AP®︎ Environmental Science: Topic 1.5 Flashcards

Movement and chemical transformation of nitrogen among the atmosphere, soil, water, and organisms; the atmosphere is its largest reservoir

Dominant atmospheric form of nitrogen; its strong triple bond makes it directly unusable by most organisms

Nitrogen compound produced during fixation and decomposition; in soil, it quickly converts to ammonium

Biologically available inorganic nitrogen ion that producers can assimilate and nitrifying microorganisms can convert to nitrite

Intermediate formed when ammonia or ammonium is oxidized to nitrate during nitrification

Biologically available, highly soluble nitrogen ion produced by nitrification and commonly absorbed by producers

Nitrogen incorporated into compounds in living organisms, wastes, and dead organic matter

Gaseous nitrogen compound that may be released as an intermediate or final product of denitrification; it is also a greenhouse gas

Conversion of atmospheric N₂ into reactive nitrogen compounds; biologically, certain bacteria and archaea produce NH₃, which becomes NH₄⁺.

Microbial oxidation of ammonia or ammonium to nitrite and then nitrate, usually under oxygenated conditions

Uptake of ammonium or nitrate by producers and incorporation of its nitrogen into organic molecules and biomass

Decomposer conversion of organic nitrogen in wastes and dead matter into ammonia or ammonium

Microbial conversion of nitrate to gaseous N₂, often through N₂O, generally under low-oxygen conditions

Industrial combination of atmospheric nitrogen and hydrogen to manufacture ammonia, chiefly for synthetic fertilizer

A nutrient whose low availability restricts biological growth; usable nitrogen often limits primary production