Denise M. Akob, Ph.D.
Denise Akob is a Research Microbiologist for the USGS Geology, Energy & Minerals (GEM) Science Center in Reston, VA.
Dr. Denise M. Akob is a microbial ecologist and biogeochemist whose research aims to understand interactions between microbes and their environment and address effects of anthropogenic contaminants on environmental health and water quality. Her research focuses primarily on understanding microbial impacts on Cold War Biogeochemistry (uranium and chlorinated solvent contamination); energy production (either by mitigating degradation of contaminants (from hydraulic fracturing or oil spills) or by enhancing natural gas production); and carbon cycling. Dr. Akob joined the U.S. Geological Survey in 2012 as a research scientist in the Water Mission Area, and move to the Geology, Energy, and Minerals Science Center in 2020. For more information, please visit the Reston Microbiology Lab website.
Professional Experience
Research Microbiologist, U.S. Geological Survey, Geology, Energy, & Minerals Science Center, Reston Microbiology Laboratory, 2020-current
Affiliated Professor, Department of Biology at George Mason University, 2017-current
Affiliated Professor, Department of Geology, Appalachian State University, 2017-current
Affiliated Professor, Department of Geography and Planning, Appalachian State University, 2016-current
Affiliated Professor, Environmental Science and Policy Department at George Mason University, 2013-current
Research Microbiologist, U.S. Geological Survey, Water Mission Area, Reston Microbiology Laboratory, 2012-2020
Postdoctoral Research Fellow, Friedrich-Schiller University Jena, 2010-2012
Marie Curie Postdoctoral Research Fellow, Friedrich-Schiller University Jena, 2008-2010
Education and Certifications
Ph.D. 2008, Florida State University, Department of Oceanography, Advisor: Dr. Joel E. Kostka
B.A. 2002, St. Mary’s College of Maryland, Major: Biology
Affiliations and Memberships*
Chair, 2025 Applied and Environmental Microbiology Gordon Research Conference
Chair, American Society for Microbiology’s Council on Microbial Sciences (COMS), 2023-2024
Vice Chair, American Society for Microbiology’s Council on Microbial Sciences (COMS), 2022-2023
Vice Chair, 2023 Applied and Environmental Microbiology Gordon Research Conference
Editorial Board Member, FEMS Microbiology Ecology, 2016-present
Editorial Board Member, Applied and Environmental Microbiology, January 1, 2018-present
Editorial Board Member, ISME Communications, 2020-present
Associate Editor, Biogeosciences, 2016-2023
Councilor, Washington, D.C. Branch of the American Society for Microbiology, 2021-2022
President, Washington, D.C. Branch of the American Society for Microbiology, 2019-2021
President-Elect, Washington, D.C. Branch of the American Society for Microbiology, 2017-2019
USGS Community for Data Integration’s Bioinformatics Community of Practice, co-organizer, 2017-present
USGS Eastern Water Science Series, co-organizer, 2017-present
Applied and Environmental Microbiology Gordon Research Seminar Mentor, July 15-16, 2017
USGS NRP-EB Weekly Science Series, co-organizer (2013-2017)
Geobiology Theme Chair, Goldschmidt 2015 25th Anniversary Meeting
Co-Chair for Session T50. Microbial Hydrocarbon Formation and Biodegradation: Organisms, Pathways, Environmental Limitations, and Isotope Signatures, 2015 Geological Society of America Annual Meeting
Honors and Awards
USGS Early Career Leadership Award, 2017
Science and Products
Detection of diazotrophy in the acetylene-fermenting anaerobe Pelobacter sp. strain SFB93
Archaeal diversity and CO2 fixers in carbonate-/siliciclastic-rock groundwater ecosystems
Shifts in microbial community structure and function in surface waters impacted by unconventional oil and gas wastewater revealed by metagenomics
Environmental signatures and effects of an oil and gas wastewater spill in the Williston Basin, North Dakota
Complete genome sequences of two acetylene-fermenting Pelobacter acetylenicus strains
Complete genome sequence of the acetylene-fermenting Pelobacter sp. strain SFB93
Microbially mediated barite dissolution in anoxic brines
Environmental drivers of differences in microbial community structure in crude oil reservoirs across a methanogenic gradient
Biological low pH Mn(II) oxidation in a manganese deposit influenced by metal-rich groundwater
Wastewater disposal from unconventional oil and gas development degrades stream quality at a West Virginia injection facility
Endocrine disrupting activities of surface water associated with a West Virginia oil and gas industry wastewater disposal site
Dominance of 'Gallionella capsiferriformans' and heavy metal association with Gallionella-like stalks in metal-rich pH 6 mine water discharge
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Publications
Filter Total Items: 43
Detection of diazotrophy in the acetylene-fermenting anaerobe Pelobacter sp. strain SFB93
Acetylene (C2H2) is a trace constituent of the present Earth's oxidizing atmosphere, reflecting a mixture of terrestrial and marine emissions from anthropogenic, biomass-burning, and unidentified biogenic sources. Fermentation of acetylene was serendipitously discovered during C2H2 block assays of N2O reductase, and Pelobacter acetylenicus was shown to grow on C2H2 via acetylene hydratase (AH). AHAuthorsDenise M. Akob, Shaun Baesman, John M. Sutton, Janna L. Fierst, Adam Mumford, Yesha Shrestha, Amisha T. Poret-Peterson, Stacy C. Bennett, Darren S. Dunlap, Karl B. Haase, Ronald S. OremlandArchaeal diversity and CO2 fixers in carbonate-/siliciclastic-rock groundwater ecosystems
Groundwater environments provide habitats for diverse microbial communities, and although Archaea usually represent a minor fraction of communities, they are involved in key biogeochemical cycles. We analysed the archaeal diversity within a mixed carbonate-rock/siliciclastic-rock aquifer system, vertically from surface soils to subsurface groundwater including aquifer and aquitard rocks. ArchaealAuthorsCassandre Sara Lazar, Wenke Stoll, Robert Lehmann, Martina Herrmann, Valérie F. Schwab, Denise M. Akob, Ali Nawaz, Tesfaye Wubet, François Buscot, Kai-Uwe Totsche, Kirsten KüselShifts in microbial community structure and function in surface waters impacted by unconventional oil and gas wastewater revealed by metagenomics
Unconventional oil and gas (UOG) production produces large quantities of wastewater with complex geochemistry and largely uncharacterized impacts on surface waters. In this study, we assessed shifts in microbial community structure and function in sediments and waters upstream and downstream from a UOG wastewater disposal facility. To do this, quantitative PCR for 16S rRNA and antibiotic resistancAuthorsN.L. Fahrenfeld, Hannah Delos Reyes, Alessia Eramo, Denise M. Akob, Adam Mumford, Isabelle M. CozzarelliEnvironmental signatures and effects of an oil and gas wastewater spill in the Williston Basin, North Dakota
Wastewaters from oil and gas development pose largely unknown risks to environmental resources. In January 2015, 11.4 M L (million liters) of wastewater (300 g/L TDS) from oil production in the Williston Basin was reported to have leaked from a pipeline, spilling into Blacktail Creek, North Dakota. Geochemical and biological samples were collected in February and June 2015 to identify geochemicalAuthorsIsabelle M. Cozzarelli, Katherine Skalak, D.B. Kent, Mark A. Engle, Adam J. Benthem, Adam Mumford, Karl B. Haase, Aïda M. Farag, David Harper, S. C. Nagel, Luke R. Iwanowicz, William H. Orem, Denise M. Akob, Jeanne B. Jaeschke, Joel M. Galloway, Matthias Kohler, Deborah L. Stoliker, Glenn D. JollyComplete genome sequences of two acetylene-fermenting Pelobacter acetylenicus strains
Acetylene fermentation is a rare metabolism that was serendipitously discovered during C2H2-block assays of N2O reductase. Here, we report the genome sequences of two type strains of acetylene-fermenting Pelobacter acetylenicus, the freshwater bacterium DSM 3246 and the estuarine bacterium DSM 3247.AuthorsJohn M. Sutton, Shaun Baesman, Janna L. Fierst, Amisha T. Poret-Peterson, Ronald S. Oremland, Darren S. Dunlap, Denise M. AkobComplete genome sequence of the acetylene-fermenting Pelobacter sp. strain SFB93
Acetylene fermentation is a rare metabolism that was previously reported as being unique to Pelobacter acetylenicus. Here, we report the genome sequence of Pelobacter sp. strain SFB93, an acetylene-fermenting bacterium isolated from sediments collected in San Francisco Bay, CA.AuthorsJohn M. Sutton, Shaun Baesman, Janna L. Fierst, Amisha T. Poret-Peterson, Ronald S. Oremland, Darren S. Dunlap, Denise M. AkobMicrobially mediated barite dissolution in anoxic brines
Fluids injected into shale formations during hydraulic fracturing of black shale return with extraordinarily high total-dissolved-solids (TDS) and high concentrations of barium (Ba) and radium (Ra). Barite, BaSO4, has been implicated as a possible source of Ba as well as a problematic mineral scale that forms on internal well surfaces, often in close association with radiobarite, (Ba,Ra)SO4. The dAuthorsBingjie Ouyang, Denise M. Akob, Darren S. Dunlap, Devon RenockEnvironmental drivers of differences in microbial community structure in crude oil reservoirs across a methanogenic gradient
Stimulating in situ microbial communities in oil reservoirs to produce natural gas is a potentially viable strategy for recovering additional fossil fuel resources following traditional recovery operations. Little is known about what geochemical parameters drive microbial population dynamics in biodegraded, methanogenic oil reservoirs. We investigated if microbial community structure was significaAuthorsJenna L. Shelton, Denise M. Akob, Jennifer C. McIntosh, Noah Fierer, John R. Spear, Peter D. Warwick, John E. McCrayBiological low pH Mn(II) oxidation in a manganese deposit influenced by metal-rich groundwater
The mechanisms, key organisms, and geochemical significance of biological low-pH Mn(II) oxidation are largely unexplored. Here, we investigated the structure of indigenous Mn(II)-oxidizing microbial communities in a secondary subsurface Mn oxide deposit influenced by acidic (pH 4.8) metal-rich groundwater in a former uranium mining area. Microbial diversity was highest in the Mn deposit compared tAuthorsTsing Bohu, Denise M. Akob, Michael Abratis, Cassandre S. Lazar, Kirsten KüselWastewater disposal from unconventional oil and gas development degrades stream quality at a West Virginia injection facility
The development of unconventional oil and gas (UOG) resources has rapidly increased in recent years; however, the environmental impacts and risks are poorly understood. A single well can generate millions of liters of wastewater, representing a mixture of formation brine and injected hydraulic fracturing fluids. One of the most common methods for wastewater disposal is underground injection; we arAuthorsDenise M. Akob, Adam Mumford, William H. Orem, Mark A. Engle, Julia (Grace) Klinges, Douglas B. Kent, Isabelle M. CozzarelliEndocrine disrupting activities of surface water associated with a West Virginia oil and gas industry wastewater disposal site
Currently, >95% of end disposal of hydraulic fracturing wastewater from unconventional oil and gas operations in the US occurs via injection wells. Key data gaps exist in understanding the potential impact of underground injection on surface water quality and environmental health. The goal of this study was to assess endocrine disrupting activity in surface water at a West Virginia injection wellAuthorsChristopher D. Kassotis, Luke R. Iwanowicz, Denise M. Akob, Isabelle M. Cozzarelli, Adam Mumford, William H. Orem, Susan C. NagelDominance of 'Gallionella capsiferriformans' and heavy metal association with Gallionella-like stalks in metal-rich pH 6 mine water discharge
Heavy metal-contaminated, pH 6 mine water discharge created new streams and iron-rich terraces at a creek bank in a former uranium-mining area near Ronneburg, Germany. The transition from microoxic groundwater with ~5 mm Fe(II) to oxic surface water may provide a suitable habitat for microaerobic iron-oxidizing bacteria (FeOB). In this study, we investigated the potential contribution of these FeOAuthorsMaria Fabisch, Gina Freyer, Carol A. Johnson, Georg Buchel, Denise M. Akob, Thomas R. Neu, Kirsten KuselNon-USGS Publications**
Keiner, R., A. Rusznyak, D. M. Akob, S. Hanf, K. Küsel, J. Popp, and T. Frosch. 2013. Raman spectroscopy – an innovative and versatile tool to follow the respirational activity and carbonate biomineralization of important cave bacteria. Analytical Chemistry, 85(18): 8708–8714 (DOI: 10.1021/ac401699d).Gray, S. M., D. M. Akob, S. J. Green, and J. E. Kostka. 2012. The predictability of bacterial composition within the Sarracenia purpurea model system: local scale differences and relationships with the other members of the food web. PLoS One 7(12): e50969.Akob, D. M.*, S. H. Lee*, M. Sheth, K. Küsel, D. B. Watson, A.V. Palumbo, J.E. Kostka, and K.-J. Chin. 2012. Gene expression correlates with process rates quantified for sulfate- and Fe(III)-reducing bacteria in U(VI)-contaminated sediments. Frontiers in Terrestrial Microbiology, 3:280. *Equal contribution.Risse-Buhl, U., M. Herrmann, D. M. Akob, P. Geesink, N. Pizani, W. Schönborn, K.-U. Totsche and K. Küsel. 2012 Phagotrophic protist diversity in the groundwater of a karstic aquifer - morphological and molecular analysis. Journal of Eukaryotic Microbiology, 60(5): 467–479 (DOI: 10.1111/jeu.12054.Rusznyák, A., D. M. Akob, S. Nietzsche, K. Eusterhues, K. U. Totsche, T. R. Neu, T. Frosch, J. Popp, R. Keiner, J. Geletneky, L. Katzschmann, E.-D. Schulze, and K. Küsel. 2012. Calcite biomineralization by bacterial isolates from the recently discovered pristine karstic Herrenberg Cave. Applied and Environmental Microbiology 78(4): 1157–1167.Akob, D. M. and K. Küsel. 2011. Where microorganisms meet rocks in the Earth's Critical Zone. Biogeosciences 8, 3531-3543.
Akob, D. M., L. Kerkhof, K. Küsel, D. B. Watson, A. V. Palumbo, and J. E. Kostka. 2011. Linking specific heterotrophic bacterial populations to bioreduction of uranium and nitrate using stable isotope probing in contaminated subsurface sediments. Applied and Environmental Microbiology. 77(22):8197-8200
Burkhardt, E.-M., S. Bischoff, D. M. Akob, G. Büchel, and K. Küsel. 2011. Heavy metal tolerance of Fe(III)-reducing microbial communities in a contaminated creek bank soil. Applied and Environmental Microbiology 77(9): 3132-3136.
Lu, S., S. Gischkat, M. Reiche, D. M. Akob, K. B. Hallberg, and K. Küsel. 2010. Ecophysiology of Fe-cycling Bacteria in Acidic Sediments. Applied and Environmental Microbiology 76 (24): 8174-8183.
Vishnivetskaya, T. A., C. C. Brandt, A. S. Madden, M. S. Drake, J. E. Kostka, D. M. Akob, K. Küsel, and A. V. Palumbo. 2010. Microbial Community Changes in Response to Ethanol or Methanol Amendments for U(VI) Reduction. Applied and Environmental Microbiology 76(17): 5728-5735.
Sitte, J., D. M. Akob, C. Kaufmann, K. Finster, D. Banerjee, E.-M. Burkhardt, J. E. Kostka, A. Scheinost, Georg Büchel and K. Küsel. 2010. Microbial Links between Sulfate Reduction and Metal Retention in Uranium and Heavy Metal-contaminated Soil. Applied and Environmental Microbiology 76(10): 3143–3152.
Green, S. J., O. Prakash, T. M. Gihring, D. M. Akob, P. Jasrotia, P. M. Jardine, D. B. Watson, S. D. Brown, A. V. Palumbo and J. E. Kostka. 2010. Denitrifying bacteria from the terrestrial subsurface exposed to mixed waste contamination. Applied and Environmental Microbiology 76(10): 3244–3254.
Burkhardt, E.-M., D. M. Akob, S. Bischoff, J. Sitte, J. E. Kostka, D. Banerjee, A. C. Scheinost, K. Küsel. 2010. Impact of Biostimulated Redox Processes on Metal Dynamics in an Iron-rich Creek Soil of a former Uranium Mining Area. Environmental Science & Technology 44(1): 177-183.O. Prakash, T.M. Gihring, D.D. Dalton, K.-J. Chin, S.J. Green, D.M. Akob, G. Wanger, J.E. Kostka. 2010. Geobacter daltonii sp. nov., an iron(III)- and uranium(VI)-reducing bacterium isolated from the shallow subsurface exposed to mixed heavy metal and hydrocarbon contamination. International Journal of Systematic and Evolutionary Microbiology 60: 546-553.D. M. Akob, H. J. Mills, T. M. Gihring, L. Kerkhof, J. W. Stucki, Kuk-Jeong Chin, Kirsten Kuesel, Anthony V. Palumbo, David B. Watson, and Joel E. Kostka. 2008. Functional diversity and electron donor dependence of microbial populations capable of U(VI) reduction in radionuclide contaminated subsurface sediments. Applied and Environmental Microbiology 74: 3159-3170.
Blöthe, M., D.M. Akob, K. Walter, J.E. Kostka, H.L. Drake, and K. Küsel. 2008. Heterogeneity of Fe(III)-reducing microorganisms in coal-mining lake sediments caused by a pH gradient. Applied and Environmental Microbiology 74(4): 1019–102.
D. M. Akob, H. J. Mills, D. L. Swofford, J. E. Kostka. 2007. Metabolically-Active Microbial Communities in Uranium-Contaminated Subsurface Sediments. FEMS Microbiology Ecology 59: 95-107.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government