Our long-term seabird research at Admiralty Bay has documented annual variability in the life history parameters of the breeding biology and ecology of Adélie, gentoo, and chinstrap penguins. Long-term data acquired on these species including: survival and recruitment, population size and breeding success, diets and foraging ecology, provide clear evidence linking offshore biological and physical processes to their effects on dependent predators in the Southern Ocean. Our most recent results present a conceptual model linking increasing temperatures and decreasing sea ice cover in the Antarctic Peninsula region to declines in krill and penguin populations. Winter temperatures in the Antarctic Peninsula region have increased 4-5°C over the last 50 years (Smith et al. 1996, 1999), affecting the periodicity of sea ice cover in the region. This climate change, and the associated reduction in winter sea ice cover, has profoundly impacted the Antarctic, krill-based food web (Loeb et al. 1997, Smith et al. 1999, Trivelpiece and Trivelpiece, in prep.).