Ronald Oremland (Former Employee)
Science and Products
Filter Total Items: 119
Formation of methane and carbon dioxide from dimethylselenide in anoxic sediments and by a methanogenic bacterium
Anaerobic San Francisco Bay salt marsh sediments rapidly metabolized [14C]dimethylselenide (DMSe) to 14CH4 and 14CO2. Addition of selective inhibitors (2-bromoethanesulfonic acid or molybdate) to these sediments indicated that both methanogenic and sulfate-respiring bacteria could degrade DMSe to gaseous products. However, sediments taken from the selenium-contaminated Kesterson Wildlife Refuge pr
Authors
Ronald S. Oremland, Jon P. Zehr
Measurement of nitrous oxide reductase activity in aquatic sediments
Denitrification in aquatic sediments was measured by an N2O reductase assay. Sediments consumed small added quantities of N2O over short periods (a few hours). In experiments with sediment slurries, N2O reductase activity was inhibited by O2, C2H2, heat treatment, and by high levels of nitrate (1 mM) or sulfide (10 mM). However, ambient levels of nitrate (<100 μM) did not influence activity, and m
Authors
L.G. Miller, Ronald S. Oremland, S. Paulsen
Metabolism of reduced methylated sulfur compounds in anaerobic sediments and by a pure culture of an estuarine methanogen
Addition of dimethylsulfide (DMS), dimethyldisulfide (DMDS), or methane thiol (MSH) to a diversity of anoxic aquatic sediments (e.g., fresh water, estuarine, alkaline/hypersaline) stimulated methane production. The yield of methane recovered from DMS was often 52 to 63%, although high concentrations of DMS (as well as MSH and DMDS) inhibited methanogenesis in some types of sediments. Production o
Authors
R.P. Kiene, Ronald S. Oremland, Anthony Catena, Laurence G. Miller, D.G. Capone
Aspects of the biogeochemistry of Big Soda Lake, Nevada
No abstract available.
Authors
Ronald S. Oremland, R. L. Smith, Charles W. Culbertson
Isolation of anaerobic oxalate-degrading bacteria from freshwater lake sediments
Enrichment cultures that anaerobically degraded oxalate were obtained from lake sediment inocula. From these, 5 pure cultures of anaerobic oxalate-degrading bacteria were isolated and partially characterized. The isolates were Gram-negative, non-sporeforming, non-motile, obligate anaerobes. Oxalate was required for growth and was stoichiometrically converted to formate; 14CO2 was also recovered wh
Authors
R. L. Smith, F.E. Strohmaier, Ronald S. Oremland
Denitrification in San Francisco Bay intertidal sediments
The acetylene block technique was employed to study denitrification in intertidal estuarine sediments. Addition of nitrate to sediment slurries stimulated denitrification. During the dry season, sediment-slurry denitrification rates displayed Michaelis-Menten kinetics, and ambient NO3− + NO2− concentrations (≤26 μM) were below the apparent Km (50 μM) for nitrate. During the rainy season, when ambi
Authors
Ronald S. Oremland, Cindy Umberger, Charles W. Culbertson, Richard L. Smith
Anaerobic oxalate degradation: Widespread natural occurrence in aquatic sediments
Significant concentrations of oxalate (dissolved plus particulate) were present in sediments taken from a diversity of aquatic environments, ranging from 0.1 to 0.7 mmol/liter of sediment. These included pelagic and littoral sediments from two freshwater lakes (Searsville Lake, Calif., and Lake Tahoe, Calif.), a hypersaline, meromictic, alkaline lake (Big Soda Lake, Nev.), and a South San Francisc
Authors
Richard L. Smith, Ronald S. Oremland
Methanogenesis and sulfate reduction: Competitive and noncompetitive substrates in estuarine sediments
Sulfate ions did not inhibit methanogenesis in estuarine sediments supplemented with methanol, trimethylamine, or methionine. However, sulfate greatly retarded methanogenesis when hydrogen or acetate was the substrate. Sulfate reduction was stimulated by acetate, hydrogen, and acetate plus hydrogen, but not by methanol or trimethylamine. These results indicate that sulfate-reducing bacteria will o
Authors
Ronald S. Oremland, Sandra Polcin
Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures
Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloramphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Ace
Authors
Charles W. Culbertson, Alexander J. B. Zehnder, Ronald S. Oremland
Microbial formation of ethane in anoxic estuarine sediments
Estuarine sediment slurries produced methane and traces of ethane when incubated under hydrogen. Formation of methane occurred over a broad temperature range with an optimum above 65°C. Ethane formation had a temperature optimum at 40°C. Formation of these two gases was inhibited by air, autoclaving, incubation at 4 and 80°C, and by the methanogenic inhibitor, 2-bromoethanesulfonic acid. Ethane pr
Authors
Ronald S. Oremland
Methanogenic activity in plankton samples and fish intestines A mechanism for in situ methanogenesis in oceanic surface waters
When plankton samples were incubated anaerobically with a cysteine-sulfide reducing agent, pronounced methane evolution occurred. This activity was inhibited by air, CHCl3, C2H2, and 2-bromoethanesulfonic acid. Adding [14C]CO32− resulted in accumulation of [14C]CH4. Portions of the digestive tracts of three fishes were incubated in methanogenic media, and two of the samples showed the presence of
Authors
Ronald S. Oremland
Science and Products
Filter Total Items: 119
Formation of methane and carbon dioxide from dimethylselenide in anoxic sediments and by a methanogenic bacterium
Anaerobic San Francisco Bay salt marsh sediments rapidly metabolized [14C]dimethylselenide (DMSe) to 14CH4 and 14CO2. Addition of selective inhibitors (2-bromoethanesulfonic acid or molybdate) to these sediments indicated that both methanogenic and sulfate-respiring bacteria could degrade DMSe to gaseous products. However, sediments taken from the selenium-contaminated Kesterson Wildlife Refuge pr
Authors
Ronald S. Oremland, Jon P. Zehr
Measurement of nitrous oxide reductase activity in aquatic sediments
Denitrification in aquatic sediments was measured by an N2O reductase assay. Sediments consumed small added quantities of N2O over short periods (a few hours). In experiments with sediment slurries, N2O reductase activity was inhibited by O2, C2H2, heat treatment, and by high levels of nitrate (1 mM) or sulfide (10 mM). However, ambient levels of nitrate (<100 μM) did not influence activity, and m
Authors
L.G. Miller, Ronald S. Oremland, S. Paulsen
Metabolism of reduced methylated sulfur compounds in anaerobic sediments and by a pure culture of an estuarine methanogen
Addition of dimethylsulfide (DMS), dimethyldisulfide (DMDS), or methane thiol (MSH) to a diversity of anoxic aquatic sediments (e.g., fresh water, estuarine, alkaline/hypersaline) stimulated methane production. The yield of methane recovered from DMS was often 52 to 63%, although high concentrations of DMS (as well as MSH and DMDS) inhibited methanogenesis in some types of sediments. Production o
Authors
R.P. Kiene, Ronald S. Oremland, Anthony Catena, Laurence G. Miller, D.G. Capone
Aspects of the biogeochemistry of Big Soda Lake, Nevada
No abstract available.
Authors
Ronald S. Oremland, R. L. Smith, Charles W. Culbertson
Isolation of anaerobic oxalate-degrading bacteria from freshwater lake sediments
Enrichment cultures that anaerobically degraded oxalate were obtained from lake sediment inocula. From these, 5 pure cultures of anaerobic oxalate-degrading bacteria were isolated and partially characterized. The isolates were Gram-negative, non-sporeforming, non-motile, obligate anaerobes. Oxalate was required for growth and was stoichiometrically converted to formate; 14CO2 was also recovered wh
Authors
R. L. Smith, F.E. Strohmaier, Ronald S. Oremland
Denitrification in San Francisco Bay intertidal sediments
The acetylene block technique was employed to study denitrification in intertidal estuarine sediments. Addition of nitrate to sediment slurries stimulated denitrification. During the dry season, sediment-slurry denitrification rates displayed Michaelis-Menten kinetics, and ambient NO3− + NO2− concentrations (≤26 μM) were below the apparent Km (50 μM) for nitrate. During the rainy season, when ambi
Authors
Ronald S. Oremland, Cindy Umberger, Charles W. Culbertson, Richard L. Smith
Anaerobic oxalate degradation: Widespread natural occurrence in aquatic sediments
Significant concentrations of oxalate (dissolved plus particulate) were present in sediments taken from a diversity of aquatic environments, ranging from 0.1 to 0.7 mmol/liter of sediment. These included pelagic and littoral sediments from two freshwater lakes (Searsville Lake, Calif., and Lake Tahoe, Calif.), a hypersaline, meromictic, alkaline lake (Big Soda Lake, Nev.), and a South San Francisc
Authors
Richard L. Smith, Ronald S. Oremland
Methanogenesis and sulfate reduction: Competitive and noncompetitive substrates in estuarine sediments
Sulfate ions did not inhibit methanogenesis in estuarine sediments supplemented with methanol, trimethylamine, or methionine. However, sulfate greatly retarded methanogenesis when hydrogen or acetate was the substrate. Sulfate reduction was stimulated by acetate, hydrogen, and acetate plus hydrogen, but not by methanol or trimethylamine. These results indicate that sulfate-reducing bacteria will o
Authors
Ronald S. Oremland, Sandra Polcin
Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures
Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloramphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Ace
Authors
Charles W. Culbertson, Alexander J. B. Zehnder, Ronald S. Oremland
Microbial formation of ethane in anoxic estuarine sediments
Estuarine sediment slurries produced methane and traces of ethane when incubated under hydrogen. Formation of methane occurred over a broad temperature range with an optimum above 65°C. Ethane formation had a temperature optimum at 40°C. Formation of these two gases was inhibited by air, autoclaving, incubation at 4 and 80°C, and by the methanogenic inhibitor, 2-bromoethanesulfonic acid. Ethane pr
Authors
Ronald S. Oremland
Methanogenic activity in plankton samples and fish intestines A mechanism for in situ methanogenesis in oceanic surface waters
When plankton samples were incubated anaerobically with a cysteine-sulfide reducing agent, pronounced methane evolution occurred. This activity was inhibited by air, CHCl3, C2H2, and 2-bromoethanesulfonic acid. Adding [14C]CO32− resulted in accumulation of [14C]CH4. Portions of the digestive tracts of three fishes were incubated in methanogenic media, and two of the samples showed the presence of
Authors
Ronald S. Oremland