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  2. Nitrogen cycle - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_cycle

    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 ...

  3. Dissimilatory nitrate reduction to ammonium - Wikipedia

    en.wikipedia.org/wiki/Dissimilatory_nitrate...

    Dissimilatory nitrate reduction to ammonium (DNRA), also known as nitrate/nitrite ammonification, is the result of anaerobic respiration by chemoorganoheterotrophic microbes using nitrate (NO 3−) as an electron acceptor for respiration. [1][2] In anaerobic conditions microbes which undertake DNRA oxidise organic matter and use nitrate (rather ...

  4. Nitrification - Wikipedia

    en.wikipedia.org/wiki/Nitrification

    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.

  5. Ammonium - Wikipedia

    en.wikipedia.org/wiki/Ammonium

    An example of a reaction forming an ammonium ion is that between dimethylamine, (CH 3) 2 NH, and an acid to give the dimethylammonium cation, [(CH 3) 2 NH 2] +: Quaternary ammonium cations have four organic groups attached to the nitrogen atom, they lack a hydrogen atom bonded to the nitrogen atom.

  6. Denitrification - Wikipedia

    en.wikipedia.org/wiki/Denitrification

    Denitrification. Nitrogen cycle. Denitrification is a microbially facilitated process where nitrate (NO 3−) is reduced and ultimately produces molecular nitrogen (N 2) through a series of intermediate gaseous nitrogen oxide products. Facultative anaerobic bacteria perform denitrification as a type of respiration that reduces oxidized forms of ...

  7. Nitrifying bacteria - Wikipedia

    en.wikipedia.org/wiki/Nitrifying_bacteria

    Nitrifying bacteria are chemolithotrophic organisms that include species of genera such as Nitrosomonas, Nitrosococcus, Nitrobacter, Nitrospina, Nitrospira and Nitrococcus. These bacteria get their energy from the oxidation of inorganic nitrogen compounds. [1] Types include ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB).

  8. Anammox - Wikipedia

    en.wikipedia.org/wiki/Anammox

    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 ...

  9. Nitrogen fixation - Wikipedia

    en.wikipedia.org/wiki/Nitrogen_fixation

    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]