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Have you ever felt something slimy brush against your foot while swimming in a lake? It's often just a plant. And a lot of people think of plants that grow in lakes as a nuisance, as like weeds. Well, property owners often use machines or chemicals to get rid of them, but native aquatic plants are essential to keeping lakes healthy. Kirsti Marohn from Minnesota Public Radio reports on an effort to change how we think about these plants.
KIRSTI MAROHN, BYLINE: Donna Perleberg is wearing hip waders and carrying a rake as she scans Nisswa Lake in central Minnesota.
DONNA PERLEBERG: There's over two dozen species of aquatic plants here. We can see many of them right here at the dock.
MAROHN: Perleberg is an aquatic plant ecologist with the Minnesota Department of Natural Resources. When she peers into the water, she sees a diverse ecosystem that helps keep Nisswa Lake one of the clearest in the state. Some plants, like water lilies, are rooted to the lake bottom, but their leaves float on the surface. Others stay submerged, like an underwater forest.
PERLEBERG: This is a bladderwort. It's one of Minnesota's carnivorous plants. It eats animals.
MAROHN: What kind of animals?
PERLEBERG: Little insects.
MAROHN: Perleberg says the roots of aquatic plants anchor the lake bottom, keeping sediment from getting stirred up and clouding the water, and they help reduce algae blooms by absorbing nutrients that wash in from lawns, golf courses and farm fields.
PERLEBERG: If Nisswa Lake did not have all of these what we think of as weeds or aquatic plants, the water clarity would not be as high.
MAROHN: Native aquatic plants also helped create a robust ecosystem that benefits critters who live in lakes. Jay Ferrell is director of the University of Florida's Center for Aquatic and Invasive Plants.
JAY FERRELL: We're talking insect larvae, snails, crayfish, all of these other type of species now have this very rich environment where they can operate, where they can hide.
MAROHN: Ferrell says native plants have lots of natural enemies that feed on them, so they rarely dominate a lake, unlike invasive species, which have a tendency to take over. Many states, including Minnesota, allow property owners to remove some aquatic plants to create access for swimming or boating. Ferrell says the loss of native aquatic plants is a concern nationwide. He says it's a challenge to balance protecting the health of a lake with the competing interests of all the people who use it.
FERRELL: The duck hunter usually wants something different than the pleasure boater. The pleasure boater wants something different from the angler. The angler wants something different from the home and dock owner.
MAROHN: Heather Baird is a lake habitat supervisor with the Minnesota DNR. She says most people don't understand the consequences of removing native plants.
HEATHER BAIRD: Like, I think if more people knew, they would clear what they needed, yes, or they'd know the detriment. Oh, I cleared that whole lily bed and now I've got all this erosion, and now I have to pay to keep my property from eroding into the lake every year.
MAROHN: And Baird says people might not be aware of how many chemical pesticides are applied to lakes every year to kill aquatic plants. Some of the products contain PFAS, sometimes known as forever chemicals because they don't break down easily in the environment. That may prompt some lake residents to seek more natural alternatives or choose to leave native plants alone.
For NPR News, I'm Kirsti Marohn in Nisswa, Minnesota.
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