EGU25-12282, updated on 15 Mar 2025
https://doi.org/10.5194/egusphere-egu25-12282
EGU General Assembly 2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Oral | Friday, 02 May, 09:55–10:05 (CEST)
 
Room 0.31/32
Interactions between Antarctic ice-sheet extent and summer sea-ice variability over the last 45,000 years in the Weddell Sea-Dronning Maud Land as reconstructed from snow petrel stomach-oil deposits
Erin McClymont1, Thale Damm-Johnsen1, Ewan Wakefield1, Anna Rix2, Michael Bentley1, Yasmin Cole1, W. James Grecian1, Dominic Hodgson3, Eleanor Maedhbh Honan1, Zhongxuan Li1, Claire Penny1, Kerry Strong1, Mark Stevenson1, Philippa Ascough4, Darren Grocke5, A. Rus Hoelzel2, Richard Phillips3, Louise Sime3, and Stephen Willis2
Erin McClymont et al.
  • 1Durham University, Department of Geography, Durham, United Kingdom of Great Britain – England, Scotland, Wales (erin.mcclymont@durham.ac.uk)
  • 2Durham University, Department of Biosciences, Durham, U.K.
  • 3British Antarctic Survey, Cambridge, U.K.
  • 4Scottish Universities Environmental Research Centre, University of Glasgow, U.K.
  • 5Durham University, Department of Earth Sciences, Durham, U.K.

Constraining the nature and timing of changes to the East Antarctic ice sheet in the Weddell Sea-Dronning Maud Land sector over the last glacial cycle has been challenging, due to limited geological evidence and contrasting models of past ice sheet extents and retreat behaviour. It is important to distinguish between these scenarios, because this region is also a source of Antarctic Bottom Water, and there are regions of the ice sheet which are sensitive to ocean warming.

Here, we present a novel archive of past sea-ice environments from regurgitated stomach oils of snow petrels (Pagodroma nivea) spanning the last ~45,000 years. Snow petrels forage within sea ice, and record changes to their diet and surface ocean properties within their stomach oil biochemistry. The stomach-oil deposits we examine here are preserved at breeding colonies extending from the Theron Mountains (30°W) to the Sør Rondane Mountains (23°W). We use the deposits to constrain the presence of bedrock for breeding, which becomes available as the ice sheet thins or retreats.

We show major variations in snow petrel occupation over time, in part related to availability of breeding habitat as ice sheet extent fluctuated. Reconstructions of snow petrel diet using multi-proxy analysis of fatty acids, stable carbon and nitrogen isotope ratios, and elemental composition (via XRF) shows centennial-scale variations in diet and regional differences in sea ice histories. We propose that open waters (‘polynyas’) were present in the sea ice during Marine Isotope Stages 2 and 3, and that their properties evolved through time as summer sea ice expanded to its maximum extent (~29-22 ka) and retreated across the last deglaciation. We explore how these changes in summer sea-ice environment are linked to changes in ice-sheet extent and ocean/atmospheric circulation over the last ~45 ka.

How to cite: McClymont, E., Damm-Johnsen, T., Wakefield, E., Rix, A., Bentley, M., Cole, Y., Grecian, W. J., Hodgson, D., Honan, E. M., Li, Z., Penny, C., Strong, K., Stevenson, M., Ascough, P., Grocke, D., Hoelzel, A. R., Phillips, R., Sime, L., and Willis, S.: Interactions between Antarctic ice-sheet extent and summer sea-ice variability over the last 45,000 years in the Weddell Sea-Dronning Maud Land as reconstructed from snow petrel stomach-oil deposits, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12282, https://doi.org/10.5194/egusphere-egu25-12282, 2025.