HOLLAND, Mich., (WOOD) — Large chunks of the lake at Holland State Park are covered in green floating matter. 

Environmental scientists believe the reason is an increase in rain and wind.

Alan Steinman serves as the Allen and Helen Hunting Director at Grand Valley State University’s Robert B. Annis Water Resources Institute. Steinman has been working on Lake Macatawa, which runs into Lake Michigan, for 20 years.

He says the algae people are seeing is likely Cladophora or filamentous green algae, which grows on the bottom of the lake. 

At the state park on Wednesday, the green algae could be seen collecting on Lake Michigan near the the National Oceanic and Atmospheric Administration station. The algae also collected on the southside of the pier near private residences.

The public portion of the beach appeared to be mostly unimpacted.

Algae collects on a portaion of Lake Michigan at Holland State Park on June 30, 2021.

“You’ve got a lot of algae on the beach and that’s going to decay, and birds will get into it and you see the dog in there,” GVSU professor Rick Rediske said as he looked at a photo of the algae. “It’s going to attract wildlife.”

Rediske who studies environmental chemistry says the algae will be more of a nuisance than a public health issue. 

“It’s going to limit use of the beach because you’re going to have rotting algae all day and people aren’t going to want to go into the water,” Rediske said. “I think people will naturally avoid it just because of the green color. It will start to decay and smell like rotting fish. It’s going to be an aesthetic issue and I think people will stay away from it just because of that.” 

The algae aren’t expected to impact drinking water because the intake is at least a mile offshore. Beachgoers can expect some unpleasant smells over the next few days. 

Both Rediske and Steinman say the algae should start to dissipate in the next week.