Nitrospinota is a bacterial phylum. Despite only few described species, members of this phylum are major nitrite-oxidizing bacteria in surface waters in oceans. By oxidation of nitrite to nitrate they are important in the process of

nitrification ''Nitrification'' is the biological oxidation of ammonia to nitrite followed by the oxidation of the nitrite to nitrate occurring through separate organisms or direct ammonia oxidation to nitrate in comammox bacteria. The transformation of amm ...

in marine environments. Although genus Nitrospina is aerobic bacterium, it was shown to oxidize nitrite also in

oxygen minimum zone The oxygen minimum zone (OMZ), sometimes referred to as the shadow zone, is the zone in which oxygen saturation in seawater in the ocean is at its lowest. This zone occurs at depths of about , depending on local circumstances. OMZs are found worl ...

of the ocean. Depletion of oxygen in such zones leads to preference of anaerobic processes such as

denitrification Denitrification is a microbially facilitated process where nitrate (NO3−) is reduced and ultimately produces molecular nitrogen (N2) through a series of intermediate gaseous nitrogen oxide products. Facultative anaerobic bacteria perform denitr ...

and nitrogen loss through

anammox Anammox, an abbreviation for anaerobic ammonium oxidation, is a globally important microbial process of the nitrogen cycle that takes place in many natural environments. The bacteria mediating this process were identified in 1999, and were a grea ...

. Nitrospina thus outweight nitrogen loss by

also in these oxygen depleted zones. Among the cultivated isolates within the genus ''Nitrospina'' are '' Nitrospina gracilis'' and '' Nitrospina watsonii''. Further genomes were resolved by culture-independent metagenome binning. The two ''Nitrospina'' species are, however, distantly related to environmentally abundant uncultured Nitrospinota. The two other strains were cultivated in 2020 each in the binary culture with

alphaproteobacteria Alphaproteobacteria is a class of bacteria in the phylum Pseudomonadota (formerly Proteobacteria). The Magnetococcales and Mariprofundales are considered basal or sister to the Alphaproteobacteria. The Alphaproteobacteria are highly diverse and p ...

heterotroph A heterotroph (; ) is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly plant or animal matter. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but ...

. They are called "''Candidatus'' Nitrohelix vancouverensis" and "''Candidatus'' Nitronauta litoralis". " Nitrohelix vancouverensis" is closely related to uncultivated environmentally abundant Nitrospinota clades 1 and 2.

Taxonomy

The currently accepted taxonomy is based on the

List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclature ...

(LPSN) and

National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The ...

(NCBI). Phylum Nitrospinota Lücker et al. 2021 * Class "Nitrospinia" Lücker et al. 2013 ** Order "Nitrospinales" Lücker et al. 2013 *** Family Nitrospinaceae Garrity, Bell & Lilburn 2006 **** Genus "''Candidatus'' Nitrohelix" Mueller et al. 2021 ***** "''Ca.'' N. vancouverensis" Mueller et al. 2021 **** Genus "''Candidatus'' Nitromaritima" Ngugi et al. 2016 **** Genus "''Candidatus'' Nitronauta" Mueller et al. 2021 ***** "''Ca.'' N. litoralis" Mueller et al. 2021 **** Genus '' Nitrospina'' Watson & Waterbury 1971 ***** '' N. gracilis'' Watson & Waterbury 1971 ***** "'' N. watsonii''" Spieck et al. 2014

References

{{Taxonbar, from=Q26714852 Nitrogen cycle Bacteria phyla Bacteria