FRANKLIN, Maine — Earlier this summer, Georges Pond looked more like a vast, 350-acre bowl of pea soup than a freshwater lake. But it wasn’t anything you would want to eat. The pronounced discoloration was a severe algae bloom in the lake, which is ringed by property owned by people who come each summer to enjoy the view and swim in the lake’s cool waters.
Such blooms in Georges Pond — and in dozens of other lakes throughout Maine — have alarmed abutting property owners who have reduced use of the pond. And the blooms appear to be getting worse, but property owners aren’t sure why.
“It never looked like this before this year,” John Eliasberg, a seasonal resident from San Diego who heads the board of Georges Pond Association, said last week, referring to photos of the bloom in June that made the lake look like spinach puree.
“This year, it covered the whole lake,” said Lisa Branch, who serves on the association’s board. Driving her jet ski on the lake during the bloom “was like going through oil” and smelled bad, she said.
Last week, the pond’s water was clear with a slight greenish tint, an improvement over the conditions three months ago but slightly greener than it had been the week before.
The timing of algae blooms in the pond have proven to be unpredictable. In 2017, a lesser bloom occurred in late summer and early fall and, in other years, winter ice on the pond has had a green tint on the bottom after trapping late-season algae in the pond.
Eliasberg said water tests show that spikes in algae in the pond have been getting more frequent. Phosphorus levels in the pond, which are a significant factor in blooms, reached 15 parts per billion in 1982 but for many years after that stayed relatively low. In 2012, however, the pond had a phosphorus readings of more than 30 ppb and since then has often exceeded 20 ppb.
But it takes more than just high phosphorus levels to produce a bloom. Temperature, sunlight, turbidity, oxygen levels and water flow are among other factors, though precisely how these things affect each other to produce a bloom is unclear. And the combination of these factors usually varies from one lake to another.
Scott Williams, program director for Lake Stewards of Maine, said Thursday that different lakes can react differently under similar conditions. Some lakes may be fairly clear in droughts because there is little runoff to wash phosphorus into them, whereas other lakes that have phosphorus naturally released from their bottom sediments might be clearer in persistent rainy conditions, because the phosphorus gets flushed out downstream.
But in each scenario, he said, limiting or reducing phosphorus levels in the lake is key to mitigating algae blooms, and in both cases whatever phosphorus that washes into the lake from the surrounding watershed will only aggravate the problem. For that reason, he said, heavier rainfall events caused by climate change are likely to make algae blooms in Maine more prevalent overall.
“It’s a complicated puzzle,” Williams said. “With more extreme weather events due to climate change, we’re problem going to see more extreme responses [such as algae blooms] in Maine lakes.”
Not only do algae blooms interfere with the lake use, but they can also have impacts on the environment. Some algae can produce toxins that could affect people or animals in an affected lake, Williams said, and reduced oxygen levels caused by algae blooms could prove fatal for fish or other aquatic creatures.
“Our advice is to exercise caution” around algae blooms, he said.
On Georges Pond, many of the lake’s 160 or so shorefront property owners have been exploring ways to lessen the lake’s phosphorus load. Properly maintaining and regularly pumping out septic systems is encouraged, as is limiting road and driveway development. Chemicals such as fertilizers should be properly stored and used sparingly or not at all, and vegetative buffer zones along the pond’s edge should be preserved.
“These things are fairly simple to do,” said Ginger Eliasberg, another association board member, and she said they are known to help universally protect lake water quality.
But the association is weighing other possible measures, too. It has consulted with the town, with environmental consultants and with the state Department of Environmental Protection, and is raising money to help with planning and testing. Options for more intensive and costly treatments include aerating the pond, emitting underwater ultrasound signals, dredging and targeted applications of aluminum, which binds to the phosphorus and prevents it from feeding algae blooms.
That last option isn’t cheap, John Eliasberg said. This summer, an aluminum treatment of East Pond in the Belgrade Lakes region cost about $1 million but is expected to deter algae blooms for more than a dozen years.
“It’s a big deal for everyone” on Georges Pond, John Eliasberg said of protecting the lake’s water quality. Continued blooms will “make Georges Pond less desirable. It’s going to affect all of us economically.”
This story appears through a media sharing agreement with Bangor Daily News.