The Weddell Polynya or Weddell Sea Polynya is a polynya or irregular area of open water surrounded by sea ice in the Weddell Sea of the Southern Ocean off the Antarctica and near the Maud Rise. The size of New Zealand, it re-occurred each winter between 1974 and 1976. These were the first three austral winters observed by the Nimbus-5 Electrically Scanning Microwave Radiometer (ESMR). Since 1976, the polynya has never been seen again. Since the 1970s, the polar Southern Ocean south of the Antarctic Circumpolar Current has freshened and stratified, likely a result of anthropogenic climate change. Such stratification may be responsible for suppressing the return of the Weddell Sea polynya.
Other Antarctic polynyas
The presence of polynyas in McMurdo Sound provides an ice-free area where penguins can feed, so is important for the survival of the Cape Royds penguin colony.