New Shallow Horizon (IMAGE) University of Alaska Fairbanks Caption This figure illustrates a new relatively shallow layer emerging in the Southern Ocean where the concentration of carbonate ions in the water is too low for pteropods to maintain their shells. Credit International Arctic Research Center Usage Restrictions Image may only be used with caption and credit. License Licensed content 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.