tubing, canoeing, windsurfing, kayaking, and sailing. With an average freeze date of December 20, Lake Mendota is used in the winter by sports enthusiasts for ice boating, ice skating, ice fishing, cross-country skiing, ice hockey and snowkiting. The Wisconsin State Capitol and much of the state government is located on the narrow Madison Isthmus, and the University of Wisconsin–Madison campus is situated along the southern shore of Lake Mendota. In the early 20th century, Chancey Juday and Edward A. Birge founded an influential school of limnology there as a component of the university, which was reorganized and expanded into the Center for Limnology in July 1982. The university's Hoofer Sailing Club operates at the Memorial Union. Lake study Lake Mendota has been called "the most studied lake in the world," with the UW–Madison Center for Limnology resting on its southern bank. The lake has a remote sensor buoy, affectionately known as 'David Buoy,' that is part of the Global Lake Ecological Observatory Network. The buoy was first anchored in Lake Mendota in 2008 and has collected data in each subsequent year from early spring until late fall, when it is removed before the lake freezes in the winter. Several of the lake and atmospheric data collected by the buoy include wind direction, wind speed, air temperature, dissolved oxygen, and chlorophyll. In March 2021, researchers from the Center for Limnology concluded that climate change and the associated lengthening of summer weather have driven the annual formation of dead zones in Lake Mendota, which are oxygen-deficient layers deep in the water column. These dead zones have been shown to remain in the lake for up to two months in the summer and have the potential to devastate the habitats of benthic fish. The increasing eutrophication of Lake Mendota has led to an increased frequency of harmful algal blooms, which sink to the bottom of the lake when they die. Once at the bottom, they are broken down by decomposers via a process that requires oxygen, thus depleting the benthic supply of oxygen and forming dead zones. In the absence of programs designed to mitigate climate change locally, the researchers indicated that the only way to reduce the frequency and severity of the dead zones is to limit the amount of fertilizer and nutrients that flow into Lake Mendota. On September 11, 2009, the invasive spiny water flea was discovered by the limnology