Editing Nitrogen cycle (section)

=== Ammonification ===
When a plant or animal dies or an animal expels waste, the initial form of nitrogen is [[Organic matter|organic]], present in forms such as amino acids and DNA.<ref>{{Cite web |title=The Nitrogen Cycle: Processes, Players, and Human Impact {{!}} Learn Science at Scitable |url=https://www.nature.com/scitable/knowledge/library/the-nitrogen-cycle-processes-players-and-human-15644632/ |access-date=2025-02-13 |website=www.nature.com |language=en}}</ref> Bacteria and fungi convert this organic nitrogen into [[ammonia]] and sometimes ammonium through a series of processes called ammonification or [[Mineralization (soil)|mineralization]]. This is the last step in the nitrogen cycle step involving organic compounds.<ref>{{Citation |last=Strock |first=J.S. |title=Ammonification |date=2008 |pages=162–165 |url=https://www.sciencedirect.com/topics/earth-and-planetary-sciences/ammonification |access-date=2025-02-13 |publisher=Elsevier |language=en |doi=10.1016/B978-008045405-4.00256-1 |isbn=978-0-08-045405-4 |encyclopedia=Encyclopedia of Ecology|url-access=subscription }}</ref> Myriad enzymes are involved including [[Dehydrogenase|dehydrogenases]], [[Protease|proteases]], and [[Deamination|deaminases]] such as [[glutamate dehydrogenase]] and [[glutamine synthetase]].<ref name=":2">{{Citation |last=Cabello |first=P. |title=Nitrogen Cycle |date=2009-01-01 |work=Encyclopedia of Microbiology (Third Edition) |pages=299–321 |editor-last=Schaechter |editor-first=Moselio |url=https://www.sciencedirect.com/science/article/abs/pii/B9780123739445000559 |access-date=2025-03-18 |place=Oxford |publisher=Academic Press |isbn=978-0-12-373944-5 |last2=Roldán |first2=M. D. |last3=Castillo |first3=F. |last4=Moreno-Vivián |first4=C.}}</ref> Nitrogen mineralization and ammonification have a positive correlation with organic nitrogen in the soil,<ref>{{Cite journal |last=Marion |first=G. M. |last2=Black |first2=C. H. |date=1988 |title=Potentially Available Nitrogen and Phosphorus Along a Chaparral Fire Cycle Chronosequence |url=https://acsess.onlinelibrary.wiley.com/doi/abs/10.2136/sssaj1988.03615995005200040048x?getft_integrator=sciencedirect_contenthosting&src=getftr&utm_source=sciencedirect_contenthosting |journal=Soil Science Society of America Journal |language=en |volume=52 |issue=4 |pages=1155–1162 |doi=10.2136/sssaj1988.03615995005200040048x |issn=1435-0661|url-access=subscription }}</ref> soil microbial biomass, and average annual precipitation.<ref name=":3">{{Cite journal |last=Li |first=Zhaolei |last2=Tian |first2=Dashuan |last3=Wang |first3=Bingxue |last4=Wang |first4=Jinsong |last5=Wang |first5=Song |last6=Chen |first6=Han Y. H. |last7=Xu |first7=Xiaofeng |last8=Wang |first8=Changhui |last9=He |first9=Nianpeng |last10=Niu |first10=Shuli |date=2019 |title=Microbes drive global soil nitrogen mineralization and availability |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.14557?getft_integrator=sciencedirect_contenthosting&src=getftr&utm_source=sciencedirect_contenthosting |journal=Global Change Biology |language=en |volume=25 |issue=3 |pages=1078–1088 |doi=10.1111/gcb.14557 |issn=1365-2486|url-access=subscription }}</ref> They also respond closely to changes in temperature.<ref>{{Cite journal |last=Pierre |first=S. |last2=Hewson |first2=I. |last3=Sparks |first3=J. P. |last4=Litton |first4=C. M. |last5=Giardina |first5=C. |last6=Groffman |first6=P. M. |last7=Fahey |first7=T. J. |date=2017 |title=Ammonia oxidizer populations vary with nitrogen cycling across a tropical montane mean annual temperature gradient |url=https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/ecy.1863?getft_integrator=sciencedirect_contenthosting&src=getftr&utm_source=sciencedirect_contenthosting |journal=Ecology |language=en |volume=98 |issue=7 |pages=1896–1907 |doi=10.1002/ecy.1863 |issn=1939-9170|url-access=subscription }}</ref> However, these processes slow in the presence of vegetation with high carbon to nitrogen ratios<ref>{{Cite journal |last=Gosz |first=J. R. |date=1981 |title=Nitrogen Cycling in Coniferous Ecosystems |url=https://www.jstor.org/stable/45128679 |journal=Ecological Bulletins |issue=33 |pages=405–426 |issn=0346-6868}}</ref><ref>{{Cite journal |last=Vitousek |first=Peter M. |last2=Gosz |first2=James R. |last3=Grier |first3=Charles C. |last4=Melillo |first4=Jerry M. |last5=Reiners |first5=William A. |date=1982 |title=A Comparative Analysis of Potential Nitrification and Nitrate Mobility in Forest Ecosystems |url=https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/1942609?getft_integrator=sciencedirect_contenthosting&src=getftr&utm_source=sciencedirect_contenthosting |journal=Ecological Monographs |language=en |volume=52 |issue=2 |pages=155–177 |doi=10.2307/1942609 |issn=1557-7015|url-access=subscription }}</ref> and fertilization with sugar.<ref>{{Cite journal |last=Zagal |first=Erick |last2=Persson |first2=Jan |date=1994-10-01 |title=Immobilization and remineralization of nitrate during glucose decomposition at four rates of nitrogen addition |url=https://www.sciencedirect.com/science/article/abs/pii/0038071794902127 |journal=Soil Biology and Biochemistry |volume=26 |issue=10 |pages=1313–1321 |doi=10.1016/0038-0717(94)90212-7 |issn=0038-0717|url-access=subscription }}</ref><ref>{{Cite journal |last=DeLuca |first=T. H. |last2=Keeney |first2=D. R. |date=1993-01-01 |title=Glucose-induced nitrate assimilation in prairie and cultivated soils |url=https://link.springer.com/article/10.1007/BF00001116 |journal=Biogeochemistry |language=en |volume=21 |issue=3 |pages=167–176 |doi=10.1007/BF00001116 |issn=1573-515X|url-access=subscription }}</ref>

[[File:Nitrogen Cycle - Reactions and Enzymes.svg|thumb|upright=1.5| {{center|'''Microbial nitrogen cycle'''{{hsp}}<ref name="Sparacino-Watkins 2013" /><ref name="Simon 2013" />}} [[Anammox|ANAMMOX]] is anaerobic ammonium oxidation, [[Dissimilatory nitrate reduction to ammonium|DNRA]] is dissimilatory nitrate reduction to ammonium, and [[Comammox|COMAMMOX]] is complete ammonium oxidation.]]