Ocean acidification affects iron speciation in seawater
1Bjerknes Centre for Climate Research, University of Bergen, Bergen, Allégaten 55, 5007 Bergen, Norway
2Department of Chemistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
3Leibniz Institute of Marine Sciences (IFM-GEOMAR), Düsternbrooker Weg 20, 24105 Kiel, Germany
4Norwegian University of Science and Technology, Department of Chemistry, 7491 Trondheim, Norway
Abstract. 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 μatm pCO2, 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, 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.