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The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes.
The nitrogen cycle is the process by which nitrogen is converted into multiple chemical forms as it circulates among atmosphere, terrestrial, and marine ecosystems. The conversion of nitrogen can be carried out through both biological and physical processes.
In the marine environment, nitrogen is often the limiting nutrient, so the nitrogen cycle in the ocean is of particular interest. [36] [37] The nitrification step of the cycle is of particular interest in the ocean because it creates nitrate, the primary form of nitrogen responsible for "new" production.
A biogeochemical cycle, or more generally a cycle of matter, [1] is the movement and transformation of chemical elements and compounds between living organisms, the atmosphere, and the Earth's crust. Major biogeochemical cycles include the carbon cycle, the nitrogen cycle and the water cycle. In each cycle, the chemical element or molecule is ...
Biogeochemistry is the scientific discipline that involves the study of the chemical, physical, geological, and biological processes and reactions that govern the composition of the natural environment (including the biosphere, the cryosphere, the hydrosphere, the pedosphere, the atmosphere, and the lithosphere).
The marine nitrogen cycle consists of complex microbial transformations which include the fixation of nitrogen, its assimilation, nitrification, anammox and denitrification. [94] Some of these processes take place in deep water so that where there is an upwelling of cold waters, and also near estuaries where land-sourced nutrients are present ...
The diagram on the right shows some human impacts on the marine nitrogen cycle. Bioavailable nitrogen (Nb) is introduced into marine ecosystems by runoff or atmospheric deposition, causing eutrophication, the formation of dead zones and the expansion of the oxygen minimum zones (OMZs).
In 1958, almost a quarter century after first discovering the ratios, Redfield leaned toward the latter mechanism in his manuscript, The Biological Control of Chemical Factors in the Environment. [3] Redfield proposed that the ratio of nitrogen to phosphorus in plankton resulted in the global ocean having a remarkably similar ratio of dissolved ...