Thought to be the oldest lake in North America and the largest freshwater natural lake in California, Clear Lake also bears the distinction of being highly polluted. The Sulphur Bank Mercury Mine at the east end of the lake was declared a U.S. Environmental Protection Agency Superfund site in the early 1990s. Since 1991, UC Davis researchers have worked to assess the lake ecologically, in particular to learn more about the mercury that flowed from the mine into the lake. Clear Lake also experiences frequent blooms of scum forming blue-green algae. UC Davis scientists are researching the nutrients that have caused the algae to form. In addition, scientists from the campus are undertaking historical investigations of sediments and are studying the mixing and transport of mercury in the lake. Last month, the UC Davis Clear Lake Environmental Research Center had its grand opening. Dedicated to ecological research in the Clear Lake watershed, the center's goal is to improve the environmental awareness of the lake and its watershed by integrating biological and cultural data. Thomas H. Suchanek and Peter J. Richerson are the principal investigators for the center.