“Antarctic Glacier’s Breakup Is Controlled by Seafloor Topography”
by Katherine Kornei
Scientific American, September 3, 2018
Water trickling off Antarctica’s Pine Island Glacier is a major contributor to global sea-level rise. Now, researchers have mapped a swath of seafloor recently exposed by the retreating glacier after several spectacular calving events, observations impossible to make through ice. They found mountainous terrain that they believe both buttressed the ice against retreat and contributed to its calving.
Working aboard the icebreaker R/V Polarstern, the scientists surveyed hundreds of square kilometers of the floor of the Amundsen Sea near the current edge of Pine Island Glacier using echo sounding. They found an undersea ridge that reached within 375 meters of the water’s surface, tall enough that it had previously rubbed against the bottom of the glacier. This rubbing produced surface features on the ice (“rumples”) that the researchers spotted in archival satellite images. Even after the glacier lifted off the ridge–likely around 2006, the team estimated–it sometimes hit the undersea feature as it advanced. These collisions created rifts in the ice that then led to calving events, the researchers found.
This study was published last month in The Cryosphere: