Black algae (IMAGE) Aarhus University Caption The algae that colour the ice look like this under a microscope. Long microorganisms that protect themselves against the sun's radiation with dark pigment. Credit Alexandre Anesio Usage Restrictions May only be used for telling about this research License Original 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.