Sulfur geochemistry of hydrothermal waters in Yellowstone National Park, Wyoming, USA. III. An anion-exchange resin technique for sampling and preservation of sulfoxyanions in natural waters

A sampling protocol for the retention, extraction, and analysis of sulfoxyanions in hydrothermal waters has been developed in the laboratory and tested at Yellowstone National Park and Green Lake, NY. Initial laboratory testing of the anion-exchange resin Bio-Rad™ AG1-X8 indicated that the resin was well suited for the sampling, preservation, and extraction of sulfate and thiosulfate. Synthetic solutions containing sulfate and thiosulfate were passed through AG1-X8 resin columns and eluted with 1 and 3 M KCl, respectively. Recovery ranged from 89 to 100%. Comparison of results for water samples collected from five pools in Yellowstone National Park between on-site 1C analysis (U.S. Geological Survey mobile lab) and IC analysis of resin-stored sample at SUNY-Stony Brook indicates 96 to 100% agreement for three pools (Cinder, Cistern, and an unnamed pool near Cistern) and 76 and 63% agreement for two pools (Sulfur Dust and Frying Pan). Attempts to extract polythionates from the AG1-X8 resin were made using HCl solutions, but were unsuccessful. Bio-Rad™ AG2-X8, an anion-exchange resin with weaker binding sites than the AG1-X8 resin, is better suited for polythionate extraction. Sulfate and thiosulfate extraction with this resin has been accomplished with KCl solutions of 0.1 and 0.5 M, respectively. Trithionate and tetrathionate can be extracted with 4 M KCl. Higher polythionates can be extracted with 9 M hydrochloric acid. Polythionate concentrations can then be determined directly using ion chromatographic methods, and laboratory results indicate recovery of up to 90% for synthetic polythionate solutions using AG2-X8 resin columns

High resolution profiling of sulfur and oxygen speciation in microbial mats: Implications for coupling of hydrogen peroxide with sulfur species

Hydrogen sulfide is produced in microbial mats by sulfate reducing bacteria, and diffuses towards the surface until it is consumed. Cyanobacteria in these mats are able to produce oxygen photochem., and when subjected to high UV light intensity, can also produce hydrogen peroxide. Microelectrodes have proven to have sufficient resoln. to resolve the sulfur and oxygen chem. in these mats, demonstrating the links between these populations of bacteria in modern mats. In sulfur-dominated cyanobacterial mats in several settings, we have obsd. both high hydrogen sulfide fluxes and the periodic prodn. of significant amts. of hydrogen peroxide at times of high UV stress using voltammetric Au-amalgam microelectrodes. We review the use of voltammetric and amperometric microelectrodes in approaching this chem., and how the relative rates of sulfur species oxidn. with oxygen or peroxide may play a significant role in shaping the chem., isotopic, and biol. compn. of these systems

Cloning and In Situ Expression Studies of the Hydrogenobaculum Arsenite Oxidase Genes▿

Novel arsenite [As(III)] oxidase structural genes (aoxAB) were cloned from Hydrogenobaculum bacteria isolated from an acidic geothermal spring. Reverse transcriptase PCR demonstrated expression throughout the outflow channel, and the aoxB cDNA clones exhibited distribution patterns relative to the physicochemical gradients in the spring. Microelectrode analyses provided evidence of quantitative As(III) transformation within the microbial mat