Biogeosciences www.biogeosciences.net 1726-4170 1726-4189 7 3 2010 10.5194/bg-7-1065-2010 http://www.biogeosciences.net/7/1065/2010/ http://www.biogeosciences.net/7/1065/2010/bg-7-1065-2010.html http://www.biogeosciences.net/7/1065/2010/bg-7-1065-2010.pdf 1065 1073 2010-03-19 Ocean acidification affects iron speciation during a coastal seawater mesocosm experiment E. Breitbarth ebreitbarth@chemistry.otago.ac.nz R. J. Bellerby C. C. Neill M. V. Ardelan M. Meyerhöfer E. Zöllner P. L. Croot U. Riebesell Bjerknes Centre for Climate Research, University of Bergen, Bergen, Allégaten 55, 5007 Bergen, Norway Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand Norwegian University of Science and Technology, Department of Chemistry, 7491 Trondheim, Norway Leibniz Institute of Marine Sciences (IFM-GEOMAR), Düsternbrooker Weg 20, 24105 Kiel, Germany Rising atmospheric CO₂ is acidifying the surface ocean, a process which is expected to greatly influence the chemistry and biology of the future ocean. Following the development of iron-replete phytoplankton blooms in a coastal mesocosm experiment at 350, 700, and 1050 &mu;atm <i>p</i>CO₂, we observed significant increases in dissolved iron concentrations, Fe(II) concentrations, and Fe(II) half-life times during and after the peak of blooms in response to CO₂ enrichment and concomitant lowering of pH, suggesting increased iron bioavailability. If applicable to the open ocean this may provide a negative feedback mechanism to the rising atmospheric CO₂ by stimulating marine primary production. % vor jede Referenz Barbeau, K., Moffett, J. W., Caron, D. A., Croot, P. 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