Detroit Democratic US Senator Carl Levin plans to introduce what he calls the "Great Lakes Cultural Heritage Assessment Act" next month. 

Two weeks after The Washington Post reported that President Obama announced his intention to double the size of ocean bottom that would be off limits to fishing and other human intrusion, Science20 says Levin wants to have Obama's  National Oceanic and Atmospheric Administration conduct an analysis of the Great Lakes to find more areas that also could be cordoned off as federal marine sanctuaries. 

The only one in fresh water is Thunder Bay National Marine Sanctuary on Lake Huron near Alpena.

Levin says the protection would provide  scientific, cultural and economic benefits.