The Southern Ocean and Antarctic systems offer remarkable natural experimental models for studying disrupted ecosystems. The long-term stability of the Antarctic has led to the development of a tightly coupled marine trophic structure, but the recent synergy between climate induced and anthropogenic influences (fisheries) has seen some regions undergo environmental change. Mammals are likely to be susceptible to the potential effects of anthropogenic pollutants and global warming. Unlike many other predators in the region, many of the seals (leopard, crabeater, Ross and Weddell seals) were never directly harvested by humans; so that their population trajectories track the impacts of biological and environmental changes in this ecosystem. By investigating changes in the food web, particularly foraging and spatial patterns of seal populations, we can compare with historic samples and changes seen in the West Antarctic.
Crabeater seals are common across the Southern Ocean but actually eat krill not crabs.
Analysis of the seal skin and blubber can provide precious insights into their diet.
The research program
* listen to Sea Leopard song recorded on the expedition on Soundcloud.
The Southern Ocean plays a fundamental role in global climate but suffers from a dearth of observational data. As the Australasian Antarctic Expedition 2013-2014 we have developed the first annually-resolved temperature record using trees from subantarctic southwest Pacific (52˚-54˚S) to extend the climate record back to 1870. With modeling we show today’s high climate variability became established in the ~1940s and likely driven by an atmospheric signal that originated in the tropical Pacific. Our results suggest that the influence of contemporary equatorial Pacific temperatures may now be a permanent feature across the mid- to high latitudes of the Southern Hemisphere, with substantial impacts on seabird and mammal populations.Download