Ice-proximal sea ice reconstruction in the Powell Basin, Antarctica, since the Last Interglacial

• DOI: 10.5194/cp-21-299-2025
• Publication Date: 2025-01-31T08:03:44Z
• Authors: Wee Wei Khoo; Juliane Müller; Oliver Esper; Wenshen Xiao; Christian Stepanek; Paul Gierz; Gerrit Lohmann; Walter Geibert; Jens Hefter; Gesine Mollenhauer
• Keywords: Deglaciation; Ice core

Abstract. In Antarctica, the presence of sea ice not only plays a critical role in climate system but also contributes to enhancing stability floating shelves. Hence, investigating past ice-proximal conditions, especially across glacial–interglacial cycles, can provide crucial information pertaining variability and deepen our understanding ocean–ice–atmosphere dynamics feedback. this study, we apply multiproxy approach, combination with numerical modeling, explore environmental variability. We analyze novel biomarker IPSO25 (a di-unsaturated highly branched isoprenoid (HBI)), open-water biomarkers (tri-unsaturated HBIs; z-/e-trienes), diatom assemblage primary productivity indicators marine sediment core retrieved from Powell Basin, NW Weddell Sea. These have been established as reliable proxies for reconstructing near-coastal conditions Southern Ocean (SO), where typical use sea-ice-related diatoms be impacted by silica dissolution. present first continuous records, close proximity Antarctic continental margin, since penultimate deglaciation. Our data shed new light on (seasonal) basin reveal dynamic setting characterized significant shifts perennial cover seasonal an open environment over last 145 kyr. results unveil stronger deglacial amplitude warming during Last Interglacial (LIG; Marine Isotope Stage (MIS) 5e) compared current one (Holocene). A short-term readvance occurred towards end each Finally, despite similar findings between proxy model data, notable differences persist both interglacials – emphasizing necessity different sheet configurations employed more robust paleoclimate enhance performance margin.