1. U.S. Geological Survey, Great Lakes Science Center, Lake Erie Biological Station, 6100 Columbus Ave., Sandusky, Ohio 44870, United States
2. U.S. Geological Survey, Great Lakes Science Center, 1451 Green Rd., Ann Arbor, Michigan 48105, United States
3. School of Public Health, University of Michigan, 1415 Washington Heights, Ann Arbor, Michigan 48109, United States
4. Center for Limnology, University of Wisconsin, 680 North Park Street, Madison, Wisconsin 53706, United States