Hydrogen Sulfide-rich Spring (IMAGE) Kansas State University Caption This hydrogen sulfide-rich spring in the Puyacatengo River in Mexico is one of many toxic environments where the Atlantic molly lives. A Kansas State University researcher has helped discover the mechanisms that help the fish species survive. Credit Kansas State University 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.