Barrel with non-toxic dye (IMAGE) University of California - San Diego Caption This barrel is filled with non-toxic fluorescent dye, which researchers released just above the sea floor to answer a longstanding question in oceanography. Credit: San Nguyen Credit San Nguyen Usage Restrictions Must credit San Nguyen 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.