Corals, currents, and phytoplankton: Reconstructing 3000 years of circulation and marine productivity in the world's largest ocean gyre

We propose to use black corals, a new high-resolution ocean archive, to study circulation andproductivity in waters around New Zealand over the last 3 millennia. These deep-sea corals areexceedingly long-lived, depositing proteinaceous skeletons that capture the chemical compositionof the plankton debris upon which they feed. Thus they preserve a history of the surface ocean overthousands of years. Using specimens from the extensive collection held by NIWA, we will generaterecords of nitrogen and carbon isotopes and trace elements which are a powerful combination ofproxies for ocean circulation and productivity. The result will be a comprehensive portrait of SouthPacific Gyre dynamics, and their impact on marine primary productivity in the southwest PacificOcean.