Great Lakes passenger steamers Lakes) and a high-speed catamaran running between Milwaukee, Wisconsin and Muskegon, Michigan. An international ferry ran on Lake Ontario from Rochester, New York to Toronto from 2004 to 2005, but it was plagued with high operating costs and low demand. The privately owned company was taken over by the City of Rochester, and the ship was sold overseas where it operated across the Strait of Gibraltar. Cruise ship traffic on the Great Lakes increased in the early-21st century, with ships like the MS Hamburg, the MS Saint Laurent and the smaller ships of the Great Lakes Cruise Company offering multi-day
Great Lakes U.S. side highlight five large municipal systems (those of Detroit, Cleveland, Buffalo, Milwaukee and Gary) as being the largest current periodic sources of untreated discharges into the Great Lakes. Algae such as diatoms, along with other phytoplankton, are photosynthetic primary producers supporting the food web of The Great Lakes. The changes in the size or in the function of the primary producers may have a direct or an indirect impact on the food web. Photosynthesis carried out by diatoms comprises about one fifth of the total photosynthesis. By taking CO2 out of the water, to photosynthesize, diatoms help to stabilize