PROGRAM TITLE: Antarctic Ecosystems ACTIVITY STREAM: Process, Observe SCIENCE ELEMENT:Ecosystem Dynamics NATIONAL SCIENCE FOUNDATION SCIENTIFIC MERIT: The Office of Polar Programs has supported global change research in the form of interdisciplinary investigations of terrestrial, limnetic, and marine ecosystems in Antarctica. Antarctic Ecosystems is focused directly on ecosystem monitoring and long-term ecological response to global climate change to answer questions such as how climate variability and change in a fragile polar environment affect the food chain. The Antarctic LTER (Long Term Ecological Research) activities at Palmer Station provide a focal point for ecosystem studies which will include measurement of both physical and biological parameters. LTER's main goal is the effect of the interannual variation of sea ice cover on the structure of the marine ecosystem of the Antarctic Peninsula. Sea ice varies widely from season to season in the Antarctic and its maximum and minimum extent varies considerably from year to year. As many components of the marine food web, ranging from algae to penguins and seals, are dependent on the sea ice, changes in its extent can have a significant impact on marine life and the structure of the food web. Some of the changes in these extents may be complex periodicities; others may be associated with overall trends in global change. The ongoing studies at the site include environmental monitoring, satellite observations, and short term experimental process studies. A periodicity in annual sea-ice has been observed resulting in penguin population oscillations. The major advantages of this site include a relatively pristine environment, a simple food chain, (phytoplankton-krill-fish- mammals/birds), a fragile ecosystem balance in a harsh climate and limited interference by humans, i.e., minimal commercial interests. On the other hand, events such as the grounding of the Bahia Paraiso, and subsequent oil spill, can introduce major uncertainties in localized areas. This work would clearly have relevance to USGCRP if global warming were responsible for a long term reduction in sea-ice. STAKEHOLDERS: The Antarctic LTER at Palmer is funded and administered by the Office of Polar Programs, but jointly reviewed by the NSF LTER program, which includes sites located throughout the US, the Antarctic and its territories. The Palmer site is part of the LTER network. NASA participates peripherally in this program through MOU agreements regarding satellite coverage at the sites. The LTER program is not a part of the Long-Term Ecological Monitoring (LTEM) component of the Global Change in the Terrestrial Environment (GCTE) project of the International Geosphere Biosphere Programme (IGBP), however it could potentially contribute significantly to the kinds of scientific goals of that program as well as GLOBEC and the UV/Ozone program. POLICY RELEVANCE: Field monitoring and process studies will provide data for the early detection of global change. Changes in sea-ice cover will have direct influence on food webs in the Antarctic, as well as direct feedback effects on climate. This program is important to the Antarctic Treaty and the implementation of the new Protocol on the Environment. It is also a provider of useful data to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) which monitors populations and recommends action/limitations to the commercial fishing nations. Thus, the program will enable more informed stewardship of one of the Earth's major ecosystems. PROGRAM CONTACTS:Polly Penhale and Dennis Peacock, Office of Polar Programs