Methane is the most abundant organic chemical in Earth's atmosphere, and its concentration increasing with time, as a variety of independent measurements have shown. Photochemical reactions oxidize methane atmosphere; through these reactions, exerts strong influence over chemistry troposphere stratosphere many species including ozone, hydroxyl radicals, carbon monoxide. Also, infrared absorption spectrum, an important greenhouse gas climate system. We describe enumerate key roles reactions....

Sulfate ions did not inhibit methanogenesis in estuarine sediments supplemented with methanol, trimethylamine, or methionine. However, sulfate greatly retarded when hydrogen acetate was the substrate. reduction stimulated by acetate, hydrogen, and plus but methanol trimethylamine. These results indicate that sulfate-reducing bacteria will outcompete methanogens for both, compete compounds like methionine, thereby allowing to operate simultaneously within anoxic, sulfate-containing sediments.

Life is mostly composed of the elements carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. Although these six make up nucleic acids, proteins, lipids thus bulk living matter, it theoretically possible that some other in periodic table could serve same functions. Here, we describe a bacterium, strain GFAJ-1 Halomonadaceae, isolated from Mono Lake, California, able to substitute arsenic for phosphorus sustain its growth. Our data show evidence arsenate macromolecules normally contain...

ABSTRACT Certain anaerobic bacteria respire toxic selenium oxyanions and in doing so produce extracellular accumulations of elemental [Se(0)]. We examined three physiologically phylogenetically diverse species selenate- selenite-respiring bacteria, Sulfurospirillum barnesii , Bacillus selenitireducens Selenihalanaerobacter shriftii for the occurrence this phenomenon. When grown with as electron acceptor, all these organisms formed granules consisting stable, uniform nanospheres (diameter,...

Sulfurospirillum barnesii is capable of anaerobic growth using ferric iron or arsenate as electron acceptors. Cell suspensions S. were able to reduce arsenite when the former oxyanion was dissolved in solution, it adsorbed onto surface ferrihydrite, a common soil mineral, by variety mechanisms (e.g., coprecipitation, presorption). Reduction Fe(III) ferrihydrite soluble Fe(II) also occurred, but dissolution not required order for reduction be achieved. This illustrated bacterial...

Interstitial water profiles of SeO 4 2− , 3 SO and Cl − in anoxic sediments indicated removal the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, complete reductive occurred under anaerobic conditions, was more rapid with H 2 or acetate, inhibited O NO MnO autoclaving but not FeOOH. Oxidation acetate could be coupled selenate molybdate. Reduction elemental selenium determined mechanism for loss from solution. Selenate reduction...

Arsenite [As(III)]-enriched anoxic bottom water from Mono Lake, California, produced arsenate [As(V)] during incubation with either nitrate or nitrite. No such oxidation occurred in killed controls live samples incubated without added A small amount of biological As(III) was observed amended Fe(III) chelated nitrolotriacetic acid, although some chemical also evident controls. pure culture, strain MLHE-1, that capable growth as its electron donor and acceptor isolated a defined mineral salts...

Demethylation of monomethylmercury in freshwater and estuarine sediments bacterial cultures was investigated with 14 CH 3 HgI. Under anaerobiosis, results inhibitors indicated partial involvement both sulfate reducers methanogens, the former dominating sediments, while were active freshwaters. Aerobes most significant demethylators but unimportant sediments. Products anaerobic demethylation mainly CO 2 as well lesser amounts 4 . Acetogenic activity resulted fixation some produced from HgI...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of selenium bioavailability to a benthic bivalve from particulate and solute pathwaysSamuel N. Luoma, Carolyn Johns, Nicholas S. Fisher, Nisan A. Steinberg, Ronald Oremland, John R. ReinfelderCite this: Environ. Sci. Technol. 1992, 26, 3, 485–491Publication Date (Print):March 1, 1992Publication History Published online1 May 2002Published inissue 1 March...

We examined microbial methylmercury (MeHg) degradation in sediment of the Florida Everglades, Carson River (NV), and San Carlos Creek (CA), three freshwater environments that differ extent type mercury contamination biogeochemistry. Degradation rate constant (kdeg) values increased with total (Hgt) both among within ecosystems. The highest kdeg's (2.8−5.8 d-1) were observed Creek, at acid mine drainage impacted sites immediately downstream former New Idria mine, where Hgt ranged from 4.5 to...

Addition of dimethylsulfide (DMS), dimethyldisulfide (DMDS), or methane thiol (MSH) to a diversity anoxic aquatic sediments (e.g., fresh water, estuarine, alkaline/hypersaline) stimulated production. The yield recovered from DMS was often 52 63%, although high concentrations (as well as MSH and DMDS) inhibited methanogenesis in some types sediments. Production these reduced methylated sulfur compounds blocked by 2-bromoethanesulfonic acid. Sulfate did not influence the metabolism millimolar...

A gram-negative, strictly anaerobic, motile vibrio was isolated from a selenate-respiring enrichment culture. The isolate, designated strain SES-3, grew by coupling the oxidation of lactate to acetate plus CO 2 with concomitant reduction selenate selenite or nitrate ammonium. No growth observed on sulfate selenite, but cell suspensions readily reduced elemental selenium (Se 0 ). Hence, SES-3 can carry out complete Se . Washed selenate-grown cells did not reduce nitrate, and nitrate-grown...

A facultative chemoautotrophic bacterium, strain MLHE-1 T , was isolated from Mono Lake, an alkaline hypersaline soda lake in California, USA. Cells of were Gram-negative, short motile rods that grew with inorganic electron donors (arsenite, hydrogen, sulfide or thiosulfate) coupled the reduction nitrate to nitrite. No aerobic growth attained arsenite sulfide, but hydrogen sustained both and anaerobic growth. occurred when nitrite nitrous oxide substituted for nitrate. Heterotrophic observed...

Phylogenetic analysis indicates that microbial arsenic metabolism is ancient and probably extends back to the primordial Earth. In biofilms growing on rock surfaces of anoxic brine pools fed by hot springs containing arsenite sulfide at high concentrations, we discovered light-dependent oxidation [As(III)] arsenate [As(V)] occurring under conditions. The communities were composed primarily Ectothiorhodospira -like purple bacteria or Oscillatoria cyanobacteria. A pure culture a photosynthetic...

The selenate-respiring bacterial strain SES-3 was able to use a variety of inorganic electron acceptors sustain growth. grew with the reduction arsenate arsenite, Fe(III) Fe(II), or thiosulfate sulfide. It also in medium which elemental sulfur, Mn(IV), nitrite, trimethylamine N-oxide, fumarate provided as an acceptor. Growth on oxygen microaerophilic. There no growth arsenite chromate. Washed suspensions cells grown selenate nitrate had constitutive ability reduce but were unable arsenite....

ABSTRACT Certain toxic elements support the metabolism of diverse prokaryotes by serving as respiratory electron acceptors for growth. Here, we demonstrate that two anaerobes previously shown to be capable respiring oxyanions selenium also achieve growth reduction either tellurate [Te(VI)] or tellurite [Te(IV)] elemental tellurium [Te(0)]. This achieves a sizeable stable-Te-isotopic fractionation (isotopic enrichment factor [ε] = −0.4 −1.0 per ml atomic mass unit) and results in formation...