Dr. Christopher Somes


Scientist at Research Unit Biogeochemical Modelling

Room: 20-211
Tel.: +49 431 600-4513
Fax: +49 431 600-4469
E-Mail: csomes(at)geomar.de

GEOMAR Helmholtz Centre for Ocean Research Kiel
Düsternbrooker Weg 20
24105 Kiel, Germany


CV (short)

Research Bio

I am a scientist interested in understanding how ocean biology and chemistry are affected by environmental change such as pollution and global warming. My research uses global Earth system climate models to predict the magnitude of the response and associated feedbacks on the Earth’s climate system. A research focus of mine analyzes and interprets elemental isotopic ratios to gain insights and constraints on marine biogeochemical cycling and ecosystem dynamics in the modern ocean, as well as during past climate change events preserved in the ocean's sedimentary record. This helps us to better quantitatively understand the impacts of climate change on marine biology and chemistry, and thus improve our predictions of the future ocean and climate.

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In Press / Just Published Articles

  • Dhurmeea Z., Pethybridge H., Langlais C., Somes C.J., Nikolic N., Bourjea J., Appadoo C., Bodin N. (2020), Spatial variation in stable isotopes and fatty acid trophic markers in albacore tuna (Thunnus alalunga) from the western Indian Ocean, Deep Sea Research Ihttps://doi.org/10.1016/j.dsr.2020.103286
  • Logan J.M., Pethybridge H., Lorrain A., Somes C.J., Allain V., Bodin N., Choy C.A., Duffy L., Goñi N., Graham B., Langlais C., Ménard F., Olson R., Young J. (2020), Global patterns and inferences of tuna movements and trophodynamics, Deep Sea Research II, https://doi.org/10.1016/j.dsr2.2020.104775
  • Lorrain, A., Pethybridge, H., Cassar, N., Receveur, A., Allain, V., Bodin, N., Bopp, L., Choy, C.A., Duffy, L., Fry, B., Goñi, N., Graham, B.S., Hobday, A.J., Logan, J.M., Ménard, F., Menkes, C., Olson, D.E., Pagendam, R.J., Point, D., Revill, A.T., Somes, C.J., Young, J.W. (2020)  Trends in tuna isotopes suggest global changes in pelgic phytoplankton communities   Global Change Biology,  doi:10.1111/GCB.14858

Current Project

    COMFORT Project (project page)

    Our common future in the Earth system - quantifying coupled cycles of carbon, oxygen and nutrients for determining and achieving safe operating spaces with respect to tipping points

    • European Union Horizon 2020 Grant
    • Position: Task Leader
    • 2020

Research Interests

  • Climate change feedbacks associated with the biological carbon pump in the past, present, and future ocean
  • Impact of anthropogenic nutrient pollutants on ocean deoxygenation and marine ecosystems
  • Nutrient (e.g. nitrogen, phosphorus, iron) co-limitation of marine phytoplankton growth
  • Isotopic constraints and insights on ocean biogeochemical cycling and marine ecosystem dynamics
  • Development of ocean biogeochemical, ecosystem, and Earth system models


  • Ph.D, Oceanography, GEOMAR Helmholtz Centre for Ocean Research/Kiel University, dissertation: "Nitrogen Isotopes in the Global Ocean", 2013
  • M.Sc., Oceanography, College of Oceanic and Atmospheric Sciences, Oregon State University, thesis: "Nitrogen Isotopes in a Global Ocean Biogeochemical Model", 2010
  • B.Sc., Physics (Geophysics option), Oregon State University, thesis: "Modeling instabilities of the global thermohaline circulation and its effect on the Pacific Ocean oxygen minimum zone", 2006
  • A.Eng., Software Engineering Technology, Oregon Institute of Technology, 2003

Peer-Reviewed Publications

  • 2018
    • Pethybridge, H., Choy, C.A., Logan, L.M., Allain, V., Lorrain, A., Bodin, N., Somes, C.J., Young, J., Menard, F., Langlais, C., Duffy, L., Hobday, A.J., Kuhnert, P., Fry, B., Menkes, C., Olson, R.J. (2018). A global meta-analysis of marine predator nitrogen stable isotopes: Relationships between trophic structure and environmental conditions. Global Ecology and Biogeography, 2018;00:1-13.  doi:10.1111/geb.12763
    • Glock, N., Erdem, Z., Wallmann, K., Somes, C. J., Liebtrau, V., Schönfeld, J., Gorb, S.,  Eisenhauer, A. (2018). Coupling of oceanic carbon and nitrogen facilitates spatially resolved quantitative reconstruction of nitrate inventories. Nature Communications, 9:1217.  doi:10.1038/s41467-018-03647-5
  • 2017
    • Muglia, J.Somes, C.Nickelsen, L. and Schmittner, A. (2017). Combined Effects of Atmospheric and Seafloor Iron Fluxes to the Glacial OceanPaleoceanography, 32, 1204-1218.  doi:10.1002/2016PA003077
    • Landolfi, A.Somes, C. J.Koeve, W.Zamora, L. M. and Oschlies, A. (2017) Oceanic nitrogen cycling and N2O flux perturbations in the Anthropocene. Global Biogeochemical Cycles, 31 (8), 1236-1255.  doi10.1002/2017GB005633
    • Somes, C. J.Schmittner, A.Muglia, J. and Oschlies, A. (2017). A Three-Dimensional Model of the Marine Nitrogen Cycle during the Last Glacial Maximum Constrained by Sedimentary IsotopesFrontiers in Marine Science, 4:108. doi:10.3389/fmars.2017.00108
  • 2016
    • Schmittner, A. and Somes, C. J. (2016). Complementary constraints from carbon (13C) and nitrogen (15N) isotopes on the glacial ocean's soft-tissue biological pumpPaleoceanography, 31 (6), 669-693. doi:10.1002/2015PA002905
    • Somes, C. J.Landolfi, A.Koeve, W. and Oschlies, A. (2016). Limited impact of atmospheric nitrogen deposition on marine productivity due to biogeochemical feedbacks in a global ocean model. Geophysical Research Letters, 43 (9), 4500-4509. doi:10.1002/2016GL068335
  • 2015
    • Somes, C. J. and Oschlies, A. (2015). On the influence of “non-Redfield” dissolved organic nutrient dynamics on the spatial distribution of Nfixation and the size of the marine fixed nitrogen inventory. Global Biogeochemical Cycles, 29 (7), 973-993. doi:10.1002/2014GB005050
    • Young, J. W.Olson, R. J.Ménard, F.Kuhnert, P. M.Duffy, L. M.Allain, V.Logan, J. M.Lorrain, A.Somes, C. J.Graham, B.Goñi, N.Pethybridge, H.Simier, M.Potier, M.Romanov, E.Pagendam, D.Hannides, C. and Choy, C. A. (2015). Setting the stage for a global-scale trophic analysis of marine top predators: a multi-workshop review. Reviews in Fish Biology and Fisheries, 25 (1), 261-272. doi:10.1007/s11160-014-9368-4
  • 2014
    • Moore, R. M.Kienast, M.Fraser, M.Cullen, J. J.Deutsch, C.Dutkiewicz, S.Follows, M. J. and Somes, C. J. (2014). Extensive hydrogen supersaturations in the western South Atlantic Ocean suggest substantial underestimation of nitrogen fixationJournal of Geophysical Research Oceans, 119 (7), 4340-4350. doi:10.1002/2014JC010017
  • 2013
    • Navarro, J.Coll, M.Somes, C. J. and Olson, R. J. (2013). Trophic niche of squids: Insights from isotopic data in marine systems worldwideDeep-Sea Research II, 95, 93-102. doi:10.1016/j.dsr2.2013.01.031
    • Somes, C. J.Oschlies, A. and Schmittner, A. (2013). Isotopic constraints on the pre-industrial oceanic nitrogen budgetBiogeosciences, 10 (9), 5889-5910. doi:10.5194/bg-10-5889-2013
    • Galbraith, E. D.Kienast, M.Galbraith, E. D.Kienast, M.Albuquerque, A. L.Altabet, M. A.Batista, F.Bianchi, D.Calvert, S. E.Contreras, S.Crosta, X.De Pol-Holz, R.Dubois, N.Etourneau, J.Francois, R.Hsu, T. C.Ivanochko, T.Jaccard, S. L.Kao, S. J.Kiefer, T.Kienast, S.Lehmann, M. F.Martinez, P.McCarthy, M.Meckler, A. N.Mix, A.Möbius, J.Pedersen, T. F.Pichevin, L.Quan, T. M.Robinson, R. S.Ryabenko, E.Schmittner-Boesch, A.Schneider, R.Schneider-Mor, A.Shigemitsu, M.Sinclair, D.Somes, C. J.Studer, A. S.Tesdal, J. E.Thunell, R. and Terence Yang, J. Y. (2013). The acceleration of oceanic denitrification during deglacial warmingNature Geoscience, 6, 579-584. doi:10.1038/ngeo1832
  • 2012
    • Robinson, R. S.Kienast, M.Luiza Albuquerque, A.Altabet, M.Contreras, S.De Pol Holz, R.Dubois, N.Francois, R.Galbraith, E.Hsu, T. C.Ivanochko, T.Jaccard, S.Kao, S. J.Kiefer, T.Kienast, S.Lehmann, M.Martinez, P.McCarthy, M.Möbius, J.Pedersen, T.Quan, T. M.Ryabenko, E.Schmittner, A.Schneider, R.Schneider-Mor, A.Shigemitsu, M.Sinclair, D.Somes, C. J.Studer, A.Thunell, R. and Yang, J. Y. (2012). A review of nitrogen isotopic alteration in marine sedimentsPaleoceanography, 27 (4), PA4203. doi:10.1029/2012PA002321
  • 2010
    • Somes, C. J.Schmittner, A. and Altabet, M. A. (2010). Nitrogen isotope simulations show the importance of atmospheric iron deposition for nitrogen fixation across the Pacific OceanGeophysical Research Letters, 37 (23), L23605. doi:10.1029/2010GL044537
    • Somes, C. J.Schmittner, A.Galbraith, E. D.Lehmann, M. F.Altabet, M. A.Montoya, J. P.Letelier, R. M.Mix, A. C.Bourbonnais, A. and Eby, M. (2010). Simulating the global distribution of nitrogen isotopes in the oceanGlobal Biogeochemical Cycles, 24 (4), GB4019. doi:10.1029/2009GB003767


  • Somes, C. J. (2013). Nitrogen Isotopes in the Global OceanDoctoral (PhD) dissertation, Christian-Albrechts-University of Kiel, Kiel, Germany, 141 pp. (url)
  • Somes, C. J. (2009). Nitrogen isotopes in a global ocean biogeochemical model : constraints on the coupling between denitrification and nitrogen fixationMaster's thesis, Oregon State University, Corvallis, Oregon, USA, 72 pp., (url)

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Past Projects

    Impacts of anthropogenic nutrient pollutants on marine productivity, deoxygenation and sedimentary feedbacks in the Anthropocene: From the coastal to the global ocean (project page)

    • Postdoctoral research grant funded by the Cluster of Excellence "The Future Ocean" from the German Research Foundation (DFG)
    • Position: Project Leader
    • 2017-2019

    Climate-Biogeochemistry Interactions in the Tropical Ocean (project page)

    • Collaborative Research Centre funded by the German Research Foundation (DFG)
    • Position: PhD, Postdoctroal Researcher
    • 2010-2017

    Reconstructing Glacial Nitrogen and Carbon Cycling Using Isotopes (project page)

    • funded by Marine Geology and Geophysics program from the National Science Foundation
    • Position: External Collaborator
    • 2011-2014

    Ocean Circulation, Oxgyen and Nutrient Cycles during the Last Glacial (project page)

    • funded by Marine Geology and Geophysics program from the National Science Foundation
    • Position: Masters' Student Researcher
    • 2007-2010