''Thiomargarita'' is a genus (family

Thiotrichaceae The Thiotrichaceae are a family of Pseudomonadota, including ''Thiomargarita namibiensis'', the largest known bacterium.George M. Garrity: ''Bergey's Manual of Systematic Bacteriology''. 2. Auflage. Springer, New York, 2005, Volume 2: ''The Prot ...

) which includes the vacuolate sulfur bacteria species ''

Thiomargarita namibiensis ''Thiomargarita namibiensis'' is a Gram-negative coccoid bacterium, found in the ocean sediments of the continental shelf of Namibia. It is the second largest bacterium ever discovered, as a rule in diameter, but sometimes attaining . Cells of ...

'', ''

Candidatus In prokaryote nomenclature, ''Candidatus'' (Latin for candidate of Roman office) is used to name prokaryotic phyla that are well characterized but yet-uncultured. Contemporary sequencing approaches, such as 16S sequencing or metagenomics, provide m ...

Thiomargarita nelsonii'', and ''Ca. Thiomargarita joergensii''. In 2022, scientists working in a Caribbean mangrove discovered an extremely large member of the genus, provisionally named '' T. magnifica'', whose cells are easily visible to the naked eye at up to long. ThiomargaritaFeeding

Representatives of this genus can be found in a variety of environments that are rich in hydrogen sulfide, including methane seeps,

mud volcano A mud volcano or mud dome is a landform created by the eruption of mud or slurries, water and gases. Several geological processes may cause the formation of mud volcanoes. Mud volcanoes are not true igneous volcanoes as they do not produce lava ...

es,

brine pool A brine pool, sometimes called an underwater lake, deepwater or brine lake, is a volume of brine collected in a seafloor depression. The pools are dense bodies of water that have a salinity that is three to eight times greater than the surround ...

s, and organic-rich sediments such as those found beneath the Benguela Current and

Humboldt Current The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America.Montecino, Vivian, and Carina B. Lange. "The Humboldt Current System: Ecosystem components and pr ...

. These bacteria are generally considered to be

chemolithotrophs Lithotrophs are a diverse group of organisms using an inorganic substrate (usually of mineral origin) to obtain reducing equivalents for use in biosynthesis (e.g., carbon dioxide fixation) or energy conservation (i.e., ATP production) via aerobic ...

that utilize reduced

inorganic In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistr ...

species of

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

as metabolic

electron donor In chemistry, an electron donor is a chemical entity that donates electrons to another compound. It is a reducing agent that, by virtue of its donating electrons, is itself oxidized in the process. Typical reducing agents undergo permanent chemi ...

s to produce energy for the fixation of carbon into biomass.

Carbon fixation Biological carbon fixation or сarbon assimilation is the process by which inorganic carbon (particularly in the form of carbon dioxide) is converted to organic compounds by living organisms. The compounds are then used to store energy and a ...

occurs via the Calvin Benson Bassham cycle and possibly the

reverse Krebs cycle The reverse Krebs cycle (also known as the reverse tricarboxylic acid cycle, the reverse TCA cycle, or the reverse citric acid cycle, or the reductive tricarboxylic acid cycle, or the reductive TCA cycle) is a sequence of chemical reactions that ...

References

Thiotrichales Lithotrophs Bacteria described in 1999 Bacteria genera {{Gammaproteobacteria-stub