Denise M Akob, Ph.D.

Biography

Dr. Denise M. Akob is a geomicrobiologist whose research focuses on understanding how microorganisms impact their environment and biogeochemical cycles and in turn, how an environment impacts microorganisms. She investigates both contaminated and pristine environments. Her research focuses primarily on understanding microbial impacts on Cold War Biogeochemistry (uranium and chlorinated solvent contamination) and energy production (either by mitigating degradation of contaminants (from hydraulic fracturing or oil spills) or by enhancing natural gas production)). 

Dr. Akob received her undergraduate degree in Biology from St. Mary’s College of Maryland.  She completed her PhD in Biogeochemical Oceanography from Florida State University in 2008 and was a post-doctoral research fellow at Friedrich Schiller University Jena, Germany from 2008-2012. Dr. Akob joined the U.S. Geological Survey’s National Research Program in 2012. For more information please visit the Reston Microbiology Lab website.

Education

  • 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

Professional Experience

  • 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, National Research Program (Water), Microbiology and Molecular Ecology Laboratory. 2012-current
  • Postdoctoral Research Fellow, Friedrich-Schiller University Jena, Institute of Ecology, Aquatic Geomicrobiology. 2010-2012
  • Marie Curie Postdoctoral Research Fellow, Friedrich-Schiller University Jena, Institute of Ecology, Aquatic Geomicrobiology. 2008-2010

Science and Products

Publications

Filter Total Items: 10
[title_1]
Year Published: 2016

Biological 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...

Bohu, Tsing; Akob, Denise M.; Abratis, Michael; Lazar, Cassandre S.; Küsel, Kirsten
Bohu, T., D.M. Akob, M. Abratis, C.S. Lazar, and K. Küsel. 2016. Biological low pH Mn(II) oxidation in a manganese deposit influenced by acidic heavy metal-rich groundwater. Applied and Environmental Microbiology, 82 (10): 3009 –3021.
[title_1]
Year Published: 2016

Endocrine 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...

Kassotis, Christopher D.; Iwanowicz, Luke; Akob, Denise M.; Cozzarelli, Isabelle M.; Mumford, Adam; Orem, William H.; Nagel, Susan C.
Kassotis, C.D., L.R. Iwanowicz, D.M. Akob, I.M. Cozzarelli, A.C. Mumford, W.H. Orem, and S.C. Nagel. 2016. Endocrine Disrupting Activities of Surface Water Associated with a West Virginia Oil and Gas Industry Wastewater Disposal Site. Science of the Total Environment, 557–558: 901–910.
[title_1]
Year Published: 2016

Wastewater 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...

Akob, Denise M.; Mumford, Adam; Orem, William H.; Engle, Mark A.; Klinges, Julia (Grace); Kent, Douglas B.; Cozzarelli, Isabelle M.
Akob, D.M., A. Mumford, W. H. Orem, M. Engle, J.G. Klinges, D. B. Kent and I. M. Cozzarelli. Wastewater Disposal from Unconventional Oil and Gas Development Degrades Stream Quality at a West Virginia Injection Facility. Environmental Science and Technology, 50 (11): 5517–5525
[title_1]
Year Published: 2016

Dominance 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...

Fabisch, Maria; Freyer, Gina; Johnson, Carol A.; Buchel, Georg; Akob, Denise M.; Neu, Thomas R.; Kusel, Kirsten
Fabisch, M., G. Freyer, C. A. Johnson, G. Büchel, D. M. Akob, T. R. Neu, and K. Küsel. 2016. Dominance of ‘Gallionella capsiferriformans’ and heavy metal association with Gallionella-like stalks in metal-rich pH 6 mine water discharge. Geobiology, 14: 68–90
[title_1]
Year Published: 2015

Organic and inorganic composition and microbiology of produced waters from Pennsylvania shale gas wells

Hydraulically fractured shales are becoming an increasingly important source of natural gas production in the United States. This process has been known to create up to 420 gallons of produced water (PW) per day, but the volume varies depending on the formation, and the characteristics of individual hydraulic fracture. PW from hydraulic fracturing of shales are comprised of injected fracturing...

Akob, Denise M.; Cozzarelli, Isabelle M.; Dunlap, Darren S.; Rowan, Elisabeth L.; Lorah, Michelle M.
Akob, D. M., I. M. Cozzarelli, D. S. Dunlap, E. L. Rowan and M. M. Lorah. 2015. Organic and Inorganic Composition and Microbiology of Produced Waters from Pennsylvania Shale Gas Wells. Applied Geochemistry, 60:116-125 (IP-061928).
[title_1]
Year Published: 2015

Characterization of pH dependent Mn(II) oxidation strategies and formation of a bixbyite-like phase by Mesorhizobium australicum T-G1

Despite the ubiquity of Mn oxides in natural environments, there are only a few observations of biological Mn(II) oxidation at pH < 6. The lack of low pH Mn-oxidizing bacteria (MOB) isolates limits our understanding of how pH influences biological Mn(II) oxidation in extreme environments. Here, we report that a novel MOB isolate, Mesorhizobium australicum strain T-G1, isolated from an acidic...

Bohu, Tsing; Santelli, Cara M; Akob, Denise M.; Neu, Thomas R; Ciobota, Valerian; Rösch, Petra; Popp, Jürgen; Nietzsche, Sándor; Küsel, Kirsten
Bohu, T., C. Santelli, D. M. Akob, T. R. Neu, V. Ciobota, P. Rösch, J. Popp, S. Nietzsche, and K. Küsel. 2015. Characterization of pH dependent Mn(II) oxidation strategies and acidic pH bixbyite formation by Mesorhizobium australicum T-G1. Frontiers in Microbiology, 6: e734.
[title_1]
Year Published: 2015

Carbon flow from volcanic CO2 into soil microbial communities of a wetland mofette

Effects of extremely high carbon dioxide (CO2) concentrations on soil microbial communities and associated processes are largely unknown. We studied a wetland area affected by spots of subcrustal CO2 degassing (mofettes) with focus on anaerobic autotrophic methanogenesis and acetogenesis because the pore gas phase was largely hypoxic. Compared with a reference soil, the mofette was more acidic (...

Beulig, Felix; Heuer, Verena B.; Akob, Denise M.; Viehweger, Bernhard; Elvert, Marcus; Herrmann, Martina; Hinrichs, Kai-Uwe; Küsel, Kirsten
Beulig, F., V. B. Heuer, D. M. Akob, B. Viehweger, M. Elvert, M. Herrmann, K.-U. Hinrichs, and K. Küsel. 2015. Carbon flow from volcanic CO2 into soil microbial communities of a wetland mofette. The ISME Journal 9(3): 746-59.
[title_1]
Year Published: 2015

Large fractions of CO2-fixing microorganisms in pristine limestone aquifers appear to be involved in the oxidation of reduced sulfur and nitrogen compounds

The traditional view of the dependency of subsurface environments on surface-derived allochthonous carbon inputs is challenged by increasing evidence for the role of lithoautotrophy in aquifer carbon flow. We linked information on autotrophy (Calvin-Benson-Bassham cycle) with that from total microbial community analysis in groundwater at two superimposed—upper and lower—limestone groundwater...

Herrmann, Martina; Rusznyák, Anna; Akob, Denise M.; Schulze, Isabel; Opitz, Sebastian; Totsche, Kai Uwe; Küsel, Kirsten
Herrmann. M., A. Rusznyák, D. M. Akob, I. Schulze, S. Opitz, K.-U. Totsche, and K. Küsel. 2015. Large fractions of CO2-fixing microorganisms in pristine limestone aquifers appear to be involved in the oxidation of reduced sulfur and nitrogen compounds. Applied and Environmental Microbiology, 81(7): 2384-2394.
[title_1]
Year Published: 2014

Identification of Mn(II)-oxidizing bacteria from a low-pH contaminated former uranium mine

Akob, Denise M.; Bohu, Tsing; Beyer, Andrea; Schäffner, Franziska; Händel, Matthias; Johnson, Carol A.; Merten, Dirk; Büchel, Georg; Totsche, Kai Uwe; Küsel, Kirsten
Identification of Mn(II)-oxidizing bacteria from a low-pH contaminated former uranium mine; 2014; Article; Journal; Applied and Environmental Microbiology; Akob, Denise M.; Bohu, Tsing; Beyer, Andrea; Schäffner, Franziska; Händel, Matthias; Johnson, Carol A.; Merten, Dirk; Büchel, Georg; Totsche, Kai Uwe; Küsel, Kirsten
[title_1]
Year Published: 2013

Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations

Fabisch, Maria; Beulig, Felix; Akob, Denise M.; Küsel, Kirsten
Surprising abundance of Gallionella-related iron oxidizers in creek sediments at pH 4.4 or at high heavy metal concentrations; 2013; Article; Journal; Frontiers in Microbiology; Fabisch, Maria;Beulig, Felix;Akob, Denise M.;Küsel, Kirsten

Pre-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.
Risse-Buhl, U., M. Herrmann, D. M. Akob, P. Geesink, N. Pizani, W. Schönborn, K.-U. Totsche and K. Küsel. 2013. Phagotrophic protist diversity in the groundwater of a karstified aquifer - morphological and molecular analysis. Journal of Eukaryotic Microbiology, 60(5): 467–479.
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 (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0050969)
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.
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, G. 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.
Prakash, O., T. M. Gihring, D. D. Dalton, K.-J. Chin, S. J. Green, D. M. Akob, G. Wanger, and 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(3): 546-553.
Akob, D. M., H. J. Mills, T. M Gihring, L. Kerkhof, J. W. Stucki, A. S. Anastacío, K.-J.Chin, K. Kusel, A. V. Palumbo, D. B. Watson, and J. 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(10): 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): 1019–1029.
Akob, D. M., H. J. Mills, & J. E. Kostka. 2007. Metabolically active microbial communities in uranium-contaminated subsurface sediments. FEMS Microbiology Ecology 59:95-107 (DOI: 10.1111/j.1574-6941.2006.00203.x).
Diaz, M. C., D. Akob, & C. S. Cary. 2004. Denaturing gradient gel electrophoresis of nitrifying microbes associated with tropical sponges. Proceedings of the 6th International Sponge Conference, Rapallo, Italy, 2002. Bollettino dei Musei e degli Istituti biologici dell'Università di Genova 68: 279–289.