1. D. G. Capone is at the Chesapeake Biological Laboratory, Center for Environmental and Estuarine Studies, University of Maryland, Solomons, MD 20688, USA. J. P. Zehr is in the Department of Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. H. W. Paerl is at the Institute of Marine Sciences, University of North Carolina, Morehead City, NC 28557, USA. B. Bergman is in the Department of Botany, Stockholm University, S-10691 Stockholm, Sweden. E. J. Carpenter is at the Marine Sciences...