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Researchers Use Wild Rice to Predict Health of Minnesota Lakes and Streams

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By studying wild rice in lakes and streams, a team of researchers led by the University of Minnesota has discovered that sulfate in waterways is converted into toxic levels of sulfide and increases other harmful elements. This includes methylmercury, the only form of mercury that contaminates fish.

By studying wild rice in lakes and streams, a team of researchers led by the University of Minnesota has discovered that sulfate in waterways is converted into toxic levels of sulfide and increases other harmful elements. This includes methylmercury, the only form of mercury that contaminates fish.

Sulfate is a compound that is released into fresh water from mining, sewage, fertilizers, fossil fuel combustion, and other human activity, as well as from natural geological sources in some parts of the state. The researchers recently published three related studies on the topic of sulfate in water in the Journal of Geophysical Research: Biogeosciences, published by the American Geophysical Union.

“Wild rice serves as a flagship species or the equivalent of our ‘canary in a coal mine,’ giving us a warning on how human activity affects our water quality in Minnesota,” said Amy Myrbo, a research associate in the University of Minnesota’s LacCore/CDSCO facility in the Department of Earth Sciences and lead author of two of the three studies. “The results of our studies are important because they show that increases in sulfate in our lakes and streams can have multiple negative consequences for ecosystems, even though sulfate itself is relatively benign.”

Wild rice is culturally important to multiple groups in Minnesota, especially Native Americans. Wild rice also provides habitat and food for waterfowl and other wildlife. Research in the 1940s and 1950s found that wild rice grew best in low-sulfate Minnesota lakes, but no one knew why. The correlation was a puzzle, since sulfate isn’t very toxic to plants or animals.

Read more at University of Minnesota

Image: Man gathering core sample.  (Credit: University of Minnesota)