Imprint of AABW dynamic on sedimentary mercury variations in the Scotia Sea, Antarctica.

Abstract

Production of Antarctic Bottom Water (AABW), which is one of components for the Thermohaline Circulation (THC), plays a crucial role on the Earth’s climate system, regulating the Earths’ heat budget and atmospheric CO₂ concentration. Numerous researches have been focused on investigating the glacial-interglacial variations of AABW production, and further their relationship to abrupt climatic changes (e.g., DO events) for example, a large increase of AABW production in Antarctic during glacial period may be linked to resumption of the THC, resulting in abrupt warming events. However, paleo-proxies on the glacial-interglacial variation of AABW production in Antarctic are still lacking. Here, we present a newhigh-resolution sedimentary Hg record in 35-kyr sediment core from the Scotia Sea, where is one of passages of AABW formed in Weddell Sea, which can provide insight into the glacial-interglacial variation of AABW production in Southern Ocean. Sedimentary Hg in the Scotia Sea sediments is likely bound to either fine clay particles or adsorbed onto the surface of clay minerals and/or complexed by colloids and organic materials. Interestingly, Hg levels and fluxes are significantly high in the glacial deposits of the core, possibly associated with strengthening of brine rejection coupled with the widespread sea-ice formation and the more frequent and pervasive occurrence of coastal polynya. Such Hg enrichment by t