Biology 2483A Lecture 24: Topic 24.docx
2 Jan 2015
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Document Summary
Tuesday december 2, 2014: atmospheric emissions of pollutants, dust, and greenhouse gases have caused widespread environmental problems, a major focus of global ecology is the study of the environmental effects of human activities. Elements move among geological, atmospheric, and biological pools at a global scale. Flux: rate of movement of an element between pools. The carbon cycle: major pools of c: atmosphere, oceans, land surface (includes soils and vegetation), and sediments and rock. Orange arrows recent contributions of human activity. In the twentieth century, major deforestation shifted from the mid-latitudes to the tropics. Higher concentrations of co2 may stimulate photosynthesis: but experiments have shown that increased photosynthetic rates may be short lived, and plants will acclimate to higher concentrations. Rate of injection is controlled to achieve a particular concentration of co2. Forests may be an important sink for anthropogenic co2: but this forest may represent the upper limit of potential co2 uptake.
