Ore Sample (1 of 2) (image) McGill University Caption One of the sulfide ore samples analyzed for the study. The bright area in the lower left, a "sulfide nodule," preserves isotopic evidence of the presence of microbes that fed on sulfate in the ancient ocean. Credit Mark. D. Hannington Usage Restrictions None 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.