Contents

01 June 2001
Vol 292, Issue 5522

About The Cover

Cover image expansion

COVER A confocal laser scanning micrograph shows cyanobacterial filaments (yellow, 5 mm wide) and calcite crystals of a soda lake biofilm (green). Cyanobacterial photosynthesis can induce biofilm calcification only in settings low in dissolved inorganic carbon and high in calcium. These conditions can be traced throughout past oceans by corresponding calcareous microfossils of cyanobacteria. 1701 [Image: G. Arp; Christian Böker, Carl Zeiss Jena]