The Amundsen Sea, located east of the Ross Sea on the western coast of Antarctica, is among the least studied regions of Antarctica due to high ice cover that makes it extremely difficult to reach.
Polynyas Drive the Ecosystem
While much remains to be discovered about the remote Amundsen Sea, researchers have found several polynyas, which generate the greatest primary productivity per square meter of anywhere around Antarctica.
This high productivity is, in part, fed by melting glaciers, which supply nutrients (especially iron) that help phytoplankton grow. Currents then carry the phytoplankton away from the coast, spreading productivity further afield.
These high levels of phytoplankton productivity are the foundation to support higher populations, biomass, and density of krill and small fish, which in turn feed other predators.
One such predator is the Antarctic toothfish — the top fish predator in the Southern Ocean. Recent research has suggested that deep areas of the Amundsen Polynya are particularly critical habitat for large toothfish, likely providing feeding grounds for these monsters of the deep sea.
The abundant krill and small fish in the Amundsen Sea also feed the array of Adélie and emperor penguin colonies in the region. The polynya, as an opening in the ice, provides an immediate access point to marine food sources for the penguins.
Climate Change Threatens Global Sea Levels
The Amundsen Sea region also is home to the Thwaites and Pine Island Glaciers, both of which are rapidly melting. Sometimes called “the Doomsday Glacier”, the Thwaites Glacier is especially concerning since its rapid melting could contribute dramatically to sea level rise and destabilizing the entire West Antarctic Ice sheet.
The Amundsen Sea: A Climate Refuge
In a strange irony, while warming temperatures threaten both the biology and the glaciers in this region, the Amundsen Sea’s hugely productive polynya is actually projected to become more productive by the end of the century. In combination with high productivity and projections of relatively little warming at the ocean surface and bottom, the polynya will likely provide climate refugia for krill and Antarctic toothfish through the end of the century. While emperor penguin populations at the two colonies in the region are projected to decline, Adélie penguin regional populations are predicted to increase in the vicinity of the polynya.
There are not yet any proposed marine protected areas for this critical region, despite its ecological importance and ongoing threats from climate change. Increasing pressure to exploit toothfish in the region compounds climate threats. Protecting this place would ensure the polynyas and all the life they sustain are safeguarded into the future.
