Microbial Mat (IMAGE) Max-Planck-Gesellschaft Caption The section through the microbial mat on top of the coral tissue shows the incident light into the mat and the related oxygen production by the cyanobacteria. The lysing coral tissue releases organic carbon that is used by the sulfate reducing bacteria, and sulfide. The tissue lesion of the corals is thus a positive feedback process. Credit M. Glas/R. Dunker Usage Restrictions None 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.