Variations of terrestrial input and marine productivity in the Southern Ocean (48°S) during the last two deglaciations

Abstract

Various biomarkers (n‐alkanes, n‐alcohols, and sterols) have been studied in a piston core TSP‐2PC taken from the Southern Ocean to reconstruct the paleoenvironmental changes in the subantarctic region for the last two deglaciations. Mass accumulation rates of terrestrial (higher molecular weight n‐alkanes and n‐alcohols) and marine (dinosterol and brassicasterol) biomarkers increased significantly at the last two glacials and stayed low during interglacial peaks (early Holocene and the Eemian). These records indicate that the enhanced atmospheric transport of continental materials and the increased marine biological productivity were synchronously linked in the Southern Ocean at the last two glacials. This suggests that increased glacial dust inputs have relieved iron limitation in the subantarctic Southern Ocean. These two processes, however, were not linked at the cooling phase from the Eemian to marine isotope stage (MIS) 5d. During this period, paleoproductivity may have been influenced by the latitudinal migration of the high‐production zone associated with the Antarctic Polar Front.