Fieldwork (IMAGE) Florida State University Caption Nevin Kozik, a former FSU doctoral student and now a visiting assistant professor at Occidental College, during fieldwork to investigate how rapid changes in marine oxygen levels may have played a significant role in driving Earth’s first mass extinction. Credit Courtesy of Nevin Kozik Usage Restrictions This image may be used with appropriate caption and credit. 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.