[ryanberg]

I was born and raised in the Traverse City area. The Great Lakes have become remarkably clearer throughout the years. I was told that it was due to the invasive species of Zebra Mussels[1] which have no natural predators in the Great Lakes. As their population exploded, they have significantly increased the clarity of the water.

-- [1] - http://www.noaa.gov/features/earthobs_0508/zebra.html

[EvanAnderson]

I didn't live there, but my grandparents did and my family summered there (on Long Lake) every year from the early 80's thru the last few years. I snorkels and later dove in Lake Michigan and surrounding connected and non-connected lakes. The water definitely got more clear in the 90's and 2000's to my unscientific eye.

It's beautiful country up there. Nothing much compares, to me, to northern lower-peninsula Michigan summers.