Ronald Oremland (Former Employee)
Science and Products
Filter Total Items: 118
Arsenite and ferrous iron oxidation linked to chemolithotrophic denitrification for the immobilization of arsenic in anoxic environments
The objective of this study was to explore a bioremediation strategy based on injecting NO3− to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flow sand filled columns were used to simulate a natural anaerobic groundwater and s
Authors
W. Sun, R. Sierra-Alvarez, L. Milner, R. Oremland, J.A. Field
Arsenic(III) fuels anoxygenic photosynthesis in hot spring biofilms from Mono Lake, California
Phylogenetic analysis indicates that microbial arsenic metabolism is ancient and probably extends back to the primordial Earth. In microbial biofilms growing on the rock surfaces of anoxic brine pools fed by hot springs containing arsenite and sulfide at high concentrations, we discovered light-dependent oxidation of arsenite [As(III)] to arsenate [As(V)] occurring under anoxic conditions. The com
Authors
T.R. Kulp, S.E. Hoeft, M. Asao, M.T. Madigan, J.T. Hollibaugh, J.C. Fisher, J.F. Stolz, C.W. Culbertson, L.G. Miller, R.S. Oremland
Electricity generation by anaerobic bacteria and anoxic sediments from hypersaline soda lakes
Anaerobic bacteria and anoxic sediments from soda lakes produced electricity in microbial fuel cells (MFCs). No electricity was generated in the absence of bacterial metabolism. Arsenate respiring bacteria isolated from moderately hypersaline Mono Lake (Bacillus selenitireducens), and salt-saturated Searles Lake, CA (strain SLAS-1) oxidized lactate using arsenate as the electron acceptor. However,
Authors
L.G. Miller, R.S. Oremland
Acetylene as fast food: Implications for development of life on anoxic primordial earth and in the outer solar system
Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan. In contrast, acetylene is only a trace component of Earth's current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been rich in acetylene. This poses a paradox, because acetylene is a potent inhibitor of many key anaerobic microbial
Authors
R.S. Oremland, M.A. Voytek
Bacterial Cycling of Methyl Halides
This chapter focuses on the monohalogenated methanes methyl chloride (MeCl) and methyl bromide (MeBr), their natural and anthropogenic sources, and their degradation by microorganisms, specifically by aerobic bacteria that can use MeBr and MeCl as sole source of carbon and energy. The biogeochemical cycle of methyl halides and the microbiology, biochemistry, genetics, and biotechnological potentia
Authors
Hendrik Schafer, Laurence G. Miller, Ronald S. Oremland, Colin Murrell
Effects of imposed salinity gradients on dissimilatory arsenate reduction, sulfate reduction, and other microbial processes in sediments from two California soda lakes
Salinity effects on microbial community structure and on potential rates of arsenate reduction, arsenite oxidation, sulfate reduction, denitrification, and methanogenesis were examined in sediment slurries from two California soda lakes. We conducted experiments with Mono Lake and Searles Lake sediments over a wide range of salt concentrations (25 to 346 g liter−1). With the exception of sulfate r
Authors
T.R. Kulp, S. Han, C.W. Saltikov, B.D. Lanoil, K. Zargar, Ron Oremland
Formation of tellurium nanocrystals during anaerobic growth of bacteria that use Te oxyanions as respiratory electron acceptors
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 of respiring oxyanions of selenium also achieve growth by reduction of either tellurate [Te(VI)] or tellurite [Te(IV)] to elemental tellurium [Te(0)]. This reduction achieves a sizeable stable-Te-isotopi
Authors
Shaun M. Baesman, Thomas D. Bullen, J. Dewald, Donghui Zhang, S. Curran, F.S. Islam, T.J. Beveridge, Ronald S. Oremland
Arsenic in ground water: A review of current knowledge and relation to the CALFED solution area with recommendations for needed research
Ground water with arsenic concentrations greater than the U.S. Environmental Protection Agency drinking water standard exists throughout much of the CALFED solution area. These high concentrations are of con-cern from the standpoint of both existing water supply and development of conjunctive use projects. Much is known about arsenic mobility in ground water subject to different hydrologic and geo
Authors
Alan H. Welch, Ronald S. Oremland, James A. Davis, Sharon A. Watkins
Arsenic and selenium in microbial metabolism
Arsenic and selenium are readily metabolized by prokaryotes, participating in a full range of metabolic functions including assimilation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse environ
Authors
John F. Stolz, Partha Basu, Joanne M. Santini, Ronald S. Oremland
Dissimilatory arsenate and sulfate reduction in sediments of two hypersaline, arsenic-rich soda lakes: Mono and Searles Lakes, California
A radioisotope method was devised to study bacterial respiratory reduction of arsenate in sediments. The following two arsenic-rich soda lakes in California were chosen for comparison on the basis of their different salinities: Mono Lake (∼90 g/liter) and Searles Lake (∼340 g/liter). Profiles of arsenate reduction and sulfate reduction were constructed for both lakes. Reduction of [73As]arsenate o
Authors
T.R. Kulp, S.E. Hoeft, L.G. Miller, C. Saltikov, J.N. Murphy, S. Han, B. Lanoil, R.S. Oremland
Microbial transformations of arsenic in the environment: From soda lakes to aquifers
Arsenic is a highly toxic element that supports a surprising range of biogeochemical transformations. The biochemical basis of these microbial interactions is described, with an emphasis on energy-yielding redox biotransformations that cycle between the As5+ and As3+ oxidation states. The subsequent impact of As3+-oxidising and As 5+-reducing prokaryotes on the chemistry of selected environments i
Authors
J.R. Lloyd, R.S. Oremland
Arsenic, microbes and contaminated aquifers
The health of tens of millions of people world-wide is at risk from drinking arsenic-contaminated well water. In most cases this arsenic occurs naturally within the sub-surface aquifers, rather than being derived from identifiable point sources of pollution. The mobilization of arsenic into the aqueous phase is the first crucial step in a process that eventually leads to human arsenicosis. Increas
Authors
Ronald S. Oremland, John F. Stolz
Science and Products
Filter Total Items: 118
Arsenite and ferrous iron oxidation linked to chemolithotrophic denitrification for the immobilization of arsenic in anoxic environments
The objective of this study was to explore a bioremediation strategy based on injecting NO3− to support the anoxic oxidation of ferrous iron (Fe(II)) and arsenite (As(III)) in the subsurface as a means to immobilize As in the form of arsenate (As(V)) adsorbed onto biogenic ferric (Fe(III)) (hydr)oxides. Continuous flow sand filled columns were used to simulate a natural anaerobic groundwater and s
Authors
W. Sun, R. Sierra-Alvarez, L. Milner, R. Oremland, J.A. Field
Arsenic(III) fuels anoxygenic photosynthesis in hot spring biofilms from Mono Lake, California
Phylogenetic analysis indicates that microbial arsenic metabolism is ancient and probably extends back to the primordial Earth. In microbial biofilms growing on the rock surfaces of anoxic brine pools fed by hot springs containing arsenite and sulfide at high concentrations, we discovered light-dependent oxidation of arsenite [As(III)] to arsenate [As(V)] occurring under anoxic conditions. The com
Authors
T.R. Kulp, S.E. Hoeft, M. Asao, M.T. Madigan, J.T. Hollibaugh, J.C. Fisher, J.F. Stolz, C.W. Culbertson, L.G. Miller, R.S. Oremland
Electricity generation by anaerobic bacteria and anoxic sediments from hypersaline soda lakes
Anaerobic bacteria and anoxic sediments from soda lakes produced electricity in microbial fuel cells (MFCs). No electricity was generated in the absence of bacterial metabolism. Arsenate respiring bacteria isolated from moderately hypersaline Mono Lake (Bacillus selenitireducens), and salt-saturated Searles Lake, CA (strain SLAS-1) oxidized lactate using arsenate as the electron acceptor. However,
Authors
L.G. Miller, R.S. Oremland
Acetylene as fast food: Implications for development of life on anoxic primordial earth and in the outer solar system
Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan. In contrast, acetylene is only a trace component of Earth's current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been rich in acetylene. This poses a paradox, because acetylene is a potent inhibitor of many key anaerobic microbial
Authors
R.S. Oremland, M.A. Voytek
Bacterial Cycling of Methyl Halides
This chapter focuses on the monohalogenated methanes methyl chloride (MeCl) and methyl bromide (MeBr), their natural and anthropogenic sources, and their degradation by microorganisms, specifically by aerobic bacteria that can use MeBr and MeCl as sole source of carbon and energy. The biogeochemical cycle of methyl halides and the microbiology, biochemistry, genetics, and biotechnological potentia
Authors
Hendrik Schafer, Laurence G. Miller, Ronald S. Oremland, Colin Murrell
Effects of imposed salinity gradients on dissimilatory arsenate reduction, sulfate reduction, and other microbial processes in sediments from two California soda lakes
Salinity effects on microbial community structure and on potential rates of arsenate reduction, arsenite oxidation, sulfate reduction, denitrification, and methanogenesis were examined in sediment slurries from two California soda lakes. We conducted experiments with Mono Lake and Searles Lake sediments over a wide range of salt concentrations (25 to 346 g liter−1). With the exception of sulfate r
Authors
T.R. Kulp, S. Han, C.W. Saltikov, B.D. Lanoil, K. Zargar, Ron Oremland
Formation of tellurium nanocrystals during anaerobic growth of bacteria that use Te oxyanions as respiratory electron acceptors
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 of respiring oxyanions of selenium also achieve growth by reduction of either tellurate [Te(VI)] or tellurite [Te(IV)] to elemental tellurium [Te(0)]. This reduction achieves a sizeable stable-Te-isotopi
Authors
Shaun M. Baesman, Thomas D. Bullen, J. Dewald, Donghui Zhang, S. Curran, F.S. Islam, T.J. Beveridge, Ronald S. Oremland
Arsenic in ground water: A review of current knowledge and relation to the CALFED solution area with recommendations for needed research
Ground water with arsenic concentrations greater than the U.S. Environmental Protection Agency drinking water standard exists throughout much of the CALFED solution area. These high concentrations are of con-cern from the standpoint of both existing water supply and development of conjunctive use projects. Much is known about arsenic mobility in ground water subject to different hydrologic and geo
Authors
Alan H. Welch, Ronald S. Oremland, James A. Davis, Sharon A. Watkins
Arsenic and selenium in microbial metabolism
Arsenic and selenium are readily metabolized by prokaryotes, participating in a full range of metabolic functions including assimilation, methylation, detoxification, and anaerobic respiration. Arsenic speciation and mobility is affected by microbes through oxidation/reduction reactions as part of resistance and respiratory processes. A robust arsenic cycle has been demonstrated in diverse environ
Authors
John F. Stolz, Partha Basu, Joanne M. Santini, Ronald S. Oremland
Dissimilatory arsenate and sulfate reduction in sediments of two hypersaline, arsenic-rich soda lakes: Mono and Searles Lakes, California
A radioisotope method was devised to study bacterial respiratory reduction of arsenate in sediments. The following two arsenic-rich soda lakes in California were chosen for comparison on the basis of their different salinities: Mono Lake (∼90 g/liter) and Searles Lake (∼340 g/liter). Profiles of arsenate reduction and sulfate reduction were constructed for both lakes. Reduction of [73As]arsenate o
Authors
T.R. Kulp, S.E. Hoeft, L.G. Miller, C. Saltikov, J.N. Murphy, S. Han, B. Lanoil, R.S. Oremland
Microbial transformations of arsenic in the environment: From soda lakes to aquifers
Arsenic is a highly toxic element that supports a surprising range of biogeochemical transformations. The biochemical basis of these microbial interactions is described, with an emphasis on energy-yielding redox biotransformations that cycle between the As5+ and As3+ oxidation states. The subsequent impact of As3+-oxidising and As 5+-reducing prokaryotes on the chemistry of selected environments i
Authors
J.R. Lloyd, R.S. Oremland
Arsenic, microbes and contaminated aquifers
The health of tens of millions of people world-wide is at risk from drinking arsenic-contaminated well water. In most cases this arsenic occurs naturally within the sub-surface aquifers, rather than being derived from identifiable point sources of pollution. The mobilization of arsenic into the aqueous phase is the first crucial step in a process that eventually leads to human arsenicosis. Increas
Authors
Ronald S. Oremland, John F. Stolz