16 June 2006
Vol 312, Issue 5780

About The Cover

Cover image expansion

COVER Bacterial mats growing around a subaquatic spring in Lake Cadagno, Switzerland. The sulfate-rich water from these springs flows to the bottom of the lake, where bacterial activity produces hydrogen sulfide, leading to permanent anoxia. A general mechanism for the enhanced preservation of organic molecules under such sulfide-rich conditions is described on page 1627. Image: Mauro and Franca Bernasconi