Sulfur Oxidation at Deep-Sea Hydrothermal Vents

Abstract

Microbial oxidation of geothermally produced reduced sulfur compounds is at the nexus of the biogeochemical carbon and sulfur cycles at deep-sea hydrothermal vents. Available information indicates that microbial symbionts and free- living gammaproteobacteria of the genera Thiomicrospira, Halothiobacillus, and Beggiatoa are important sulfur-oxidizers above the seafloor at these systems. In addition, bacteria belonging to the Epsilonproteobacteria have been identified as a major component of microbial communities at deep-sea vents. We have previously identified a novel sulfuroxidizing epsilonproteobacterium, Candidatus Arcobacter sulfidicus, which produces sulfur in filamentous form that is morphologically and chemically similar to material observed before and after submarine volcanic eruptions. In the meantime, many autotrophic epsilonproteobacteria have been isolated and characterized from deep-sea vents, providing further evidence that these organisms play an important role in sulfur and carbon cycling in these environments.