Limnological and Geochemical Survey of Williams Lake, Hubbard County, Minnesota

A limnological and geochemical survey of Williams Lake, Minnesota, was made in 1979 to provide an initial interpretive description of the lake and the contiguous ground-water system. This survey was made as part of a continuing research program related to the investigation of the interaction of lakes and their contiguous ground-water systems at Williams Lake, Minnesota, as well as other sites within the continental United States. During 1979, Williams Lake was dimictic, and the lake had high optical transparency; light penetrated to the lakebed throughout most of the lake. Aquatic macrophytes were present along the western shore and in the southern bay of the lake. Although the lake had clinograde-oxygen distributions during part of this survey, anaerobic conditions were not observed. The lake is moderately fertile with respect to its total phosphorus content. Nutrient data indicate phosphorus limits phytoplankton biomass levels in Williams Lake. Blue-green algae were the dominant group of the phytoplankton community and copepods were the dominant group of the zooplankton community when the lake was thermally stratified during the open-water season. Diatoms and rotifers were dominant when the lake was isothermal in the autumn. Calcium and bicarbonate represent more than 90 percent of the dissolved constituents in Williams Lake and the contiguous ground-water system. Major mineralogical constituents of the lake sediments are quartz, dolomite, and calcite. Marl is present only in the littoral zone of the lake. Organic sediments in the lake consist of loose organic floe and gyttja.