Upper Ocean Variability in West Antarctic Peninsula Continental Shelf Waters as Measured Using Instrumented Seals
Daniel P. Costa1, John M. Klinck2, Eileen E. Hofmann2, Michael S. Dinniman2, and Jennifer M. Burns3
1Department of Ecology and Evolutionary Biology
100 Shaffer Rd
University of California, Santa Cruz
Santa Cruz, CA 95060
2Center for Coastal Physical Oceanography
Old Dominion University
Norfolk, VA 23529
3Department of Biological Sciences, EBL 123
University of Alaska Anchorage
3211 Providence Dr.
Anchorage, AK 99508
Temperature profile data for the western Antarctic Peninsula (WAP) continental shelf waters, collected from freely ranging instrumented crabeater seals (Lobodon carcinophagus), were used to demonstrate that these platforms can be used to supplement traditional oceanographic sampling methods. The seal-derived profiles were combined with temperature profiles obtained from ship-based CTD measurements and from a numerical circulation model developed for the WAP to describe changes in temperature structure, heat content, and heat flux in the upper ocean waters of the WAP continental shelf. We provide the first description of the seasonal cycle of erosion and development of the Antarctic Surface Water (AASW) and Winter Water (WW) layers for the WAP continental shelf. Further the seal-derived data documented the shelf-wide presence of modified Circumpolar Deep Water (CDW) that is found below 150-200 m on the WAP continental shelf. The heat content of the upper 200 m calculated from the seal-derived temperature profiles ranged between 1000 and 1500 J m-3; similar estimates were obtained from the simulated temperature distributions and hydrographic measurements. Seal-derived measurements provide broader space and time resolution than could be obtained using any other currently available oceanographic sampling method.