The USC Microbial Observatory (Jed Fuhrman and David Caron, PIs) focuses on exploratory investigation of prokaryotic and unicellular eukaryotic diversity in the San Pedro Channel , California, with an initial focus on time-dependent changes in community composition in relation to environmental parameters. It also includes focused studies of particular microbial groups. We are currently in 12th year of this project. Our primary sampling site is located midway between Los Angeles and the USC Wrigley Marine Laboratory on Santa Catalina approximately 900 m of water. This site is visited monthly by ship for sampling to 500 m depth. Additional sampling is conducted on an ad hoc basis in coastal water near the lab on Catalina Island.