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Question:and even on ecological imbalance and depletion of forests !

Answers:Humanity is destroying nature. We're better off without humanity!!

Question:Describe the concept of stoichiometric homeostasis. How does one test for its existence? Which types of organisms tend to exhibit stoichiometric homeostasis, and which do not. Finally, how the presence of lack of stoichiometric homeostasis in soil bacteria and plants affect the response of terrestrial nutrient cycles to additions of a limiting nutrient.

Answers:A dry topic. Not given to light replies - or in your case, any replies. So I'll tackle: Stoichiometric homeostasis: One of the most significant themes in ecology. This is the concept that compares the elemental makeup of the tissues in living organisms with their environment. Quoting biologist J. Persson at University of Oslo, and fellow scientists in their report, "To be or not to be what you eat: Regulation of stoichiometric homeostasis among autotrophs and heterotrophs": "Homeostasis is the resistance to change of consumer body composition in response to the chemical composition of consumer's food." Until recently, autotrophs were assumed to be flexible. In contrast, heterotrophs, which were "confined to a constant (strictly homeostatic) body composition," were not. Now there's evidence to challenge that. So these guys tested it. "We examined the degree to which autotrophs and heterotrophs regulate stoichiometric homeostasis (P:C, N:C, N:P, or % P and %N). ... There was a wide range of responses from strictly homeostatic to non-homeostatic. Even within heterotrophic organisms, varying levels of homeostasis were observed... [as well as] significant differences between groups. For example, aquatic macroinvertebrates were significantly more homeostatic in terms of P:C than terrestrial invertebrates." And "with regard to N:P, heterotrophs are significantly more homeostatic than autotrophs. ..." Studying stoichiometric homeostasis helps to clarify many soil food-web relationships, "commonly driven by elemental imbalances between consumers and their resources." In stoichiometrics, organisms become molecules and ecosystems are organisms. The link is referenced below. I highly recommend one of the greatest texts on this subject: "Ecological Stoichiometry: Biology of Elements from Molecules to the Biosphere" by Sterner and Elser. There is one chapter posted online, and some of it is worth posting here: "Redfield's congruence in nutrient ratios between plankton and their aquatic medium indicated a balanced flow of C, N, and P in and out of the biota. The 'Redfield ocean' is a biological circulatory system with constant C:N:P stoichiometry moving vast quantities of constant proportions of these three elements vertically over thousands of meters. A second congruence was that the line describing the N and P data had a zero intercept, indicating that these two elements would be depleted from ocean waters simultaneously. The same was not true for carbon: there was a surplus of carbonate when N and P were depleted." They continue: "Simultaneous depletion of N and P was surprising. There is no a priori reason to expect ocean water to contain N and P in proportions identical to biological demand. Why then should this measure of the chemistry of the ocean--such a vast proportion of the Earth's surface and subjected to major influences from geology, meteorology, and others--have an N:P ratio that matches biological demand? Redfield's (1958) answer was that the biota itself determined the relative concentrations of N and P in the deep sea. He suggested that it was P that ultimately determined the biological productivity of the world's oceans, and that biological feedbacks adjusted the level of N so that its availability matched the availability of P (Fal-kowski et al. 1998). Similar arguments were later applied to soils (Walker and Adams 1958, 1959). Redfield's findings were important in a very broad context: his work was instrumental in fostering a view that the ocean's biota has a major influence on the chemistry of even this vast volume of water. In their abstract, "Soil Nutrient Stoichiometry as Influenced by Fire Return Intervals in Ponderosa Pine Forests," researcher Joss Mckinnon and colleagues declared, "Nitrogen deficiency is the primary form of nutrient limitation experienced by vegitation in western Montana. However, an examination of the quantity of available N in soil will not provide a comprehensive view of nutrient limitation status due to the complex nutrient requirements of plant species. Rather an analysis of the ratio of plant available N to plant available phosphorus (P) provides a more precise characterization of the nutrient status of the soil. Limited research has examined the role of natural fire intervals on the stoichiometric relationship between these nutrients in this system. We identified seven clustered sites in wilderness areas that represent stands that have been exposed to fire 0, 1, 2, or 3 or more times in the last 120 years across three wilderness areas in the Inland Northwest. The sites with three or more fires represent a fire return interval similar to what is thought to be natural. Mineral soil samples were collected from each of the seven sites and analyzed for total C, N and P, potentially mineralizable N (PMN), NH4+, NO3- and PO43-. Forest litter and foliage samples were also collected and analyzed for total C, N and P. Discussion of the relati

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How Ecosystems Work | Biology | Ecology :Purchase DVD here www.greatpacificmedia.com Segment from the program How Ecosystems Work: Energy Flow and Nutrient Cycles. DVD Description Looks at the processes that are fundamental to all ecosystems. First the concepts of primary productivity, trophic levels, food chains, energy pyramids and the flow of energy through ecosystems are introduced. The program then explains how carbon, nitrogen, phosphorous and water cycle through ecosystems and how human activities can disrupt these cycles and throw them out of balance leading to accelerated eutrophication in lakes in the case of phosphorous imbalances and global warming in the case of carbon imbalances.

Documentary on Sustainable Consumption. :Billions of years ago,the conditions prevailing on earth were quite different from what they are now. There was a natural balance prevailing between the biotic and abiotic components which led to peaceful coexistence of the various species. However,as human beings evolved and turned out to be the most superior among all living organisms, he began developing numerous elements of luxury,comfort and convenience like, vehicles, machinery, arms and ammunitions. In the process of fulfilling his selfish motives he overlooked the effect these developments were having on the environment. Thus began the problems of ecological imbalance, environmental pollution, obliteration of certain species and global warming. Man began cutting down big trees, hunting animals for their skin,bones and claws, and established industries. Consequently, these industries began throwing their waste materials in to the rivers which are one of the main sources of fresh water. Deforestation has led to problems like green house effect which is further responsible for global warming. The giant glaciers are melting at an alarming rate which in the near future will become a matter of real concern. Due to the decrease in number of forests, the natural habitat of wild animals is disturbed as a result of which they have begun attacking the localities of human beings. These issues arose due to the negligence of us humans and now it is our responsibility to take action to counteract the effect of our bad deeds. Use ...