VERMONT — Jeff Severson has spent much of the past 50 summers at his family’s Lake Champlain camp in West Addison. But it wasn’t until two weeks ago that the born-and-raised Vermonter had ever seen blooms of the potentially toxic cyanobacteria, or blue-green algae, engulf his favorite swim and fishing spot.
While Severson and his son were fishing on June 29, his wife Lisa Windhausen, who teaches middle school science in Jericho, watched from above as Oven Bay turned from a pool of glistening glass to chunky green sludge within hours.
“We have never witnessed anything like what we witnessed on Friday,” she said. “It was crystal clear Friday morning ... and then within six hours it was thick pea soup. Every hour, it just kept getting thicker and thicker and thicker.”
The above photo was taken by Lisa Windhausen on June 29, when blooms of cyanobacteria took over Addison's Oven Bay.
Oven Bay is not an isolated incident. After a banner year in 2011 for runoff of phosphorus, the photosynthetic bacteria’s favorite food, major parks along Lake Champlain have had to close their waters this past month.
Last week, Ferrisburgh’s Kingsland Bay State Park closed its beach due to heavy blooms, and South Burlington’s Red Rocks Beach did the same. Ryan L’Heureux, assistant ranger at Kingsland Bay, wasn’t able to find any records of the bay closing in the past for this reason, and in his four years working at the park, he had never seen the blue-green blooms take over its waters.
By the morning of July 4, the thick layer of green scum had dissipated at Kingsland Bay. But although its waters looked safe for swimming, State Toxicologist Sarah Vose of the Department of Health is warning eager lake-goers not to jump in until toxin tests have come back negative.
“The toxins are often released when the blue-green algae die off,” she said. “When the cells burst you might not see that scum anymore, but you might still have toxins in water that looks clear.”
When Windhausen witnessed the algae outbreak she quickly began taking pictures. She then grabbed a glass vase and filled it with the lake water and top scum. When the sludge floated to the top, the science teacher realized it was cyanobacteria. She promptly contacted the Department of Health, which Vose said is exactly what citizens in Windhausen’s position should do.
The next day, Windhausen delivered an algae sample to the department. Fortunately, the test came back negative for toxins.
According to Angela Shambaugh, aquatic biologist for the Watershed Management Division at the Agency of Natural Resources and a leading authority on cyanobacteria, the bacteria is fairly unpredictable.
“Not all cyanobacteria produces toxins we care about,” she said. “And even if they can, they’re not necessarily producing them at any particular time. You can’t tell by looking at it whether it’s toxic or not. But what we can say is … when you get a lot of the cells in one place the chance of taking in enough to make you really ill becomes greater. We worry when the cyanobacteria becomes very abundant.”
When state officials test cyanobacteria for toxicity, they’re looking for toxins classified as microcystins and anatoxins, said Vose. Such toxins can cause liver, neural and respiratory complications.
When blue-green algae blooms engulfed the bay next to Lisa Windhausen's family camp, the middle school science teacher filled this glass vase with the green sludge to observe its tendencies. She sent this picture to the Vermont Department of Health.
“If people just encounter it on their skin from swimming in water with an active bloom or scum, then they could experience some skin irritations,” she said. “If they happen to ingest that water by inhaling it or swallowing it, they can experience allergic reactions, like runny noses and sore throats. If they ingest a larger quantity of water that has certain toxins in it caused by blooms, they could experience diarrhea and vomiting. And on the extreme level, you could see liver or kidney damage, and that’s never been reported to us (in Vermont) in a human.”
Although in recent years two dogs died due to cyanobacteria toxins from Lake Champlain, no human has ever died from them. Babies and children, however, are at a higher risk due to their lighter weight, which Vose said is true with all toxins.
Vose also said that none of the Lake Champlain toxicity tests from this year have come back positive. But the summer is still young, and there’s strong reason for state officials to believe that these early blooms are a harbinger of much more to come.
BEHIND THE OUTBREAKS
Cyanobacteria are extremely adaptable and can be found in the far corners of the Earth.
“These organisms have been around for millions of years,” said Shambaugh. “They’re actually one of the most successful photosynthetic organisms in the world. They grow in the hot springs of Yellowstone and in the Antarctic, where they are a strong component of the soil, and they grow in deserts.”
In Vermont, cyanobacteria live in warm, shallow waters that get lots of sun and low winds. And they flourish most where their primary source of food — phosphorus — is most abundant.
“Phosphorus is key to causing the dense cyanobacteria blooms,” said Shambaugh. “That bulk of algae really can’t grow without phosphorus, and it takes a lot of phosphorus to create that amount of biomass.”
Phosphorus is something Lake Champlain got of lot of last year.
The Water Management Division’s phosphorus readings in 2011 were at an astronomical high. The state recorded 206 metric tons of phosphorus that washed into the lake from Otter Creek in 2011. The second-highest phosphorus load result was in 1997 and 1998, when an average of 167 tons per year ran into the lake. There were 382.7 tons that ran into the lake from the Missisquoi River last year. The next-highest average was also in 1997 and 1998 at 210.9 tons. And in 2011, 410.3 tons of phosphorus was recorded running into Lake Champlain from the Winooski River. The second-highest average was 235.3 tons in 2007 and 2008.
Although the two-year average — which the Watershed Management Division uses to track trends — for 2011-2012 phosphorus loads may drop if readings are lower in 2012, last year was nothing short of “extreme,” as Environmental Scientist Eric Smeltzer put it.
“What is clear if you look at 2011 (phosphorus readings) is that they were two to three times higher than the long-term average,” he said. “There’s no question it was an extreme year.”
The bulk of last year’s phosphorus run-off came after Tropical Storm Irene and the spring floods, which contributed the most phosphorus.
Generally, phosphorus loads were believed to come from two main sources: urban wastewater and agricultural runoff. But two 2011 studies of the Missisquoi River watershed, conducted by the Lake Champlain Basin Program and the U.S. Agricultural Research Service, found that 40-50 percent of the phosphorus coming from the river over a 30-year aggregate came from in-stream sources, namely erosion.
“It’s becoming very clear that we’ve got to treat river processes as (a pollution) source of equivalent magnitude to agricultural and urban runoff,” said Smeltzer.
But these phosphorus-rich river processes didn’t occur without a lot of help from people, he said.
“A large magnitude of what’s happening is not natural,” said Smeltzer. “It’s the result of the ways we’ve changed the river channel structure. We’ve straightened a lot of rivers. We’ve armored banks to prevent erosion at one spot, and that tends to transfer the energy elsewhere and cause erosion somewhere else. A really important impact has been the elimination of much of our flood plains to prevent flooding of fields and other areas near the river.
“The way we’ve developed our rivers has left them unstable in ways that add a lot more phosphorus than they normally would.”
A lot more phosphorus, Shambaugh said, means a lot more blue-green algae in Lake Champlain.
Editor’s Note: For more numbers surrounding Lake Champlain’s pollution head to addisonindependent.com and check out the Data Head blog.
Reporter Andrew Stein is at firstname.lastname@example.org.