Our research focuses on interactions between microorganisms and minerals. We are studying the behavior of the disimilatory iron reducing bacterium Shewanella oneidensis MR-1 during respiration on hematite, a crystalline iron oxide that serves as a terminal electron acceptor for this bacterium. This research is undertaken as a collaboration with scientists at the Pacific Northwest National Laboratory and the University of Guelph in Ontario, Canada. Our group is also studying how methyl mercury is produced in geothermal food webs of acidic environments in Yellowstone National Park and how organisms at different trophic levels have adapted to elevated methyl mercury concentrations during their evolution. This work is conducted in collaboration with Professor Tamar Barkay at Rutgers University, Professor Jeff Tomberlein at Texas A&M University and Kirk Nordstrom at the USGS in Boulder, Colorado.
Boyd, E.S., W.D. Leavitt and G.G. Geesey. (2009) CO2 uptake and fixation by a thermoacidophilic microbial community attached to precipitated sulfur in a geothermal spring. Appl. Environ. Microbiol. 75:2464-2475.
Boomer, S.M., K.L. Noll, G.G. Geesey, B.E. Dutton. (2009) Formation of multilayered photosynthetic biofilms in an alkaline thermal spring in Yellowstone National Park, Wyoming. Appl. Environ. Microbiol. 75:2464-2475.
Boyd, E.S., S. King, J.K. Tomberlin, D.K. Nordstrom, D.P. Krabbenhoft, T.Barkay, G.G. Geesey (2009) Methylmercury enter an aquatic food web through acidophilic microbial mats in Yellowstone National Park, Wyoming. Environ. Microbiol. 11:950-959.
Learman, D.R., H. Yi, S.D. Brown, S.L. Martin, G.G. Geesey, A.M. Stevens, M.F. Hochella Jr. (2009) Involvement of Shewanella oneidensis MR-1 LuxS in biofilm development and sulfur metabolism. Appl. Environ. Microbiol. 75:1301-1307.
Geesey, G. and A. Mitchell. (2008) Need for direct measurement of coupled microbiological and hydrological processes in porous media to improve accuracy and scalability of reactive transport models. J. Hydrol. Engineer. 13(1):28-36.
Geesey, G.G., T. Borch, C.L. Reardon (2008) Resolving geochemical phenomena at high spatial resolution through electron microscopy. Geobiology 6:263-269.
Boyd, E. S., R.A. Jackson, G. Encarnacion, J.A. Zahn, T. Beard, W.D. Leavitt, Y. Pi, C.L. Zhang, A. Pearson, and G.G. Geesey. (2007) Isolation, characterization, and ecology of sulfur-respiring Crenarchaea inhabiting acid-sulfate-chloride geothermal springs in Yellowstone National Park. Appl. Environ. Microbiol. 73:6669-6677.
Boyd, E.S., D.E. Cummings, G.G. Geesey. (2007) Mineralogy influences structure and diversity of bacterial communities associated with geological substrata in a pristine aquifer. Microb. Ecol. 54:174-182.