nitrogen cycle


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nitrogen cycle

n.
The circulation of nitrogen in nature, consisting of a cycle of chemical reactions in which nitrogen from the atmosphere is fixed in compounds in soil or water, assimilated by plants and animals, released to the soil and water through decomposition, and returned to the atmosphere through denitrification.

nitrogen cycle

n
(Biology) the natural circulation of nitrogen by living organisms. Nitrates in the soil, derived from dead organic matter by bacterial action, are absorbed and synthesized into complex organic compounds by plants and reduced to nitrates again when the plants and the animals feeding on them die and decay. See nitrification, nitrogen fixation

ni′trogen cy`cle


n.
the continuous sequence of natural processes by which nitrogen in the atmosphere and nitrogenous compounds in the soil are converted, as by nitrification and nitrogen fixation, into substances that can be utilized by green plants and then returned to the air and soil as a result of denitrification and plant decay.
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nitrogen cycle

nitrogen cycle

The continuous process by which nitrogen is exchanged between organisms and the environment. Some of the atmosphere's free nitrogen combines with other elements to form compounds that are deposited in the soil. These are then converted by bacteria, in a process called nitrification, into nutrients that are absorbed by the roots of green plants. Nitrogen is then passed into the food chain and returned to the soil by the metabolism and decay of plants and animals.

nitrogen cycle

The natural circulation of nitrogen (including nitrogen compounds) from air to consuming organisms (plants, animals and bacteria) and back to air.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.nitrogen cycle - the circulation of nitrogennitrogen cycle - 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
biological process, organic process - a process occurring in living organisms
References in periodicals archive ?
Finally, the continuous population growth in the region coupled with high rates of urbanization poses another threat to the nitrogen cycle of the region, especially the cycle of this element in the atmosphere and freshwater.
In geological terms, Townsend and colleague Stephen Porder pointed out in a new report, humanity's major disruption of the natural nitrogen cycle has lasted no longer than the blink of an eye.
We've already crossed three of these critical boundaries--climate, the nitrogen cycle and biodiversity loss.
Biochemists, microbiologists, and other medical and biological researchers provide a snapshot of the current understanding of the nitrogen cycle in bacteria.
com)-- Part 3 entitled "Steps in the nitrogen cycle," offers advice on preparing a saltwater aquarium and an explanation of the nitrogen cycle in an easy to understand manner.
Our trials so far suggest there are no major issues, although biochar may have the potential to lock in nitrogen, so slowing the nitrogen cycle and affecting crop growth, which we need to assess.
In the future, however, with rising populations and demands for food and energy, human-made sources of nitrogen are projected to double natural inputs to the environment, reported two of the world's leading nitrogen cycle experts, Nicolas Gruber of the Swiss Federal Institute of Technology and James N.
The role legumes can play in reducing excess nitrogen in the nitrogen cycle is not widely recognized," says Russelle, who is in the ARS Plant Science Research Unit at St.
Arboreal emissions of nitrogen oxides are "evidently an important component of the nitrogen cycle," Hari says.
The nitrogen cycle converts ammonia to nitrate, which is only toxic to fish in large amounts.