Dr. John R. (Jack) Vallentyne, died peacefully at his home in Hamilton on Saturday, June 16th, 2007 of colon cancer. His ashes were scattered in the Laurentian Great Lakes (Lake Superior) which he loved and cared for immensely. Dr. Vallentyne was known globally for his anti-eutrophication and phosphorus abatement campaigns, well documented in his book The Algal Bowl (1974). His campaign resulted in the reduction of phosphorus in laundry detergents, as well as in improvements in municipal wastewater treatment. Furthermore, he had tremendous influence on the revision of the Great Lakes Water Quality Agreement (GLWQA) by developing and implementing the ‘ecosystem approach’ in the management of the Great Lakes and emphasizing the need to think holistically and globally. He had a distinguished career in the environmental conservation, restoration and management of aquatic resources.Jack was a Ph.D. student of George Evelyn Hutchinson at Yale, author of A treatise on limnology (1957). He served as an Assistant Professor in Biology at Queen's University, a Fellow of the Carnegie Institution of Washington Geophysical Laboratory; and a very young professor of zoology at Cornell University. He taught everything from biogeochemistry to statistical ecology, evolutionary biology, cosmochemistry, origin of life, and even began a revolutionary pub lecture series for grad students. He worked on amino acids in meteorites and moon rocks and Silurian halite crystal liquid inclusions, Pleistocene pigments in sediment cores, and the statistics of roulette and poker games. He also spent a year in Pallanza, Italy at the Instituto Italiano di Idrobiogia with the Tonolli family.Dr. Vallentyne served with the Fisheries Research Board of Canada as the head of the Eutrophication Section at the Freshwater Institute in Winnipeg and was the architect of the world renowned Experimental Lakes Area research program. He helped establish the Board's first biological laboratory on the Great Lakes at the Canada Centre for Inland Waters (CCIW) in Burlington, Ontario. He then recruited Dr. R.A. Vollenweider as head of the laboratory to organize a biological research program. Later Jack served as a senior scientist at Fisheries & Oceans Canada in Burlington until his retirement. He also served as the Canadian Co-chair of the International Joint Commission Science Advisory Board from 1986–1991.During his tenure at CCIW, Dr. Vallentyne actively promoted the “ecosystem approach” to research, environmental conservation and education. These initiatives included a regular seminar series, public outreach and an annual environment week celebration. Jack's passion for drama and theatre were evident in his public awareness programs, which included the popular characters “Professor Trout” and “Johnny Biosphere.” He skilfully used these characters to communicate with the public especially with children and took his message of environmental conservation to elementary schools in southern Ontario and around the globe. His public outreach always focused on limnology, education and a sustainable biosphere. In order to recognize his landmark contributions to world science the Aquatic Ecosystem Health and Management Society (AEHMS) established a “J.R.Vallentyne Lecture Series” in 1997 at its biennial conferences.Up until his death, Jack paid regular visits to CCIW and was busy preparing a presentation for the SIL Congress in Montreal (August, 2007), as well as an updated version of The Algal Bowl: Overfertilization of the world's freshwaters and estuaries, 2nd Ed. (2008) co-authored with David Schindler. Dr. Vallentyne has left a rich legacy with far reaching implications for the improvement of ecosystem and human health. The biosphere will miss “Johnny” greatly.Biography composed and compiled by:Aquatic Ecosystem Health and Management SocietyBurlington, Ontario, Canada