitrate flows through the <a href="/article/Hydrologic_cycle">hydrologic system</a> until it reaches the oceans where it can be returned to the atmosphere by denitrification. Denitrification is also common in anaerobic <a href="/article/Soil">soils</a> and is carried out by heterotrophic bacteria. The process of denitrification involves the metabolic reduction of nitrate (NO₃^-) into nitrogen (N₂) or <a href="/article/Nitrous_oxide">nitrous oxide</a> (N₂O) gas. Both of these gases then diffuse into the atmosphere, thus removing nitrogen from the soil, accounting for the name, denitrification. </p><p>Almost all of the <a href="/article/Nitrogen">nitrogen</a> found in any <a href="/article/Ecosystem">ecosystem</a> originally came from the atmosphere. Significant amounts enter the <a href="/article/Soil">soil</a> in rainfall or through the effects of lightning. The majority, however, is biochemically fixed in ecosystems by specialized micro-organisms, all of which are bacteria of various types, including a varity of Gram-positive and Gram-negative bacteria, actinomycetes, and cyanobacteria. Members of the bean family (legumes) and some other kinds of plants form <a href="/article/Mutualism">mutualistic</a> symbiotic relationships with certain types of nitrogen-fixing bacteria. In exchange for some nitrogen, the bacteria receive from the plants carbohydrates and special structures (nodules) in the roots where they can exist in a protected environment. Scientists estimate that biological fixation globally adds approximately 140 million metric tons of nitrogen to ecosystems every year. </p><p>Humans now fix approximately as much nitrogen industrially as does natural nitrogen fixation, thus dramatically altering the nitrogen cycle. Some of the major processes involved in this alteration include: </p> <ul><li>The application of nitrogen fertilizers to crops has caused increased rates of denitrification and leaching of nitrate into <a href="/article/Groundwater">groundwater</a>. The additional nitrogen entering the groundwater system eventually flows into streams, rivers, lakes, and estuaries. In these systems, the added nitrogen can lead to <a href="/article/Eutrophication">eutrophication</a> and associated hypoxia. </li></ul> <ul><li>Increased deposition of <a href="/article/Nitrogen">nitrogen</a> from atmospheric sources because of fossil fuel <a href="/article/Combustion">combustion</a> and forest burning. Both of these processes release a variety of solid forms of nitrogen through combustion and contribute to <a href="/article/Acid_rain">acid rain</a>. </li></ul> <ul><li>Livestock ranching. Livestock release a large amounts of ammonia into the environment from their wastes. This nitrogen enters the <a href="/article/Soil">soil</a> system and then the <a href="/article/Hydrologic_cycle">hydrologic system</a> through leaching, <a href="/article/Groundwater">groundwater</a> flow, and runoff. </li></ul> <ul><li>Sewage waste and septic tank leaching. </li></ul> <p><strong>Further Reading</strong> </p> <ul><li><a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Nitrogen_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Nitrogen_cycle Fri, 10 Jul 2009 05:22:01 GMT http://www.eoearth.org/article/Nitrogen_cycle <a href='/article/Nitrogen_cycle'><img border='0' src='/upload/thumb/b/b9/Nitrogencycle.jpg/600px-Nitrogencycle.jpg' width='100'/></a> <p>The nitrogen cycle represents one of the most important nutrient cycles found in ecosystems. (Figure 1). <a href="/article/Nitrogen">Nitrogen</a> is a required nutrient for all living organisms to produce a number of complex organic molecules like amino acids, the building blocks of proteins, and nucleic acids, including DNA and RNA. The ultimate store of nitrogen is in the atmosphere, where it exists as nitrogen gas (N₂). This store is about one million times larger than the total nitrogen contained in living organisms. Other major stores of nitrogen include organic matter in <a href="/article/Soil">soil</a> and the oceans. Despite its abundance in the atmosphere, nitrogen is often the most limiting nutrient for plant growth. This problem occurs N₂ gas is not biochemically usable by plants. Plants can only take up nitrogen in the form of ammonium ion (NH₄⁺), nitrate ion (NO₃^-), or, less common, as amino acids. Animals receive the <a href="/article/Nitrogen">nitrogen</a> they need for metabolism, growth, and reproduction by the consumption of living or dead organic matter containing molecules composed partially of nitrogen. <br /> </p> <p><br /> In most ecosystems <a href="/article/Nitrogen">nitrogen</a> is primarily stored in living and dead organic matter. This organic nitrogen is converted into inorganic forms when it re-enters the biogeochemical cycle via decomposition. Decomposers chemically modify the nitrogen found in organic matter to ammonium ion (NH₄⁺). This process is known as mineralization and it is carried out by a variety of <a href="/article/Bacteria">bacteria</a> and fungi. </p><p><a href="/article/Nitrogen">Nitrogen</a> in the form of ammonium can be absorbed onto the surfaces of <a href="/article/Clay">clay</a> particles in the soil. The ammonium ion has a positive molecular charge and is normally held by negatively charged soil colloids. This process is sometimes called micelle fixation (see Figure 1). Ammonium is released from the colloids by way of cation exchange. When released, most of the ammonium is often chemically altered by a specific type of autotrophic <a href="/article/Bacteria">bacteria</a> (bacteria that belong to the genus Nitrosomonas) into nitrite (NO₂^-). Further modification by another type of bacteria (belonging to the genus Nitrobacter) converts the nitrite to nitrate (NO₃-). Both of these processes involve chemical oxidation and are known collectively as nitrification. However, nitrate is very soluble and it is easily lost from the soil system by leaching. Some of this leached nitrate flows through the <a href="/article/Hydrologic_cycle">hydrologic system</a> until it reaches the oceans where it can be returned to the atmosphere by denitrification. Denitrification is also common in anaerobic <a href="/article/Soil">soils</a> and is carried out by heterotrophic bacteria. The process of denitrification involves the metabolic reduction of nitrate (NO₃^-) into nitrogen (N₂) or <a href="/article/Nitrous_oxide">nitrous oxide</a> (N₂O) gas. Both of these gases then diffuse into the atmosphere, thus removing nitrogen from the soil, accounting for the name, denitrification. </p><p>Almost all of the <a href="/article/Nitrogen">nitrogen</a> found in any <a href="/article/Ecosystem">ecosystem</a> originally came from the atmosphere. Significant amounts enter the <a href="/article/Soil">soil</a> in rainfall or through the effects of lightning. The majority, however, is biochemically fixed in ecosystems by specialized micro-organisms, all of which are bacteria of various types, including a varity of Gram-positive and Gram-negative bacteria, actinomycetes, and cyanobacteria. Members of the bean family (legumes) and some other kinds of plants form <a href="/article/Mutualism">mutualistic</a> symbiotic relationships with certain types of nitrogen-fixing bacteria. In exchange for some nitrogen, the bacteria receive from the plants carbohydrates and special structures (nodules) in the roots where they can exist in a protected environment. Scientists estimate that biological fixation globally adds approximately 140 million metric tons of nitrogen to ecosystems every year. </p><p>Humans now fix approximately as much nitrogen industrially as does natural nitrogen fixation, thus dramatically altering the nitrogen cycle. Some of the major processes involved in this alteration include: </p> <ul><li>The application of nitrogen fertilizers to crops has caused increased rates of denitrification and leaching of nitrate into <a href="/article/Groundwater">groundwater</a>. The additional nitrogen entering the groundwater system eventually flows into streams, rivers, lakes, and estuaries. In these systems, the added nitrogen can lead to <a href="/article/Eutrophication">eutrophication</a> and associated hypoxia. </li></ul> <ul><li>Increased deposition of <a href="/article/Nitrogen">nitrogen</a> from atmospheric sources because of fossil fuel <a href="/article/Combustion">combustion</a> and forest burning. Both of these processes release a variety of solid forms of nitrogen through combustion and contribute to <a href="/article/Acid_rain">acid rain</a>. </li></ul> <ul><li>Livestock ranching. Livestock release a large amounts of ammonia into the environment from their wastes. This nitrogen enters the <a href="/article/Soil">soil</a> system and then the <a href="/article/Hydrologic_cycle">hydrologic system</a> through leaching, <a href="/article/Groundwater">groundwater</a> flow, and runoff. </li></ul> <ul><li>Sewage waste and septic tank leaching. </li></ul> <p><strong>Further Reading</strong> </p> <ul><li><a href="http://www.physicalgeography.net" class='external text' title="http://www.physicalgeography.net">PhysicalGeography.net</a> </li></ul> <p><a href='/article/Nitrogen_cycle'>Read Full Article...</a></p> http://www.eoearth.org/article/Nitrogen_cycle Fri, 10 Jul 2009 05:17:18 GMT http://www.eoearth.org/article/Health_effects_of_the_Chernobyl_accident <a href='/article/Health_effects_of_the_Chernobyl_accident'><img border='0' src='/upload/thumb/e/e5/Chernobyl.jpg/250px-Chernobyl.jpg' width='100'/></a> <p>April 26, 2006, was the 20th anniversary of the <a href="/article/Chernobyl%2C_Ukraine">Chernobyl accident</a>, the second major single exposure to radiation of a substantial population. The accident produced a significant <a href="/article/International_response_to_the_Chernobyl_accident">international response</a> whose effectiveness is the subject of debate. It is relevant to the current view of the consequences of Chernobyl to reflect on the understanding in 1965 of the health consequences of the first major event, radiation from the atomic bombs in Hiroshima and Nagasaki, Japan, in 1945. The only significant consequences observed in survivors 20 years after the atomic bombs were increases in leukemia and thyroid cancer, and the general view of the future was reassuring. In 1974, a significant increase in solid cancers was detected, and nearly 50 years after the event, an unexpected increase was found in non-cancer diseases. Today, leukemia and thyroid cancer form only a small fraction of the accepted total radiation-related health detriment.</p> <p>In 1990, four years after the Chernobyl accident, an increase in thyroid cancer was found in children exposed to fallout from the accident. Two years later, the first reports in the Western literature of an increase in childhood thyroid cancer (CTC) in Belarus were published. In 2000, about 2,000 cases of thyroid cancer had been reported in those exposed as children in the former Soviet Socialist Union, and in 2005, the number was estimated at 4,000; the latest estimate for the year 2056 ranges from 3,400 to 72,000. The effects are not limited by national borders; Poland has recorded cases in spite of a rapid precautionary distribution of stable <a href="/article/Iodine">iodine</a>. The causative agent, ¹³¹I, was detected in many European countries with as yet unknown effects. Interestingly, a significant increase in leukemia has not been reliably reported in the three most affected countries.</p><p>This dramatic contrast between the two incidents is in part due to the different types of radiation exposure, but both show that the effects of massive exposures to radiation are immensely complex. In comparing the health effects after <a href="/article/Chernobyl%2C_Ukraine">Chernobyl</a> with those after the atomic bombs, it must be remembered that apart from workers in or close to the <a href="/article/Nuclear_power_reactor">power plant</a>, the Chernobyl accident involved mainly exposure to radioactive isotopes, and the atomic bombs primarily involved direct exposure to gamma rays and neutrons. Because of the prominence given to thyroid carcinoma after Chernobyl, less attention has been given to whole-body exposure from the ingestion and inhalation of all isotopes, together with the shine from the radioactive cloud and deposited radioactivity. Consideration of the health effects of Chernobyl must take into account both tissue-specific doses due to <a href="/article/Isotope">isotope</a> concentration and whole-body <a href="/article/Dose">doses</a>.</p><p>The most prominent tissue-specific dose is that to the thyroid, largely from ¹³¹I, with a smaller contribution from short-lived isotopes of <a href="/article/Iodine">iodine</a>. For many in the 30-km zone (135,000), there were relatively high <a href="/article/Absorption_of_toxicants">absorbed</a> doses to other <a href="/article/Organ_systems_and_organs">organs</a> as well as the thyroid until evacuation, and for those living in the contaminated areas around the 30-km zone (5 million), relatively high dose rate exposure (days to weeks) was followed by prolonged (years) exposure to a low dose rate. This exposure was a complex mixture of external radiation and internal emitters. For others living farther from the accident, in Western Europe, for example, their average exposure was equivalent to an additional ≤ 50% of average annual natural background level of radiation. About 600,000 liquidators assisted with the cleanup. Those working at the site shortly after the accident (200,000) received substantial doses. For all of these groups, estimates of numbers of fatal cancers can be derived from the collective doses. However, such estimates depend on the assumed risk coefficient, but of the order of 60,000 such fatalities in total can be estimated, based on the collective dose estimated by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), less than half of which would derive from the declared contaminated areas. A more recent estimate of the numbers of fatal cancers based on a collective dose of less than half the UNSCEAR estimate gives a central value of 16,000 (95% confidence interval, 7,000–38,000).</p> <p><a href='/article/Health_effects_of_the_Chernobyl_accident'>Read Full Article...</a></p> http://www.eoearth.org/article/Health_effects_of_the_Chernobyl_accident Thu, 09 Jul 2009 05:12:53 GMT http://www.eoearth.org/article/Vertical_farming <a href='/article/Vertical_farming'><img border='0' src='/upload/thumb/6/60/C_Jacobs_VFs_solar.jpg/200px-C_Jacobs_VFs_solar.jpg' width='100'/></a> <p>The advent of <a href="/article/Agriculture">agriculture</a> ushered in an unprecedented increase in the human <a href="/article/Population">population</a> and their <a href="/article/Domestication">domesticated animals</a>. Farming catalyzed the transformation of hunter-gatherers into urban dwellers. Today, over 800 million hectares is committed to agriculture, or about 38% of the total landmass of the Earth. Farming has <a href="/article/Land-use_and_land-cover_change">re-arranged the landscape</a> in favor of cultivated fields and herds of cattle, and has occurred at the expense of natural ecozones, reducing most of them to fragmented, semi-functional units, while completely eliminating others. Undeniably, a reliable food supply has allowed for a healthier life style for most of the civilized world, while the very act of farming has created new health hazards. </p> <p>For example, the transmission of numerous infectious disease agents - avian influenza, rabies, yellow fever, dengue fever, <a href="/article/Malaria">malaria</a>, trypanosomiasis, hookworm, <a href="/article/Schistosomiasis">schistosomiasis</a> - occur with relentlessly devastating regularity at the tropical and sub-tropical agricultural interface. Emerging infections, many of which are viral zoonoses (e.g., Ebola, Lassa fever), rapidly adapt to the human host following encroachment into natural environments. Exposure to <a href="/article/Toxicity">toxic</a> levels of some classes of agrochemicals (<a href="/article/Pesticide">pesticides</a>, fungicides) and trauma are two other significant health risks associated with traditional agricultural practices. Over the next 50 years, the human population is expected to rise to at least 8.6 billion, requiring an additional 10⁹ hectares to feed them using current technologies. That quantity of farmland is no longer available. Thus, alternative strategies for obtaining an abundant and varied food supply without encroachment into the few remaining functional ecosystems must be seriously entertained. </p><p>If traditional farming could be replaced by constructing urban food production centers - vertical farms - then a long-term benefit would be the gradual repair of many of the world’s damaged ecosystems through the systematic abandonment of farmland. In temperate and tropical zones, the re-growth of hardwood forests could play a significant role in <a href="/article/Carbon_capture_and_storage">carbon sequestration</a> and may help reverse current trends in global climate change. Social benefits of vertical farming include the creation of a sustainable urban environment that encourages good health for all who choose to live there; new employment opportunities; fewer abandoned lots and buildings; cleaner air; and an abundant supply of safe drinking water. </p> <p><a href='/article/Vertical_farming'>Read Full Article...</a></p> http://www.eoearth.org/article/Vertical_farming Wed, 08 Jul 2009 07:24:34 GMT http://www.eoearth.org/article/Vertical_farming <a href='/article/Vertical_farming'><img border='0' src='/upload/thumb/6/60/C_Jacobs_VFs_solar.jpg/200px-C_Jacobs_VFs_solar.jpg' width='100'/></a> <p>The advent of <a href="/article/Agriculture">agriculture</a> ushered in an unprecedented increase in the human <a href="/article/Population">population</a> and their <a href="/article/Domestication">domesticated animals</a>. Farming catalyzed the transformation of hunter-gatherers into urban dwellers. Today, over 800 million hectares is committed to agriculture, or about 38% of the total landmass of the Earth. Farming has <a href="/article/Land-use_and_land-cover_change">re-arranged the landscape</a> in favor of cultivated fields and herds of cattle, and has occurred at the expense of natural ecozones, reducing most of them to fragmented, semi-functional units, while completely eliminating others. Undeniably, a reliable food supply has allowed for a healthier life style for most of the civilized world, while the very act of farming has created new health hazards. </p> <p>For example, the transmission of numerous infectious disease agents - avian influenza, rabies, yellow fever, dengue fever, <a href="/article/Malaria">malaria</a>, trypanosomiasis, hookworm, <a href="/article/Schistosomiasis">schistosomiasis</a> - occur with relentlessly devastating regularity at the tropical and sub-tropical agricultural interface. Emerging infections, many of which are viral zoonoses (e.g., Ebola, Lassa fever), rapidly adapt to the human host following encroachment into natural environments. Exposure to <a href="/article/Toxicity">toxic</a> levels of some classes of agrochemicals (<a href="/article/Pesticide">pesticides</a>, fungicides) and trauma are two other significant health risks associated with traditional agricultural practices. Over the next 50 years, the human population is expected to rise to at least 8.6 billion, requiring an additional 10⁹ hectares to feed them using current technologies. That quantity of farmland is no longer available. Thus, alternative strategies for obtaining an abundant and varied food supply without encroachment into the few remaining functional ecosystems must be seriously entertained. </p><p>If traditional farming could be replaced by constructing urban food production centers - vertical farms - then a long-term benefit would be the gradual repair of many of the world’s damaged ecosystems through the systematic abandonment of farmland. In temperate and tropical zones, the re-growth of hardwood forests could play a significant role in <a href="/article/Carbon_capture_and_storage">carbon sequestration</a> and may help reverse current trends in global climate change. Social benefits of vertical farming include the creation of a sustainable urban environment that encourages good health for all who choose to live there; new employment opportunities; fewer abandoned lots and buildings; cleaner air; and an abundant supply of safe drinking water. </p> <p><a href='/article/Vertical_farming'>Read Full Article...</a></p> http://www.eoearth.org/article/Vertical_farming Wed, 08 Jul 2009 05:55:47 GMT http://www.eoearth.org/article/Strip_mining <a href='/article/Strip_mining'><img border='0' src='/upload/thumb/5/57/Stripmining.jpg/200px-Stripmining.jpg' width='100'/></a> <p>Strip mining is a type of surface mining that involves excavating earth, rock, and other material to uncover a tabular, lens-shaped, or layered mineral reserve. The mineral extracted is usually <a href="/article/Coal">coal</a> or other rocks of sedimentary origin. The mineral reserve is extracted after the overlying material, called overburden is removed. The excavation of the overburden is completed in rectangular blocks in plain view called pits or strips. The pits are parallel and adjacent to each other with each strip of overburden and the mineral beneath extracted sequentially. The mining process using equipment and explosives move the overburden laterally to the adjacent empty pit where the mineral has been extracted. This lateral movement is called casting or open-casting. The overburden is moved by explosives, draglines, bucketwheel excavators, stripping shovels, dozers, and other equipment. The uncovered mineral is excavated and hauled out of the pit to down-stream processing operations. Filling the adjacent empty pits with the overburden is systemic to the process and therefore insures the genesis of mined-land land reclamation, an advantage of this method of surface mining. Planning strip mining utilizes a cross-section or range diagram of the earth to be removed. Strip mining is also called open-cut mining, open-cast mining, and stripping. </p><p><b>Further reading</b><br /> </p><p>Schissler, Andrew P., “Design and Methods of Coal Mining," in <i>The Encyclopedia of Energy</i>, Volume 1, Cutler J. Cleveland Editor-in-Chief, Elsevier Inc., Kidlington, Oxford, pp. 485-494. </p> <p><a href='/article/Strip_mining'>Read Full Article...</a></p> http://www.eoearth.org/article/Strip_mining Tue, 07 Jul 2009 06:12:45 GMT http://www.eoearth.org/article/Strip_mining <a href='/article/Strip_mining'><img border='0' src='/upload/thumb/5/57/Stripmining.jpg/200px-Stripmining.jpg' width='100'/></a> <p>Strip mining is a type of surface mining that involves excavating earth, rock, and other material to uncover a tabular, lens-shaped, or layered mineral reserve. The mineral extracted is usually <a href="/article/Coal">coal</a> or other rocks of sedimentary origin. The mineral reserve is extracted after the overlying material, called overburden is removed. The excavation of the overburden is completed in rectangular blocks in plain view called pits or strips. The pits are parallel and adjacent to each other with each strip of overburden and the mineral beneath extracted sequentially. The mining process using equipment and explosives move the overburden laterally to the adjacent empty pit where the mineral has been extracted. This lateral movement is called casting or open-casting. The overburden is moved by explosives, draglines, bucketwheel excavators, stripping shovels, dozers, and other equipment. The uncovered mineral is excavated and hauled out of the pit to down-stream processing operations. Filling the adjacent empty pits with the overburden is systemic to the process and therefore insures the genesis of mined-land land reclamation, an advantage of this method of surface mining. Planning strip mining utilizes a cross-section or range diagram of the earth to be removed. Strip mining is also called open-cut mining, open-cast mining, and stripping. </p><p><b>Further reading</b><br /> </p><p>Schissler, Andrew P., “Design and Methods of Coal Mining," in <i>The Encyclopedia of Energy</i>, Volume 1, Cutler J. Cleveland Editor-in-Chief, Elsevier Inc., Kidlington, Oxford, pp. 485-494. </p> <p><a href='/article/Strip_mining'>Read Full Article...</a></p> http://www.eoearth.org/article/Strip_mining Tue, 07 Jul 2009 06:10:50 GMT http://www.eoearth.org/article/Waste-to-energy <a href='/article/Waste-to-energy'><img border='0' src='/upload/thumb/9/96/Waste_combustors.gif/300px-Waste_combustors.gif' width='100'/></a> <p>Waste-to-energy is the process in which waste is used to generate useful energy –electricity, <a href="/article/Heat">heat</a> or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory <a href="/article/Combustion">combustion</a> conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per <a href="/article/Kilogram">kilogram</a>. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery <a href="/article/Boiler">boiler</a> to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families. </p><p>Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of <a href="/article/Methane">methane</a>, a high-fuel value gas. </p><p><strong>Further reading</strong><br /> <a href="http://www.wte.org/" class='external text' title="http://www.wte.org/">Waste to Energy systems</a>, Integrated Waste Services Association </p> <p><a href='/article/Waste-to-energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Waste-to-energy Mon, 06 Jul 2009 05:27:21 GMT http://www.eoearth.org/article/Waste-to-energy <a href='/article/Waste-to-energy'><img border='0' src='/upload/thumb/9/96/Waste_combustors.gif/300px-Waste_combustors.gif' width='100'/></a> <p>Waste-to-energy is the process in which waste is used to generate useful energy –electricity, <a href="/article/Heat">heat</a> or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory <a href="/article/Combustion">combustion</a> conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per <a href="/article/Kilogram">kilogram</a>. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery <a href="/article/Boiler">boiler</a> to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families. </p><p>Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of <a href="/article/Methane">methane</a>, a high-fuel value gas. </p><p><strong>Further reading</strong><br /> <a href="http://www.wte.org/" class='external text' title="http://www.wte.org/">Waste to Energy systems</a>, Integrated Waste Services Association </p> <p><a href='/article/Waste-to-energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Waste-to-energy Mon, 06 Jul 2009 05:26:10 GMT http://www.eoearth.org/article/Waste-to-energy <a href='/article/Waste-to-energy'><img border='0' src='/upload/thumb/9/96/Waste_combustors.gif/300px-Waste_combustors.gif' width='100'/></a> <p>Waste-to-energy is the process in which waste is used to generate useful energy –electricity, <a href="/article/Heat">heat</a> or both. This is possible (and convenient) when the heat generated by burning the waste is high enough to warrant satisfactory <a href="/article/Combustion">combustion</a> conditions and make available enough energy to overcome losses and auxiliary consumption: in practice, a lower heating value of at least 4 megajoules per <a href="/article/Kilogram">kilogram</a>. Waste-to-energy is the offspring of waste incineration, which was originally introduced to sterilize and reduce the volume of waste by combusting it in a furnace. Modern waste-to-energy plants allow the export of energy, with very low environmental impact. The plant comprises four basic sections: waste combustor, recovery boiler, flue gas treatment and steam cycle. The design of the combustor varies widely with the waste characteristics: physical state (solid vs. liquid), size distribution, heating value, ash and moisture content, etc. Municipal solid waste (MSW) typically is burned on a moving grate, where it is kept 20-30 minutes until it is completely combusted. The hot gases generated in the combustor go through the recovery <a href="/article/Boiler">boiler</a> to generate steam, which is used directly as heat carrier or sent to a steam turbine to produce power. Flue gases are treated by adding reactants called sorbents and by filtering the particulate matter. A modern, large plant treating half-million tons of municipal solid waste per year can generate more than 400 million kWh per year, meeting the electricity needs of more than 150,000 families. </p><p>Another method of converting waste to energy is biomethanation where putrescible waste is anaerobically digested to create biogas which consists mainly of <a href="/article/Methane">methane</a>, a high-fuel value gas. </p><p><strong>Further reading</strong><br /> <a href="http://www.wte.org/" class='external text' title="http://www.wte.org/">Waste to Energy systems</a>, Integrated Waste Services Association </p> <p><a href='/article/Waste-to-energy'>Read Full Article...</a></p> http://www.eoearth.org/article/Waste-to-energy Mon, 06 Jul 2009 05:25:37 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Mon, 06 Jul 2009 05:25:18 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Mon, 06 Jul 2009 05:22:34 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Thu, 02 Jul 2009 06:01:29 GMT http://www.eoearth.org/article/Recycling <a href='/article/Recycling'><img border='0' src='/upload/thumb/9/96/Curbside_recycling.jpg/300px-Curbside_recycling.jpg' width='100'/></a> <p>Recycling is the process of turning used products into raw materials that can be used to make new products. Its purpose is to conserve natural resources and reduce pollution. Recycling reduces energy consumption, since it generally takes less energy to recycle a product than to make a new one. Similarly, recycling causes less pollution than <a href="/article/Essential_economic_activities">manufacturing</a> a new product, and conserves raw materials. It also decreases the amount of waste sent to landfills or incinerators. Although people have always reused things, recycling as we know it today emerged as part of the modern environmental movement. </p><p>During World War II, Americans experimented with conservation and recycling as a matter of national security. Afterward, 1950s middle class life unapologetically adopted the ethics of expansion and newness. As more and more middle-class Americans began to express environmental attitudes, the wastefulness of modern <a href="/article/Essential_economic_activities">consumption</a> became obvious to more and more consumers. More Americans than ever before became willing to integrate such practices into their lives as part of a commitment to the environment. For instance, most children born after the 1980s assume the &quot;recycle, reduce, and re-use&quot; mantra has been part of the U.S. since its founding. In actuality, it serves as a continuation of the cultural and social impact of <a href="/article/Earth_Day_%2770:_What_It_Meant">Earth Day 1970</a> and the effort of Americans to begin to live within limits. </p><p>Belittled by many environmentalists, recycling often seems like busy-work for kids with little actual environmental benefit. However, such a minor shift in human behavior suggests the significant alteration made to many humans&#39; view of their place in nature by the late 1900s. This change in worldview, caused by many political, social, and intellectual shifts, forced humans in developed nations to question their lack of restraint. In particular, the culture of consumption of post-World War II America re-enforced carelessness, waste, and a drive for newness. Environmental concerns contributed to a new &quot;ethic&quot; within American culture that began to value restraint, re-use, and living within limits. This ethic of restraint, fed by over-used landfills and excessive litter, gave communities a new mandate in maintaining the waste of their population. Re-using products or creating useful byproducts from waste offered application of this new ethic while also offering new opportunity for <a href="/article/Economic_growth">economic profit and development</a>. </p><p>Non-profit recycling centers began opening around the country, followed by municipal recycling programs. Today, most U.S. communities have such programs. A typical program asks people to separate their recyclables from their trash before placing them at the curb for collection. To encourage recycling, some communities also charge residents for the quantity of trash put out for collection. The most commonly recycled household items are paper and cardboard; metal, glass, and plastic containers and packaging; and <a href="/article/Yard_waste">yard waste</a>. Recycling the recovered materials is simple for metals and glass; they can be melted down, reformed, and reused. Yard waste can be <a href="/article/Composting">composted</a> with little or no equipment. Paper, the most important recycled material, must be mixed with water, and sometimes de-inked, to form a pulp that can be used in papermaking. Plastics recycling requires an expensive process of separation of different resins. </p><p>In the US, plastics are all numerically coded according to type, including: polyethylene terphthalate (PETE or PET; 1) an example of these plastics are virtually all soft drink bottles, high density polyethylene (HDPE; 2) an example would be detergent bottles, polyvinyl chloride (PVC; 3), sometimes used for water or oil bottles but now rare in food beverage packaging, due to concerns about its environmental hazards; low density polyethylene (LDPE; 4) often used for plastic bags, polypropylene (PP; 5) examples are some yogurt containers and bottle caps, and polystyrene (PS; 6) used to make Styrofoam containers. Number 7 seen on some packaging, refers to all plastics other than these six. It is not a single plastic material. </p><p>The American Chemistry Council reports that in the US in 2005, 922 million pounds of HDPE bottles (those thick plastic bottles like milk jugs and laundry detergent bottles) were recycled, as were over one billion pounds of PET and PP bottles, although they note that this represents only about 25-30% of all recyclable bottles. The majority of this is attributed to PET, as PP recycling is rare, and a large part of the recycling of bottles comes from the 11 states with deposit legislation. </p><p>Depending on the type, plastics can be recycled into anything from fiberfill to polyester-like fibers, to blue recycling bins, or plastic lumber furniture. Fleece is an example of a textile that can be produced from recycled plastics. While many companies still rely on “virgin” polyester to produce fleece, there are now several “eco-fleece” products on the <a href="/article/Market">market</a> that are made primarily or entirely from recycled bottles. </p><p><br /> <strong>Further Reading</strong> </p> <ul><li> Strasser, Susan. <em>Waste and Want: A Social History of Trash</em>. NY: Owl Books, 2000. <a href="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0805065121/?tag=encycofearth-20">ISBN: 0805065121</a> </li><li> Zimring, Carl A. <em>Cash for Your Trash: Scrap Recycling in America</em>. Rutgers University Press, 2005. <a href="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20" class='external text' title="http://www.amazon.com/dp/0813536863/?tag=encycofearth-20">ISBN: 0813536863</a> </li></ul> <p><a href='/article/Recycling'>Read Full Article...</a></p> http://www.eoearth.org/article/Recycling Thu, 02 Jul 2009 05:31:49 GMT http://www.eoearth.org/article/Forestry <a href='/article/Forestry'><img border='0' src='/upload/thumb/5/56/Forestry.jpeg/350px-Forestry.jpeg' width='100'/></a> <p>Forestry is the science and practice of managing a <a href="/article/Forest_biome">forest</a> for some goal. Prior to the establishment of forestry as a science-based discipline, the exploitation of forests for various products was carried out without sufficient regard for consequences. For example, trees were cut without ensuring tree regeneration. Logged areas were often burned catastrophically without regard for <a href="/article/Soil">soil</a> resources and logs dragged or flushed down <a href="/article/Stream">stream</a> valleys to a mill without concern for the stream habitat or water quality. </p><p>Scientific forestry is intended to alleviate these unintended consequences by basing management on research and a goal of sustainable management. The practice of forestry encompasses forest protection, forest engineering, silviculture, forest ecology, economics, biometrics, hydrology, wildlife management, and other disciplines. </p><p>Forests face multiple threats, such as fire, disease, insect outbreak, and <a href="/article/Air_pollution_emissions">air pollution</a>. Some of these factors can negatively impact large forest areas over short time periods. Other factors may create chronic stresses which may have long-term consequences on the nature of a forest ecosystem and the species within. Forest management activities are, therefore, undertaken to reduce fire risk, control pests, and to guide forest development processes towards specific, often multiple-use, management goals. Techniques include thinning and controlled burns to reduce fire risk, application of <a href="/article/Pesticide">pesticides</a> to control insect outbreaks, removal of diseased trees, and etc. </p><p>Modern forestry utilizes large equipment, and thus must utilize engineers. Unique achievements of forest engineers include cable yarding systems, the design of forest roads that produce less sediment, and the development of field harvesting equipment that increases efficiency. </p><p>Silviculture is the art and science of growing trees. Various silvicultural systems have been devised to harvest a stand (or selected trees) at lowest cost and with minimal damage, to ensure restocking of the site, to help trees grow rapidly, to favor particular species, and to protect <a href="/article/Biodiversity">biodiversity</a>. </p><p>Forest ecology is the study of the <a href="/article/Forest_biome">forest</a> as an ecological system. Facets of this science include tree physiology and life history, wildlife biology, nutrient cycling, biogeography, and other topics. The results of studies in forest ecology help inform silviculture as well as efforts to document and conserve biodiversity. </p><p>Since forestry is often conducted as a business, the economic aspect of forestry has long received attention. Forest economics encompasses field operations (such as harvesting), long-term stand management strategies, firm-wide (or forest-wide) economic planning, assessments of the impact of forest policy on nearby communities, and even international <a href="/article/Market">market</a> assessments of wood supply and effects of tariffs and tax policies. </p><p>Forest hydrology is concerned with the effects of forestry operations on hydrologic properties of <a href="/article/Stream">streams</a> and <a href="/article/Watershed">watersheds</a>, water yield, water quality, and stream biota. </p><p>Biometrics and forest mensuration are concerned with sampling and measuring properties such as stem form and biomass, site index, stand wood yield, etc. These fields are called upon also for the design of forest inventories and analysis of inventory data. </p><p>Forest management is typically extensive rather than intensive. The basic spatial unit of management is the forest stand, which is a more-or-less homogenous and identifiable spatial unit. When a prescription like thinning or <a href="/article/Fertilizer">fertilization</a> is applied, it is applied to one or more stands as whole units. This is because operational efficiencies can only be achieved in this manner and because detailed spatial manipulations (e.g., fertilizing at different levels for each tree) are not feasible with the information and techniques available. While certain scales of complexity of spatial pattern can be achieved, such as by selection or strip cutting or leaving remnant trees or patches, not all possible configurations are feasible. In addition, there may not be any known prescription that would favor a particular species (such as an endangered species) or remove a pest species. </p><p>Commercial forestry is necessarily carried out based on an expectation of profit. Non-market benefits (e.g., <a href="/article/Biodiversity">biodiversity</a> goals, aesthetics) can and need to be accommodated to maintain a social license to manage the <a href="/article/Forest_biome">forest</a> but they must not be too demanding of corporate resources (e.g., staff time, land area) or competing <a href="/article/Land-use">land-uses</a> will be selected. Forests on public lands, and particular those located in designated wilderness areas, are sometimes managed for non-commercial goals, including wildlife habitat restoration, old-growth preservation, water resource protection, preservation of biodiversity, and rare or endangered species conservation. Management strategies for preservation-related purposes may not generate net income from the harvesting of forest resources although other local and regional economic benefits may be derived from recreation related activities and by other environmental services provided by forests such as water and air protection and purification. </p> <p><a href='/article/Forestry'>Read Full Article...</a></p> http://www.eoearth.org/article/Forestry Wed, 01 Jul 2009 05:40:04 GMT http://www.eoearth.org/article/Land-use_and_land-cover_change <a href='/article/Land-use_and_land-cover_change'><img border='0' src='/upload/thumb/a/af/Brazil_deforestation.jpg/250px-Brazil_deforestation.jpg' width='100'/></a> <p><strong>Land-use and land-cover change</strong> (<strong>LULCC</strong>); also known as <strong>land change</strong>) is a general term for the human modification of Earth&#39;s terrestrial surface. Though humans have been modifying land to obtain food and other essentials for thousands of years, current rates, extents and intensities of LULCC are far greater than ever in history, driving unprecedented changes in ecosystems and environmental processes at local, regional and global scales. These changes encompass the greatest environmental concerns of human populations today, including climate change, <a href="/article/Biodiversity">biodiversity</a> loss and the pollution of water, soils and air. Monitoring and mediating the negative consequences of LULCC while sustaining the production of essential resources has therefore become a major priority of researchers and policymakers around the world.</p> <p><a href='/article/Land-use_and_land-cover_change'>Read Full Article...</a></p> http://www.eoearth.org/article/Land-use_and_land-cover_change Tue, 30 Jun 2009 05:38:56 GMT http://www.eoearth.org/article/Biosphere <a href='/article/Biosphere'><img border='0' src='/upload/thumb/0/03/Earth_spheres.jpg/300px-Earth_spheres.jpg' width='100'/></a> <p>The<strong> biosphere</strong> is the biological component of earth systems, which also include the lithosphere, hydrosphere, <a href="/article/Atmosphere_layers">atmosphere</a> and other &quot;spheres&quot; (e.g. <a href="/article/Cryosphere">cryosphere</a>, anthrosphere, etc.). The biosphere includes all living organisms on earth, together with the dead organic matter produced by them. </p> <p>The biosphere concept is common to many scientific disciplines including astronomy, geophysics, geology, hydrology, biogeography and <a href="/article/Evolution">evolution</a>, and is a core concept in <a href="/article/Ecology">ecology</a>, earth science and <a href="/article/Physical_geography">physical geography</a>. A key component of earth systems, the biosphere interacts with and exchanges <a href="/article/Matter">matter</a> and energy with the other spheres, helping to drive the global biogeochemical cycling of <a href="/article/Carbon_cycle">carbon</a>, <a href="/article/Nitrogen_cycle">nitrogen</a>, phosphorus, sulfur and other <a href="/article/Elements">elements</a>. From an ecological point of view, the biosphere is the &quot;global <a href="/article/Ecosystem">ecosystem</a>&quot;, comprising the totality of <a href="/article/Biodiversity">biodiversity</a> on earth and performing all manner of biological functions, including <a href="/article/Photosynthesis">photosynthesis</a>, respiration, decomposition, nitrogen fixation and denitrification. </p><p>The biosphere is dynamic, undergoing strong seasonal cycles in primary productivity and the many biological processes driven by the energy captured by photosynthesis. Seasonal cycles in solar irradiation of the hemispheres is the main driver of this dynamic, especially by its strong effect on <a href="/article/Terrestrial_biome">terrestrial</a> primary productivity in the temperate and boreal <a href="/article/Biome">biomes</a>, which essentially cease productivity in the winter time. </p><p>The biosphere has evolved since the first single-celled organisms originated 3.5 billion years ago under atmospheric conditions resembling those of our neighboring planets Mars and Venus, which have atmospheres composed primarily of <a href="/article/Carbon_dioxide">carbon dioxide</a>. Billions of years of primary production by plants released <a href="/article/Oxygen">oxygen</a> from this carbon dioxide and deposited the carbon in sediments, eventually producing the oxygen-rich <a href="/article/Atmospheric_composition">atmosphere</a> we know today. Free oxygen, both for breathing (O₂, respiration) and in the stratospheric <a href="/article/Ozone">ozone</a> (O₃) that protects us from harmful UV radiation, has made possible life as we know it while transforming the chemistry of earth systems forever. </p><p>As a result of long-term interactions between the biosphere and the other earth systems, there is almost no part of the earth&#39;s surface that has not been profoundly altered by living organisms. The earth is a living planet, even in terms of its physics and chemistry. A concept related to, but different from, that of the biosphere, is the <a href="/article/Environmental_ethics_and_the_Gaia_theory">Gaia hypotheses</a>, which posits that living organisms have and continue to transform earth systems for their own benefit. </p> <p><a href='/article/Biosphere'>Read Full Article...</a></p> http://www.eoearth.org/article/Biosphere Mon, 29 Jun 2009 04:04:20 GMT http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils <a href='/article/Hillslope_processes_and_mass_movement_of_soils'><img border='0' src='/upload/thumb/f/f7/Scree_slope.jpg/250px-Scree_slope.jpg' width='100'/></a> <p>Hillslopes are an important part of the <a href="/article/Physiography_of_the_Earth%27s_terrestrial_surface">terrestrial landscape</a>. The Earth's landscape can be thought of as being composed of a mosaic of slope types, ranging from steep mountains and cliffs to almost flat plains. On most hillslopes large quantities of <a href="/article/Soil">soil</a> and sediment are moved over time via the mediums of air, water, and ice often under the direct influence of gravity. The form a hillslope takes is dependent on the various geomorphic processes acting on it. Hillslopes are also the source of materials that are used to construct a number of depositional landforms. </p><p>In practical terms, hillslopes have direct and indirect influence on a number of human activities. The steepness and structural stability of hillslopes determines their suitability for <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, and human settlement. Hillslopes can also become a hazard to humans if their materials move rapidly through the process of mass wasting. </p> <p><a href='/article/Hillslope_processes_and_mass_movement_of_soils'>Read Full Article...</a></p> http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils Fri, 26 Jun 2009 05:33:23 GMT http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils <a href='/article/Hillslope_processes_and_mass_movement_of_soils'><img border='0' src='/upload/thumb/f/f7/Scree_slope.jpg/250px-Scree_slope.jpg' width='100'/></a> <p>Hillslopes are an important part of the <a href="/article/Physiography_of_the_Earth%27s_terrestrial_surface">terrestrial landscape</a>. The Earth's landscape can be thought of as being composed of a mosaic of slope types, ranging from steep mountains and cliffs to almost flat plains. On most hillslopes large quantities of <a href="/article/Soil">soil</a> and sediment are moved over time via the mediums of air, water, and ice often under the direct influence of gravity. The form a hillslope takes is dependent on the various geomorphic processes acting on it. Hillslopes are also the source of materials that are used to construct a number of depositional landforms. </p><p>In practical terms, hillslopes have direct and indirect influence on a number of human activities. The steepness and structural stability of hillslopes determines their suitability for <a href="/article/Agriculture">agriculture</a>, <a href="/article/Forestry">forestry</a>, and human settlement. Hillslopes can also become a hazard to humans if their materials move rapidly through the process of mass wasting. </p> <p><a href='/article/Hillslope_processes_and_mass_movement_of_soils'>Read Full Article...</a></p> http://www.eoearth.org/article/Hillslope_processes_and_mass_movement_of_soils Fri, 26 Jun 2009 05:32:35 GMT http://www.eoearth.org/article/Viral_hemorrhagic_fevers <a href='/article/Viral_hemorrhagic_fevers'><img border='0' src='/upload/thumb/a/ab/BSL4_containment_CDC.jpg/199px-BSL4_containment_CDC.jpg' width='100'/></a> <p>The Centers for Disease Control and Prevention&#39;s National Center for Infectious Diseases has prepared answers to questions about the nature of the group of illnesses characterized as viral hemorrhagic fevers.</p> <p><a href='/article/Viral_hemorrhagic_fevers'>Read Full Article...</a></p> http://www.eoearth.org/article/Viral_hemorrhagic_fevers Thu, 25 Jun 2009 04:17:10 GMT http://www.eoearth.org/article/Viral_hemorrhagic_fevers <a href='/article/Viral_hemorrhagic_fevers'><img border='0' src='/upload/thumb/a/ab/BSL4_containment_CDC.jpg/199px-BSL4_containment_CDC.jpg' width='100'/></a> <p>The Centers for Disease Control and Prevention&#39;s National Center for Infectious Diseases has prepared answers to questions about the nature of the group of illnesses characterized as viral hemorrhagic fevers.</p> <p><a href='/article/Viral_hemorrhagic_fevers'>Read Full Article...</a></p> http://www.eoearth.org/article/Viral_hemorrhagic_fevers Thu, 25 Jun 2009 04:16:46 GMT http://www.eoearth.org/article/Viral_hemorrhagic_fevers <a href='/article/Viral_hemorrhagic_fevers'><img border='0' src='/upload/thumb/a/ab/BSL4_containment_CDC.jpg/199px-BSL4_containment_CDC.jpg' width='100'/></a> <p>The Centers for Disease Control and Prevention&#39;s National Center for Infectious Diseases has prepared answers to questions about the nature of the group of illnesses characterized as viral hemorrhagic fevers.</p> <p><a href='/article/Viral_hemorrhagic_fevers'>Read Full Article...</a></p> http://www.eoearth.org/article/Viral_hemorrhagic_fevers Thu, 25 Jun 2009 04:16:23 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Thu, 25 Jun 2009 04:15:44 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its potential economic contributions. Capital stocks are also often referred to as “capital assets.” </p><p>We can identify four types of <a href="/article/Capital">capital</a> that contribute to an economy’s productivity. <a href="/article/Capital">Natural capital</a> refers to physical assets provided by nature, such as land that is suitable for <a href="/article/Agriculture">agriculture</a> or other human uses, fresh <a href="/article/Water_resources">water sources</a>, and stocks of minerals and crude oil that are still in the ground. <a href="/article/Capital">Manufactured capital</a> means physical assets that are generated by applying human productive activities to natural capital. These include such things as buildings, machinery, stocks of <a href="/article/Petroleum_refining">refined oil</a>, transportation infrastructure, and inventories of produced goods that are waiting to be sold or to be used in further production. <a href="/article/Capital">Human capital</a> refers to individual people’s capacity for labor, particularly the knowledge and skills each can personally bring to his or her work. <a href="/article/Capital">Social capital</a> means the stock of trust, mutual understanding, shared values, and socially held knowledge that facilitates the social coordination of economic activity. </p><p>Lastly, there is a fifth sort of resource, <a href="/article/Capital">financial capital</a>, which is a fund of purchasing power available to an economic actor. While financial capital doesn’t directly help to produce anything, it indirectly contributes to production by making it possible for people to produce goods and services in advance of getting paid for them. It also facilitates the activities of distribution and consumption. Key examples of financial capital would be a bank checking account, filled with funds that have been either saved up by the economic agent who owns it or loaned to the agent by a bank. </p><p>Notice that economists’ description of “<a href="/article/Capital">capital</a>” is different from what you might hear in everyday use. In common usage, sometimes people take “capital” to mean only financial capital. We hear this in everyday references to “capital markets,” “undercapitalized businesses,” “venture capital,” etc. Economists take a broader view. </p><p>Capital stocks may increase or decrease as a consequence of natural forces, as in the case of a natural forest; or they may be deliberately managed by humans, in order to provide needed inputs for the production of desired goods and services. When the quantity or quality of a non-financial resource is increased now in order to make benefits possible in the future, this is what economists mean by investment. The activity of “<a href="/article/Resource_maintenance_in_economies">resource maintenance</a>” is about making sure that investments are sufficient to provide an economy with good asset base for future years and future generations. You, right now, are investing in your “human capital” by studying economics. </p> <p><a href='/article/Essential_economic_activities'>Read Full Article...</a></p> http://www.eoearth.org/article/Essential_economic_activities Wed, 24 Jun 2009 04:25:57 GMT http://www.eoearth.org/article/Essential_economic_activities <a href='/article/Essential_economic_activities'><img border='0' src='/upload/thumb/1/17/Financial_Capital_Commercial_Production_diagram.gif/300px-Financial_Capital_Commercial_Production_diagram.gif' width='100'/></a> <p><a href="/article/Resource_maintenance_in_economies">Resource maintenance</a> means tending to, preserving, or improving the stocks of resources that form the basis for the preservation and quality of life. A <a href="/article/Capital">capital</a> stock is a quantity of any resource that is valued for its