Lake Michigan Clearer, But With Caveat

According to a study by the Michigan Tech Research Institute, Lake Michigan has dramatically increased in clarity since 1998, the Chicago Tribune reports. The reason? Researchers say the introduction of mussels, one of the biggest invasive species in the Great Lakes.

Researchers from the Michigan Tech Research Institute compared satellite images of lakes Michigan, Huron and Superior between 1998 and 2012. They found that lakes Michigan and Huron have become clearer than Lake Superior, with Lake Michigan’s waters turning from a swampy brownish-green to a clearer blue. Although the study states that limiting the amount of agricultural and sewage runoff into the lake has helped, the introduction of mussels has also had a significant impact.

“Clearer is not necessarily better,” Robert Shuchman, co-director of the Michigan Tech Research Institute, told the Chicago Tribune. “Clearer water means less phytoplankton in the water column, and they’re the basic building block in the food web. The idea is, the little fish eat algae, and the bigger fish eat the little fish.

Some environmentalists worry that mussels, in filtering the lake water, have decimated the phytoplankton population, thus threatening the entire food chain, ecosystem and $7 billion fishing industry. Researchers say they will have to monitor the mussel population to better predict what will happen in the future.

Read the full article here.

[Photo by Flickr/anttler.]