''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 ''Bergey's Manual of Systematic Bacteriology'' is the main ...

) 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 la ...

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 surrou ...

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

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 chemist ...

species of sulfur 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 occurs via the Calvin Benson Bassham cycle and possibly the reverse Krebs cycle.

References

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