Using Organic Geochemistry to Assess Holocene Sea-Ice Variability in Novel Snow Petrel Stomach Oil Deposits from Antarctica

Stomach oil deposits from the sea-ice associated seabird, the snow petrel (Pagodroma nivea) can be found close to nesting sites beneath crevices and boulders in many Antarctic mountain ranges. These deposits are ideally suited for organic geochemistry due to their predominant wax-ester composition, originating from regurgitated snow petrel stomach oils. At nesting sites stomach oils are regurgitated to feed their young, used to warn off competitors and dissuade predatory skuas. As deposits build up over time, the stomach oil remnants provide a biochemical signature of the prey consumed. The deposits have been demonstrated to contain well-preserved stratigraphy, and are excellent palaeoenvironmental archives (Berg et al. 2019; McClymont et al., 2022). Snow petrels feed both within the perennial sea ice in polynyas and at the ice edge (depending on conditions) on a mixed diet of fish, squid and krill. The composition of the snow petrel’s diet reflects the available food at that time, which may be linked in turn to the sea ice conditions.