Ecology of the Bacteria of the Sulphur Cycle with Special Reference to Anoxic-Oxic Interface Environments [and Discussion]

• Published in: Philosophical transactions of the Royal Society of London. Series B, Biological sciences Biological sciences, 1982-09, Vol.298 (1093), p.543-561
• Main Authors: Jorgensen, B. B., Postgate, J. R.
• Format: Article
• Language: English
• Subjects: Bacteria; Beggiatoa; Carbon dioxide; Ecology; Electrons; Environment; Gram-Negative Anaerobic Bacteria - metabolism; Hydrogen Sulfide - metabolism; Hypoxia; Light; Marine ecology; Oxidation; Oxidation-Reduction; Oxygen; Sea water; Sediments; Sulfides - metabolism; Sulfur; Sulfur - metabolism; Thiobacillus - metabolism
• ISSN: 0962-8436; 0080-4622; 1471-2970; 2054-0280
• DOI: 10.1098/rstb.1982.0096

H$_2$S is produced as a main end-product of anaerobic mineralization in anoxic, sulphate-rich environments by a diverse population of sulphate-reducing bacteria. The sulphate reducers can carry out an almost complete oxidation of detrital organic matter to CO$_2$. The H$_2$S consequently becomes an important electron carrier from the anoxic to the oxic world. Thiobacilli and other colourless sulphur bacteria have the potential to oxidize the H$_2$S at the oxic-anoxic interface in sediments or stratified waters, but their role is still poorly understood. A comparison of sulphide oxidation processes in the chemoclines of the Black Sea, the Solar Lake and in a Beggiatoa mat indicated that depth scales and retention times of coexisting O$_2$ and H$_2$S regulate the bacterial involvement in the sulphide oxidation. The H$_2$S specialists, Beggiatoa and Thiovulum, are optimally adapted to compete with the autocatalytic oxidation of H$_2$S by O$_2$. Microelectrode measurements show retention times of O$_2$-H$_2$S in the bacterial mats or veils of less than 1 s. In photic chemoclines of stratified waters or sulfureta, the phototrophic sulphur bacteria or cyanobacteria interact with the sulphide oxidation at the O$_2$-H$_2$S interface. Short cycles between H$_2$S and intermediate oxidation products, S$^0$ or S$_2$O$^{2-}_3$, are created. The bacteria of the sulfuretum are highly adapted to the diurnal rhythm of light, O$_2$ and H$_2$S.