Beach closures impacts both sides of lake
By Zachary Matson
It didn’t take long for Lindsey Carlson to find cyanobacteria during a routine monitoring trip to Law Island on Lake Champlain last month.
“Here’s some,” she said after dipping a jar into the lake to fill it with water.
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Cyanobacteria is widespread in the lake and other waterbodies across the region, but when warm, still, nutrient-rich water induces a proliferation of the microscopic algae, it can form large blooms, which can be harmful to people and pets and force beach closures.
The specks of cyanobacteria in Carlson’s jar didn’t rate as a worrying bloom and would be compatible with recreation, but it was a reminder that cyanobacteria are always lurking and waiting for the conditions in which they thrive.
RELATED READING: Understanding algal blooms
Carlson, the water and science program coordinator at the Burlington-based Lake Champlain Committee, leads a sprawling harmful algal blooms monitoring program on both sides of the lake. When volunteer monitors spot a suspected bloom at one of hundreds of monitoring sites, Carlson and others check photos and descriptions to confirm the state of a bloom and reports it to Vermont’s lakewide tracking system.
“Reliable data is important for public safety and tracking conditions,” said Jenny Patterson, executive director of the nonprofit, which has worked on Lake Champlain issues since 1963 and overseen the HABs monitoring since 2003.
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The organization trained over 350 volunteers this year. Carlson conducted two dozen of the virtual trainings this season. Last year, volunteers monitored over 150 sites across lakewide, with sites in New York, Vermont and Quebec. Around 200 volunteers are monitoring the lake this summer, Carlson said.
The program’s growing database on the prevalence and extent of HABs in the region’s largest lake is crucial to understand the water quality threat closing beaches and expected to worsen as water and air temperatures continue to warm and torrential rainstorms that flush nutrients into the lake increase in frequency. Phosphorus runoff from farms, particularly the Vermont side of the lake, the discharge of wastewater plants and a litany of other sources fuels and exacerbates the algal blooms.
So far this summer, cyanobacteria blooms have caused beaches to close along the New York and Vermont shorelines. Public beaches in Westport, Willsboro and Port Henry all faced HABs-related closures in July, and nearly all of Burlington’s city beaches were closed in late July.
“When we have to close beaches, it really does impact people that have limited resources and access,” said Julie Silverman, the Lake Champlain Lakekeeper, who each week visits Law Island as a HABs monitor. “It’s a huge issue and that’s why we have to work really hard on trying to figure out how we can change the food, how can we stop that much phosphorus running into the lake.”
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The monitors, with their training and connection to Carlson and others who review the reports, are the boots on the ground for ensuring unsafe water conditions are reported as quickly as possible. Beaches are typically closed on both sides of the lake after a monitor observes a bloom in progress. After the bloom has dissipated for at least 24 hours and the water tests negative for the toxins that can form in a bloom, the beach can reopen.
The program aims to post any active bloom within an hour, Carlson said. Follow-up visits are conducted if possible to determine when the bloom breaks up. The monitoring season — and the time of year that blooms are being found — has increased deeper into the shoulder seasons in recent years.
“When the program started in 2003, it ran from July to the end of August or early September,” Carlson said. “Now, it runs from early June and we wrap up right before Thanksgiving. The season of when we see blooms is expanding.”
While few blooms are ever tested directly for toxins, they can be harmful without toxins and health officials and scientists caution people to avoid any visible blooms they encounter.
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“Our message is to take the precautionary approach: If you see a bloom, avoid contact with it.”
Lindsey Carlson, water and science program coordinator at the Burlington-based Lake Champlain Committee
What monitors look for
After signing up to participate as a monitor, volunteers attend a two-and-a-half-hour training and are assigned a site based on their location and interests. Some of the sites, like Law Island, require a paddle to get to.
They classify the cyanobacteria into three categories: 1, 2, and 3. A “category 3” rating means there is an active bloom at the site and triggers a “high alert” warning in Vermont’s tracker. A bloomed considered “category 3” will typically result in a beach closure if at a public swimming location.
A “category 2” rating means cyanobacteria is present on the surface water but has not formed a full bloom. “Category 1” means there is no cyanobacteria present or only a small amount of it showing as specks (like what Carlson pulled up in her jar dip).
The monitors are also asked to classify the water conditions when cyanobacteria is not present, describing it as clever or brown and turbid. The training helps monitors differentiate other common water conditions that could be confused with a cyanobacteria, including pollen accumulations, duckweed and non-toxic green algae. A “stick test” can be used to tell the difference between non-toxic algae and HABs: if the algae clings to a stick, it is most likely non-toxic green algae.
And not all cyanobacteria blooms look the same.
“Cyanobacteria blooms can present a wide variety of colors, ranging from brown and yellow to vibrant green and teal,” according to the monitoring program’s criteria. “These colors are influenced by the pigments within the cyanobacteria, environmental factors, and the stage of the bloom.”
Top photo: A recent harmful algal bloom that displayed a mix of colors taken by a Lake Champlain Committee monitor at Black Bridge in St. Albans, Vermont. Photo courtesy Lake Champlain Committee
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