Research Aims:
As recorded in Earth's geologic history and inferred by climate scientists today, the atmospheric concentration of methane plays a significant role in the 'greenhouse' warming of the Earth's surface. In addition to abiological sources of methane to the atmosphere (e.g. fossil fuel and biomass burning), the largest biological inputs are emissions from rice paddies, wetlands, animals and insects, and seepage from ocean sediments. Methane emission rates are relatively well constrained for all sources except from the ocean, which is less well known because the aerial extent and magnitude of seepage is poorly understood. Biology is a major factor influencing methane seepage from ocean sediments. Although methanogenic microorganisms convert buried organic matter into methane in anoxic zones of the marine subsurface, an estimated 90% (averaged globally) of methane is prevented from escaping the ocean sediment by the action of an effective microbial filter within the overlying sulfate-rich sediment. Surprisingly, relatively little is known about how the anaerobic oxidation of methane (AOM) proceeds, in terms of the identity, diversity and quantity of microorganisms involved and the factors influencing the performance of the process. Available evidence suggests that, in marine sediments, sulfate is the dominant oxidant for AOM, and that the process is mediated by a consortium of methanotrophic archaea and sulfate reducing bacteria, although the currency of their syntrophy is not known. Additional data indicate that AOM is biochemically a reversal of methanogenic pathways. In this thesis, a variety of different methane-rich habitats - ranging from the deep marine subsurface up to cold seep systems featuring mud volcanoes, brine pools, and oil-laden gas hydrates - were investigated using a multidisciplinary approach to gain a systematic understanding of the microbial regulation of methane flux in the marine subsurface. To this end, the distribution and magnitude of methane cycling in the various environments as well as the responsible microbial communities were identified and quantified.

Education
University of Georgia, Department of Marine Sciences, Athens, GA
Ph.D. candidate, Fall 2006
Dissertation Title: Anaerobic oxidation of methane in cold seeps and gas hydrates: Responsible microorganisms, rates of activity, and interactions with other processes

Bachelor of Science Interdisciplinary Studies, emphasis Marine Geochemistry, Minor: Geology, May 2002
Thesis: Anaerobic methane oxidation in shallow gas hydrates of the Gulf of Mexico

Addditional Academic Experience:
Participant: 2003 International Geobiology Course, Wrigley Institute, University of Southern California, Catalina Island, CA

Visiting Scientist: Max Planck Institute for Marine Microbiology, Bremen, Germany; Invitation from Prof. Dr. Antje Boetius, recurring visits since 09/2002

Visiting Scientist: Research Center Ocean Margins, Department of Organic Geochemistry, Bremen, Germany; Invitation from Prof. Dr. Kai-Uwe Hinrichs, recurring visits since 05/2004

Awards:
National Science Foundation Graduate Research Fellow, 08/2003 – 08/2006

Recruitment Scholarship, Department of Marine Sciences, University of Georgia, 07/2002 – 07/2003.

Barry M. Goldwater Scholar in Mathematics, Science and Engineering, 04/2001 – 06/2002

Georgia H.O.P.E. Scholar, 08/1998 – 06/2002

Publications:
Moran, M.A., Belas, R., Schell, M.A., Gonzalez, J.M., Sun, F., Sun, S., Binder, B.J., Edmonds, J., Ye, W., Orcutt, B., Howard, E., Meile, C., Palefsky, W., Goesmann, A., Ren, Q., Paulsen, I., Ulrich, L.E., Jouline, I.B., Thompson, L.S., Saunders, E., Buchan, A. (in preparation for Science) Ecological genomics of marine Roseobacters.

Joye, S.B., Samarkin, V.S., Orcutt, B! N., Elvert, E., Hinrichs, K.-U., MacDonald, I.R., Meile, C., Montoya, J. (in prep. for Science) Dynamic patterns of microbial activity in seafloor brines from the Gulf of Mexico.

Niemann, H., Elvert, M., Hovland, M., Orcutt, B., Judd, A., Suck, I., Gutt, J., Joye, S., Damm, E., Finster, K., Boetius, A. (2005) Methane emission and consumption at a North Sea gas seep (Tommeliten area). Biogeosciences 2: 335-351. (pdf)

Orcutt, B., Joye, S.B., Boetius, A., Elvert, M., Samarkin, V. (2005) Molecular biogeochemistry of sulfate reduction, methanogenesis, and the anaerobic oxidation of methane at Gulf of Mexico methane seeps. Geochimica et Cosmochimica Acta 69: 4267-4281. (pdf)

MacDonald, I.R., Bohrmann, G., Escobar, E., Abegg, F., Blanchon, P., Blinova, V., Bruckmann, W., Drews, M., Eisenhauer, A., Han, X., Heeschen, K., Meier, F., Mortera, C., Naehr, T., Orcutt, B., Bernard, B., Brooks, J., de Farago, M. (2004) Asphalt volcanism and chemosynthetic life in the Campeche Knolls, Gulf of Mexico. Science 304: 999-1002. (pdf)

Orcutt, B. N., Boetius, A., Lugo, S. J., MacDonald, I. R., Samarkin, V., Joye, S. B. (2004) Life at the edge of methane ice: methane and sulfur cycling in Gulf of Mexico gas hydrates. Chemical Geology 205: 239-251. (pdf)

Joye, S. B., Orcutt, B. N., Boetius, A., Montoya, J. P., Schulz, H. N., Erickson, M. J., Lugo, S. K. (2004) The anaerobic oxidation of methane and sulfate reduction in sediments from Gulf of Mexico cold seeps. Chemical Geology 205: 219-238. (pdf)

Carini, S. A., Orcutt, B., and Joye, S.B. (2003) Interactions between methane oxidation and nitrification in coastal sediments. Geomicrobiology Journal 20: 35-374. (pdf)

Presentations:
Orcutt, B., Joye, S., Boetius, A., Samarkin, V. Interaction of the anaerobic oxidation of methane and methanogenesis in Gulf of Mexico methane seeps (poster). The Joint International Symposia for Subsurface Microbiology (ISSM 2005) and Environmental Biogeochemistry (ISEB XVII), Jackson Hole, WY, 08/2005.

Harnmeijer, J., Orcutt, B., Devol, A., Joye, S.B. Quantifying the role manganese in biotic and abiotic nitrogen cycling (poster). 15th Annual Goldschmidt Conference, Moscow, ID, 05/2005.

Orcutt, B., Joye, S.B., Boetius, A., Samarkin, V. Molecular biogeochemistry of sulfate reduction, methanogenesis, and the anaerobic oxidation of methane at Gulf of Mexico methane seeps (oral presentation). The American Society of Limnology and Oceanography 2005 Aquatic Sciences Meeting, Salt Lake City, UT, 02/2005.

Orcutt, B., Treude, T., Samarkin, V., Boetius, A., Joye, S.B. Carbon and sulfur cycling in gas hydrate-bearing sediments of the Gulf of Mexico (oral presentation). 10th International Symposium on Microbial Ecology, Cancun, Mexico, 08/2004.

Orcutt, B., Boetius, A., Joye, S. B. Anaerobic oxidation of methane in gas hydrates and cold seep sediments (invited seminar). Danish Center for Earth System Science, Syddansk Universitet, Denmark, 06/2004.

Orcutt, B., Boetius, A., MacDonald, I., Samarkin, V., Joye, S. Life in methane ice (poster). Astrobiology Graduate Student Conference, Tucson, AZ, 01/2004.

Orcutt, B., Joye, S. B., Samarkin, V., Boetius, A., MacDonald, I.R. Patterns of the anaerobic oxidation of methane in Gulf of Mexico gas hydrates (invited seminar). Max Planck Institute for Marine Microbiology, Bremen, Germany, 05/2003.

Orcutt, B., Samarkin, V., Erickson, M., Amann, R., Boetius, A., Joye, S. Molecular biogeochemistry of sediments near gas hydrates in the Gulf of Mexico. EGS-AGU-EUG Joint Assembly, Nice, France, 04/2003.

Orcutt, B., Boetius, A., MacDonald, I.R., Amann, R., Samarkin, V., Joye, S. Patterns of anaerobic methane oxidation in Gulf of Mexico gas hydrates (poster). EGS-AGU-EUG Joint Assembly, Nice, France, 04/2003.

Teaching Experience:
01/2005 – 05/2005: Instructor for Biology of the Marine Environment laboratory taught in conjunction with Marine Biology (science for non-science majors) lecture led by Dr. Robert Hodson and Dr. Catherine Teare-Ketter in the Marine Science Department at the University of Georgia. Responsible for preparing weekly lab for 20 students, developing and grading weekly assessment work and lab reports, and engaging students in dialogue about current issues in the marine environment.

Current Research:
Anaerobic oxidation of methane and related microbial processes at Gulf of Mexico cold seeps (07/2001 - present)
Responsibilities: To identify the responsible microorganisms, rates of activity, distribution and interactions of the anaerobic oxidation of methane with other processes in oil- and gas-charged, hydrate- and/or asphalt-rich sediments in the northern and southern Gulf of Mexico by geochemical analyses, radiotracer incubations, lipid biomarker identification, molecular phylogenetic analysis, reaction-transport modeling, and enrichment.
Funding: Life in Extreme Environments Program of the National Science Foundation; OTEGA II program of the GEOMAR research group (Bremen, Germany) of the BMBF; Petroleum Research Fund

Anaerobic oxidation of methane and related microbial processes in the Hydrate Ridge deep biosphere
Responsibilities To identify the responsible microorganisms, rates of activity, distribution and interactions of the anaerobic oxidation of methane with other processes in the deep biosphere at Hydrate Ridge by geochemical analyses, radiotracer incubations, lipid biomarker identification, and molecular phylogenetic analysis.
Funding: Ocean Drilling Program Leg 204, 08/2002 – present

Anaerobic oxidation of methane and related microbial processes at Monterey Canyon cold seeps
Responsibilities: To measure rates of activity of microorganisms mediating the anaerobic oxidation of methane, methanogenesis, and sulfate reduction in sediments at various Monterey Canyon cold seeps and on anodes of an experimental biobattery by geochemical analysis and radiotracer incubation.
Collaboration: invitation by Dr. Peter Girguis, formerly of the Monterey Bay Aquatic Research Institute, currently at Harvard University, 06/2004 – present.

Manganese-dependent nitrogen cycling in marine sediments
Responsibilities: To discover the interaction of metal (Mn and Fe) and nitrogen cycling in marine sediments from the western Gulf of Mexico and San Pedro Basin by geochemical analysis and stable isotope enrichments.
Collaboration: Jelte Harnmeijer (graduate student, University of Washington); (Gulf of Mexico) GoMex 2004 project of Dr. Allen Devol (University of Washington, Department of Oceanography); (San Pedro Basin) Dr. William Berelson of the 2004 International Geobiology summer course sponsored by the Agouron Institute (University of Southern California); 11/2004 – present.

Former Projects:
Methane oxidation above cold seeps in the North Sea
Responsibilities: To assist in the measurement of methane oxidation activity in the water column and sediments at North Sea cold seeps by geochemical analysis.
Collaboration: EU-funded METROL project test cruise with Dr. Antje Boetius and Helge Niemann (Max Planck Institute for Marine Microbiology, Bremen, Germany); 10/16-27/2002.

Coupled methane and nitrogen cycling in Mono Lake and estuarine sediments
Responsibilities: As an undergraduate research assistant, to assist in the measurement of aerobic methane and nitrogen cycling in alkaline, hypersaline Mono Lake and in coastal sediments from Galveston Bay
Funding: (Mono Lake) NSF-funded Microbial Observatory, 06/2000 – 06/2001; (Galveston Bay) NSF-funded Nitrogen-cycling in coastal ecosystems project, 05/1999 – 06/2000.

Oceanographic Cruises:
To western Gulf of Mexico aboard R/V Seward Johnson I (Harbor Branch Oceanographic Instittute), 11/2004-12/2004.

To San Pedro Basin aboard R/V SeaWatch (University Southern California), 06/30/2004.

To Monterey Canyon aboard R/V Point Lobos (MBARI) equipped with ROV Ventana, 06/28/2004

To northern and southern Gulf of Mexico aboard German research vessel R/F SONNE, 10/2003-11/2003.

To North Sea aboard the German research vessel R/F Heincke, 10/2002

To northern Gulf of Mexico aboard the R/V Seward Johnson II with the research submersible Johnson SeaLink, 07/2002

To Northern Gulf of Mexico aboard the R/V Seward Johnson I with the research submersible Johnson SeaLink, 07/2001