Applications are invited for a 12-month postdoctoral position from candidates with a PhD in biogeochemical oceanography or similar. The postdoc will work within the Integrated Carbon Observation System (ICOS France) using carbon observations from ships. The successful candidate will be based at the LOCEAN laboratory in Sorbonne Université, in Paris (


The ocean plays an important role in the carbon cycle as it absorbs about 25% of the annual CO2 emissions by fossil fuel combustion and cement production. There is uncertainty on how much CO2 the oceans will absorb in the future under increasing atmospheric CO2. The ocean includes regions of sources of CO2 (e.g. tropical Atlantic) and sinks of CO2 (e.g. North Atlantic) and shows significant year-to-year variability in surface CO2 concentrations. In addition, the uptake of CO2 by the global ocean leads to ocean acidification by decreasing the pH but the rate of acidification is likely to vary from one oceanic region to another.

ICOS is a European research infrastructure ( designed to monitor the increase of atmospheric CO2 and the exchange of CO2 between the ocean and the terrestrial biosphere. We are hiring a postdoctoral fellow to work within the marine component of ICOS-France.

Project summary:

The objective of the project is to better quantify the sources and sinks of CO2 and their variability using CO2 observations. The postdoc fellow will also try to detect long-term trends (evolution of the CO2 flux, ocean acidification rate) in given oceanic regions of the French ICOS. The French marine ICOS includes underway measurements of the fugacity of CO2 (fCO2), or the partial pressure of CO2 (pCO2), made routinely on merchant ships and discrete inorganic carbon and alkalinity observations. The merchant ships have been recorded the surface fCO2 from France to Brazil since 2008 (>75 voyages) and from France to French Guiana from 2006 (>85 voyages). Observations are also available in the Antarctic Ocean (from Tasmania to Dumont d’Urville station) where more than 10,000 observations of inorganic carbon and alkalinity have been analyzed since 2002. Repeated CO2 observations from ships will be used to assess the seasonal and interannual variability of the carbon system (e.g. Ibánhez et al., 2015; Wanninkhof et al., 2019). The temporal evolution of the different oceanic regions will be compared in terms of their source/ sink patterns and their acidification rate. Satellite measurements of temperature, salinity and ocean colour (chlorophyll) will provide the environmental setting of the observations and will help in determining the drivers of the carbon variability. Additional carbon observations are available in the SOCAT (Surface Ocean CO2 Atlas project) database ( Simulations of the global biogeochemical-physical Mercator-Ocean model are also available.


Benallal, M.A., Moussa, H., Lencina-Avila, J.M., Touratier, F., Goyet, C., El Jai, M.C., et al. (2017). Satellite-derived CO2 flux in the surface seawater of the Austral Ocean south of Australia. International Journal of Remote Sensing 38(6), 1600-1625. doi: 10.1080/01431161.2017.1286054. Ibánhez, J.S.P., Diverrès, D., Araujo, M., and Lefèvre, N. (2015). Seasonal and interannual variability of sea-air CO2 fluxes in the tropical Atlantic affected by the Amazon River plume. Global Biogeochemical Cycles 29, doi:10.1002/2015GB005110. Wanninkhof, R., Triñanes, J., Park, G.-H., Gledhill, D., and Olsen, A. (2019). Large Decadal Changes in Air-Sea CO2 Fluxes in the Caribbean Sea. Journal of Geophysical Research: Oceans 124(10), 6960-6982. doi:


  • PhD in biogeochemical oceanography or related discipline
  • Knowledge of carbon cycle and statistics
  • Experience in analysis of observed data and/or model outputs
  • Skills in programming (Matlab, Python or equivalent), and in writing peer-reviewed scientific papers in English

The salary will be commensurate with experience.


Interested candidates should send to Nathalie Lefèvre ( the following documents: a detailed Curriculum Vitae, a statement of previous research and motivations for the present project, an abstract of the PhD manuscript (and the date of defense), a list of publications and contacts of at least two referees.

Closing date:

January 31, 2021