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

Khoo, Wee Wei; Müller, Juliane; Esper, Oliver; Xiao, Wenshen; Stepanek, Christian; Gierz, Paul; Lohmann, Gerrit; Geibert, Walter; Hefter, Jens; Mollenhauer, Gesine

In Antarctica, the presence of sea ice in front of ice shelves promotes their stability and prevents the risk of catastrophic collapse as witnessed in recent events along the Antarctic Peninsula. Investigating past ice-proximal sea-ice conditions, especially across glacial-interglacial cycles, can provide crucial information pertaining to sea-ice variability and deepen our understanding of ocean-ice-atmosphere dynamics and feedbacks. In this study, we apply a multiproxy approach, analyzing the novel sea ice biomarker IPSO 25 (a di-unsaturated highly branched isoprenoid (HBI)), open-water biomarkers (tri-unsaturated HBIs; z-/e-trienes), and the diatom assemblage and primary productivity indicators in a marine sediment core retrieved from Powell Basin, NW Weddell Sea. These biomarkers have been established as reliable proxies for reconstructing near-coastal sea ice conditions in the Southern Ocean, where the typical use of sea ice-related diatoms can be impacted by silica dissolution. Our data shed new light on the variability of sea ice since the penultimate deglaciation, ca. 145 ka before present, and reveal a highly dynamic glacial-interglacial sea-ice setting characterized by significant shifts from perennial ice cover to seasonal sea-ice cover and open marine environment.



Khoo, Wee Wei / Müller, Juliane / Esper, Oliver / et al: Ice-proximal sea-ice reconstruction in Powell Basin, Antarctica since the Last Interglacial. 2024. Copernicus Publications.


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