title: Novel observations of Thiobacterium, a sulfur-storing Gammaproteobacterium producing gelatinous mats.
abstract: The genus Thiobacterium includes uncultivated rod-shaped microbes containing several spherical grains of elemental sulfur and forming conspicuous gelatinous mats. Owing to the fragility of mats and cells, their 16S ribosomal RNA genes have not been phylogenetically classified. This study examined the occurrence of Thiobacterium mats in three different sulfidic marine habitats: a submerged whale bone, deep-water seafloor and a submarine cave. All three mats contained massive amounts of Thiobacterium cells and were highly enriched in sulfur. Microsensor measurements and other biogeochemistry data suggest chemoautotrophic growth of Thiobacterium. Sulfide and oxygen microprofiles confirmed the dependence of Thiobacterium on hydrogen sulfide as energy source. Fluorescence in situ hybridization indicated that Thiobacterium spp. belong to the Gammaproteobacteria, a class that harbors many mat-forming sulfide-oxidizing bacteria. Further phylogenetic characterization of the mats led to the discovery of an unexpected microbial diversity associated with Thiobacterium.
authors.affiliation: HGF-MPG Joint Research Group for Deep Sea Ecology and Technology, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany. sgruenke@mpi-bremen.de
authors.forename: Stefanie
authors.initials: S
authors.lastname: Grünke
authors.forename: Anna
authors.initials: A
authors.lastname: Lichtschlag
authors.forename: Dirk
authors.initials: D
authors.lastname: de Beer
authors.forename: Marcel
authors.initials: M
authors.lastname: Kuypers
authors.forename: Tina
authors.initials: T
authors.lastname: Lösekann-Behrens
authors.forename: Alban
authors.initials: A
authors.lastname: Ramette
authors.forename: Antje
authors.initials: A
authors.lastname: Boetius
mesh_terms: D020563:Gammaproteobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D005780:Gelatin / Q000378:metabolism*; D019015:Geologic Sediments / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D013455:Sulfur / Q000378:metabolism*; D041962:Thiotrichaceae / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D014871:Water Microbiology
chemical_list: D013455:Sulfur; D005780:Gelatin