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| Amundsen Sea Sea Ice Zone | |
|---|---|
| Name | Amundsen Sea Sea Ice Zone |
| Location | Amundsen Sea, Southern Ocean |
| Frozen | seasonal |
| Notable features | Pine Island Glacier, Thwaites Glacier, Ross Ice Shelf, Getz Ice Shelf |
Amundsen Sea Sea Ice Zone is a seasonal sea-ice region in the southeastern Pacific sector of the Southern Ocean adjacent to the Antarctic coastline near the Amundsen Sea. It lies west of the Bellingshausen Sea and east of the Ross Sea and is influenced by major glaciological features such as Pine Island Glacier, Thwaites Glacier, and the Getz Ice Shelf. The zone is a focus for international scientific efforts from organizations like the National Science Foundation (United States), British Antarctic Survey, and Australian Antarctic Division.
The zone borders coastal features including Marie Byrd Land, the Walgreen Coast, and the Getz Ice Shelf and is contiguous with the continental shelf off the Amundsen Sea Embayment. Oceanographic connections include the eastward flow of the Antarctic Circumpolar Current, cross-shelf exchanges driven by Polynya formation, and intrusion of warm waters via Circumpolar Deep Water onto the continental shelf. Bathymetric controls such as submarine troughs (e.g., the Pine Island Bay Trough) and connections to the Bellingshausen Basin modulate upwelling, while atmospheric forcing from the Southern Annular Mode and transient events like the El Niño–Southern Oscillation affect sea surface conditions. Research campaigns often coordinate platforms including RV Nathaniel B. Palmer, RRS James Clark Ross, and the Icebreaker USCGC Polar Star.
Sea ice in the zone exhibits strong seasonality with formation typically in austral autumn and retreat through austral spring and summer, influenced by wind patterns tied to the Antarctic Oscillation and synoptic storms tracked by European Centre for Medium-Range Weather Forecasts reanalysis. Ice types range from new and young ice to first-year and fragmented pack ice, with dynamic processes such as ridging and leads occurring along shear zones near the Amundsen Sea Polynya and grounding lines of Pine Island Glacier and Thwaites Glacier. Remote sensing from satellites like MODIS, ICESat-2, CryoSat-2, and passive microwave sensors (e.g., SSM/I) provides time-series of extent, concentration, thickness, and melt onset, while in situ measurements from ice camps and autonomous instruments (e.g., Argo floats adapted for polar use) yield validation data.
Observed trends include declining sea-ice duration and multi-decadal variability tied to atmospheric teleconnections such as Southern Annular Mode shifts and episodic influences from El Niño events. Warming of the Amundsen Sea continental shelf and increased incursion of Circumpolar Deep Water have been linked to basal melt of outlet glaciers including Pine Island Glacier and Thwaites Glacier, with implications for local sea-ice production and regional circulation changes documented by teams from Scripps Institution of Oceanography, Woods Hole Oceanographic Institution, and the University of Washington. Coupled climate models developed by groups at the Met Office Hadley Centre, National Center for Atmospheric Research, and NASA Goddard Institute for Space Studies project continued variability and possible reductions in seasonal sea-ice under scenarios assessed by the Intergovernmental Panel on Climate Change.
The sea-ice zone supports trophic interactions among krill-dependent and ice-associated communities including Antarctic krill, silverfish (Pleuragramma antarcticum), and benthic assemblages linked to the Ross Sea and Amundsen Sea food webs. Apex and mesopredators such as Emperor penguin, Adélie penguin, Crabeater seal, Weddell seal, and leopard seal utilize the ice and adjacent polynyas for foraging and breeding, while migratory species like Antarctic minke whale and southern elephant seal exploit seasonal prey concentrations. Primary productivity is modulated by seasonal light regimes and nutrient upwelling associated with glacial meltwater and seafloor processes, studied by institutions including the Monterey Bay Aquarium Research Institute and the Australian Antarctic Division.
Human presence is primarily scientific, with research stations and field camps operated by actors such as the United States Antarctic Program, British Antarctic Survey, Korea Polar Research Institute, and Institut polaire français Paul-Émile Victor. Observational programs include ice-core drilling, oceanographic moorings, autonomous gliders, and airborne surveys by platforms like NASA Operation IceBridge. International collaborations under frameworks including the Scientific Committee on Antarctic Research coordinate logistics, data sharing, and interdisciplinary studies on ice dynamics, oceanography, and ecology. Ship-based logistics face hazards from sea-ice conditions, navigational challenges charted by the International Hydrographic Organization, and operational constraints overseen by the Council of Managers of National Antarctic Programs.
Threats to the zone arise from climate-driven warming, increased basal melt of glaciers (e.g., Thwaites Glacier destabilization), altered sea-ice phenology, and cascading impacts on species such as Emperor penguin colonies monitored by the IUCN Red List. Governance falls under the Antarctic Treaty System and instruments like the Convention on the Conservation of Antarctic Marine Living Resources, which inform marine protected area proposals and fisheries management for species such as Antarctic toothfish exploited under national permits coordinated by the Commission for the Conservation of Antarctic Marine Living Resources. Ongoing research priorities emphasize monitoring of cryosphere–ocean coupling, resilience of ice-associated ecosystems, and scenario modeling by research centers including British Antarctic Survey, Scripps Institution of Oceanography, and University of Cambridge to inform policy discussions at forums like the Scientific Committee on Antarctic Research.
Category:Antarctic sea ice zones