Editing Nitrogen fixation (section)

=== Importance of nitrogen ===
{{biogeochemical cycle sidebar|nutrient}}
Atmospheric nitrogen cannot be metabolized by most organisms,<ref>{{cite book | vauthors = Delwiche CC | chapter = Cycling of Elements in the Biosphere|date=1983 | title = Inorganic Plant Nutrition|pages=212–238| veditors = Läuchli A, Bieleski RL |series=Encyclopedia of Plant Physiology|place=Berlin, Heidelberg|publisher=Springer|language=en|doi=10.1007/978-3-642-68885-0_8|isbn=978-3-642-68885-0 }}</ref> because its triple covalent bond is very strong. Most take up fixed nitrogen from various sources. For every 100 atoms of carbon, roughly 2 to 20 atoms of nitrogen are assimilated. The atomic ratio of carbon (C) : nitrogen (N) : phosphorus (P) observed on average in planktonic biomass was originally described by Alfred Redfield,<ref name="REDFIELD 1958 230A–221">{{Cite journal| vauthors = Redfield AC |title=The Biological Control of Chemical Factors in the Environment|date=1958|url=https://www.jstor.org/stable/27827150|journal=American Scientist|volume=46|issue=3|pages=230A–221|jstor=27827150|issn=0003-0996}}</ref> who determined the stoichiometric relationship between C:N:P atoms, The Redfield Ratio, to be 106:16:1.<ref name="REDFIELD 1958 230A–221"/>