15 February, 2002
THE PALMER LTER
In 1991, the Palmer Long-Term Ecological Research (LTER) program was established. An LTER is a project that receives funding for more than the usual three-year cycle of government grants for research. This allows groups of scientists to study a broad question over many years. The Palmer LTER has a team of scientists studying the sea ice in this area. They have studied how the sea ice changes during the year. They have looked at the impact of this annual change on the ecosystem of the Antarctic Peninsula.
Palmer Station is on the west coast of the Antarctic Peninsula. It can be found on a map or a globe at 64°46' South latitude and 64°03' West longitude. This part of Antarctica has great annual changes in the amount of sea ice (frozen sea water). In the winter time, the sea water freezes to form pack ice. In the winter at Palmer Station, the pack ice extends between the islands. People can walk from island to island on the frozen sea ice.
In the summer months, we still have large chunks of ice in the water, but a lot of that comes from the glacier or the ice shelf. The pieces that break off from the glacier are "land ice", and they are frozen pieces of fresh water. We have had sea ice here this summer, however. It is leftover from the winter or it has come from other areas.
The sea ice is very important to the plants and animals living in this area. The food web is affected by the timing of the sea ice (when it forms in the year and when it melts), the duration of the sea ice (how long it lasts), and the extent of the sea ice (the size of the area it covers). The Palmer LTER scientists study many parts of the food web affected by these changes. They study the bacteria and other microbes; the phytoplankton; the zooplankton (especially krill); and the penguins and other seabirds.
After the first ten years of work, the Palmer LTER has shown how the yearly variation in sea ice impacts this marine ecosystem. There is satellite data from the past twenty years to show the annual changes in the sea ice.
Now the Palmer LTER will be asking a new question: "What are the consequences of climate change on this ecosystem and its processes?" There is fifty years of temperature data to show that the mean (average) annual winter temperature in this area has warmed 4-5 degrees Celsius. Scientists in the Palmer LTER will be investigating the ways in which a changing climate will affect the numbers and kinds of plants and animals living here.
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