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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. Important processes in the nitrogen cycle include fixation ...
Nitrogen cycle. Nitrification is the biological oxidation of ammonia to nitrate via the intermediary nitrite.Nitrification is an important step in the nitrogen cycle in soil.The process of complete nitrification may occur through separate organisms [1] or entirely within one organism, as in comammox bacteria.
Human impact on the nitrogen cycle is diverse. Agricultural and industrial nitrogen (N) inputs to the environment currently exceed inputs from natural N fixation. [1] As a consequence of anthropogenic inputs, the global nitrogen cycle (Fig. 1) has been significantly altered over the past century. Global atmospheric nitrous oxide (N 2 O) mole ...
Nitrogen fixation is a chemical process by which molecular dinitrogen (N. 2) is converted into ammonia (NH. 3). [1] It occurs both biologically and abiologically in chemical industries. Biological nitrogen fixation or diazotrophy is catalyzed by enzymes called nitrogenases. [2]
The nitrogen cycle is as important in the ocean as it is on land. While the overall cycle is similar in both cases, there are different players and modes of transfer for nitrogen in the ocean. [81] Nitrogen enters the ocean through precipitation, runoff, or as N 2 from the atmosphere.
e. 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 ...
The nitrogen cycle is one of the Earth's biogeochemical cycles. It involves the conversion of nitrogen into different chemical forms. The main processes of the nitrogen cycle are the fixation, ammonification, nitrification, and denitrification. As one of the macronutrients, nitrogen plays an important role in plant growth.
Anammox, an abbreviation for "anaerobic ammonium oxidation", is a globally important microbial process of the nitrogen cycle [1] that takes place in many natural environments. The bacteria mediating this process were identified in 1999, and were a great surprise for the scientific community. [2] In the anammox reaction, nitrite and ammonium ...