Ironing Out Algal Issues in the Southern Ocean

Periods of iron supply to the ocean over geological time scales may have altered climate by increasing the amount of COfixed by anaemic (iron-limited) phytoplankton. In his perspective, Boyd comments on three papers ( Coale et al., Bishop et al., and Buesseler et al.) that report results from recent large-scale experiments in which ocean waters have been enriched with iron. By measuring how much carbon fixed by phytoplankton is sequestered into the abyss, the experiments test the hypothesis that enhanced iron supply leads to enhanced export of particulate organic carbon.