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Biogeochemical Cycles Hydrological Carbon Nitrogen Phosphorous Hydrological Cycle Precipitation to land Transpiration from plants Evaporation from land Runoff Surface runoff (rapid) Evaporation from ocean Surface runoff (rapid) Percolation Groundwater movement Ocean storage Precipitation to ocean Hydrological Cycle (water cycle) 1. Reservoir – oceans, air (as water vapor), groundwater, lakes and glaciers; evaporation, wind and precipitation (rain) move water from oceans to land 2. Release – plants transpire, animals breathe and expel liquid wastes Atmosphere Burning fossil fuels burning photosynthesis decay Soil and Organic matter Coal, oil, gas Sediments and sedimentary rock respiration Carbon Dioxide Excahnge vegetation Weathering and Runoff Ocean surface phytoplankton Deep circulation Rock formation Sinking sediment Deep ocean Carbon Cycle 1. Reservoir – atmosphere (as CO2), fossil fuels (oil, coal), 2. Assimilation – plants use CO2 in photosynthesis; animals consume plants. 3. Release – plants and animals release CO2 through respiration and decomposition; CO2 is released; wood and fossil fuels are burned. Nitrogen Cycle (Nitrogen is required for the manufacture of amino acids and nucleic acids) 1. Reservoir – atmosphere (as N2); soil (as NH4+ or ammonium, NH3 or ammonia, N02- or nitrite, N03- or nitrate Nitrogen Cycle 2. Assimilation – plants absorb nitrogen as either NH4+ or as N03-, animals obtain nitrogen by eating plants and other animals. The stages in the assimilation of nitrogen are as follows: Nitrogen Fixation: N2 to NH4+ by nitrogen-fixing bacteria (prokaryotes in the soil and root nodules), N2 to N03- by lightning. Nitrification: NH4+ to N02- and N02- to N03by various nitrifying bacteria. Nitrogen Cycle 3. Release – Denitrifying bacteria convert N03- back to N2 (denitrification); detrivorous bacteria convert organic compounds back to NH4+ (ammonification); animals excrete NH4+ (or NH3) urea, or uric acid. Phosphorus Cycle Phosphorus Cycle (Phosphorus is required for the manufacture of ATP and all nucleic acids) 1. Reservoir – erosion transfers phosphorus to water and soil; sediments and rocks that accumulate on ocean floors return to the surface as a result of uplifting by geological processes 2. Assimilation – plants absorb inorganic PO43(phosphate) from soils; animals obtain organic phosphorus from plants and other animals 3. Release – plants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste products