Plankton Net Sampling (IMAGE) University of California - San Diego Caption Study co-author Nelson Javier Aranguren-Riaño and fellow hippo project researchers captured a variety of ecological data, including oxygen levels, water chemistry and audio soundscapes. Credit Photo by Natalie Jones/UC San Diego Usage Restrictions Must be used in conjunction with Colombian hippo project. 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.