Giraud, Xavier, Dr.

Research Interests

• Paleoproxy modelling: nitrogen isotopes, alkenones, carbon isotopes
• Coastal ocean processes : upwelling
• Ocean Biogeochemistry Models: regional and global

Current Research

The sequestration of the atmospheric carbon into the ocean during the glacial interglacial time scale is driven by processes that are still poorly understood.
Using an ocean biogeochemistry model, the National Center for Atmospheric Research – Community Climate System Model (NCAR-CCSM), we aim to better understand the CO2 oceanic storage mechanisms during glacial interglacial periods, using carbon isotope (13C)‏ as paleoproxy of the carbon cycle.

Academic Career

Publications

In prep. or submitted

• Giraud X. and Paul A., submitted to Paleoceanography, Interpretation of paleo primary production record in NW Africa coastal upwelling biased by sea level change.

In press or published

• Giraud X., Le Quéré C., and Cotrim da Cunha L., 2008, Importance of coastal nutrient supply for global ocean biogeochemistry, Global Biogeochem. Cycles, 22, GB2025, doi:10.1029/2006GB002717. pdf
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• Cotrim da Cunha L., Buithenhuis E. T., Le Quéré C., Giraud X., and Ludwig W., 2007, Potential impact of changes in river nutrient supply on global ocean biogeochemistry. Global Biogeochem. Cycles, 21, GB4007, doi:10.1029/2006GB002718. pdf
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• Giraud X., 2006, Modelling an alkenone-like proxy record in the NW African upwelling, Biogeosciences, 3 (3), 251-269. pdf
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• Le Quéré C., Harrison S. P., Prentice I. C., Buithenhuis E. T., Aumont O., Bopp L., Claustre H., Cotrim da Cunha L., Geider R., Giraud X., Klaas C., Kohfeld K. E., Legendre L., Manizza M., Platt T., Rivkin R. B., Sathyendranath S., Uitz J., Watson A. J., and Wolf-Gladrow D., 2005, Ecosystem dynamics based on plankton functional types for global ocean biogeochemistry models, Global Change Biology, 11 (11), 2016-2040, doi:10.1111/j.1365-2486.2005.1004.x.pdf
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• Schmittner A., Oschlies A., Giraud X., Eby M., and Simmons H.L., 2005, A global model of the marine ecosystem for long-term simulations: Sensitivity to ocean mixing, buoyancy forcing, particle sinking, and dissolved organic matter cycling, Global Biogeochem. Cycles, 19, GB3004, doi:10.1029/2004GB002283. pdf
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• Giraud X., Bertrand P., Garçon V. and Dadou I., 2003, Interpretation of the nitrogen isotopic signal variations in the Mauritanian upwelling with a 2D physical-biogeochemical model, Global Biogeochem. Cycles, 17 (2), 1059, doi:10.1029/2002GB001951. pdf
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• Bertrand P., Pedersen T., Schneider R., Shimmield G., Lallier-Verges E., Disnar J.R., Massias D., Villanueva J., Tribovillard N., Huc A.Y., Giraud X., Pierre C. and Vénec-Peyré M.T., 2003, Organic-rich sediments in ventilated deep-sea environments: Relationship to climate, sea-level and trophic changes, J. Geoph. Res., 108 (C2), 3045, doi:10.1029/2000JC000327. pdf
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• Giraud X., Bertrand P., Garçon V. and Dadou I., 2000, Modeling d15N evolution: First palaeoceanographic applications in a coastal upwelling system, J. Mar. Res., 58, 609-630. pdf