APES Vocabulary 3 Flashcards

4680396885	Hydrological cycle	The natural cycle by which water is circulated between various reservoirs on or beneath the Earth's surface and the atmosphere. The main source of energy that drives the cycle is heat from the Sun. Evaporation, transpiration, runoff, condensation, precipitation and infiltration.	0
4680402661	Nitrogen fixation	The process by which atmospheric nitrogen (N2) is converted from unusable diatomic form into usable ammonia (NH3) (by bacteria such as rhizobium or cyanobacteria) that can be absorbed by plants.	1
4680406581	Ammonification	Nitrogen is converted into ammonifying bacteria; may occur when nitrogen in organic wastes in the soil are converted to ammonia or when atmospheric nitrogen (N2) is converted to (NH3)	2
4680408352	Nitrification	The biological oxidation of ammonia or ammonium (in dead organic material) into nitrates and nitrites by soil bacteria. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification.	3
4680412766	Denitrification	Bacteria convert nitrate (NO3-) and nitrite (NO2-) back into atmospheric nitrogen. Bacteria convert ammonia (NH3) back to nitrogen (N2) or N2O-typically done by anaerobic bacteria	4
4680420013	Assimilation	Inorganic nitrogen (N2) is converted into organic molecules such as DNA/amino acids and proteins. Plants assimilate N as ammonium (NH4+) or nitrate (NO3-) through their roots Animals assimilate organic N compounds by eating plants	5
4680425868	Distinguishing characteristic of Phosphate Cycle	Phosphorus does not circulate as easily as nitrogen because it does not exist as a gas, but is released by slow weathering of phosphate (PO4 3-) rocks. This is an exclusively sedimentary cycle...it is never found as a gas	6
4680429465	Excess phosphate in aquatic ecosystems	Added through runoff of animal wastes, excess fertilizer, and discharge of sewage. A limiting factor in freshwater ecosystems. Excess P leads to eutrophication.	7
4680432172	Carbon sinks	Places such as forests, ocean sediments, and rocks and soil, where accumulated carbon does not readily reenter the carbon cycle.	8
4680438917	Biome	A large region characterized by a specific type of climate, soil, and certain types of plant and animal communities. Terrestrial biome determining factors are temperature and precipitation. Aquatic biome determining factors are salinity and sunlight.	9