WELLS — Experts allege that the muck and dense vegetation on the bottom of Little Lake St. Catherine and the water body as a whole can be cleared up using aeration technologies, despite claims from state experts who say they have no proof that it will.
“Most people would not use aeration to reduce sediment in a lake,” said Dr. Alex Horne, professor emeritus at the University of California, Berkeley. “But it does work under some circumstances, and in this specific case, there is evidence that aeration has reduced the lake.”
Horne, who has been studying and examining water bodies since 1964, said the buildup of cellulose at the bottom of a lake — such as withered and sunken milfoil, weeds and other vegetation — can be broken down by bacteria, but only if oxygen is able to get to it, which is why introducing oxygen to lake systems has proven to speed the decomposition process.
“There’s very little oxygen in water,” Horne said. “You get a layer of organic matter but low oxygen, (which leads to) slow rot. … In these specific cases, the conventional wisdom is not applicable. This is a special set of circumstances.”
In the long term, Horne said installing aerators or oxygenating the lake can keep phosphorus from being released during the decomposition process in water bodies, helping to prevent cyanobacteria from causing dangerous algal blooms.
Though much of the sediment in lakes comes from runoff nutrients, buildups of cellulose and plant matter can be alleviated with a sped-up decomposition process, which would steadily decrease the layer of muck in Little Lake St. Catherine, leaving less area where sunlight-seeking plants can root, spread, and take over normally deep water, Horne said.
“This is a eutrophic lake,” said Emily Boedecker, commissioner of the Department of Environmental Conservation. “It’s in a (uniform) state. It has natural plant growth every year. … It’s in stable condition.”
Horne disagrees that the state of the lake was permanently “eutrophic,” as eutrophication — the process by which a body of water fills in with nutrients and sediments — happens gradually as more plants fall to the bottom of the body of water and more sediment is created.
“Putting oxygen in lakes is generally a good thing,” Horne said. “There’s no downside — there’s no reason not to have oxygen and aeration in the lake … a lot of places are bending over backwards to reverse eutrophication.”
But Misha Cetner, permitting analyst for Lake and Shoreland Permitting with the Vermont DEC, aired on the side of caution. She maintained that though aeration could yield some effects if deemed appropriate for a small lake ecosystem like Little Lake, the natural health of the lake and flourishing plant life also needed to be considered and protected.
Aeration has been cleared in the past for solving problems with cyanobacteria blooms — permits were issued to Putnam Valley, New York, for the treatment of Lake Peekskill, and for Lake Carmi in Franklin, which was approved by Gov. Phil Scott in June — but Cetner said aeration has not been shown to decrease the amount of muck and sediment in water bodies.
Cetner cited the work done on Lake Apopka in Florida, where, in 2015, 96 aerators were put in a 250-acre portion of the lake, along with two different applications of 1,000 pounds of microbes and 400 gallons of enzymes to try to hasten the decomposition of organic matter in the lake.
After monthly sampling, researchers from the University of Florida recorded “no detectable difference” in ammonia, total phosphorus, total nitrogen, total chlorophyll, Secchi depths or turbidity from the areas of the lake without aerators, and muck levels remained the same, according to excerpts from a January 2019 report from the Vermont DEC: “Aeration as a lake management tool and its use in Vermont.”
The program was subsequently shut down in 2017, having been labelled as ineffective, the report said, and other subsequent reports deemed the scientific literature regarding muck and organic sediment not supportive of aeration as a remedy.
But cyanobacteria blooms result from an abundance of phosphorus which, Horne concluded, could result from bacteria breaking down organic sediment without oxygen at the bottom of the lake.
Horne said the closer to the surface the sediment gets, the faster the eutrophication process goes: more plants find their way into the sediment bed, spread rapidly, creating more muck at the bottom of the lake as the plants die off in the winter.
Horne said both nitrogen and phosphorus need to be reduced and oxygen increased, but warned that experts should also be measuring the mercury and methyl mercury.
Without proper oxygen, Horne said, the bacteria in the lake transforms mercury into methyl mercury, a nerve poison very toxic to humans once it interacts with water and plant life, according to Medline.com.
In Putnam Valley, New York, Town Supervisor Sam Oliverio said outbreaks of blue-green algae in Lake Peekskill lasted for years in the 80-acre lake that measures 14-feet at its deepest, resulting in many closed beaches throughout the lakefront.
So in 2018, the town decided to implement a Clean-Flo diffuser system, and Oliverio said now, a year later, the results are astonishing: zero algal blooms.
“This summer, we have not had to close once,” Oliverio said. “The lake is crystal clear, and there’s more fish than I’ve ever seen.”
Oliverio explained that enzymes introduced in the lake ate away at the churned-up nutrients at the bottom and kept the phosphorus levels too low to release cyanobacteria.
“We’re seeing results in the particularly small area in Lake St. Catherine,” said Brian Kling, president of Clean-Flo systems, who installed diffusers in both Lake Peekskill and Little Lake St. Catherine.
The Little Lake St. Catherine aerators remain shut off because the Lake St. Catherine Conservation Fund has yet to apply for another permit, Cetner said.
“They (Little Lake) are showing depth increases…(but) we talked to the state numerous times about the enzymes, and they’ve been rejected out of hand,” Cetner said.
Kling said the enzymes are currently used by his company and others throughout the country and in over a dozen countries for a host of water projects, including drinking water reservoirs.
“Milfoil, at the end of the year, drops to the bottom and starts to decay,” Kling said. “When you fully oxygenate a body of water, you get natural, microbial activity.”
Kling alleged that herbicides, dredging and milfoil harvesting are just addressing symptoms of the problem, when the real issue was the overload of nutrients, including dead water flora.
“We’ve been operating in thousands of water bodies over the course of 50 years,” Kling said. “When you have a lot of muck, milfoil roots and grows, and milfoil grows very quickly. It’s hard to even get a boat through the water.”
Along with clearer waters and less sediment, Kling said the fishermen in and around their lake and pond projects are the first to compliment the company on the subsequently booming fish populations who become healthier and more lively with the new found oxygen in the water.
As far as disturbing the peace of the water bodies, Kling said their water quality samples have never indicated increased turbidity.
“If we increase turbidity, our job gets shut down,” Kling said. “There’s no basis for the claim that the systems move stuff around. With our design, we’ve never seen it.”
katelyn.barcellos
@rutlandherald.com