Meeting Abstract

S7.1  Tuesday, Jan. 5  The Changing Ecosystem of the West Antarctic Peninsula STEINBERG, D.K.*; SCHOFIELD, O.M.E.; FRASER, W.R.; STAMMERJOHN, S.E.; MARTINSON, D.G.; DONEY, S.C.; MONTES-HUGO, M.; DUCKLOW, H.W.; Virginia Institute of Marine Science, Gloucester Point, Virginia ; Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey; Polar Oceans Research Group, Sheridan, Montana ; University of California, Santa Cruz; Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York ; Woods Hole Oceanographic Institution, Woods Hole, Massachusetts ; Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey; Marine Biological Laboratory, Woods Hole, Massachusetts debbies@vims.edu

The West Antarctic Peninsula (WAP) is one of the most rapidly warming regions on Earth. The Palmer, Antarctica Long-Term Ecological Research (PAL LTER) Program is investigating marine ecosystem response to this climate change along the peninsula’s marine continental shelf and marginal sea ice zone. Regional warming and sea ice decline in the northern part of the study area are already leading to changes from the base of the foodweb to its apex. Changes in the mean standing stocks of phytoplankton and rates of primary production in response to sea ice decline are complex: phytoplankton have declined by 89% in the north and increased by 66% in the south as a result of differential changes in vertical mixing and exposure to sunlight resulting from reductions in sea ice cover and duration. Changes in distribution and relative abundance of zooplankton taxa such as krill and salps could lead to changes in biogeochemical cycling and export of carbon from surface waters. Moving further up the foodweb, Adélie penguins have declined locally by over 70% and are being replaced by sub-Antarctic congeners. We are now attempting to understand the mechanisms of ecosystem response to rapid climate change by conducting detailed, ship-based process studies addressing trophic linkages and biogeochemical dynamics.