Research shows Great Lakes algae and microplastics connect

Sheri McWhirter, The Record-Eagle, Traverse City, Mich.
·4 min read

Mar. 21—TRAVERSE CITY — Scientists discovered plastic microfibers in the Great Lakes are sticking to green algae that grows along the bottomlands in a way that could help keep the pollution out of the environment.

Researchers at Valparaiso University in Indiana last week published their findings in science journal "Environmental Pollution" that showed electrostatic attraction between tiny, plastic particles and green algae cells, which then leads to bio-adsorption. That means the microplastics physically adhere to cladophora, a unique discovery made in first-time research in the Great Lakes.

Cladophora samples from Lake Michigan from offshore of Sleeping Bear Dunes National Lakeshore and Indiana Dunes National Park — collected as part of other, ongoing federal research into the relationship among invasive mussels and algae growth — were examined as part of the study. Additional samples came from Lake Erie.

"We didn't really need a lot to do our research," said Julie Peller, Valparaiso University organic chemistry professor and lead author of the research paper.

The scientist said the first indication her research team had that microplastic particles and cladophora algae were more than just bumping into each other in the Great Lakes happened when they realized plastics were found among the algae samples, even after a thorough rinsing process a U.S. Geological Survey team did as part of its sample collection protocol.

"It's not easy to shake these things out of there," Peller said.

Samples about the size of a penny were chemically processed, she said, oxidized to reduce carbon matter and leave behind plastics. At least one plastic microfiber was found in the large majority of the examined samples, Peller said.

The team so far analyzed samples collected in 2018 and 2019, she said, and are now moving on those from 2020.

The plastic microfibers line up with cladophora cell walls, "kind of laying on the cell wall," Peller said, adding that, in other cases, the ends of the microfibers attach to the cell wall in a loop.

"We wanted to learn how this algae pulls in these microfibers and plastics," she said. "It's not just a physical entanglement."

Researchers observed indications of strong electrostatic forces and physical connections via adsorption, similar to how other types of algae may take up metals, according to the published research paper.

"From an investigation so far, yes, the cladophora is gathering this stuff up. So in one way, it's cleaning it up," Peller said.

Excessive cladophora growth around the Great Lakes has for many years been connected to the presence of invasive zebra and quagga mussels filtering the water, increasing the depth sunlight reaches within the water column. When the algae mats die off it creates a lack of oxygen in the water and causes subsequent outbreaks of botulism — often killing fish, birds and mammals that feed on tainted carrion along the beach.

In fact, organisms feeding on the cladophora leads Peller to believe microplastics will also make their way up the food chain, as botulism infection does.

She said one exciting possible outcome of her team's discovery could be future engineered advances to improve wastewater treatment processes for facilities that cannot currently remove microplastics and microfibers from the sewage stream.

Microplastics and microfibers often enter the Great Lakes and other surface waters through the use of certain beauty products, rural and urban stormwater runoff, and laundering clothing made with synthetic materials.

Liz Kirkwood, executive director for Traverse City-based nonprofit For Love of Water, said this is a remarkable revelation by the Valparaiso University research team. And it offers multiple benefits, she argued.

"This is an extraordinarily important scientific discovery and it really illustrates how interwoven our actions are to the water itself and how something as small as a microfiber could have impacts on the environment," she said.

It's also a valid hope that wastewater treatment as an industry could one day benefit from technological advances made because of this scientific discovery, Kirkwood said, especially when focus is placed on critical financing for such efforts.

Furthermore, the nonprofit leader said this type of proof of physical impacts on the environment could be used to hold polluters accountable for their contamination of public resources. Kirkwood pointed to the textile industry and its rampant use of synthetic fabrics rather than natural, biodegradable options.

"We could demand fabrics that aren't going to end up polluting our waters," she argued.

Other local scientists also found the discovery interesting, including Jillian Votava, education and STEM coordinator for nonprofit Inland Seas Education Association. The Great Lakes-focused education nonprofit has for years taught schoolchildren about the effects of plastics pollution in the Great Lakes.

Votava said this study helps scientists better understand how microplastics move around within the Great Lakes — perhaps even from where it comes — and underscores the importance of plastic pollution prevention efforts.

"We all collectively need to be more aware of this and reduce the amount of plastics used out there," Votava said.

Scott Tucker, superintendent of the national lakeshore in Benzie and Leelanau counties, said that while green algae samples for this study were collected outside the park's physical boundaries offshore, the results demonstrate how forever-preserved national parkland creates ideal laboratory conditions to monitor climate change and other environmental impacts.