Elephant Seals Provide Clues to Wilkins Ice Shelf Breakups
14.06.2010 - Water & Oceans, Ice & Snow, Flora & Fauna, Antarctic
The Wilkins Ice Shelf in Antarctica has suffered several breakups recently: in 1998, 2008, and 2009. What is unknown, however, is the cause of the collapses. In an effort to find out more, researchers equipped elephant seals with sensors to study the ocean depths beneath the ice shelf.
Daniel Costa of the Institute of Marine Science at the University of California Santa Cruz explained at the IPY Oslo Science Conference that these sensors revealed that seals dive to greater depths than originally thought. This shows the presence of troughs in the continental shelf underneath the ice. These troughs, they think, could have enabled warm circumpolar deep water to travel onto the continental shelf and weaken the ice above.
The data gathered thanks to the elephant seals will also be useful to predict what might happen to seal populations in the region. If climate models are right, and the winds speed up in the future, more circumpolar deep water will likely intrude onto the continental shelf and bring additional heat to the region, reducing sea ice extent off the coast of Antarctica. This would be good for elephant seals, as they forage for fish and squid in such waters; however at the same time it could be detrimental to crabeater seals who rely on sea ice to breed and feed on krill which live under pack ice.
