Blue Green Algae

ST. ALBANS TOWN-- It’s peak summertime in Vermont, which means fireworks, camping and picnics in the park. 

It also means the return of one of Vermont’s most unwelcome guests: cyanobacteria, also known as blue-green algae. 

“Usually it comes right around this time of year,” said St. Albans Town Facilities Manager and Parks Supervisor John Montagne. “We don’t currently have a way of testing for blue green algae, it just blooms in the sunlight.” 

The Centers for Disease Control reported that testing for the algae is limited and only available in specialized laboratories, and efforts are currently underway to make testing for cyanobacteria more widespread and available.

What is cyanobacteria?

According to the Center for Disease Control, cyanobacteria are single-cell microscopic organisms that use sunlight to create their own nutrients and live in fresh, brackish and and salt waters. 

In warm waters that are rich in phosphorus and nitrogen, the bacteria can multiply rapidly which manifests as a “bloom” that grows across the water’s surface and can often be seen. 

“Sometimes people mistake duckweed for blue-green algae,” Montagne said. “But it really looks like oil in the water.”

In addition to making the beaches look even more pristine, Montagne said St. Albans Town crews regularly remove the washed-up seaweed from the beaches to further limit the amount of phosphorus emitted by their decomposition, lest it add to the amount of nutrients in the water. 

Because more nutrients probably means more algal blooms. 

“We usually have to shut down the beaches for one to two weeks during the year,” Montagne said. “And we haven’t had to do it yet.”

Why is it harmful?

According to the CDC, cyanobacteria not only blocks sunlight from benefiting other organisms, but rapidly feeds on the nutrients and oxygen that other organisms need to survive. 

They also make toxins called cyanotoxins, which are some of the most powerful natural poisons identified, and the CDC reports that there are no currently identified remedies for the effects. 

Because dogs are more likely to drink the contaminated water and swim in it without knowing, cyanobacteria can pose a particularly serious risk to canine health and has caused the death of dogs in the past. 

Though Burlington closed its beaches recently due to a cyanobacteria bloom, the beaches have reopened, and while Montagne said he expects blooms in St. Albans Bay every year, he hasn’t seen them yet. 

“It’s a huge problem for St. Albans Town,” Montagne said. “Last year I saw it going up the Maquam shore side. I can understand it being in the Bay because there’s not a lot of current or flow, but that’s in the broad lake.”

Montagne said the State of Vermont regularly checks for cyanobacteria blooms on a weekly basis and each of the farmers around the Bay area are required to have buffer strips to help keep nutrients from their fertilizers from entering into the water. 

Additionally, the St. Albans Town has established their new stormwater utility, dug conversion canals and maintains retention ponds -- including the Hawk’s nest retention pond -- to filter silt and nutrients out of the water. 

Montagne said the Town also contributes to funding for ongoing research as to how municipalities can prevent cyanobacteria blooms and augment their systems to limit the release of nutrients. 

About the watershed

According to the Saint Albans Area Watershed website, it drains approximately 50 square miles of land -- agricultural, forested and urban -- into the Bay, which measures a surface area of about 1,700 acres, 7.5 square miles and an average depth of 11 feet with a maximum of 64. 

SAAWA urges those living around the lake to switch to phosphorous-free fertilizers to aid in efforts to limit the amount of nutrients, and has issued guidance as to how residents can make sure their septic systems aren’t leeching nutrients into St. Albans Bay.

Want to know more about cyanobacteria? Check out this helpful video from by clicking here!

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