Cochlan Examines Phytoplankton Sample (IMAGE) San Francisco State University Caption San Francisco State University researcher William Cochlan checks a culture of phytoplankton diatoms, taken out of a cell incubator at SF State's Romberg Tiburon Center for Environmental Studies. Cochlan's latest study finds that nitrogen that enters the ocean -- regardless of its source -- fuels the growth of a toxic phytoplankton species. Credit Chris Ikeda/SF State 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.