Effect of climate change on Great Lakes' algae under review

Algal mats can contain bacteria harmful to humans and wildlife.

Editor's Note: This is the third installment of Capital News Service’s six-part exploration of the recent Popular Science finding that Michigan will be the best place to live in 2100 because of how the state will weather climate change.

LANSING — Climate change experts are trying to predict what will happen to the waters of the Great Lakes — including a surge of algae blooms.

A warmer climate is conducive to more of these harmful blooms, according to the National Oceanic and Atmospheric Administration, but experts often deal in hypotheticals.

Jeffrey Andresen, Michigan’s state climatologist and a geography professor at Michigan State University, expects relatively more warming in the winter than warming in the summer. That means a chance for more rain or snow during months that precede spring. That means more nutrients from livestock, farm fields and urban streets that can run into lakes. And all those extra nutrients can fuel the growth of algae.

“A massive rain will wash a bunch of stuff into the lake which would fuel the production of plankton in the lake,” said Hank Vanderploeg, a researcher with the Great Lakes Environmental Research Lab in Ann Arbor. “That can be a factor in the harmful algae bloom.”

Tim Davis, another researcher with the Great Lakes Environmental Research Laboratory, “If you have a changing precipitation pattern, leading to more rain and runoff, that will all potentially increase blooms of greater size that last longer and potentially be more toxic.”

Both Davis and Vanderploeg say that how much algae shows up is dictated by when nutrients are washed into the lake. With heavier runoff due to storms in the spring, there will be more harmful algae blooms later in the summer.

“We know that we can’t continue on the course that we’re on or else these blooms are going to continue and get worse, and that’s not good for anybody in the region,” Davis said.

The worst algal bloom in Lake Erie in over a decade occurred in October 2011. The event created enough concern that half a million people were told to avoid using their tap water.

Such concerns have prompted policy decisions. The Great Lakes Water Quality Agreement calls for a 40 percent reduction of phosphorus, one of the culprits in surface runoff, by 2025.

“One thing that we do know about projections for the future is all of them, and there are no exceptions, all of them call for warmer mean temperatures,” said Andresen.

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