Modeling the Prehistoric Ocean (IMAGE) Iowa State University Caption This is a graduated cylinder model of the ocean. The green shows cyanobacteria and the brown shows the oxidized iron. Credit Iowa State University's College of Liberal Arts and Sciences Usage Restrictions None 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.