ODNR taking action to eradicate green gunk at pond

Driving or walking past the Ohio Department of Natural Resources building on East State Street in Athens provides a view of a pond with what some might guess is an algae problem…

But what ODNR has had to deal with since last summer in the pond is a small, flowering plant that goes by the name of watermeal, coupled with duckweed.

The pond, which has been a spot for local fishing and aquatic life, provides a habitat for these plants on the surface, and though natural, they can threaten other pond life.

“It’s a very small flowery plant, actually the smallest flowering plant. And so… a lot of people confuse it with plankton or algae, and it’s actually a very small floating plant,” said Mike Greenlee, an aquatic biologist with the ODNR Division of Wildlife District 4 (with an office in the building next to the pond).

He emphasized that it isn’t necessarily the watermeal itself that’s directly harmful, but that its presence can have negative consequences.

“The plant is not harmful; it’s a natural plant,” said Greenlee. “It’s not algae, or plankton so other than that, the keys are trying to get the rooted aquatic plants established, and provide a stable oxygen supply, and at the same time, try to gradually eliminate this watermeal.”

There are several problems with watermeal’s existence in this pond, or in ponds across Athens County in general. The aforementioned rooted plants at the bottom of the pond need high amounts of oxygen and feed from the direct sunlight. Watermeal can block that sunlight and deprive not only the plants of oxygen, but can kill off fish who rely on the oxygen from the rooted plants.

“It will tend to shade out the rooted aquatic plants that grow up from the bottom of the pond, which are very beneficial for oxygen fraction,” said Greenlee. “About 80 percent of the oxygen in a pond is supplied from plant life.”

Greenlee has helped lead the job of eliminating the watermeal nuisance. The water has been treated with an aeration system and a herbicide. The aeration system de-stratifies the water by pushing a curtain of air in the water to the surface. Greenlee suggested that it works like an air stone in an aquarium. The herbicide has been effective as well.

“That herbicide can also control the non-target plants, the rooted ones that we want to try and get started,” said Greenlee. “But it’s a delicate balance and a difficult thing…”

The herbicide also has a timetable that requires a waiting period in between applications, making the mitigation process timely.

It’s hard to pinpoint the source of the watermeal. Once it takes hold in a body of water, it reproduces rapidly. Someone could have inadvertently carried watermeal seed to the pond, perhaps on a fishing pole or line, or even a bird of some kind could have carried the seed and dropped it in the pond.

ODNR and Greenlee remain optimistic about the dual methods they’re using to attack the watermeal problem.

“I think this last treatment we made some headway on it; it’s not as dense as it was, we’re hoping that’s a good sign,” Greenlee said.

Photo caption: Photo Credits: Photo by Lori Crook, The Athens NEWS.  The Ohio Division of Wildlife is using a combination of an aeration system and herbicide to eradicate the watermeal plant that’s covering the pond at the East State Street ODNR facility.

Kaleb Carter, Athens News

View original article at: ODNR taking action to eradicate green gunk at pond

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