Tamar Barkay


Research Interests:

Microbial transformation of metals

Research in my laboratory is focused on the microbial ecology of the interactions of microbes with toxic metals. Specifically, we are looking at microbial transformations of metals and how they affect metal toxicity and accumulation patterns in the environment and at the genetics and physiology of metal resistance and transformations in bacteria. This research supports efforts in bioremediation of metal contaminated environments. One on-going research projects is focused on the role of microbes in the formation and accumulation of methylmercury in aquatic environments. Methylmercury is the most toxic form of mercury that is accumulated and biomagnified in fish and shellfish posing a risk to predators (including humans) that rely on the aquatic food chain for sustenance. A second project examines the role of horizontal gene transfer among bacteria on the spread of mercury and antibiotics resistance genes. Such genetic spread might lead to the formation of antibiotics resistance gene pools in mercury-contaminated environments. Our research relies heavily on the application of molecular tools, such as cloning, gene probing, mRNA transcript analysis, metagenomics, and metatranscriptomics, in microbial ecology.


Selected Publications:

Lu, X., Y, Liu, A. Johs, L. Zhao, T. Wang, Z. Yang, H. Lin, D.A. Elias, E.M. Pierce, L. Liang, T. Barkay, and B. Gu. 2016. Anaerobic mercury methylation and demethylation by Geobacter bemidjensisBem. Environ. Sci. Technol. 50:4366-4373.

Janssen, S., M.W. Johnson, J.D. Blum, T. Barkay, and J.R. Reinfelder. 2015. Separation of monomethylmercury from estuarine sediments for mercury isotope analysis. Chem. Geol. 411:19-25

Møller, A.K., T. Barkay, M.A. Hansen, A. Norman, L. H. Hansen, S.J. Sørensen, E.B. Boyd and N. Kroer. 2014. Mercuric reductase genes (merA) and mercury resistance plasmids in High Arctic snow, freshwater, and sea-ice brine. FEMS Microbiol. Ecol. 87:52-63

Yu, R.-Q, J. Reinfelder, M. Hines, and T. Barkay. 2013. Mercury methylation by the methanogen Methanospirillum hungatei. Appl. Environ. Microbiol. 79:6325-6330. doi: 10.1128/AEM.01556-13

Poulain, A.J., and T. Barkay. 2013. Cracking the mercury methylation code. Science 339:1280-1281. doi: 10.1126/science.1235591


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Name: Tamar Barkay
Address: Department of Biochemistry and Microbiology
Cook College, Rutgers University
76 Lipman Drive
New Brunswick, NJ 08901-8525
Telephone: 848 932-5664
E-mail: barkay@aesop.rutgers.edu


B.Sc. School of Agronomy, The Hebrew University, Rehovot; June 1974 (Undergraduate degree in Agronomy, major in Microbiology)
M.Sc. Hebrew University, Jerusalem; June 1976 (Master in Environmental Health)
Ph.D. The University of Maryland; December 1980 (Major in Microbiology, Minor in Biochemistry)

Academic positions:

Distinguished Professor Dept. of Biochemistry and Microbiology, Rutgers University, 2015– present
Professor Dept. of Biochemistry and Microbiology, Rutgers University, 2007 – 2015 
Associate Professor  Dept. of Biochemistry and Microbiology, Rutgers University, 2003 – 2007 
Assistant Professor  Dept. of Biochemistry and Microbiology, Rutgers University, 1999 – 2003 

Other positions held

Research Microbiologist Environmental Research Laboratory, The Environmental Protection Agency, 1984 – 1996
Visiting Scientist Dept. of Molecular Microbiology and Biotechnology, Tel Aviv University, Israel, 1997 – 1998
Visiting Associate Professor Center for Environmental Diagnostics and Bioremediation, University of West Florida, 1998 – 1999
Visiting Professor National Environmental Research Institute, Aarhus University, Roskilde, Denmark, 2010

Honors and Awards

  • Charles H. Revson Postdoctoral Fellowship Award, Weizmann Institute, Rehovot, Israel, 1981 1982.
  • University of California, Irvine, Career Development Award, 1983.
  • National Research Council Residence Associateship, 1985 (declined)
  • The Environmental Protection Agency Scientific and Technological Achievement Award in the Category of Ecology - Level II, 1988
  • American Academy of Microbiology, elected member, 1990
  • Research Excellence Award, Cook College, Rutgers University, 2004
  • The Waksman Award, Theobald Smith Society, 2005
  • A European Commission's Marie-Currie Incoming Scholar Program award ($143,000) given for a project titled "MERCTIC - Mercury biogeochemistry in the high Arctic". 2010
  • The Board of Trustees Award for Excellence in Research, Rutgers University, 2015 Elected member of the AAAS, 2015

External Grants and Contracts:

National Science Foundation. Population Biology and Physiological Ecology. "An assessment of stressor induced gene occurrence in Soil Bacterial Communities". Co-Principal Investigator 1985-1986.

EPA Region IV, RARE study on "Investigation on specific rates of mercury transformations as a source of methylmercury contamination in the Everglades drainage Basin". Oct. 1991 - Sept. 1992. $50,000

Electric Power Research Institution, Palo Alto, CA. "Bioremediation of mercury contaminated sites". Jan. 1992 - December 1993. $215,487.

Parks Service, Everglades National Park. "Methylation and demethylation Rrtes in Everglades soils". Oct. 1991 - Sept. 1993. $86,000.

Electric Power Research Institution, Palo Alto, CA. "Genomic Characterization of environmental Isolates of Pseudomonas cepacia". Co-principle investigator with T.G. Lessie. July 1995 - June 1998. $225,000.

National Science Foundation. Environmental Geochemistry/Biogeochemistry Program. "Mercury biogeochemistry in a semi-arid aquatic ecosystem: Processes controlling methylation and demethylation" Co-principle investigator (1 of 5). Sept. 1995 - Aug. 1998. $583,179.

National Science Foundation. International Division. "Mercury biogeochemistry in the Idrija river system, Slovenia: Processes controlling methylation and demethylation" .Co -principle investigator (1 of 5). June 1997 - July 2000. $51,515.

Israel Ministry of Science. Infrastructure Research. "Center for bioremediation of pollutants from industrial, urban and agricultural origin" Co-principle investigator (1 of 7). Jan. 98 Dec. 2000. IS 8,886,380 ($2.5 M).

Fisheries and Oceans, Canada. "The preparation of mer-gfp bioassessors for Hg(II)". Dec. 1998 - March, 2000. $20,000.

Aluminum Company of America, Inc., "The development of bioassessors for determination of mercury that is bioavailable to mercury methylating bacteria in anaerobic sediments". Jan. 1999 - Dec. 2001. $150,000

National Science Foundation. Environmental Geochemistry/Biogeochemistry Program. "Collaborative study: Mercury cycling in soils: Dynamic sources for aquatic environments". Sept. 1999 - Aug. 2002. $138,000.

Department of Energy. NABIR Program. "Molecular and microcosm analyses of the potential for gene transfer in radionuclei and metal-contaminated subsurface environments". Sept. 1999 - Aug. 2002. $809,000.

National Science Foundation. International Division. "Mercury biogeochemistry in the Idrija river system, Slovenia: Processes controlling methylation and demethylation" .Coprinciple investigator (1 of 4). Sept. 1999 - Aug. 2002. $64,000.

New Jersey Water Resources Research Institute. "Factors controlling methylmercury degradation in Pine Barrens lakes". March 2000 – Feb. 2002. $55,000.

Meadowlands Environmental Research Institute. "Factors controlling mercury contamination in Berry's Creek and downstream ecosystems". 2002 – 2003. $63,602

Department of Energy. NABIR Program. "Lateral gene transfer among subsurface bacteria". Lead PI (with P. Sobecky, GA Technical U.). Sept. 2002 – Aug. 2006. $818,476.

National Science Foundation. Biocomplexity Program. "Atmospheric deposition, transport, transformations and bioavailability of mercury across a northern forest landscape". Coprinciple investigator (Lead PI: C. Driscol, Syracuse U.). Aug. 2003 – July 2008. $294,696.

Department of Energy. NABIR Program. "Importance of mobile genetic elements and conjugal gene transfer for subsurface community adaptation to biotransformation of metals". Coprinciple investigator (Lead PI: S. Sørensen, U. of Copenhagen). Sept. 2003 – Aug. 2006. $149,251.

National Science Foundation and Dept. of Energy. "A workshop on horizontal gene flow in microbial communities". Co-PI (with B. Smets, Uconn). ~$100.000.

National Science Foundation. Biogeoscience Program. "Collaborative research: Mercury isotope fractionation during microbial and abiotic redox transformations". Co-PI (with Joel Blum, U. of Michigan) Sept. 2004 – Aug. 2008. $226,846.

Department of Energy. NABIR Program. "Microbial pathways for the reduction of mercury in saturated subsurface sediments". Lead PI (with Lily Young and Gerben Zylstra, RU). $694,769. Jan. 2005 – Dec. 2008.

National Science Foundation. Research Experience for Undergraduates supplement to "Collaborative research: Mercury isotope fractionation during microbial and abiotic redox transformations", June 2005 – Aug. 2005. $10,400

E.I. du Pont de Nemours and Co. "Factors controlling methylmercury production in the South River, VA: Substrate bioavailability and potentials for methylation and demethylation". $93,280. Jan. 2008 – Dec. 2008.

Department of Energy. ERSP Program. "Reduction of mercury in saturated subsurface sediments and its potential to mobilize mercury in its elemental form". Lead PI (with Lily Young, Gerben Zylstra, Nathan Yee, RU and Ravi Kukkadapu, PNNL). $996,813. Sept. 2008 – Aug. 2011.

National Science Foundation/Geobiology&Low Temperature Geochemistry. "Collaborative research: mass-dependent and independent mercury isotope fractionation during microbial methylation and redox transformations of mercury in natural waters". Co-PI (with John Reinfelder, RU, and Joel Blum, University of Michigan). $468,495 (RU part). June 2010 – May 2013.

Department of Energy. SBR Program. "Microbial Oxidation of Hg(0): Its Effect on Hg Stable Isotope Fractionation and Methylmercury Production". Lead PI (with Nathan Yee and John Reinfelder). $1,099,555. Sept. 2011 – Aug. 2014

Utah, Dept. of Environmental Resources. "Mercury Biogeochemistry in Great Salt Lake: The Role of Microorganisms in Methylation". Co-PI (with Bonnie Baxter [Westminster Collage] and Eric Boyd [Montana State University]). $62,082. Sept. 2011 – Aug. 2012.

National Science Foundation/office of Polar Programs. "Collaborative research: Effects of trophic status alterations on pathways of mercury methylation in northern wetlands". Co-PI (with Mark Hines, UMass Lowell. $384,630 (RU part). July 2013 – June 2016

Colgate-Palmolive Co. "The effect of zinc and tin on the growth and oxidative stress response of key oral bacteria". Co-PI (with Jeff Boyd, Rutgers). $145,274. Sept, 2014 - Aug. 2015

Internal awards in support of research and research infrastructure:

Cook College, Research Equipment Grant. "An optical thermocycler module to allow the quantitative analysis of specific genes and mRNA transcripts". Dec. 2000. $35,000

Rutgers University Research Infrastructure Award. "Upgrading temperature controlled incubation rooms in Lipman Hall", 2006, $35,000

Rutgers University Research Infrastructure Award." Upgrading of autoclaving facilities in Lipman Hall", 2007, $26,000

NJAES Competitive Intramural Research Program for Illumina sequencing. "'mer gene expression to the rescue': the development of a metagenomic/metatranscriptomic approach to study how mercury resistance facilitates microbial community adaptation to mercury toxicity". 2012, $6,697

Internal awards in support of education:

Rutgers University, Research Council Grant. "Factors controlling methylmercury accumulation in New Jersey's freshwater streams". 2001/2002. $1,500.

Rutgers Undergraduate Research Fellow Program. "Identification of mer genes in microorganisms from deep sea hydrothermal vents of the East Pacific Rise". (for Yein Chew) 2001 – 2002. $1,500.

Rutgers Undergraduate Research Fellow Program. "Microbial diversity of mer genes in bacteria isolated from mercury contaminated environments". (for Christopher Asakiewicz) 2002 – 2003. $1,500.

Rutgers Undergraduate Research Fellow Program. "The isolation and characterization of new organomercury degrading enzymes". (for Rachel Kaletzky) 2002 – 2003. $1,500.

Rutgers Undergraduate Research Fellow Program. "Mercury resistance among bacteria from mercury and sulfur enriched geothermal springs". (for Raul Singh) 2003 – 2005. $1,500.

Grants to Enhance the Undergraduate Curriculum and Teaching. "Experiences in applied and environmental molecular microbiology". Rutgers University. 2004. $5,000.

Rutgers Undergraduate Research Fellow Program. "Isolation and characterization of novel merA sequences from anaerobic mercury resistant microorganisms". (for Rita Theofanopoulos) 2004 – 2005. $1,500.

Review boards and committees

Advisor. Mercury Accumulation Pathways and Processes. Bureau of Research, Wisconsin Department of Natural Resources. 1989

Member of the Editorial Board, Applied and Environmental Microbiology: Jan. 1990 – July 1996.

Member of the Editorial Board, Journal of Industrial Microbiology: Jan. 1996 – Dec. 1998.

Electric Power Research Institute review committee on "Genetic and Microbial Ecology of Biofilms". 1991

Florida Mercury Technical Committee – Advisory committee to Florida DER regarding mercury in fish and wildlife. 1991.

Dept. of Energy, NABIR program, Proposal review panel. 2000

Dept. of Energy, Microbial Genome Program, Proposal review panel. 2001

Dept. of Energy, Science Advisory Board, Sub-committee for the NABIR program. 2003

Dept. of Energy, Genome to Life Program, Proposal review panel. 2003

Rice University, NSF Center of Excellence on Nano-biotechnology. Reviewer, 2003

Nat. Inst. Health. General Medical Sciences. Minority Biomedical Research Support Program.

Review panel (by teleconferencing), 2004

Dept. of Energy, Microbial Genome Program, Proposal review panel. June 2004

National Science Foundation, MIP Program, proposal review panel, Nov. 2004

Dept. of Energy, Microbial Genome Program, Proposal review panel. May 2005

National Science Foundation, MIP Program, proposal review panel, Feb. 2006

American Museum of Natural History, Center for Biodiversity and Conservation's annual symposium "Thinking Small: Microbial Diversity and Its Role in Conservation", steering committee, Apr. 2007

National Science Foundation, MIP Program, proposal review panel, Feb. 2007

National Science Foundation, Organism Environment Interactions panel, Oct. 2009

National Science Foundation, Organism Environment Interactions–plants panel, Apr. 2012

Oak Ridge National Laboratory, SFA Science Advisory Committee (Chair since 2011), 2009 – 2013

Dept. of Energy, DOE Office of Science Early Career Research Program, Feb. 2014 Aarhus University, Construction of Villum research Station, Greenland, Science Advisory Board (2013 – 2014)

F1000Research, Science Advisory Board (2014 – present)

Professional Organizations:

American Society for Microbiology
American Association for the Advancement of Science
American Academy of Microbiology
International Society for Microbial Ecology
International Association of Geochemistry

Professional publications:

Olson, B.H., T. Barkay, D. Nies, M. Bellama and R.R. Colwell. 1979. Plasmid mediation of mercury volatilization and methylation by estuarine bacteria. Develop. Ind. Microbiol. 20:275-284.

Olson, B.H., T. Barkay, and R.R. Colwell. 1979. The role of plasmids in mercury transformations by bacteria isolated from the aquatic environment. Appl. Environ. Microbiol. 38:278-285.

Barkay, T., B. Olson, and R. R. Colwell. 1979. Heavy metal biotransformations mediated by estuarine bacteria. Manage. Control Heavy Met. Environ. Int. Conf. 1979, pp. 356-363.

McNicol, L.A., T. Barkay, M. J. Voll and R. R. Colwell. 1982. Plasmid carriage in Aeromonas hydrophila and other bacteria isolated from the aquatic environment. J. Wash. Acad. Sci. 72:6066.

Barkay, T., and A. Goldfarb. 1982. Processing of bacteriophage T4 primary transcripts with ribonuclease III. J. Molec. Biol. 162:299-315.

Barkay, T., S. Tripp, and B. H. Olson. 1983. The effect of sewage Sludge application on cadmium resistance in soil bacterial populations. Manag. Control Heavy Met. Environ. Int. Conf. 1983, pp. 309-313.

Barkay, T., and R. R. Colwell. 1983. Cell wall alteration responsible for increased resistance to mercurials in Pseudomonas fluorescens B69. J. Gen. Microbiol. 129:2945-2950.

Barkay, T., D. L. Johnson, and B. H. Olson. 1984. Use of genetic adaptation to assess pollution in natural environments. Environ. Manag. Int. Conf. London 10-13 July 1984.

Barkay, T., S. Tripp, and B. H. Olson. 1985. The effects of metal rich sewage sludge application on the bacterial communities of grasslands. Appl. Environ. Microbiol. 49:333-337.

Barkay, T., D. Fouts, and B. Olson. 1985. Preparation of a DNA gene probe for detection of mercury resistance genes in gram negative bacterial communities. Appl. Environ. Microbiol. 49:686-692.

Colwell, R.R., D. Allen-Austin, T. Barkay, J. Barja, and J. D. Nelson, Jr. 1986. Antibiotic resistance associated with heavy metal mineralization. in: Mineral Exploration Biological Systems and Organic Matter. Carlisle, W., J. Berry, J. Watterson, and I. Kaplen (eds). Vol. 5. Princeton Hall, Inc. Englewood Cliffs, NJ p. 171-177.

Olson, B. H., and T. Barkay. 1986. The feasibility of using bacterial resistance to metals in mineral exploration. in: Mineral Exploration Biological Systems and Organic Matter. Carlisle, W., J. Berry, J. Watterson, and I. Kaplen (eds). Vol. 5. Princeton Hall, Inc. Englewood Cliffs, NJ p. 171-177.

Barkay, T., D. F. Shearer, and B. H. Olson. 1986. Toxicity testing in soil using microorganisms, in: Toxicity Testing Using Microorganisms Vol. II, Dutka, B. J., and G. Bitton (eds), CRC Press, Boca Raton, FL. p. 133-155.

Barkay, T., and B. H. Olson. 1986. Phenotypic and genotypic adaptation of aerobic heterotrophic sediment bacterial communities to mercury stress. Appl. Environ. Microbiol. 52:403-406.

Levin, M.A., R. Seidler, A.W. Bourquin, J.R. Fowle III, and T. Barkay. 1987. EPA developing methods to assess environmental release. Bio/technology 5:38-45.

Trevors, J.T., T. Barkay, and A.W. Bourquin. 1987. Bacterial gene transfer in soil and aquatic environments. A review. Can. J. Microbiol. 33:191-198.

Barkay, T. 1987. Adaptation of aquatic microbial communities to Hg2+stress. Appl. Environ. Microbiol. 53:2725-2732.

Ogram, A., G.S. Sayler, and T. Barkay. 1987. The extraction and purification of microbial DNA from sediments. J. Microbiol. Meth. 7:57-66.

Genthner F.J., P. Chatterjee, T. Barkay, and A.W. Bourquin. 1988. Capacity of aquatic bacteria to act as recipients for plasmid DNA. Appl. Environ. Microbiol. 54:115-117

Barkay, T., and G.S. Sayler. 1988. Gene probes as a tool for the detection of specific genomes in the environment. in: Aquatic Toxicology and Hazard Assessment: 10th Volume ASTM STP 971, Adams, W.J., G.A. Chapman, and W.G. Landis, (eds), American Society for Testing and Materials, Philadelphia, pp. 29-36.

Barkay, T., and P. Pritchard. 1988. Adaptation of aquatic microbial communities to pollutant stress. Microbiol. Sci. 5:165-169.

Liebert C., and T. Barkay. 1988. A direct viable counting method for measuring tolerance of aquatic microbial communities to Hg2+. Can. J. Microbiol. 34:1090-1095.

Barkay, T., D. Chatterjee, S. Cuskey, R. Walter, F. Genthner, and A. Bourquin. 1989. Bacteria and the environment. in: A Revolution in Biotechnology. J. Marx (ed). Cambridge University Press, Cambridge, New Rochelle, Melbourne, Sydney. pp. 94 - 102.

Barkay, T., C. Liebert, and M. Gillman. 1989. The environmental significance of the potential for mer(Tn21) mediated reduction of Hg2+ to Hg0 in natural waters. Appl. Environ. Microbiol. 55:1196-1202.

Barkay, T., C. Liebert, and M. Gillman. 1989. Hybridization of DNA probes with whole community genome for detection of genes that encode microbial responses to pollutants: mer genes and Hg2+resistance. Appl. Environ. Microbiol. 55:1574-1577.

Summers, A.O., and T. Barkay. 1989. Metal resistance genes in the environment. in: Gene Transfer in the Environment. S. Levy, and R. Miller (Eds), McGraw-Hill Publishing Co. New York. pp. 287-308

Barkay, T., and R. Turner. 1989. Gene probes to predict responses of aquatic microbial communities to toxic metals. Manag. Control Heavy Met. Environ. Int. Conf. 1989, pp. 57.

Turner, R., A.J. VandenBrook, T. Barkay, and J.W. Elwood. 1989. Volatilizaiton, methylation and demethylation of mercury in a mercury-contaminated stream. Manag. Control Heavy Met. Environ. Int. Conf. 1989, pp. 353.

Barkay, T., M. Gillman, and C. Liebert. 1990. Genes encoding mercuric reductases from selected gram negative aquatic bacteria have a low degree of homology with merA of transposon 501. Appl. Environ. Microbiol. 56:1695-1701.

Liebert, C., T. Barkay, and R. Turner. 1991. Microbial acclimation to CH3Hg+ and Hg2+ in a mercury polluted freshwater pond. Microb. Ecol. 21:139-149.

Barkay, T., R. Turner, A. VandenBrook, and C. Liebert. 1991. The relationships of Hg(II) volatilization from a freshwater pond to abundance of mer genes in the gene pool of the indigenous microbial community. Microb. Ecol. 21:151-161.

Barkay, T., and C. Liebert. 1991. Distribution of metal-resistant microorganisms in the environment, p. 663-682. in: Levin, M.A., R.J. Seidler, and M. Rogul (eds). Microbial Ecology: Principles, Methods, and Applications. McGraw-Hill, Inc., New York.

Barkay, T. The mercury cycle. 1992. Encyclopedia of Microbiology. Vol. 3 p. 65-74. Academic Press, Inc., San Diego.

Barkay, T., R. Turner, E. Saouter, and J. Horn. 1992. Mercury biotransformations and their potential for remediation of mercury contamination. Biodegradation. 3:147-159.

Barkay, T., C. Liebert, and M. Gillman. 1993. Conjugal gene transfer to aquatic bacteria detected by the generation of a new phenotype. Appl. Environ. Microbiol. 59:807-814.

Selifonova, O., R. Burlage, and T. Barkay. 1993. Preparation of bioluminescent sensors for detection of Hg(II) in the environment. Appl. Environ. Microbiol. 59:3083-3090.

Saouter, E., R. Turner, and T. Barkay. 1994. Mercury microbial transformations and their potential for the remediation of a mercury-contaminated site. In: Means, J.L., and R.E. Hinchee (eds), Emerging Technology for Bioremediation of Metals, Lewis Publishers, Boca Raton, FL. pp. 99-104.

Saouter, E., R. Turner, and T. Barkay. 1994. Microbial reduction of ionic mercury for the removal of mercury from contaminated environments. Proceedings of the Symposium on "Recombinant DNA technology II". Ann. NY Acad. Sci. 721:423-427.

Devereux, R., T. Barkay, and J. Harvey. 1994. Application of microbial ecology research to environmental problems. Water Report: Quality, Resources and Technology 4:8-11.

Selifonova, O., and T. Barkay. 1994. Role of sodium in transport of mercuric ions and induction of the Tn21 mer operon. Appl. Environ. Microbiol. 60:3503-3507.

Nazaret, S., W.H. Jeffrey, E. Saouter, R. Von Haven, and T. Barkay. 1994. merA gene expression in aquatic environments measured by mRNA production and Hg(II) volatilization. Appl. Environ. Microbiol. 60:4059-4065.

Saouter, E., M. Gillman, R. Turner, and T. Barkay. 1995. Development and field validation of a microcosm to simulate the mercury cycle in a contaminated pond. J. Environ. Toxicol. Chem. 14:69-77.

Barkay, T., N. Kroer, L.D. Rasmussen, and S. J. Sorensen. 1995. Conjugal transfer at natural population densities in a microcosm simulating an estuarine environment. FEMS Microbiol. Ecol. 16:43-54.

Barkay, T., S. Nazaret, and W. Jeffrey. 1995. Biodegradative genes in the environment. in: Transformation and Degradation of Toxic Organic Chemicals, Young, L. and C. Cerniglia (eds), J. Wiley Sons, Inc. pp. 545-577.

Saouter, E., M. Gillman, and T. Barkay. 1995. An evaluation of mer specified reduction of ionic mercury as a remedial tool of a mercury contaminated freshwater pond. J. Ind. Microbiol. 14:343-348.

Oremland, R.S., L.G. Miller, P. Dowdle, T. Connell, and T. Barkay. 1995. Methylmercury oxidative degradation potentials in contaminated and pristine sediments of the Carson River, Nevada. Appl. Environ. Microbiol. 61:2745-2753.

Vaithiyanathan, P., R.G. Kavanaugh, , C.B. Craft, C. J. Richardson, and T. Barkay. 1996. The role of eutrophication in the distribution and potential net methylation of mercury in the peat soils of the Everglade. Env. Sci. Technol. 30:2591-2597.

Jeffrey, W.H., S. Nazaret, and T. Barkay. 1996. Detection of the merA gene and its expression in the environment. Microb. Ecol. 32:293-303.

Sørensen, S.J., N. Kroer, E. Sørensen, G. Sengeløv, and T. Barkay. 1996. Conjugation in aquatic environments. in: Molecular Microbial Ecology Manual, Akkermans, A.D.L., J.D. van Elsas, and F.J. de Bruijn (eds.), Kluwer Academic Publishers.

Rasmussen, L.D., R.R. Turner, and T. Barkay. 1997. Cell-density dependent sensitivity of a mer-lux bioassay. Appl. Environ. Microbiol. 63:3291-3293.

Barkay, T., M. Gillman, and R.R. Turner. 1997. Effects of dissolved organic carbon and speciation of Hg(II) on bioavailability of mercury. Appl. Environ. Microbiol. 63:4267-4271.

Barkay, T. 1997. A mer-lux reporter system to study factors that determine mercury availability to bacteria. in: Progress in Microbial Ecology, Martins, M.T. M.I.Z. Sato, J.M. Tiedje, L.C.N. Hagler, J. Döbereiner, and P.S. Sanchez (eds), SBM - Brazilian Society for Microbiology, Sâo Paulo, Brazil, pp. 551-557.

Kroer, N., T. Barkay, S.J. Sørensen, and D. Weber. 1998. Effects of root exudates and bacterial metabolic activity on conjugal gene transfer in the rhizosphere of a marsh plant. FEMS Microbiol. Ecol. 25:375-384.

Barkay, T., R.R. Turner, L.D. Rasmussen, C. Kelly, and J.Rudd. 1998. Lux-facilitated detection of mercury in natural waters. in: Bioluminescent Protocols, LaRossa, R. (ed). Humana Press, Inc. Totowa, NJ. pp. 231-246.

Kurtz, J.C., R. Devereux, T. Barkay, and R.B. Jonas. 1998. Evaluation of sediment slurry microcosms for modeling microbial communities in estuarine sediments. Environ. Toxicol. Chem. 17:1274-1281.

de Lipthay, J.R., T. Barkay, J. Vekova, and S.J. Sørensen. 1999. Utilization of phenoxyacetic acid by strains using either the ortho or meta cleavage of catechol during phenol degradation after conjugal transfer of tfdA, the gene encoding a 2,4-dichlorophenoxyacetic acid/2-oxoglutarate dioxygenase. Appl. Microbiol. Biotechnol. 51:207-214.

Rosenberg, E., T. Barkay, S. Navon-Venezia, and E.Z. Ron. 1999. Role of Acinetobacter bioemulsans in petroleum degradation. In: Novel Approaches for Bioremediation of Organic Pollution. Fass, R., Y. Flashner, and S. Reuveny (eds) Kluwer Academic/Plenum Publishers, New York, pp/ 171-180.

Barkay, T., S. Navon-Venezia, E.Z. Ron, and E. Rosenberg. 1999. Enhanced solubilization and biodegradation of polyaromatic hydrocarbons by the bioemulsifier alasan. Appl. Environ. Microbiol. 65:2697-2702.

Barkay, T. The mercury cycle. 2000. Encyclopedia of Microbiology. 2nd edition. Academic Press, Inc., San Diego. pp. 171-181.

Rasmussen, L.D., S.J. Sørensen, T.R. Turner, and T. Barkay. 2000. Application of a mer-lux biosensor for estimating bioavailable mercury in soil and its utility in relating the response of soil microbial communities to bioavailable mercury. Soil Biol. Biochem. 32:639-646.

Hines, M.E., M. Horvat, J. Faganeli, J.-C. Bonzongo, T. Barkay, E.B. Major, K.J. Scott,
E.A, Bailey, J.J. Warwick, and W.B. Lyons. 2000. Mercury biogeochemistry in the Idrija River, Slovenia from above the mine into the Gulf of Trieste. Environ. Res. 83:129-139.

de Lipthay, R.J., T. Barkay, and S.J. Sørensen. 2001. Enhanced degradation of phenoxyacetic acid in soil by horizontal transfer of the tfdA gene encoding a 2,4-dichlorophenoxyacetic acid dioxygenase. FEMS Microbiol. Ecol. 35:75-84.

Barkay, T., and J. Schaefer. 2001. Metal and radionuclide bioremediation: Issues, considerations, and potentials. Curr. Opion. Microbiol. 4:318-323.

Barkay, T. 2001. Molecular and biochemical investigation of the potential for microbial mercury volatilisation in the Idrijca River – Gulf of Trieste ecosystem. Materials Geoenviron. 48:109-115.

Schaefer, J.K., R. Dorn, and T. Barkay. 2001. Microbial factors controlling methylmercury accumulation in freshwater ecosystems in New Jersey, USA. Materials Geoenviron. 48:219-225.

Sørensen, S.J., J. Radnoti de Lipthay, A.K. Müller, T. Barkay, L.H. Hansen, and L.D. Rasmussen. 2002. Molecular methods for assessing and manipulating the diversity of microbial populations and processes. In: Enzymes in the Environment. Burns, R.G. (ed). Marcel Dekker. pp. 363 – 389.

Schaefer, J.K., J. Letowski, and T. Barkay. 2002. mer-mediated resistance and volatilization of Hg(II) under anaerobic conditions. Geomicrobiol. J. 19:87-102.

de Lipthay, J.R. , J. Aamand , and T. Barkay. 2002. Expression of the tfdA gene in aquatic microbial communities during degradation of 2,4-dichlorophenoxyacetic acid. FEMS Microbiol. Ecol. 40:205-214.

Golding G.R., C.A Kelly, R. Sparling, P.C. Loewen, J.W.M. Rudd, and T. Barkay. 2002. Demonstration of facilitated uptake of Hg(II) by Vibrio anguillarum and Escherichia coli under anaerobic and aerobic conditions. Limnol. Oceanog. 47:967-975.

Benyehuda, G., J. Coombs, P.M. Ward, D. Balkwill, and T. Barkay. 2003. Metal resistance among aerobic chemoheterotrophic bacteria from the deep terrestrial subsurface. Can. J. microbiol. 49:151-156.

Barkay, T., S. Miller, and A.O. Summers. 2003. Bacterial mercury resistance from atoms to ecosystems. FEMS Microbiol. Rev. 27:355-384.

Coombs, J.M., and T. Barkay. 2004. Molecular evidence for the evolution of metal homeostasis genes by lateral gene transfer in bacteria from the deep terrestrial subsurface. Appl. Environ. Microbial. 70:1698-1707.

Schaefer, J.K., J. Yagi, J. Reinfelder, T. Cardona, K. Ellickson, S. Tel-Or, and T. Barkay. 2004. The role of the bacterial organomercury lyase (MerB) in controlling methylmercury accumulation in mercury contaminated natural waters. Env. Sci. Technol. 38:4304-4311.

Poulain, A., M. Amyot, D. Findlay, S. Telor, T. Barkay, and H. Hintelmann. 2004. Biological and photochemical production of dissolved gaseous mercury in a boreal lake. Limnol. Oceanog. 49:2265-2275.

Vetriani, C., Y.S., Chew, S.M. Miller, J. Yagi, R.A. Lutz, and T. Barkay. 2005. Mercury adaptation among bacteria from a deep-sea hydrothermal vent. Appl. Enviorn. Microbiol. 71:220-226.

Barkay, T., and I. Wagner-Döbler. 2005. Microbial transformations of mercury: potentials, challenges, and achievements in controlling mercury toxicity in the environment. Adv. Appl. Microbiol. 57:1-52

Wiatrowski, H.A., and T. Barkay. 2005. Monitoring of microbial metal transformations in the environment. Curr. Opin. Biotechnol. 16:261-268

Barkay, T., and B.F. Smets. 2005. Horizontal gene flow in microbial communities. ASM News 71:412-419

Smets B.F., and T. Barkay. 2005. Horizontal gene transfer: Perspectives at a crossroads of scientific disciplines. Nat. Rev. Microbiol. 3:675-678

Coombs, J.M., and T. Barkay. 2005. Horizontal gene transfer of metal homeostasis genes and its role in microbial communities of the deep terrestrial subsurface. Sixty-fifth Symposium of the Society of General Microbiology “Micro-organisms and Earth Systems – Advances in Geomicrobiology”. pp. 109–129. Cambridge University Press, New York.

Coombs, J.M., and T. Barkay. 2005. New findings on evolution of metal homeostasis genes: Evidence from comparative genome analysis of bacteria and archaea. Appl. Environ. Microbial. 71:7083-7091

Martinez, R.J. Y. Wang, M.A. Raimondo, J.M. Coombs, T. Barkay, and P.A. Sobecky. 2006.
Horizontal gene transfer of PIB-type ATPases among bacteria isolated from radionuclide- and metal contaminated subsurface soils. Appl. Environ. Microbiol. 72:3111-3118

Ní Chadhain, S., J.K. Schaefer, S. Crane, G.J. Zylstra, and T. Barkay. 2006. Analysis of mercuric reductase (merA) gene diversity in an anaerobic mercury–contaminated sediment enrichment. Environ. Microbiol. 8:1746-1752

Wiatrowski, H.A., P.M. Ward, and T. Barkay. 2006. Novel reduction of mercury(II) by mercury-sensitive dissimilatory metal reducing bacteria. Env. Sci. Technol. 40:6690-6696

Barkay, T. and A.J. Poulain. 2007. Mercury (micro)biogeochemistry in polar environments. 2007. FEMS Microbiol. Ecol. 59:232

Kritee K., J. Blum, M. Johnson, B. Bergquist, and T. Barkay. 2007. Mercury stable isotope fractionation during reduction of Hg(II) to Hg(0) by mercury resistant microorganisms. Env. Sci. & Technol. 41:1889-1895

Poulain, A.J. S.M. Ní Chadhain, P.A. Ariya, M. Amyot, E. Garcia, P.G.C. Campbell, G.J. Zylstra, and T. Barkay. 2007. Potential for mercury reduction by microbes in the high Arctic. Appl. Environ. Microbiol. 73: 2230–2238

Chatziefthimiou, A., M. Crespo-Medina, Y. Wang, C. Vetriani, and T. Barkay. 2007. The
isolation and initial characterization of mercury resistant chemolithotrophic thermophilic bacteria from mercury rich geothermal springs. Extremophiles 11:469-479

Nemergut, D.R., T. Barkay, and J. Coombs. 2007. Mobile gene elements in environmental
microbial communities. Manual of Environmental Microbiology, 3rd edition, C.J. Hurst, R.L.Crawford, J.L. Garland, D.A. Lipson, A.L. Mills, and L.D. Stetzenbach (eds), ASM Press, Washington, DC, pp. 758-768.

Golding, G.R., C. A. Kelly, R. Sparling, P. C. Loewen, and T. Barkay. 2007. Evaluation of mercury toxicity as a predictor of mercury bioavailability. Env. Sci. & Technol. 41:5685-5692

Cardona-Marek, T., J. K. Schaefer, K. Ellickson, T. Barkay, and J.R. Reinfelder. 2007. Mercury speciation, reactivity, and bioavailability in a highly contaminated estuary, Berry’s Creek, New Jersey Meadowlands, U.S.A. Env. Sci. & Tachnol. 41:8268-8274.

Atamna-Ismaeel, N., Sharon, I., Sabehi, G., Witzel, K-.P., Labrenz, M., Jürgens, K., Barkay, T. Stomp, M., Huisman, J., and Beja, O. 2008. Widespread distribution of proteorhodopsins in freshwater and brackish ecosystems. ISME J. 2:656-662

Kritee, K., J.D. Blum, and T. Barkay. 2008. Constraints on the extent of mercury stable isotope fractionation during reduction of Hg(II) by different microbial species. Env. Sci. Technol. 42:9171-9177

Crespo-Medina, M., A.D. Chatziefthimiou, N.S. Bloom, G.W. Luther III, D.D. Wright, J.R. Reinfelder, C. Vetriani, and T. Barkay. 2009. Adaptation of chemosynthetic microorganisms to elevated mercury concentrations in deep-sea hydrothermal vents. Limnol. Ocaenog. 54:41-49

Wang, Y., Z. Freedman, P. Lu-Irving, R. Kaletsky, and T. Barkay. 2009. An initial characterization of the mercury resistance (mer) system of the thermophilic bacterium Thermus thermophilus HB27. FEMS Microbiol. Ecol. 67:118-129

Kritee, K., T. Barkay, and J.D. Blum. 2009. Mass dependent stable isotope fractionation of mercury during microbial degradation of methylmercury. Geochim. Cosmochim. Acta. 73:1285-1296

Sherman, L.S., J. D. Blum, D.K. Nordstrom, R.B. McCleskey, T. Barkay, and C. Vetriani. 2009. Mercury isotopic composition of hydrothermal systems in the Yellowstone Plateau volcanic field and Guaymas Basin sea-floor rift. Earth Planet. Sci. Lett. 279:86-96

Boyd, E., S. King, J.K. Tomberlin, D.K. Nordstrom, D.P. Krabbenhoft, T. Barkay, and G. Geesey. 2009. Methylemrcury enters an aquatic food web through acidophilic microbial mats in Yellowstone National Park, Wyoming. Environ. Microbiol. 11:950-959

Crespo-Medina, M., A. Chatziefthimiou, R. Cruz-Matos, I. Pérez-Rodríguez, T. Barkay, R.A. Lutz, V. Starovoytov, and C. Vetriani. 2009. Salinisphaera hydrothermalis sp. nov, a mesophilic, halotolerant, facultative autotrophic, thiosulfate oxidizing Gammaproteobacterium from deep-sea hydrothermal vents. Int. J. Syst. Evol. Microbiol. 59:1497-1503

Wiatrowski, H.A. S. Das, R. Kukkadapu, E. Ilton, T. Barkay, and N. Yee. 2009. Reduction of Hg(II) to Hg(0) by Magnetite. Env. Sci & Technol. 42:5307-5313

Crane, S., T. Barkay, and J. Dighton. 2010. Growth responses to and accumulation of mercury by ectomycorrhizal Fungi. Fungal Biol. 114:873-880

Barkay. T., K. Kritee, E. Boyd, and G. Geesey. 2010. A thermophilic bacterial origin and subsequent constraints by redox, light, and salinity on the evolution of the microbial mercuric reductase. Environ. Microbiol. 12:2904-2917. Evaluated as a “Must Read” by Faculty of 1000

Yu, R.-Q., Adatto, I., Montesdeoca, M.R., Driscoll, C.T., Hines, M.E., and Barkay, T. 2010. Mercury methylation in Sphagnum moss mats and its association with sulfate reducing bacteria in an acidic Adirondack forest lake wetland. FEMS Microbiol. Ecol. 74:655-668.

Shin, D. H.S. Moon, C.-C. Lin, T. Barkay, K. Nam. 2011. Use of reporter-gene based bacteria to quantify phenanthrene biodegradation and toxicity in soil. Environ. Poll. 159:509-514

Møller, A.K., T. Barkay, W. Abu Al-Soud, S.J. Sørensen, H. Skov, and N. Kroer. 2011. Diversity and characterization of culturable mercury resistant bacteria in snow, freshwater and sea-ice
brine from the high Arctic. FEMS Microbiol. Ecol. 75:390-401

Hamelin, S., M. Amyot, T. Barkay, Y. Wang, and D. Planas. 2011. Methanogens: principal methylators of mercury in lake periphyton. Environ. Sci. Technol. 45:7693-7700.

Wang, Y., E. Boyd, S. Crane, P. Lu-Irving, D. Krabbenhoft, S. King, J. Dighton, G. Geesey, and T. Barkay. 2011. Environmental conditions constrain the distribution and diversity of archaeal merA in Yellowstone National Park, Wyoming. Microb. Ecol. 62:739-752

Barkay, T., N. Kroer, and A. Poulain. 2011. Some like it cold: microbial transformations of Hg in polar regions. Polar Res. 30, 15469, DOI: 10.3402/polar.v30i0.15469

Lin, C.-C., N. Yee, and T. Barkay. 2012. Microbial transformation in the mercury cycle. In: Environmental Chemistry and Toxicology of Mercury. G. Liu, Y. Cai, and N. O’Driscoll (eds.).
John Wiley & Sons, Inc. pp. 155-191

Crane, S., T. Barkay, and J. Dighton. 2012. The effect of mercury on the establishment of Pinus rigida seedlings and the development of their ectomycorrhizal communities. Fungal Ecol. 5:245-251

Yu, R.-Q, J. R. Flanders, E. E. Mack, R. Turner, M. B. Mirza, and T. Barkay. 2012. Coexisting Sulfate and Iron Reducing Bacteria Contribute to Methylmercury Production in Freshwater River Sediments. Environ. Sci. Technol. 46:2684-2691

Douglas, T.A, L. Loseto, R. Macdonald, P. Outridge, A. Dommergue, A. Poulain, M. Amyot, T. Barkay, T. Berg, J. Chételat, P. Constant, M. Evans, C. Ferrari, N. Gantner, M. Johnson, J. Kirk, N. Kroer, C. Larose, D. Lean, T.G. Nielsen, L. Poissant, S. Rognerud, H. Skov, S. Sørensen, F. Wang, S. Wilson, and C.M. Zdanowicz. 2012. The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review. Environ. Chem. 9:321-355.

Freedman, Z., C. Zhu, and T. Barkay. 2012. Mercury resistance, mercuric reductase activities and expression among chemotrophic thermophilic Aquificae. Appl. Environ. Microbiol. 78:6568-6575.

Boyd, E., and T. Barkay. 2012. The mercury resistance operon: from an origin in geothermal environments to an efficient detoxification machine. Front. Microbiol. 3: Article 349, 10.3389/fmicb.2012.00349.

Meredith, M.M., Parry, E.M., Guay, J.A., Markham, N.O., Danner, G.R., Johnson, K.A., Barkay, T., and Fekete, F.A. 2012. Concomitant antibiotic and mercury resistance among gastrointestinal microflora of feral brook trout, Salvelinus fontinalis. Curr. Microbiol. 65:575-582

Wang, Y., H.A. Wiatrowski, R. John, C.-C. Lin, L.Y. Young, L.J. Kerkhof, N. Yee, and T. Barkay. 2013. Impact of mercury on denitrification and denitrifying microbial communities in nitrate enrichments of subsurface sediments. Biodegradation 24:33-46

Kritee, K., J.D. Blum, J.R. Reinfelder, and T. Barkay. 2013. Microbial stable isotope fractionation of mercury: a synthesis of present understanding and future directions. Chem. Geol. 336:13-25

Poulain, A.J., and T. Barkay. 2013. Cracking the mercury methylation code. Science 339:1280-1281. DOI: 10.1126/science.1235591

Colombo, M., J. Ha, J.R. Reinfelder, T.Barkay, and N. Yee. 2013. Anaerobic oxidation of Hg(0) and methylmercury formation by Desulfovibrio desulfuricans ND132. Geochim. Cosmochim. Acta. 112:166-177.

Yu, R.-Q, J. Reinfelder, M. Hines, and T. Barkay. 2013. Mercury methylation by the methanogen Methanospirillum hungatei. Appl. Environ. Microbiol. 79:6325-6330. DOI: 10.1128/AEM.01556-13

Møller, A.K., T. Barkay, M.A. Hansen, A. Norman, L. H. Hansen, S.J. Sørensen, E.B. Boyd and N. Kroer. 2014. Mercuric reductase genes (merA) and mercury resistance plasmids in High Arctic snow, freshwater, and sea-ice brine. FEMS Microbiol. Ecol. 87:52-63

Shah, M., C.-C. Lin, R. Kukkadapu, M.H. Engelhard, X. Zhao, Y.Wang, T. Barkay, and N. Yee. 2014. Syntrophic effects in a subsurface clostridial consortium on Fe(III)-(Oxyhydr)oxide reduction and secondary mineralization. Geomicrobiol. J. 31:101-115

Colombo, M., J. Ha, J. Reinfelder, T. Barkay, and N. Yee. Oxidation of Hg(0) to Hg(II) by Diverse Anaerobic Bacteria. 2014. Chem. Geol. 363:334-340

Santos-Gandelman, J.F., G., Muricy, M. Giambiagi-deMarval, T. Barkay, and M.S. Laport. 2014. Potential application in mercury bioremediation of a marine sponge-isolated Bacillus cereus strain Pj1. Curr. Microbiol. 69:374-380

Santos-Gandelman, J.F., Giambiagi-deMarval, M., Guilherme M., T. Barkay, and M.S. Laport. 2014. Mercury and methylmercury detoxification potential by sponge-associated bacteria. Antonie van Leeuwenhoek J. Microbiol. 106:585-590.

S. Janssen, M.W. Johnson, J.D. Blum, T. Barkay, and J.R. Reinfelder. Separation of monomethylmercury from estuarine sediments for mercury isotope analysis. Chem. Geol. 411:19-25.


Ndu, U., T. Barkay, R.P. Mason, A.T. Schartup, R. Al-Farawati, J. Liu, and J.R. Reinfelder. 2015. The use of a mercury biosensor to evaluate the bioavailability of mercury-thiol complexes and mechanisms of mercury uptake in bacteria. PLoS ONE. 10(9):e0138333. doi: 10.1371/journal.pone.0138333

Ndu, U., T. Barkay, A. Traore Schartup, R.P. Mason, and J. R. Reinfelder. 2016. The effect of aqueous speciation and cellular ligand binding on the biotransformation and bioavailability of methylmercury in mercury-resistant bacteria. Biodegradation 27:29-36.

Cabral, L., R.-Q. Yu, S. Crane, P. Giovanella, T. Barkay, and F.A.O. Camargo. Methylmercury degradation by Pseudomonas putida V1. Ecotoxicol. Environ. Safety. Accepted.

Lu, X., Y, Liu, A. Johs, L. Zhao, T. Wang, Z. Yang, H. Lin, D.A. Elias, E.M. Pierce, L. Liang, T. Barkay, and B. Gu. Anaerobic Mercury Methylation and Demethylation by Geobacter bemidjensis Bem. Environ. Sci. and Technol. Accepted.

Janssen, S.E., J.K. Schaefer, T. Barkay, and J.R. Reinfelder. Fractionation of mercury stable isotopes during microbial methylmercury production by iron- and sulfate- reducing bacteria. Environ. Sci. Technol. Submitted

Ha, J., X. Zhao, R.-Q Yu, T. Barkay, and N. Yee. Hg(II) Reduction by Siderite (FeCO3). Appl. Geochem. Submitted

Geesey, G.G., T. Barkay, D.K. Nordstrom, and S. King. Geothermal mercury and microbes in western North America. Sci. Tot. Environ. Submitted

N. Lloyd, S. Janssen, J.R. Reinfelder, and T. Barkay. Exposure to Hg selects for antibiotic resistance in the Fundulus heteroclitis gut microbiome. Curr. Microbiol. In preparation.

Norambuena Morales, J., Y. Wang, J. Boyd, T. Hanson and T. Barkay. The mer operon of Thermus thermophilus: evidence for a direct link between low-molecular weight thiol metabolism and mercury stress. J. Bacteriol. In preparation

Cruz, K., Crespo-Medina, M., C. Vetriani, and T. Barkay. mer–independent mercury resistance among chemotrophic bacteria from deep-sea hydrothermal vents. PLoS ONE. In preparation.

Cruz, K., J. Guezennec, and T. Barkay. The roles of bacterial exopolysaccharides in mercury sorption and resistance. In preparation.

Yu, R.-Q, J. R. Reinfelder, M. Hines, and T. Barkay. Syntrophic pathways for microbial mercury methylation. Nat. Geosci. In preparation.


11:680:491 | Microbial Ecology & Diversity
11:680:390 | General Microbiology
16:682:572 | Microbial Ecology & Diversity