Microbial Mat (IMAGE) Penn State Caption A microbial mat above a methane seep in the Eel River Basin, Calif. This methane seep is being cored to obtain sediment from the seep. The sediment used in our experiments was sampled in this manner. Credit Emily Beal, Penn State Usage Restrictions Non-commercial use only 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.