The Great Lakes region contains nearly 85 percent of North America's surface freshwater, and more than 20 percent of the world's supply of surface freshwater ... [Click here or on the map above for a ...

As executive director of the Great Lakes Observing System, she's leading a campaign to map every meter of the lakes' bottom.

The Great Lakes region contains nearly 85 percent of North America's surface freshwater, and more than 20 percent of the world's supply of surface freshwater ... [Click here or on the map above for a ...