Use of Avian Stomach Oil Deposits (‘Mumiyo’) for Reconstructing Antarctic Ice Sheet History, Palaeoceanography and Seabird Palaeodiet (Masters or PhD)
Supervised by Professor Mike Bentley & Dr Erin McClymont
This project aims to develop methods for analysing a deposit found commonly in remote mountain ranges in Antarctica. Some Antarctic seabirds, especially petrels, nest up to 300km from the coast on ice-free nunataks in East Antarctica. At their nest sites the petrels regurgitate stomach oil as a defence mechanism; this accumulates as a waxy grey coating on the rocks, 100 - 500mm thick, typically weighing several kilograms, with a stratified internal structure, and 14C ages increase with depth confirming deposition by progressive accumulation of regurgitated oil, at a rate of 9 - 100mm / ka. These deposits are termed 'mumiyo'. Dating of the base of mumiyo deposits has been shown to provide a minimum age for local ice thinning, and has been used along altitudinal transects in combination with cosmogenic isotopes to determine ice sheet thickness changes in some parts of Antarctica. However because of their origin and mechanism of formation the deposits also contain additional information on changes in the ocean feeding grounds of the birds through time. Such information has not yet been extracted to any significant degree from mumiyo deposits.
This project seeks to develop 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 the palaeoceanographic conditions including sea-ice coverage and other parameters from changes in their feeding grounds?
The student will develop analytical methods on existing mumiyo samples from a range of sites in Antarctica. She / he will receive training in laboratory analytical techniques such as organic and inorganic geochemistry, isotopes, as well as radiocarbon dating, microscopic analysis, palaeoceanography, Antarctic ice sheet history and analysis of palaeoenvironmental change in Antarctica.
The project is collaborative with the British Antarctic Survey and the Alfred Wegener Institute for Polar and Marine Research, Germany. It will involve travel to both of these institutions. There is no fieldwork planned.
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.