Great Lakes
Great Lakes shoreline. (Photo by Frank Gates)

WI - ATMOSPHERIC CARBON MIGHT MAKE GREAT LAKES MORE ACIDIC AND INHOSPITABLE FOR SOME FISH AND PLANTS

The Great Lakes have endured a lot the past century, from supersized algae blobs to invasive mussels and bloodsucking sea lamprey that nearly wiped out fish populations.

Now, another danger: They, and other big lakes around the world, might be getting more acidic, which could make them less hospitable for some fish and plants.

Scientists are building a sensor network to spot Lake Huron water chemistry trends. It’s a first step toward a hoped-for system that would track carbon dioxide and pH in all five Great Lakes over multiple years, said project co-leader Reagan Errera of the National Oceanic and Atmospheric Administration.

“If you change things chemically, you’re going to change how things behave and work and that includes the food web,” said Errera, a research ecologist with NOAA’s Great Lakes Environmental Research Laboratory in Ann Arbor, Michigan.

“Does that mean your favorite fish might not be around any more? We don’t know that, but we know things will change. Maybe where and when they spawn, where they’re located, what they eat.”

Oceans are becoming more acidic as they absorb carbon dioxide that human activity pumps into the atmosphere — the primary cause of climate change. Acidification endangers coral reefs and other marine life.

Studies based on computer models suggest the same thing may be happening in big freshwater systems. But few programs are conducting long-term monitoring to find out — or to investigate the ecological ripple effects.

“This doesn’t mean the waters are going to be unsafe to swim in. It’s not like we’re making super acid battery liquid,” said Galen McKinley, a Columbia University environmental sciences professor. “We’re talking about long-term change in the environment that to humans would be imperceptible.”

A 2018 study of four German reservoirs found their pH levels had declined — moving closer to acidity — three times faster in 35 years than in oceans since the Industrial Revolution.

Researchers say Great Lakes also could approach acidity around the same rate as in oceans by 2100. Data from the Lake Huron project will help determine if they’re right.

Two sensors have been attached to a floating weather buoy at Thunder Bay National Marine Sanctuary near Alpena, Michigan. One measures carbon dioxide pressure in the water column and the other pH. Additionally, crews are collecting water samples at varying depths within the 4,300-square-mile area for chemical analysis.

Besides disrupting aquatic life and habitat, acidification could deteriorate hundreds of wooden shipwrecks believed resting on the bottom, said Stephanie Gandulla, the sanctuary’s resource protection coordinator and a study co-leader.

Other monitoring stations and sampling sites are planned, Errera said. The goal is to take baseline measurements, then see how they change over time.

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