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Texas A&M University

MS 3146,
College Station, Texas 77843

Dr. John Kessler

Assistant Professor

Ph.D. Earth System Science, University of California Irvine, 2005

M.S. Earth System Science, University of California Irvine, 2003

B.S. Chemistry and Mathematics, Gettysburg College, 1998


Please note that Prof. Kessler and his lab have recently relocated and can be found at the University of Rochester.



Dr. Kessler is a chemical oceanographer who focuses on isotope biogeochemistry to elucidate methane dynamics within the oceanic system as well as across other earth systems. He is driven to conduct this research by a desire to quantify feedbacks associated with global climate change. The oceanic methane system is not only the largest global methane reservoir, but one of the largest global carbon reservoirs. In addition, the oceanic methane system is a dynamic, metastable, and relatively unexplored reservoir that has the potential for large and explosive feedbacks with climate due to the potency of methane as a greenhouse gas.  His research strives to quantify sources, sinks and fluxes of oceanic methane using analytical chemistry measurements with particular emphasis on stable and radiocarbon isotopes. These measurements are then used in regional geochemical models to quantify methane’s biogeochemical dynamics. In past projects, these techniques were used to study methane geochemistry in the Gulf of Mexico, Alaskan Arctic, Bering Sea, Cariaco Basin, Black Sea, and Southern California Bight to determine 1) whether methane was formed by biological, abiological (e.g. serpentization) or thermogenic processes, 2) what the present-day fluxes of methane are from sediments, methane clathrate hydrates, permafrost, hydrocarbon seeps, vents and mud volcanoes, and 3) how quickly methane is being produced and/or consumed by indigenous microorganisms thus enhancing and/or limiting its atmospheric release. Overall, the long term goal of his laboratory is to study the mechanisms controlling the dynamics of the oceanic methane system especially with respect to climate change.

While most people tell him to be thankful for his youthful appearance, Dr. Kessler hopes to one day take a picture that doesn't make him look like an undergraduate.

Information for Prospective Undergraduate and Graduate Students

Meet the Lab Group

Research Interests


  • Isotope geochemistry
  • Analytical chemistry


  • Understanding oceanic methane’s role in past, present, and future global carbon cycles and global climate change.
  • Determining sources and sinks of oceanic methane with natural isotopic measurements.
  • Quantifying the present day release rate of methane from hydrocarbon seeps, vents, and decomposing clathrate hydrates with analytical geochemical measurements and mathematical models

More Information on Kessler's Research Interests


  • Gulf of Mexico Oil Spill Project
  • Developing a portable Cavity-Ringdown Spectrometer for shipboard measurements of methane concentration, δ2H-CH4, and δ13C-CH4
  • Understanding the source of elevated levels of radiocarbon in methane dissolved in the subsurface ocean
  • Quantifying the cycling of methane released from seeps in the Cariaco Basin

Past and Present Projects with Pictures


  • 2008-present, Assistant Professor Department of Oceanography, Texas A&M University, College Station, Texas.
  • 2005-2008, Postdoctoral Research Associate, Department of Geosciences, Princeton University, Princeton, NJ
  • 2000-2005, Graduate Research Assistant, Department of Earth Systems Science, University of California Irvine, Irvine, CA
  • 1998-2000, Research Chemist, Atmospheric Chemistry Group, National Institute of Standards and Technology, Gaithersburg, MD


  • 2012: Sloan Research Fellow: Ocean Sciences
  • 2011: Discover Magazine: Top 100 Stories of 2011
  • 2001: Distinguished Scholar Award: Microbean Analysis Society


  • Du, M. and J.D. Kessler (2012). "Assessment of the Spatial and Temporal Variability of Bulk Hydrocarbon Respiration Following the Deepwater Horizon Oil Spill." Environmental Science & Technology, doi: 10.1021/es301363k.
  • Ryerson, T.B., R. Camilli, J.D. Kessler, E.B. Kujawinski, C.M. Reddy, D.L. Valentine, E. Atlas, D.R. Blake, J. de Gouw, S. Meinardi, D.D. Parrish, J. Peischl, J.S. Seewald, and C. Warneke (2012). “Chemical data quantify Deepwater Horizon hydrocarbon flow rate and environmental distribution.” Proceedings of the National Academy of Sciences, doi: 10.1073/pnas.1110564109.
  • Hu, L., S.A. Yvon-Lewis, J.D. Kessler, I.R. MacDonald (2012). "Methane fluxes to the atmosphere from deepwater hydrocarbon seeps in the northern Gulf of Mexico." J. Geophys. Res., 117 (C1), C01009, doi:10.1029/2011JC007208.
  • Kessler, J.D., D.L. Valentine, M.C. Redmond, M. Du, E.W. Chan, S.D. Mendes, E.W. Quiroz, C.J. Villanueva, S.S. Shusta, L.M. Werra, S.A. Yvon-Lewis, T.C. Weber (2011). "A Persistent Oxygen Anomaly Reveals the Fate of Spilled Methane in the Deep Gulf of Mexico."  Science, 331, 312-315, doi:10.1126/science.1199697. (Abstract, Full Text, Reprint)
  • Kessler, J. D., Valentine, D. L., Redmond, M. C., and Du, M. R. (2011) Response to Comment on "A Persistent Oxygen Anomaly Reveals the Fate of Spilled Methane in the Deep Gulf of Mexico". Science, 332, doi:10.1126/science.1203428.
  • Pasche, N., Schmid, M., Vazquez, F., Schubert, C. J., Wuest, A., Kessler, J. D., Pack, M. A., Reeburgh, W. S., and Burgmann, H. (2011) Methane sources and sinks in Lake Kivu. J Geophys Res-Biogeo, 116, G03006, doi:10.1029/2011JG001690.
  • S.A. Yvon-Lewis, L. Hu, J.D. Kessler (2011).  "Methane flux to the atmosphere from the Deepwater Horizon oil disaster."  Geophysical Research Letters, 38, L01602, doi: 10.1029/2010GL045928.
  • Valentine, D.L., J.D. Kessler, M.C. Redmond, S.D. Mendes, M.B. Heintz, C. Farwell, L. Hu, F.S. Kinnaman, S.A. Yvon-Lewis, M. Du, E.W. Chan, F. Garcia-Tigreros, C.J. Villanueva (2010). "Propane respiration jump-starts microbial response to a deep oil spill."  Science, 330, 208-211, doi:10.1126/science.1196830.
  • Crowe, S.A., S. Katsev, K. Leslie, A. Sturm, C. Magen, S. Nomosatryo, M.A. Pack, J.D. Kessler, W.S. Reeburgh, J.A. Roberts, L. Gonzalez, G. Douglas Haffner, A. Mucci, B. Sundby, D.A. Fowle (2010).  "The methane cycle in ferruginous Lake Matano."  Geobiology, doi: 10.1111/j.1472-4669.2010.00257.x.
  • Pape, T., A. Bahr, J. Rethemeyer, J. D. Kessler, H. Sahling, K. Hinrichs, S. A. Klapp, W. S. Reeburgh, G. Bohrmann (2010). "Molecular and isotopic partitioning of low-molecular-weight hydrocarbons during migration and gas hydrate precipitation in deposits of a high-flux seepage site." Chemical Geology, 269 (3-4), 350–363, doi:10.1016/j.chemgeo.2009.10.009.
  • Kessler, J.D., W.S. Reeburgh, D.L. Valentine, F.S. Kinnaman, E.T. Peltzer, P.G. Brewer, J. Southon, and S.C. Tyler (2008). “A survey of methane isotope abundance (14C, 13C, 2H) from five nearshore marine basins that reveals unusual radiocarbon levels in subsurface waters.” Journal of Geophysical Research, 113, C12021, doi:10.1029/2008JC004822.
  • Kessler, J.D., W.S. Reeburgh , S.C. Tyler (2006).   “ Controls on Methane Concentration and Stable Isotope (δ2H-CH4 and δ13C-CH4) Distributions in the water columns of the Black Sea and Cariaco Basin .”   Global Biogeochemical Cycles, 20 (4), GB4004, doi:10.1029/2005GB002571.
  • Kessler, J.D., W.S. Reeburgh, J. Southon, R. Seifert, W. Michaelis, S.C. Tyler (2006).   “Basin-wide Estimates of Input of Methane from Seeps and Clathrates to the Black Sea .”   Earth and Planetary Science Letters, 243, 366-375.
  • Onstott, T.C., D. McGown, J. Kessler, B. Sherwood Lollar, K.K. Lehmann, S.M. Clifford (2006).   “Martian CH4: Sources, Flux, and Detection.”   Astrobiology, 6 (2), 377-395.
  • Kessler, J.D., W.S. Reeburgh, J. Southon, R. Varela (2005).   “Fossil Methane Source Dominates Cariaco Basin Water Column Methane Geochemistry.”   Geophysical Research Letters, 32, L12609, doi:10.1029/2005GL022984.
  • Kessler, J.D. and W.S. Reeburgh (2005).   “Preparation of Natural Methane Samples for Stable Isotope and Radiocarbon Analysis.”   Limnology and Oceanography: Methods, 3, 408-418. [PDF]
  • Currie, L.A. and J.D. Kessler (2005).   “On the isolation of elemental carbon (EC) for micro-molar 14C accelerator mass spectrometry: development of a hybrid reference material for 14C-EC accuracy assurance, and a critical evaluation of the thermal optical kinetic (TOK) isolation procedure.”   Atmospheric Chemistry and Physics, 5, 2833-2845.
  • Currie, L.A. , J.D. Kessler, R.A. Fletcher, J.E. Dibb (2005).   “Long range transport of biomass aerosol to Greenland : Multi-spectroscopic investigation of particles deposited in snow.”   Journal of Radioanalytical and Nuclear Chemistry, 263 (2), 399-411.
  • Currie, L.A., B.A. Benner, Jr, H. Cachier, R. Cary, J.C. Chow, E.R.M. Druffel, T.I. Eglinton, O. Gustafsson, P.C. Hartmann, J.I. Hedges, J.D. Kessler, T.W. Kirchstetter, D.B. Klinedinst, G.A. Klouda, J.V. Marolf, C.A. Masiello, T. Novakov, A. Pearson, K.M. Prentice, H. Puxbaum, J.G. Quinn, C.M. Reddy, H. Schmid, J.F. Slater, J. Watson, and S.A. Wise (2002).   "A Critical Evaluation of Interlaboratory Data on Total, Elemental, and Isotopic Carbon in the Carbonaceous Particle Reference Material, NIST SRM 1649a."   Journal of Research of the National Institute of Standards and Technology, 107, 279-298. [PDF]
  • Currie, L.A., J.D. Kessler, J.V. Marolf, A.P. McNichol, D.R. Stuart, J.C. Donoghue, D.J. Donahue, G.S. Burr, D. Biddulph (2000).   “Low-level (submicromole) Environmental 14C Metrology.”   Nuclear Instruments and Methods B, 172, 440-448.


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