The Great Lakes tend to be lumped together, but one lake can be very different from another, as I learned when I spent the weekend at Stone Laboratory on Gibraltar Island (next to Put-in-Bay) as part of my Great Waters Institute journalism fellowship.
Jeff Reutter, director of Ohio Sea Grant, dramatizes the contrast between Lake Superior and Lake Erie with what he calls the 50 to 2 ratio. Lake Superior has 50 percent of the water of the Great Lakes, but only 2 percent of the fish. Lake Erie has only 2 percent of the water in the Great Lakes, but 50 percent of the fish.
Lake Erie, the warmest and shallowest lake, is the most biologically productive lake because it has the most nutrients -- phosphates and nitrates that mostly come from fertilizers farmers spread on their fields. The chemicals stimulate the growth of organisms that provide food for the fish. But the load of chemicals in the lakes is going up -- soluble phosphates have been rising since 1995 -- and that has stimulated increases in harmful algal blooms, which put toxins in the water. Water quality in Lake Erie has been doing down since 1995, Reutter says.