The Southern Ocean will never be adequately understood without knowing the reasons why major nutrients never go to depletion in offshore, open-ocean waters. Dr. Martin proposes to test the hypothesis that phytoplankton productivity in the Southern Ocean varies in direct relation to iron availability. Samples to test this hypothesis were collected in the open-ocean waters of the Drake Passage in March/April 1989 and in the Ross Sea in January/February 1990. Initial results suggest that iron deficiency is the primary reason that the phytoplankton fail to bloom and use up major nutrients in offshore Southern Ocean waters. Renewed funding for one year to support our continued analysis of samples and testing of the iron deficiency hypothesis is requested in this proposal.
