Nitrification is a crucial component of the nitrogen cycle, especially in
the oceans. The production of nitrate (NO3−) by oxidation of nitrite (NO2−)
by nitrification the process that produces the inorganic nitrogen that
supplies much of the demand by marine oxygenic, photosynthetic organisms
such as phytoplankton <https://en.wikipedia.org/wiki/Phytoplankton>,
particularly in areas of upwelling <https://en.wikipedia.org/wiki/Upwelling>.
For this reason, nitrification supplies much of the nitrogen that fuels
planktonic primary production
<https://en.wikipedia.org/wiki/Primary_production> in the world's oceans.
Nitrification is estimated to be the source of half of the nitrate consumed
by phytoplankton globally.[10]
<https://en.wikipedia.org/wiki/Nitrobacter#cite_note-:6-10> Phytoplankton
are major contributors to oceanic production, and are therefore important
for the biological pump <https://en.wikipedia.org/wiki/Biological_pump>
which exports carbon and other particulate organic matter
<https://en.wikipedia.org/wiki/Particulate_organic_matter> from the surface
waters of the world's oceans. The process of nitrification is crucial for
separating recycled production from production leading to export.
Biologically metabolized nitrogen returns to the inorganic dissolved
nitrogen pool in the form of ammonia. Microbe-mediated nitrification
converts that ammonia into nitrate, which can subsequently be taken up by
phytoplankton and recycled.[10]
<https://en.wikipedia.org/wiki/Nitrobacter#cite_note-:6-10>
<https://en.wikipedia.org/wiki/Nitrobacter#cite_note-:6-10>In the oceans,
nitrite-oxidizing bacteria such as *Nitrobacter* are usually found in close
proximity to ammonia-oxidizing bacteria.[11]
<https://en.wikipedia.org/wiki/Nitrobacter#cite_note-:7-11> These two
reactions together make up the process of nitrification. The
nitrite-oxidation reaction generally proceeds more quickly in ocean waters,
and therefore is not a rate-limiting step in nitrification. For this
reason, it is rare for nitrite to accumulate in ocean waters.
*Nitrosomonas* prefers an optimum pH of 6.0-9.0 and a temperature range of
20 to 30°C. Most species are motile <https://en.wikipedia.org/wiki/Motility>
with a flagellum located in the polar regions.
Unlike plants, which fix carbon into sugar through energy gained through
the process of photosynthesis <https://en.wikipedia.org/wiki/Photosynthesis>,
*Nitrosomonas* use energy gained through the oxidation of ammonia to fix
gaseous carbon dioxide into organic molecules. *Nitrosomonas* must consume
large amounts of ammonia before cell division can occur, and the process of
cell division may take up to several days. This microbe is photophobic
<https://en.wikipedia.org/wiki/Photophobia_%28biology%29>, and will
generate a biofilm matrix or form clumps with other microbes to avoid light.
[1] <https://en.wikipedia.org/wiki/Nitrosomonas#cite_note-Microbewiki-1>