Shell samples (IMAGE) University of California - San Diego Caption California mussels collected during the new study were sampled, measured and eventually ground to a fine dust in order to reveal how the mineral composition of their shells have changed over 60 years. Credit Roy Lab, UC San Diego Usage Restrictions Must be used in conjunction with PNAS paper on impacts of ocean acidification on California mussels. 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.