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Blue green algae is not actually an algae, but a type of bacteria known as cyanobacteria, which are common in Minnesota waters.

Naturally occurring phenomenon can be noxious, but shouldn’t be worrisome, says watershed district

While a sample of Forest Lake for blue-green algal blooms turned up negative, an employee for the Forest Lake/Comfort Lake Watershed District is saying he believes a recent potential occurrence of the noxious algae was indeed present. However, Garrett Miller, a watershed assistant at the watershed district, said that the blooms are typical for this time of year, though he said it was a little early given the hot summer we’ve had so far.

“A lake goes through cycles from spring to fall. Terrific lakes are nutrient rich; they go through a cycle. In the spring, we have good water quality. Then in July, when the water temps are high, it creates the perfect conditions for those algae blooms. It’s just a natural cycle,” Miller said.

And while the blooms shouldn’t be alarming, Miller offers guidance in how to watch out for the noxious algae and how to prevent it.

Miller said he got a call on June 29 by the Forest Lake Lake Association about a possible bloom. The president of the association was notified by another member that their dog got sick and realized that the likely culprit was blue-green algae. Miller was notified shortly after, and he and another member of the watershed district went out to take a sample. By the time he got out there to take the sample, the algae was already gone, but he still took a sample for testing. While there are labs that test specifically for blue-green algae, none are available for a fast turnaround at this time. Instead, the Minnesota Department of Natural Resources has a “do it yourself” instruction set for how to test for the algae. That is what Miller did with the sample. He said that while the test came back negative, it was likely because they didn’t have a good sample of the algae, and he thinks it was a false negative.

“We received photos, and from the looks of it, it was probably blue-green algae just before the Fourth [of July],” Miller said. He said that because of the high heat in June, the water temperature was primed for an early season of blue-green algae, and toward the end of June, it rained. “My guess is that a little bit of rain pulled some nutrients on land into the lake and that, mixed with the warm ambient temperatures of the water, created some algae blooms.”

Blue-green algae

Blue-green algae is actually not an algae at all, but a bacteria called cyanobacteria, which are common in Minnesota, especially when the waters get warm and are filled with nutrients. When the water is warm and has little circulation, this type of bacteria can produce a “bloom,” which looks like pea soup or spilled green paint, Miller said.

That bacteria can make humans and animals sick if they ingest or get the water in their mouths, or inhale airborne water droplets which include the bacteria. According to the Minnesota Pollution Control Agency, symptoms may include vomiting, diarrhea, rash, eye irritations, a sore throat, and a headache, and can generally begin hours to two days after exposure. 

Miller noted that not all blooms are toxic, but if you suspect blue-green algae is near, he recommends not getting in the water. He said to watch out for that “green paint” or “pea soup” look, and said it might be accompanied by a bad odor.

“We always just tell people to err on the side of caution,” Miller said. 

How to help

Miller said one of the causes of blue-green algal blooms are still waters that are warm, which is much of Forest Lake, given how shallow the water is around much of the perimeter of the lake. The algae is a natural part of the lake, but the best way for area residents to enjoy the lake is by helping reduce the frequency and intensity of the blooms. He said one of the best ways to reduce the blooms is for area residents — even those that don’t live on the lake — to avoid the use of nutrient-dense fertilizers. For residents who live near or on the lake, it’s planting native plants as a buffer from the shoreline, which he said, “will not only protect your shoreline, but the lake from the flow of water nutrients that could increase the chances of a noxious bloom. It stabilizes the ground, but also filters the water.” 

Miller said if anyone suspects blue-green algae is present near them, to visit pca.state.mn.us/water/blue-green-algae-and-harmful-algal-blooms for more information on the bacteria or how to perform an at-home test to determine if it is present.

Hannah Davis is the Area Editor at the Forest Lake Times. You can contact her at hannah.davis@ecm-inc.com or (763)233-0709

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