Real-Time Characterization of Adelie Penguin Foraging Environment Using an Autonomous Underwater Vehicle

Abstract: The Antarctic Peninsula is among the most rapidly warming regions on earth. Increased heat from the Antarctic Circumpolar Current has elevated the temperature of the 300 m of shelf water below the permanent pycnocline by 0.7 degrees C. This trend has displaced the once dominant cold, dry continental Antarctic climate, and is causing multi-level responses in the marine ecosystem. One striking example of the ecosystem response to warming has been the local declines in ice-dependent Adélie penguins. The changes in these apex predators are thought to be driven by alterations in phytoplankton and zooplankton community composition, and the foraging limitations and diet differences between these species. One of the most elusive questions facing researchers interested in the foraging ecology of the Adélie penguin, namely, what are the biophysical properties that characterize the three dimensional foraging space of this top predator? The research will combine the real-time site and diving information from the Adélie penguin satellite tags with the full characterization of the oceanography and the penguins prey field using an autonomous underwater vehicle (AUV). While some of these changes have been documented over large spatial scales of the WAP, it is now thought that the causal mechanisms that favor of one life history strategy over another may actually operate over much smaller scales than previously thought, specifically on the scale of local breeding sites and over-wintering areas. Characterization of prey fields on these local scales has yet to be done and one that the AUV is ideally suited. The results will have a direct tie to the climate induced changes that are occurring in the West Antarctic Peninsula. This study will also highlight a new approach to linking an autonomous platform to bird behavior that could be expanded to include the other two species of penguins and examine the seasonal differences in their foraging behavior and prey selection. From a vehicle perspective, this effort will inform the AUV user community of new sensor suites and/or data processing approaches that are required to better evaluate foraging habitat. The project also will help transition AUV platforms into routine investigative tools for this region, which is chronically under sampled and will remain difficult to access