In summer 2014, an unusually large toxic algae bloom in Lake Erie threatened drinking water for parts of Ohio, Michigan and southern Ontario.
Those kinds of algae blooms won’t be so unusual as the 21st century continues, according to a new study from Ohio State University.
According to the study, climate change could end up causing more algae blooms in the next 100 years. In Lake Erie, the number of severe blooms could double.
“Our assessment of climate in the region reveals less winter snow, more heavy spring rains and hotter summers,” said Noel Aloysius, one of the study’s authors. “Those are perfect growing conditions for algae.”
The researchers combined climate change models and a model predicting the severity of algae blooms in the watershed to come up with the study.
While Lake Erie is one of the smaller lakes in the Great Lakes system, the impact that such blooms could have on the Midwest could be fairly large.
The lake contains 50 percent of the fish in the Great Lakes, supporting a $1.7 billion tourism industry based on fishing, according to the study. Eleven million people depend on the lake for drinking water and its watershed supplies water to corn, soybean and wheat farms covering 75 percent of the 6,600-square-mile Maumee Watershed, the study reports.
In 2012, Ohio, Michigan and Ontario agreed to reduce the amount of phosphorous that could run off into Lake Erie by 40 percent by 2022. However, the researchers worry that might not be enough.
According to the study, climate change will act as an accelerator to help algae grow even without the phosphorous included in nutrient runoff. Even if nutrients are reduced, the effects of climate change could mean that fewer nutrients would be needed to cause a severe bloom.
“Right now, we can only make recommendations based on the past, but the climate is not a constant,” said Jay Martin, professor of ecological engineering at Ohio State University. “We need to look to climate models of the future to protect water quality in Lake Erie and around the world. Maybe 40 percent is not enough of a reduction.”
The ultimate goal is to find a way to reduce nutrient runoff without hurting farming production, according to the study.
Aloysius points out that there needs to be a solution that involves using less fertilizer because running tractors longer to apply fertilizer would increase fossil fuel use.
“Farmers need to be very efficient to make a living,” he said.
In addition to Lake Erie, the researchers believe the study could end up being a guide to show how hundreds of other coastal areas around the world that are affected by toxic algae will handle climate change.
Hans Paerl, a researcher at the Institute of Marine Sciences as the University of North Carolina at Chapel Hill, provided the Ohio State researchers similar models for the rest of the U.S. and China. Paerl’s contribution showed that lakes in China are susceptible to algae blooms due to the growth in urbanization and agriculture in that country.
He said many lakes around the world have already been saturated with so many nutrients that reducing runoff isn’t enough. New technologies and strategies need to be used to reduce the nutrients already in lakes, such as enhanced freshwater flushing of lakes and rivers affected by heavy nutrient content.
Still, reducing nutrients should be a part of the future, he said.
“It should be noted that no matter what types of physical or chemical treatments we use to mitigate blooms, they should be accompanied by nutrient input reductions,” he said.
