New research suggests an ancient hotspot helped shape the Great Lakes, challenging traditional formation theories.

In 2002, the Great Lakes basin had just 11.9% ice coverage, NOAA said. In 2012, Lake Superior had 8.5% coverage. In 2002, Lake Michigan had 12.4% coverage. In 2012, Lake Huron had 22.8% coverage.

The "areas of concern" are the most polluted and damaged sites across the basin, largely due to legacy contamination from industry and habitat degradation. Funding for the massive cleanup effort is ...