AP Biology - Biogeochemical Cycles

water cycle reservoirs

oceans, water vapor, groundwater, glaciers. (Evaporation, wind, and precipitation move water from oceans to land.)

water cycle assimilation

plants absorb water from the soil; animals drink water or eat other organisms (which are mostly water).

water cycle release

plants transpire (release water through stomata in their leaves); animals and plants decompose

carbon

element required for the building of all organic compounds

carbon cycle reservoirs

atmosphere (CO^2), bodies of water (as bicarbonate) fossil fuels (coal, oil), peat, durable organic material (ex: cellulose)

carbon cycle assimilation

plants use CO^2 in photosynthesis, animals consume plants or other animals

carbon cycle release

plants and animals release CO^2 through respiration and decomposition; CO^2 is released when organic material (such as wood and fossil fuels) is burned.

nitrogen

element required for all amino acids and nucleic acids

nitrogen cycle reservoirs

atmosphere (N^2); soil (NH^4+ aka ammonium)

nitrogen cycle assimilation

plants absorb nitrogen either as nitrate or ammonium; animals obtain nitrogen by eating plants or other animals

nitrogen fixation

atmospheric nitrogen to ammonium by nitrogen - fixing prokaryotes (in soil and root nodules); atmospheric nitrogen to nitrate by lightning and UV radiation

nitrification

ammonium to nitrite and nitrite to nitrate by various nitrifying bacteria

nitrogen cycle release

denitrification, ammonification, excreting

denitrification

denitrifying bacteria convert nitrite back to atmospheric nitrogen

ammonification

bacteria convert organic compounds back to ammonium

phosphorus

element required for making ATP energy and nucleic acids

phosphorus cycle reservoirs

rocks and ocean sediments. (erosion transfer 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).

phosphorus cycle assimilation

plants absorb inorganic phosphate from soils; animals obtain organic phosphorus when they eat plants or other animals

phosphorus cycle release

plants and animals release phosphorus when they decompose; animals excrete phosphorus in their waste products