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Summer Blooms

By Alex Piazza
apiazza@umich.edu

Captain Paul Pacholski cruises along the shore of Lake Erie, navigating through waves in search of walleye.

Pacholski has chartered fishing trips for 35 years, sharing his passion with fellow anglers and those who have never picked up a fishing rod.

Pacholski

Paul Pacholski has chartered fishing trips for 35 years.
Photo: Joseph L. Murphy/Iowa Soybean Association

But business has slowly declined, highlighted last year by a 25 percent dip in sales for Pacholski and some of his fellow Lake Erie charter captains.

The culprit, they say, are toxic algae.

“Harmful algal blooms are extremely detrimental to our livelihood,” said Pacholski, president of the Lake Erie Charter Boat Association. “A lot of our business is booked up to a year in advance, but as soon as people get wind of a significant bloom in Lake Erie, they get spooked and cancel their trips. It’s almost like a thick, green pudding in certain spots, so you can only imagine how people would react to the sight of it.”

Harmful algal blooms are a growing problem in coastal communities nationwide. They occur when bodies of water become overloaded with nitrogen and phosphorus from farms, wastewater treatment plants and other sources.

Warm water, precipitation and excess nutrients promote rapid growth of algae that can be toxic and potentially fatal to aquatic life and people. Algae eventually settle to the bottom and decay, depleting dissolved oxygen in the water, which creates dead zones where oxygen levels are low enough to kill fish.

Researchers at the University of Michigan are working to pinpoint the main drivers of harmful algal blooms, partnering with coastal communities to prevent further environmental crises.

“The only way you’re going to fight something like this is through education,” said Pacholski, who works with researchers to tackle harmful algal blooms. “We can’t sit back and expect this problem to correct itself. We have to put our heads together and come up with some solutions here because it’s not going away anytime soon.”

Ground Zero

Lake Erie

Pilots from Aerodata flew over Lake Erie's western basin in
August 2017 to map out harmful algal blooms.
Photo: Aerial Associates Photography, Inc. by Zachary Haslick

Lake Erie is the shallowest and warmest Great Lake, and thus is no stranger to harmful algal blooms.

In August 2014, blue-green algae developed along the western basin of Lake Erie and eventually contaminated the drinking water supply of more than 400,000 nearby residents.

Allison Steiner is working with researchers and residents along Lake Erie to explore how climate change impacts the formation of harmful algal blooms.

“These blooms have been increasing globally over the past decade, and they directly impact fundamental human needs in coastal communities across the country,” said Steiner, associate professor of climate and space sciences and engineering at U-M. “Understanding, predicting and alleviating this serious water quality issue is a problem of great societal relevance.”

With support from the National Science Foundation, Steiner is leading a research project that brings together community partners in water treatment, beach management and recreational fishing to develop strategies to prevent harmful algal blooms.

ManningSteiner

Allison Steiner and Nate Manning

“We are one of only two plants in Michigan that treats water out of Lake Erie, so we definitely understand the severity of this seasonal issue,” said Christopher Knight, water treatment superintendent for the City of Monroe in southeast Michigan. “We are constantly testing for toxins, June through October, to ensure quality drinking water for our residents. So whether its folks like me in water treatment or recreation, we all have the same mission, and that’s to clean up our lake.”

But with each summer, there is uncertainty among Lake Erie residents as to when and where harmful algal blooms will appear.

As part of the project, Nate Manning and his colleagues are following historical data to better predict the location of future blooms. Using data from 2002 through 2016, researchers identified when harmful algal blooms first appear, their size and when they faded.

“Seasonal forecasts are great because they give us a snapshot of the expected severity of an overall bloom, but they don’t offer much insight on its expected location,” said Manning, a postdoctoral research fellow at the U-M Graham Sustainability Institute. “By linking predictive models and regional estimates, we are able to better predict potential bloom impacts at scales and in regions, which allows for better management response.”

Airborne Algae

WavesWaves breaking against the shoreline is a common sight along Michigan beaches.

But what if harmful algal blooms contaminated the water?

Beyond its unsightly blue-green appearance, organic material from the crashing waves could go airborne.

Over the past four years, Andrew Ault and Kerri Pratt have explored whether toxins from harmful algal blooms can be spread by air when waves break against the shoreline. Their research focuses on tiny aerosol particles, which are about 100 times smaller than a human hair.

With support from the U-M Water Center, researchers collected water samples from Lake Erie and Lake Michigan with varying degrees of blue-green algae. In order to simulate waves breaking against the shoreline, U-M graduate student Nathaniel May sent water samples through a lake spray aerosol generator.

Ault and Pratt then collected air samples from the generator, which they found contained aerosolized biological material from the harmful algal blooms.

PrattAult

Andrew Ault and Kerri Pratt

“We found that when we had higher blue-green algae concentrations in water, we saw more aerosol particles that contained markers of biological content,” said Pratt, assistant professor of chemistry and earth and environmental sciences.

Their study, published this year, is the first to show that waves contaminated with harmful algal blooms can release material into the atmosphere when they break against the shoreline, which may cause respiratory health issues. Their findings also show that particles of this size can be carried hundreds to thousands of miles by air, and wind speeds as little as seven miles per hour can create lake spray aerosols.

“We now know that organic material from this blue-green algae can get into the air, so we need to further explore whether actual toxins from harmful algal blooms can also go airborne,” said Ault, assistant professor of chemistry and environmental health sciences. “Airborne toxins have major implications regarding harmful algal blooms’ effects on our respiratory health, beyond the traditional health risks that revolve around drinking water contamination.

In conjunction with their work, researchers across U-M will continue to partner with coastal communities in an effort to predict and prevent harmful algal blooms

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