Glacial/Interglacial Export Production in the Subantarctic South Pacific

Abstract

Atmospheric CO2 varied considerably in the past; however, the mechanisms that drive this variability are poorly understood. CO2 is linked to marine primary productivity through the biological carbon pump (BCP), leading to hypotheses that past increases in BCP efficiency in areas such as the Southern Ocean may have contributed to glacial CO2 drawdown (Sarmiento & Toggweiler, 1984). Productivity has varied considerably in the past, but the extent, timing, and impacts remain poorly understood. The Subantarctic South Pacific is an area of the ocean that is crucial to the understanding of both glacial climate and paleo-export productivity. Unfortunately, few studies have investigated the central South Pacific because it is so remote. The sediment core MV0502-04JC was recovered from the Subantarctic South Pacific in February-March 2005 at 50°S. The results of this study will be compared with data from ODP Leg 189, Site 1171, also in the Subantarctic South Pacific. Data from these cores will be used to evaluate glacial/interglacial paleo-export production and terrigenous provenance using bulk sediment geochemical proxies, including detailed P geochemistry, P, Ba, and metal elemental ratios, and Baxs. The results of this research suggest each site has variable terrigenous provenance that may have relatively different Fe content. Export production at MV0502-4JC is invariant down core; however, Site 1171 does exhibit glacial/interglacial variations in export production.