Tetrathionate production by sulfur-oxidizing bacteria and the role of tetrathionate in the sulfur cycle in sediments of the Baltic Sea

The role of tetrathionate in the sulfur cycle of Baltic Sea sediments was investigated in different habitats and under a variety of environmental conditions. Sediment profiles were recorded with regard to numbers of thiosulfate oxidizing bacteria, concentrations of sulfur compounds, and potential rates of thiosulfate oxidation. Products of thiosulfate oxidation were quantified in incubated sediment samples and in pure cultures. Evidence was found that tetrathionate is formed within these sediments, that sulfur oxidizing bacteria are present in considerable numbers, that these bacteria are of major importance in the oxidation of reduced sulfur compounds in their habitat, and that tetrathionate is an important oxidation product of these bacteria. Thiosulfate is oxidized by bacteria isolated from these sediments to varying proportions of tetrathionate, sulfate, and also elemental sulfur. In highly sulfidic sediments and in the presence of large amounts of organic matter, tetrathionate was present in sediment horizons in which thiosulfate and elemental sulfur also accumulated. A tetrathionate cycle is proposed to be active in natural marine and brackish water sediments in which, due to combined bacterial action and chemical reactions, a net oxidation of sulfide to elemental sulfur occurs in the presence of catalytic amounts of thiosulfate and tetrathionate

Correlation of viable cell counts, metabolic activity of sulphur-oxidizing bacteria and chemical parameters of marine sediments

Viable counts of aerobic and anaerobic chemotrophic sulphur-oxidizers as well as phototrophic sulphur bacteria were determined in sediment samples taken from two different areas along the Baltic Sea shore which were known to regularly develop sulphidic conditions. Depth profiles of bacterial cell counts were correlated with concentration profiles of chloride, sulphate, sulphide, nitrate and phosphate in the pore water of these sediments and with potential activities of nitrate reduction, thiosulphate transformation and sulphate formation. The data revealed a complex multilayered structure within the sediments. Sulphide was released into the water from sediments of both sampling areas, but it was found that light and the availability of oxygen significantly reduced this amount. In the highly reduced sediment at Hiddensee, the highest numbers of phototrophic and chemotrophic sulphur-oxidizers were found near the sediment surface. Therefore, it was concluded that the combined action of both groups of bacteria most efficiently oxidizes reduced sulphur compounds in the top layers of the sediments. Nitrate may replace oxygen as final electron acceptor and will support oxidation of sulphide, in particular when oxygen and light are limitin

Diversity of thiosulfate-oxidizing bacteria from marine sediments and hydrothermal vents

Author Posting. © American Society for Microbiology, 2000. This article is posted here by permission of American Society for Microbiology for personal use, not for redistribution. The definitive version was published in Applied and Environmental Microbiology 66 (2000): 3125-3133, doi:10.1128/AEM.66.8.3125-3133.2000.Species diversity, phylogenetic affiliations, and environmental occurrence patterns of thiosulfate-oxidizing marine bacteria were investigated by using new isolates from serially diluted continental slope and deep-sea abyssal plain sediments collected off the coast of New England and strains cultured previously from Galapagos hydrothermal vent samples. The most frequently obtained new isolates, mostly from 103- and 104-fold dilutions of the continental slope sediment, oxidized thiosulfate to sulfate and fell into a distinct phylogenetic cluster of marine alpha-Proteobacteria. Phylogenetically and physiologically, these sediment strains resembled the sulfate-producing thiosulfate oxidizers from the Galapagos hydrothermal vents while showing habitat-related differences in growth temperature, rate and extent of thiosulfate utilization, and carbon substrate patterns. The abyssal deep-sea sediments yielded predominantly base-producing thiosulfate-oxidizing isolates related to Antarctic marine Psychroflexus species and other cold-water marine strains of the Cytophaga-Flavobacterium-Bacteroides phylum, in addition to gamma-proteobacterial isolates of the genera Pseudoalteromonas and Halomonas-Deleya. Bacterial thiosulfate oxidation is found in a wide phylogenetic spectrum of Flavobacteria and Proteobacteria.Andreas Teske was supported by DFG postdoctoral fellowship 262-1/1 and a subsequent WHOI postdoctoral fellowship

Absorption of carbon dioxide by ionic liquids with carboxylate anions.

International audienceExperimental values of the absorption of carbon dioxide in two ionic liquids with carboxylate anions - the 1-butyl-3-methylimidazolium levulinate [C1C4Im][LEV] and the 1-butyl-1-methylpyrrolidinium acetate [C1C4Pyrro][OAc] - are reported as a function of temperature and at pressures close to atmospheric. Mole fraction absorption of carbon dioxide in [C1C4Im][LEV] and [C1C4Pyrro][OAc] is equal to 0.93 × 10−2 and 1.10 × 10−2 at 303.15 K and 89.2 kPa and 353.15 K and 67.1 kPa, respectively. The effect of the presence of controlled amounts of water on the absorption of carbon dioxide was measured for [C1C4Pyrro][OAc]. The presence of a 0.35 mole fraction of water in [C1C4Pyrro][OAc] decreases the viscosity of the ionic liquid phase and dramatically increases the amount of carbon dioxide absorbed, pointing toward a chemical reaction between the gas and the liquid absorbent. Increasing the amounts of water lowers the viscosity further but also the absorption capacity of the ionic liquid. Molecular dynamics simulations were used to interpret the molecular mechanism of solvation of carbon dioxide in [C1C4Pyrro][OAc]. Results show that carbon dioxide is solvated preferentially in the non-polar domain of the solvent, and that the CO2-anion interactions dominate over the CO2-cation interactions. Molecular simulations could reproduce the experimental solubility of CO2 in [C1C4Im][TFA] (known to be a physical process), but not in [C1C4Pyrro][OAc] and reinforcing the conclusion that the higher solubility of carbon dioxide in the acetate based ionic liquid can be ascribed to a chemical reaction

DYSMON I, A2. Bakterielle Sulfidoxidation in Sedimenten von Ost- und Nordsee. Vorkommen und oekologische Bedeutung beteiligter Bakterienarten Schlussbericht

In dependence on the input of organic matter, sulfate reduction and sulfide oxidation in coastal sediments are highly dynamic processes. The importance of colorless aerobic and anaerobic sulfur-oxidizing bacteria and of phototrophic sulfur bacteria have been investigated. Viable cell numbers of these bacteria have been determined in selective media and at appropriate culture conditions within sediment profiles of two sites of the Baltic Sea. Activities of thiosulfate oxidation and nitrate reduction have been measured in the same sediments and the results were compared with concentrations of various chemical parameters in the pore water of these sediment profiles. Cell numbers of all investigated bacterial groups were high showing maxima near the sediment surface. While maxima of activity measurements generally correlated well with the chemical concentration gradients, a correlation to bacterial cell numbers was less pronounced. Changes in environmental conditions first of all had an influence on the activity of the bacteria present but much later also on the cell numbers. All three bacterial groups mentioned play an important role in the reoxidation of reduced sulfur compounds in the investigated coastal sediments. (orig.)SIGLEAvailable from TIB Hannover: F95B613+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman