Sea Ice Marginal Zone in Front of West Antarctic Ice Sheet (image) CAGE - Center for Arctic Gas Hydrate, Climate and Environment Share Print E-Mail Caption Sea ice marginal zone in front of West Antarctic ice sheet. Polynias, ice free corridors between the sea ice and land based ice sheets, are common in Antarctica today. Credit Photo: M. Forwick Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.