Life in Biofilm (IMAGE) Cary Institute of Ecosystem Studies Caption Microorganisms like bacteria and algae grow in complex assemblages called biofilms -- the slimy coatings found on rocks in streambeds. These taxonomically diverse communities are essential to maintaining freshwater health. Credit Sylvia Lee Usage Restrictions To promote this press release. 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.