Nitrogen cycle

The nitrogen cycle is the biogeochemical cycle that describes the transformations of nitrogen and nitrogen-containing compounds in nature.Earth's atmosphere is about 78% nitrogen, making it the largest pool of nitrogen. Nitrogen is essential for many biological processes; and is crucial for any life here on Earth. It is in all amino acids, is incorporated into proteins, and is present in the bases that make up nucleic acids, such as DNA and RNA. In plants, much of the nitrogen is used in chlorophyll molecules which are essential for photosynthesis and further growth.
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Noun
1. the circulation of nitrogen; nitrates from the soil are absorbed by plants which are eaten by animals that die and decay returning the nitrogen back to the soil
(hypernym) organic process, biological process

Cyclic movement of nitrogen in different chemical forms from the environment, to organisms, and then back to the environment.

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