Geological Society of America

T242 Ice-Sheet and Sea-Ice Paleo-Reconstructions from the Arctic, Antarctica, and the Southern Ocean

Friday, 30 October 2020
10:00 AM - 2:00 PM
Meeting Rooms

SUMMER SEA-ICE VARIABILITY IN THE EASTERN WEDDELL SEA DURING THE LAST GLACIAL STAGE AS RECORDED IN SNOW PETREL STOMACH OILS (‘MUMIYO’)

Paper number: T242-11
Program: Technical Sessions
Time: 12:15 PM – 12:25 PM

Authors

Erin McClymont Presenting Author
Durham University, DURHAM
Louise Sime
British Antarctic Survey, Cambridge
Michael J. Bentley
Durham University, Durham
Dominic Hodgson
British Antarctic Survey, Cambridge
Richard Phillips
British Antarctic Survey, Cambridge
Charlotte Spencer-Jones
Open University, Milton Keynes
Charlotte Spencer-Jones
Durham University, Durham
Sonja Berg
University of Cologne, Cologne
Ian Croudace
National Oceanography Centre Southampton at the University of Southampton, Southampton
Darren R. Gröcke
Durham University, Durham
Darren R. Gröcke
University of Durham, Science Labs, Durham
Gerhard Kuhn
Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven

Abstract

Antarctic sea ice is a critical component of the climate system, affecting a range of physical and biogeochemical feedbacks, and supporting unique ecosystems. During the last glacial stage, Antarctic sea ice was more extensive than today. However, uncertainties in both empirical data sets and climate models over the seasonal distribution and character of the sea-ice pack limit our understanding of sea-ice drivers, ecosystem response, and climate impacts. Here, we exploit a unique biological archive of conditions in the sea-ice pack: the preserved remains of regurgitated snow petrel stomach oils (sometimes referred to as ‘Antarctic mumiyo’), deposited on nunataks above the ice sheet. We present results from a sequence recovered from the Lake Untersee Oasis, central Dronning Maud Land (71°20.2’S, 13°23.6’E ), which records snow petrel foraging in the eastern Weddell Sea. By linking dietary signals in the stomach oils to modern feeding habits, we demonstrate centennial-scale variability to the summer sea-ice pack close to the Antarctic continent early in the last glacial stage (ca. 24.5-30.7 cal. ka. BP). By identifying the presence and evolution of open waters (‘polynyas’) within the sea-ice pack, the results challenge existing hypotheses which emphasise the development of an extensive, thick, multi-year ‘sea-ice cap’ as the key for positive sea ice / climate feedbacks during glacial stages.

Geological Society of America Abstracts with Programs. Vol. 52, No. 6

doi: 10.1130/abs/2020AM-354545

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