The central hypothesis of the Palmer LTER (Long-Term Ecological Research) program is that the annual advance and retreat of sea ice underlies spatial and temporal changes in structure and function of all levels of the Antarctic marine ecosystem. The Palmer LTER is testing hypotheses on the links between meteorology, hydrography and sea ice and 1) the microbial loop and particle flux, 2) seasonal primary production, 3) population dynamics of Antarctic krill, and 4) survivorship and reproductive success of Adelie penguins. A primary objective is to document interannual variability in the environment and in biological processes in the study region west of the Antarctic Peninsula (WAP) and distinguish between natural cycles and long-term trends. A small-spatial long-temporal scale study is conducted each year during the growth season (Oct-Mar) from small boats. The mesoscale annual research cruise uses the LM Gould, a 220 ft ice strengthened research vessel, to investigate the ecosytem of the continental shelf and shelf slope.

Time series data for primary productivity in the WAP area shows large seasonal, interannual and spatial variability, often associated with the marginal sea ice zone. New linkages have been found between seasonal sea ice dynamics and a variety of biological functions, including reproductive success in Antarctic krill, and timing and magnitude of carbon flux. Specific phytoplankton areas have been identified which display high pigment biomass and CO2 drawdown. Reproductive success in Adelie penguins has been shown to depend on snow deposition in addition to prey availability. All evidence, paleo to modern, consistently shows a warming trend in the LTER region, especially during the latter half of this century. These combined records show the Palmer LTER region is particularly sensitive to climate change.