S1-3 Saturday, Jan. 4 08:30 - 09:00 Advances in the use of biogeochemical markers to track the diets and movement of Antarctic marine predators POLITO, MJ*; MICHELSON, CI; MCMAHON, KW; Louisiana State University; Louisiana State University; University of Rhode Island email@example.com http://www.oceanography.lsu.edu/politolab/
Quantifying the diets, foraging ecology, and at-sea distribution of wide-ranging marine predators is critical to understanding their ecological responses to recent environmental change and predicting species responses in the future. However, logistical, financial, and ethical constraints can often limit researchers’ ability to directly measure these key life history characteristics in Antarctic marine predators. The analysis of intrinsic biogeochemical markers, such as stable isotopes, fatty-acids, DNA, and bioaccumulating contaminants, represent powerful techniques that provide proxies of the diets and movements of marine predators when they cannot be directly observed. These methods are based on the principle that consumers “are what and where they eat” with conservative transfer of biomarker compounds from the base of the food web to consumers across the food web. This presentation will briefly review recent advances in the use of biogeochemical markers in studies of Antarctic predator ecology. It will also highlight two case studies. The first study uses compound-specific stable isotope analysis of feather amino acids to evaluate the diets and migration patterns of penguins from the genus Pygoscelis during the winter months when they are away from their breeding colonies. The second study uses this same technique to examine the trophic responses of sympatric chinstrap (P. antarctica) and gentoo (P. papua) penguins from the Antarctic Peninsula to nearly 100 years of shared environmental change. These studies highlight the potential that intrinsic biogeochemical markers have in complementing traditional diet and tracking methods to significantly expand the spatial and temporal scope of Antarctic marine predator studies.