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The DEC assembled and deployed ultrasonic devices as part of the strategies to clean Lake Agawam.
Southampton Village Mayor Jesse Warren watched as staff assembled the devices.
The ultrasonic devices were floated out into the lake.
It’s an experiment that’s never been attempted before, combining the sun, sound and the old school disinfectant hydrogen peroxide, to target the blue-green algae that’s been the bane of bucolic Lake Agawam in Southampton Village.
On April 14, as Mayor Jesse Warren watched, staff from the New York State Department of Environmental Conservation assembled and deployed three ultrasonic devices on floating solar-powered buoys that combine continuous water quality monitoring, web-based software, and ultrasonic technology.
A sound layer in the top layer of water created by ultrasonic waves emitted from the devices has a direct impact on the buoyancy of the algal cells. They sink into the darkness of the lower water column and, in the absence of light, die.
The second prong of the trial on tap for execution this summer will involve the application of hydrogen peroxide, a method noted water quality expert Dr. Christopher Gobler has tried in his own lab at Stony Brook University’s School of Marine and Atmospheric Sciences in Southampton.
Dr. Gobler has been monitoring downstate lakes and ponds for the DEC for years. Governor Andrew Cuomo announced his Harmful Algal Bloom action plan for the state in 2017, following the appearance of toxic algal blooms in upstate lakes in Syracuse and Rochester that imperiled public water supplies, he recalled. That had never happened before and the action plan targeted the blue-green algae for 12 lakes “all upstate,” he continued.
Soon enough, eyes turned south to Long Island and Lake Agawam. A HABs plan specifically for the lake was subsequently ratified.
Over the years, the DEC vetted dozens of techniques for combating blue-green algae, Dr. Gobler recalled. “Many of them washed out,” he said. “This is one of the technologies that hasn’t washed out yet.”
The professor continued, “The DEC and I sort of kicked around ideas for Lake Agawam and what it came to was, the fact that sonic technology has been tried with mixed results, and this other approach has been tried before, too. And so the idea was, here’s two technologies that seem to show some efficacy. They don’t seem to be the silver bullet, but no one’s ever tried the two of them together.” More important, the scientist noted, “They’re two approaches that are not harmful.”
In deciding to move ahead with the untried trial, Dr. Gobler made note of the input and support of local stakeholders, such as the Southampton Village Board, the Town Trustees and the Lake Agawam Conservancy.
Offering a statement on behalf of the conservancy, board member Chuck Scarborough wrote this week, “The placement of ultrasonic devices in Lake Agawam is step-one in an exciting experiment by the DEC, in partnership with the Lake Agawam Conservancy, the Village of Southampton, and the Town Trustees. These devices have been shown to interrupt the life cycle of blue-green algae without harming other aquatic life.
“The Conservancy and Village are funding step-two: several applications of hydrogen peroxide, which converts to water and oxygen in a matter of hours after attacking the algae, also without harming other aquatic life. The ultrasonic devices and hydrogen peroxide have the potential to rapidly mitigate the danger to humans and animals posed by the harmful algal blooms that occur every summer in Lake Agawam.
“This experiment is a stop-gap measure, a bit like putting the lake on life support until we can implement a permanent cure. That cure will require cutting off the nitrogen and phosphorus from septic systems and fertilizers from as far away as North Sea that feed the blue-green algae. The Lake Agawam Conservancy is also working closely with the village, town and DEC on a comprehensive plan to solve those watershed-wide problems, restoring the lake to its original pristine condition so that we can all safely boat, fish and swim in ‘the Jewel of Southampton.’
“We are thrilled to have the DEC here for this exciting project,” Mayor Warren said after the buoys were deployed on April 14. “This is an important week for the environment and the well-being of our village community. Come July or August, we are optimistic residents will be able to see a visible decrease of algae, and we are grateful for the brilliant folks at the DEC and Gobler lab who will help us to measure the percentage of improvement.”
The DEC began monitoring blue-green algae blooms in hundreds of lakes across the state in 2013, according to the 2017 Lake Agawam Water Quality Study prepared for the village by Dr. Gobler. The lake had been burdened with dense blooms since 2003, the study notes. Over those four years from the DEC monitoring in 2013 to the study in 2017, Dr. Gobbler reported, “No lake has experienced blue-green algal blooms more frequently than Lake Agawam.”
It got worse.
By the following year, the lake was coated in the densest growth ever recorded in a Long Island water body, measuring hundreds of times the Environmental Protection Agency’s thresholds for harmful conditions.
The good news is the lake’s size and depth, water chemistry profile, and the presence of persistent open water HABs throughout the summer season will provide optimal conditions to evaluate the use of ultrasonic technology and the hydrogen peroxide application, according to a release from the DEC announcing the trials. The hydrogen peroxide is found in a product called Green Clean Liquid. Should the experiment be successful, the method will be used at other waterbodies burdened with HABs statewide.
Throughout the last several years, varied methods to control blue- green algae have been implemented. In 2019, the village, working with the county and state, deployed a mobile harvester to the lake. It separated algae from water and returned the clean water to the lake.
Last May, a device crafted by student technicians at Dr. Gobler’s lab and designed to monitor the lake’s water quality on a real-time basis was launched into the lake. It checked for levels of blue-green algae, other algae, temperature, dissolved oxygen, pH and nitrate.
Blue-green algae, or cynobacteria, are naturally occurring in low numbers in lakes and ponds. They can become abundant, forming blooms in shades of green, blue-green, yellow, brown, or red. The 2018 bloom in Lake Agawam had a pea soup look. The algae blossoms into a harmful bloom due to an overabundance of nutrients in the water, blamed by researchers on aging septic systems and fertilizer runoff.
Contact with the bloom may cause an array of medical problems ranging from nausea to skin irritations to breathing difficulties.
