Sea ice evolution and ecosystem responses recorded by Antarctic seabirds

Overview

This project aims to develop novel insights into the evolution of Antarctic sea ice and marine ecosystems through time, using specific sequences of preserved seabird stomach contents (‘mumiyo’) recovered from nunataks above the Antarctic ice sheet.

Snow petrels (Pagodroma nivea) nest high above the Antarctic ice sheet, but forage within the sea-ice pack. At their nest sites the snow petrels regurgitate stomach oil as a defence mechanism; this ‘mumiyo’ accumulates as a waxy grey coating on the rocks, 100-500 mm thick, typically weighing several kilograms, and with a stratified internal structure. The mumiyo hosts a range of evidence for changing snow petrel diet (e.g. from krill, fish), which can also be linked to changing sea ice. Radiocarbon dating has also enabled sequences of local ice thinning to be reconstructed, because snow petrels require ice-free sites for nesting (e.g. Bentley et al., 2014). Changes to the timing of mumiyo accumulation and evidence for weathering may also be linked to environmental conditions onshore (Berg et al., 2019).

This project seeks to develop and apply new approaches to the analysis of mumiyo deposits that will focus on questions such as: What has the diet of these seabirds consisted of? How did it change through time, and what does it tell us about past environmental changes? Where might the birds have been feeding? Can we reconstruct past sea-ice coverage?

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Image Captions

Accumulation of sub-fossil mumiyo (grey deposit) outside a Snow petrel nest, high above the Antarctic ice sheet. GPS unit for scale. Photo: Dominic Hodgson.

Methodology

A range of analytical methods will be employed during the PhD. For example, preserved microfossil remains can be analysed for their species composition and stable isotope signal, as indicators of sea ice and dietary change. Lipid analysis can detail changing snow petrel diet (e.g. krill, fish) as well as sea ice indicators (e.g. the sea ice biomarker IPSO25). The student will be able to apply state-of-the-art lipid stable isotope analysis to explore changing diet and sea ice properties. There will also be an opportunity to strengthen mumiyo interpretations through analysis of prey samples from previous expeditions by the British Antarctic Survey.

Project Timeline

Year 1

Literature review and generation of project research questions. First year Progression Paper to detail project overview, research questions, and planned methodology. Sub-sampling of existing mumiyo samples held at Durham/BAS. Training in, and application of, and initial laboratory analysis (details below).

Year 2

Physical and geochemical analysis of mumiyo sequences to build the project dataset. Selection of additional samples for dating where required. Additional sampling of sequences where required and/or analysis of snow petrel prey samples to strengthen interpretations. Training in advanced analytical techniques (e.g. lipid stable isotopes). Development of first research paper.

Year 3

Final analyses of data from mumiyo and/or prey samples. Presentation of emerging data at an international conference (target: International Conference on Paleoceanography, Bergen, 2022). Development of second research paper, and thesis writing.

Year 3.5

Completion and submission of thesis, finalisation of remaining research papers.

Training
& Skills

The supervisory team will provide the student with training in laboratory analytical techniques such as organic and inorganic geochemistry, microscope analysis, isotope analysis, and radiocarbon dating. Additional knowledge in palaeoceanography, Antarctic ice sheet history and Antarctic environmental change will be developed, especially through the formulation of the literature review and development of research papers. The student will spend an extended training visit at British Antarctic Survey, to gain knowledge on snow petrel distributions, feeding patterns and diet, bridging research groups working on Antarctic palaeoclimates and ecosystems. The supervisory team has the necessary expertise to train the student in these specialist skills, all supported by a dedicated team of technicians in Durham Geography and British Antarctic Survey.

The student will receive regular supervisory meetings and support at Durham. Through their enrolment in the graduate training programme at Durham University and through IAPETUS-specific training, the student will gain a range of transferable skills relevant to completion of the PhD and developing a career path, including writing research proposals and giving oral presentations. S/he will attend national and international conferences, networking events and outreach activities, developing an important network for feedback and future employment. The student will attend and contribute to the programme of regular departmental seminars and discussion groups, to support the development of a well-rounded scientist. S/he will attend national and international conferences, networking events and outreach activities, developing networks for feedback and future employment.

References & further reading

Bentley, M. J., et al. (2014), A community-based geological reconstruction of Antarctic Ice Sheet deglaciation since the Last Glacial Maximum, Quaternary Science Reviews, 100, 1-9.

Berg, S., M. Melles, W.-D. Hermichen, E. L. McClymont, M. J. Bentley, Hodgson, D.A. and G. Kuhn (2019), Evaluation of Mumiyo Deposits from East Antarctica as Archives for the Late Quaternary Environmental and Climatic History, Geochemistry, Geophysics, Geosystems, doi:10.1029/2018GC008054.

Hiller et al, (1988) Occupation of the Antarctic Continent by Petrels During the Past 35 000 Years: Inferences from a 14C Study of Stomach Oil Deposits, Polar Biology, 9:69-77.

Thatje et al. (2008), Life Hung by a Thread: Endurance of Antarctic Fauna in Glacial Periods, Ecology, 89(3), 682-692.

Further Information

Professor Erin McClymont, Durham University, 00 44 191 334 3498, erin.mcclymont@durham.ac.uk.

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