Sediments (IMAGE) University of Copenhagen - Niels Bohr Institute Caption Sediments from New Zealand tarns were used in the study. Credit Credit: Marcus Vandergoes Usage Restrictions Credit: Marcus Vandergoes 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.