Tiny plant hangs on over summer during Norwalk River experiment

WILTON — Since the spring, the Norwalk River has been an incubator of sorts, playing host to a plant scientists hope will re-establish itself. The experiment has been a success so far, but still has a way to go.

Western Connecticut State University graduate student Kelly Nealon will discuss the research she and her professor, Tom Philbrick, have been conducting in a virtual talk on Dec. 8 at 7 p.m. The talk, called “Restoring The Norwalk River: Working to Mediate 200 Years of Negative Impact,” can be viewed by registering at https://bit.ly/3lrMuUs.

The experiment involves cultivating the hornleaf riverweed — podostemum ceratophyllum — in the river through a variety of means. In the spring, Nealon and Philbrick re-introduced the plant from the Little River in Oxford and the Eight Mile River in Old Lyme by using different methods to attach it to rocks in the river.

It is believed the riverweed existed in the Norwalk River before it died out when numerous dams were built and areas around the river were developed. Considered a keystone species in rivers in the eastern part of North America, the plant attaches to rocks in river rapids and is a habitat for the invertebrates eaten by fish.

It is also beneficial in that it removes nitrogen, phosphorus, calcium, zinc and other elements from the water, while at the same time contributing important organic matter. Thus, it plays a significant role in water quality and river ecology.

Nealon said she and Philbrick checked on the plants throughout the summer, and in early October collected their data.

“Looking at it now, in broad terms, the plants stayed alive,” Nealon said. “That in itself is a great success.”

The plan had always been to review the plant’s progress over the course of two summers. Next spring, they will check to see if the plants survived the winter and are still growing.

“What we’re really hoping is to establish a population,” she said. “We want for them to not just exist, but to grow to new surfaces and areas of the river.”

While Nealon will eventually obtain her degree and move on from the project, she hopes to hand it off to someone else who will continue to monitor positive or negative changes.

For the program, which is being presented by Trout Unlimited, Wilton Library and the Norwalk River Watershed Association, Nealon said she will discuss the ecology of the plant, what it does for the ecosystem, and why the average person should care about it.

“It’s pretty important for the ecosystem of the river,” Nealon said. “It is a lesser-known species, but based on research people have been doing, it’s considered a foundation species.

“It provides ecological services, puts resources into the food chain, plays a role in sedimentation. The way it grows from rock to rock, it can help stabilize the substrate at the bottom of the river ... keeping it settled,” she said. “The Norwalk River is part of a huge watershed,” she said. While people may not get their drinking water directly from the river, “any part of the river ecology affects another part of the watershed. The insects, plants, animals, all have an effect on humans.”