Amundsen Sea

Amundsen Sea. The Amundsen Sea is a marginal sea of the Southern Ocean located off West Antarctica, defined by the coastline between Cape Flying Fish and Cape Dart. It is bordered by Thurston Island to the east and Peter I Island lies to the north, with its southern reaches dominated by the Getz Ice Shelf and the Pine Island Glacier. This remote and ice-choked body of water is critically important to global climate change studies due to the rapid melting of its adjacent ice sheet and glaciers.

Geography and location

The sea is situated along the Bellingshausen Sea coast of Marie Byrd Land, with its eastern boundary marked by Cape Flying Fish on Thurston Island. Its western limit extends to Cape Dart on Siple Island near the Bakutis Coast. Major features along its coastline include the extensive Getz Ice Shelf, the Dotson Ice Shelf, and the Crosson Ice Shelf. Key glacial outlets that flow into it are the Pine Island Glacier, the Thwaites Glacier, and the Smith Glacier, which drain a significant portion of the West Antarctic Ice Sheet. Notable islands within or adjacent to the sea include the Bear Peninsula, Dean Island, and Wright Island.

Oceanography and climate

The oceanography is dominated by the inflow of relatively warm, salty Circumpolar Deep Water from the Amundsen Sea Polynya, which flows onto the continental shelf and melts glacial ice from below. This process is a primary driver of the rapid retreat observed at the Pine Island Glacier and Thwaites Glacier. The region features persistent sea ice cover and is influenced by winds associated with the Amundsen Sea Low, a climatological pressure center. Currents and water masses here are studied by institutions like the British Antarctic Survey and the Alfred Wegener Institute due to their disproportionate impact on global sea level rise.

Exploration and discovery

The sea was first encountered in February 1929 by the Norwegian expedition aboard the Norvegia, led by Captain Nils Larsen. It was named in honor of the famed Norwegian polar explorer Roald Amundsen, the first person to reach the South Pole. Further mapping and exploration were conducted by the United States Antarctic Service Expedition and later by the U.S. Navy during Operation Highjump. The coastline was more thoroughly charted through aerial surveys by the Ronnie Antarctic Research Expedition and various national programs operating under the Antarctic Treaty System.

Ecology and marine life

Despite harsh conditions, the ecosystem is productive, particularly in areas of open water like the Amundsen Sea Polynya. The food web is supported by phytoplankton blooms that sustain Antarctic krill, a keystone species. This krill population supports higher predators including minke whales, Weddell seals, and seabirds like the snow petrel and Antarctic petrel. The benthic communities on the seafloor are studied by research vessels such as the RV Polarstern, revealing diverse life adapted to cold and ice-influenced environments. The region falls under the conservation purview of the Commission for the Conservation of Antarctic Marine Living Resources.

Scientific research and importance

The sea is a global epicenter for glaciology and climate science research due to the instability of the West Antarctic Ice Sheet. Long-term monitoring projects like the International Thwaites Glacier Collaboration involve agencies such as NASA, the National Science Foundation, and the British Antarctic Survey. Research focuses on ice-ocean interactions, ocean acidification, and the dynamics of the Antarctic Circumpolar Current. Data from satellites like ICESat and missions such as Operation IceBridge are critical. Findings here directly inform reports by the Intergovernmental Panel on Climate Change and are vital for predicting future sea level rise.

Category:Seas of the Southern Ocean Category:Geography of Antarctica