Weddell Sea Polynya

The Weddell Sea polynya (Maud Rise polynya) is a recurrent open-water area that opens within the Antarctic sea-ice pack far from the coast, over the Maud Rise seamount in the eastern Weddell Sea. It is an open-ocean polynya, maintained by deep convection that brings warm, salty Weddell Deep Water up to melt ice from below, rather than by wind pushing ice away. A large one persisted through the winters of 1974 to 1976, covering up to about 250,000 square kilometers, then a smaller event recurred in 2016 and 2017. These polynyas vent ocean heat to the atmosphere and can ventilate the deep ocean, releasing stored CO2 and influencing Antarctic Bottom Water formation.