As summer in Wisconsin reaches its zenith, new dangers await in Madison lakes. According to the Wisconsin Public Radio, 2020 is shaping up to be another ample year for blue-green algae blooms. Blue-green algae, or cyanobacteria as it has more recently been known, is a prokaryotic bacteria that has increased in proliferation in the past few decades. According to Everyday Health, cyanotoxins found in the algae cause skin irritation, muscle and joint pain, nausea and many other symptoms.

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Cyanobacteria thrive in warm nutrient water, blooms increasing in frequency with the temperature. According to the National Ocean Service, massive algal blooms like the ones in 2018 and 2019 cause hypoxia, where the bacteria cover a large area on a body of water, blocking out sunlight from native plants and preventing an inflow of oxygen through photosynthesis. Hypoxia has been known to cause massive animal die-outs, most commonly in Wisconsin’s native fish species. Dead cyanobacteria blooms rot and sink to the bottom, depleting oxygen levels even further.

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After numerous studies focused around Madison lakes, it has been found out that the recent explosion of cyanobacteria in the last few years is a result of climate change. Patterns in warmer weather, heavy rainfall and nutrient runoff result in large scale blooms. According to the Environmental Protection Agency, Wisconsin has seen a rise in precipitation of 5–10% over the past century, and overall Wisconsin has averaged an increase in temperature of 2 degrees fahrenheit. These conditions cause the explosions of bacteria that we see today, and scientists think that the blooms will only get worse in the future.

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David Caron, a biology professor from the University of Southern California and expert in algal blooms, explains the effects of warmer water on cyanobacterias. “Most algae can grow faster in warmer water, but there are thousands of different types of algae, and different types of algae have different optimum temperatures,” Caron said. “As global temperatures warm, there are a lot of water bodies that are going to warm, and they will select types of algae. In particular, in freshwater systems, the ones that produce toxins are typically cyanobacteria.”

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Even though Wisconsin algal blooms are thought to be caused by agricultural runoff, Professor Caron says that agriculture is not the only industry to blame, and it is a necessary part of society anyway. “Everybody shares blame in this and it is wrong to point a finger at any one industry. There is no question that agriculture is a major entity, but I think that working together on it is what needs to be done on a global scale is what needs to be done, not saying ‘agriculture you have to clean up your act.’”

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Krystyn Keiber, a PhD student in the Limnology Department at the University of Wisconsin-Madison, elaborates on the effect of climate change on eutrophication. “You have changing weather patterns leading to frequent intense rainstorms, which allows for greater weather pressure on our farms, causing runoff into our lakes.” The runoff is a mix of synthetic fertilizers and pesticides, that Keiber explains is made up of mostly phosphorus, iron and nitrogen, key ingredients in cyanobacteria reproduction. At UW Madison, Keiber works with the limnology department researching algal blooms and charting patterns over the years.

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While the overlying problem is climate change, Farmers, politicians and residents alike can all take action to stop eutrophication. In 2010, the city of Madison banned the usage of phosphorous-filled fertilizers on private lawns, taking notice of the negative effects the fertilizer causes. As of right now, the agriculture industry is still allowed to use the fertilizers, but a ban in the future may be the next step to halt eutrophication. Professor Caron says that many initiatives are being taken to pursue no-till farming, which keeps phosphorus in the soil and out of Wisconsin waterways by decreasing erosion. Although these solutions are viable, it is likely that the only way we can prevent worldwide eutrophication is by stopping climate change. It is a fact that warmer waters show an increase in bacteria, and decreasing the amount of fossil fuels in our atmosphere is the only thing that we can do to prevent this underlying problem.

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Eutrophication and the sickly state of Wisconsin waterways should be a motivating factor in advocating against climate change. Unlike other climate-related issues, we are seeing the effects of eutrophication on our lakes today, watching helplessly as our lakes become poisonous and decrepit. Motivated by saving our lakes, use this evidence as reason to advocate, and support local researchers in their search for solutions.