Translations:AY Honors/Ecology - Advanced/Answer Key/26/en

Nitrogen cycle

Schematic representation of the flow of nitrogen through the environment.

The nitrogen cycle is a much more complicated biogeochemical cycle but also cycles through living parts and nonliving parts including the water, land, and air. Nitrogen is a very important element in that it is part of both proteins, present in the composition of the amino acids that make up proteins, as well as nucleic acids such as DNA and RNA, present in nitrogenous bases. The largest reservoir of nitrogen is the atmosphere, in which about 78% of nitrogen is contained as nitrogen gas (N₂). Nitrogen gas is “fixed,” in a process called nitrogen fixation. Nitrogen fixation combines nitrogen with oxygen to create nitrates (NO₃).