Ronald Oremland (Former Employee)
Science and Products
Filter Total Items: 119
Measurement of in situ rates of selenate removal by dissimilatory bacterial reduction in sediments
A radioisotope method for measurement of bacteria respiratory reduction of selenate to elemental selenium in aquatic sediments was devised. Sediments were labeled with [75Se]selenate, incubated, and washed, and 75Se0(s) was determined as counts remaining in the sediments. Core profiles of selenate reduction, sulfate reduction, and denitrification were made simultaneously in the sediments of an agr
Authors
Ronald S. Oremland, Nisan A. Steinberg, Ann S. Maest, Laurence G. Miller, James T. Hollibaugh
Selenate reduction to elemental selenium by anaerobic bacteria in sediments and culture: Biogeochemical significance of a novel, sulfate-independent respiration
Interstitial water profiles of SeO42−, SeO32−, SO42−, and Cl− in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO42− occurred under anaerobic conditions, was more rapid with H2 or acetate, and was inhibited by O2, NO3−, MnO2, or autoclaving but not by SO42− or FeO
Authors
Ronald S. Oremland, James T. Hollibaugh, Ann S. Maest, Theresa S. Presser, Laurence G. Miller, Charles W. Culbertson
Methanogenesis in hypersaline environments
No abstract available.
Authors
Ronald S. Oremland, G.M. King
Description of an estuarine methylotrophic methanogen, which grows on dimethyl sulfite
Characteristics of an obligately methylotrophic coccoid methanogen (strain GS-16) previously isolated from estuarine sediment are described. Growth was demonstrated on dimethyl sulfide (DMS) or trimethylamine (TMA), but not on methane thiol, methane thiol plus hydrogen, dimethyl disulfide, or methionine. DMS-grown cells were able to metabolize DMS and TMA simultaneously when inoculated into media
Authors
Ronald S. Oremland, Ronald P. Kiene, Indra Mathrani, Michael J. Whiticar, David R. Boone
Use of "specific" inhibitors in biogeochemistry and microbial ecology
The above statement, although meant to be tongue in cheek, contains an essential truism: all work with inhibitors is inherently suspect. This fact has been known by biochemists for some time. However, use of chemical inhibitors of enzymic systems and membranes continues to be a common approach taken toward unraveling the biochemistry and biophysics of plants, animals, and microorganisms. Various t
Authors
Ronald S. Oremland, D.G. Capone
Big Soda Lake (Nevada). 3. Pelagic methanogenesis and anaerobic methane oxidation
In situ rates of methanogenesis and methane oxidation were measured in meromictic Big Soda Lake. Methane production was measured by the accumulation of methane in the headspaces of anaerobically sealed water samples; radiotracer was used to follow methane oxidation. Nearly all the methane oxidation occurred in the anoxic zones of the lake. Rates of anaerobic oxidation exceeded production at all de
Authors
Niels Iversen, Ronald S. Oremland, Michael J. Klug
Big Soda Lake (Nevada). 2. Pelagic sulfate reduction
The epilimnion of hypersaline, alkaline, meromictic Big Soda Lake contains an average 58 mmol sulfate liter−1 and 0.4 µmol dissolved iron liter−1. The monimolimnion, which is permanently anoxic, has a sulfide concentration ranging seasonally from 4 to 7 mmol liter−1. Depth profiles of sulfate reduction in the monimolimnion, assayed with a 35S tracer technique and in situ incubations, demonstrated
Authors
Richard L. Smith, Ronald S. Oremland
Reduction of selenate to selenide by sulfate-respiring bacteria: Experiments with cell suspensions and estuarine sediments
Washed cell suspensions of Desulfovibrio desulfuricans subsp. aestuarii were capable of reducing nanomolar levels of selenate to selenide as well as sulfate to sulfide. Reduction of these species was inhibited by 1 mM selenate or tungstate. The addition of 1 mM sulfate decreased the reduction of selenate and enhanced the reduction of sulfate. Increasing concentrations of sulfate inhibited rates of
Authors
J.P. Zehr, Ronald S. Oremland
Sources and flux of natural gases from Mono Lake, California
The ability to identify a formation mechanism for natural gas in a particular environment requires consideration of several geochemical factors when there are multiple sources present. Four primary sources of methane have been identified in Mono Lake. Two of these sources were associated with numerous natural gas seeps which occur at various locations in the lake and extend beyond its present boun
Authors
Ronald S. Oremland, L.G. Miller, Michael J. Whiticar
Big Soda Lake (Nevada). 1. Pelagic bacterial heterotrophy and biomass
Bacterial activities and abundance were measured seasonally in the water column of meromictic Big Soda Lake which is divided into three chemically distinct zones: aerobic mixolimnion, anaerobic mixolimnion, and anaerobic monimolimnion. Bacterial abundance ranged between 5 and 52 x 106 cells ml−1, with highest biomass at the interfaces between these zones: 2–4 mg C liter−1 in the photosynthetic bac
Authors
Jon P. Zehr, Ronald W. Harvey, Ronald S. Oremland, James E. Cloern, Leah H. George, Judith L. Lane
Science and Products
Filter Total Items: 119
Measurement of in situ rates of selenate removal by dissimilatory bacterial reduction in sediments
A radioisotope method for measurement of bacteria respiratory reduction of selenate to elemental selenium in aquatic sediments was devised. Sediments were labeled with [75Se]selenate, incubated, and washed, and 75Se0(s) was determined as counts remaining in the sediments. Core profiles of selenate reduction, sulfate reduction, and denitrification were made simultaneously in the sediments of an agr
Authors
Ronald S. Oremland, Nisan A. Steinberg, Ann S. Maest, Laurence G. Miller, James T. Hollibaugh
Selenate reduction to elemental selenium by anaerobic bacteria in sediments and culture: Biogeochemical significance of a novel, sulfate-independent respiration
Interstitial water profiles of SeO42−, SeO32−, SO42−, and Cl− in anoxic sediments indicated removal of the seleno-oxyanions by a near-surface process unrelated to sulfate reduction. In sediment slurry experiments, a complete reductive removal of SeO42− occurred under anaerobic conditions, was more rapid with H2 or acetate, and was inhibited by O2, NO3−, MnO2, or autoclaving but not by SO42− or FeO
Authors
Ronald S. Oremland, James T. Hollibaugh, Ann S. Maest, Theresa S. Presser, Laurence G. Miller, Charles W. Culbertson
Methanogenesis in hypersaline environments
No abstract available.
Authors
Ronald S. Oremland, G.M. King
Description of an estuarine methylotrophic methanogen, which grows on dimethyl sulfite
Characteristics of an obligately methylotrophic coccoid methanogen (strain GS-16) previously isolated from estuarine sediment are described. Growth was demonstrated on dimethyl sulfide (DMS) or trimethylamine (TMA), but not on methane thiol, methane thiol plus hydrogen, dimethyl disulfide, or methionine. DMS-grown cells were able to metabolize DMS and TMA simultaneously when inoculated into media
Authors
Ronald S. Oremland, Ronald P. Kiene, Indra Mathrani, Michael J. Whiticar, David R. Boone
Use of "specific" inhibitors in biogeochemistry and microbial ecology
The above statement, although meant to be tongue in cheek, contains an essential truism: all work with inhibitors is inherently suspect. This fact has been known by biochemists for some time. However, use of chemical inhibitors of enzymic systems and membranes continues to be a common approach taken toward unraveling the biochemistry and biophysics of plants, animals, and microorganisms. Various t
Authors
Ronald S. Oremland, D.G. Capone
Big Soda Lake (Nevada). 3. Pelagic methanogenesis and anaerobic methane oxidation
In situ rates of methanogenesis and methane oxidation were measured in meromictic Big Soda Lake. Methane production was measured by the accumulation of methane in the headspaces of anaerobically sealed water samples; radiotracer was used to follow methane oxidation. Nearly all the methane oxidation occurred in the anoxic zones of the lake. Rates of anaerobic oxidation exceeded production at all de
Authors
Niels Iversen, Ronald S. Oremland, Michael J. Klug
Big Soda Lake (Nevada). 2. Pelagic sulfate reduction
The epilimnion of hypersaline, alkaline, meromictic Big Soda Lake contains an average 58 mmol sulfate liter−1 and 0.4 µmol dissolved iron liter−1. The monimolimnion, which is permanently anoxic, has a sulfide concentration ranging seasonally from 4 to 7 mmol liter−1. Depth profiles of sulfate reduction in the monimolimnion, assayed with a 35S tracer technique and in situ incubations, demonstrated
Authors
Richard L. Smith, Ronald S. Oremland
Reduction of selenate to selenide by sulfate-respiring bacteria: Experiments with cell suspensions and estuarine sediments
Washed cell suspensions of Desulfovibrio desulfuricans subsp. aestuarii were capable of reducing nanomolar levels of selenate to selenide as well as sulfate to sulfide. Reduction of these species was inhibited by 1 mM selenate or tungstate. The addition of 1 mM sulfate decreased the reduction of selenate and enhanced the reduction of sulfate. Increasing concentrations of sulfate inhibited rates of
Authors
J.P. Zehr, Ronald S. Oremland
Sources and flux of natural gases from Mono Lake, California
The ability to identify a formation mechanism for natural gas in a particular environment requires consideration of several geochemical factors when there are multiple sources present. Four primary sources of methane have been identified in Mono Lake. Two of these sources were associated with numerous natural gas seeps which occur at various locations in the lake and extend beyond its present boun
Authors
Ronald S. Oremland, L.G. Miller, Michael J. Whiticar
Big Soda Lake (Nevada). 1. Pelagic bacterial heterotrophy and biomass
Bacterial activities and abundance were measured seasonally in the water column of meromictic Big Soda Lake which is divided into three chemically distinct zones: aerobic mixolimnion, anaerobic mixolimnion, and anaerobic monimolimnion. Bacterial abundance ranged between 5 and 52 x 106 cells ml−1, with highest biomass at the interfaces between these zones: 2–4 mg C liter−1 in the photosynthetic bac
Authors
Jon P. Zehr, Ronald W. Harvey, Ronald S. Oremland, James E. Cloern, Leah H. George, Judith L. Lane