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Unformatted text preview: Lecture 15: Chapter 59 Lecture Guide Ecosystems II Decomposition and Nutrient Cycling Tropical rainforests Organic material decomposes in a few months to a few years. Little accumulation as leaf litter on the forest floor Temperate forests Organic material decomposes in about four to six years. Temperature and water affect rates of nutrient cycling Biogeochemical Cycles Nutrient cycles involve o Biological transport mechanisms absorption of chemicals by living organisms and their subsequent release back into the environment o Geological transport mechanisms weathering and erosion of rocks, and elements transported by surface and subsurface drainage o Chemical transport mechanisms dissolved matter in rain and snow, atmospheric gases, and dust blown by the wind Cyclesbrief descriptions & key terms: Water cycle 1 A C Lecture 15: Chapter 59 Lecture Guide Description: Water cycles from oceans, to land, and back to oceans, in a flow known as the hydrological cycle. The sun drives the hydrological cycle by providing the energy to evaporate surface waters. Most of the evaporation occurs from the oceans, and the portion of the evaporated ocean water then falls on land as precipitation. Gravity completes the hydrological cycle by driving water from the land back to the oceans via rivers, coastal runoff, and groundwater flows. Water that falls on land renews water reservoirs, with water renewal being fastest (about 4 years) in lakes and rivers, important sources of our fresh water. You can imagine the hydrological cycle as a continually operating distillation machine, evaporating water from the salty oceans and dropping fresh water back on land....
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- Spring '08