Yeung, Ash, Young (IMAGE) Rice University Caption Using stable isotopic analysis, Laurence Yeung, Jeanine Ash, and Edward Young discovered that plants and plankton impart a unique biosignature on the oxygen they produce during photosynthesis. Credit Doug Rumble Usage Restrictions Must credit: 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.