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Biology & Medicine
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Dr. Polly Penhale
Program Manager
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B-045-L/P
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NSF/OPP Award 02-17282
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Station:
R/V Laurence M. Gould, Palmer Station
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RPSC POC:
Rob Edwards/Stephanie Suhr-Sliester
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Research Site(s):
Palmer Station, R/V Laurence M. Gould
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Dates in Antarctica:
Mid October to mid April
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Palmer Long Term Ecological Research Project (PLTER): Climate migration, ecological response and teleconnections in an ice-dominated environment.
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Palmer Station, as seen from the Adelie penguin colony on Torgersen Island in Arthur Harbor, Anvers Island, Antarctica. Photo by Hugh Ducklow.
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Deploying Team Members:
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Michelle A. Cochran
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Robert M. Daniels
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Hugh Ducklow
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William Thomas Ducklow
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Kristen France
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Nicole Middaugh
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Elizabeth Waterson
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Research Objectives:
The Palmer Long-Term Ecological Research Project (PAL LTER) seeks to understand the structure and function of the antarctic marine and terrestrial ecosystem in the context of physical forcing by seasonal to interannual variability in atmospheric and sea-ice dynamics, as well as long-term climate change. The PAL LTER grid is designed to study marine and terrestrial food webs consisting principally of diatom primary producers, the dominant herbivore antarctic krill, Euphausia superba, and the apex predator Adélie penguin, Pygoscelis adeliae. An attenuated microbial food web, consisting of planktonic bacteria and Archaea and bacterivorous protozoa, is also a focus of study.
This project monitors western Antarctic Peninsula ecosystems annually over a grid of oceanographic stations and seasonally at Palmer Station. The extent and variability of sea ice affect changes at all trophic levels. In recent years, sea ice has diminished in response to a general regional warming. A long-term population decline of ice-dependent Adélie penguins provides a clear example of the impact of this trend in the Palmer region. Adélie populations at the five major rookeries located near Palmer Station and studied for the past 30 years have all shown a gradual decrease in numbers. The western Antarctic Peninsula, the site of PAL-LTER research, runs perpendicular to a strong climatic gradient between the cold, dry continental regime to the south, characteristic of the interior, and the warm, moist maritime regime to the north. More maritime conditions appear to be replacing the original polar ecosystem in the northern part of the peninsula as the climatic gradient shifts southward. To date, this shift appears to be matched by an ecosystem shift along the peninsula, as evidenced by declines in Adélie penguins, which require longer snow-cover seasons.
Researchers hypothesize that ecosystem migration is most clearly manifested by changes in upper-level predators (penguins) and certain polar fishes in predator-foraging environments because these longer-lived species integrate recent climate trends and because individual species are more sensitive indicators than aggregated functional groups. In the years ahead, analogous modifications will also become evident at lower trophic levels, although these changes are likely to be seen only through long-term studies of ecosystem boundaries along the peninsula.
By studying extant food webs in both the marine and terrestrial environments, we will continue to investigate ecosystem changes at lower trophic levels; changes in response to continued, dramatic warming; and shifts in the poleward climatic gradient along the western Antarctic Peninsula.
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