Paleoclimatic Signals from the Proxy Records of the Southern Ocean: A Review

Abstract

Antarctic sea-ice extent and oceanic frontal systems are of primary importance to the marine biota since their marked meridional gradients in physical and chemical properties strongly regulate the phytoplankton contribution to primary productivity.Antarctic sea ice extent along with the Southern Ocean (SO) biological productivity varied considerably during glacial-interglacial periods, and both are known to have played a considerable role in regulating atmospheric CO2 variations in the past. In the present review paper, we seek to understand the past latitudinal variability of the Southern Ocean frontal systems and Antarctic sea-ice extent based on a multi-proxy approach. The first aspect of this paper concentrates on the diatom based reconstructions of paleo sea-ice and hydrographic changes in the Southern Ocean and its impact on diatom sizes and productivity. Secondly, emphasis would be placed on the studies based on the morphology and isotopic composition of foraminifera and its paleoceanographic implication. The foraminifera shell preserved in the sediments provide unparalleled archives of morphological change, faunal variations, and habitat characteristics as a result of hydrographic changes. To sum up, the advantage of a mulitproxy approach including the magnetic, geochemical and sedimentological parameters have been discussed in understanding the Southern Ocean paleoclimate.