Protecting lakes in Acadia National Park from the threat of harmful algal blooms

Acadia’s lakes are among the clearest and cleanest in Maine. They support fish and other wildlife, and are destinations for fishing, boating, swimming, and scenic viewing and reflection. Some, such as Eagle Lake, Long Pond, and Lower Hadlock Pond, provide drinking water to island communities—in fact, protecting the drinking water supplied by Eagle Lake was one of the factors that motivated protection of park lands in the early twentieth century.

But trouble may be on the horizon for these unique features of the park. Across Maine, warming temperatures and continued pressures from human activity are stimulating harmful algae blooms in lakes previously thought to be at low risk. Could Acadia’s lakes be next?

Fowler’s study is designed to develop an early warning system for detecting blooms of cyanobacteria, a kind of algae that thrive in warm, nutrient-rich waters and can be toxic to people and animals.

Although all of Acadia’s lakes are high-quality, they vary in nutrient levels and level of protection from pollution (for example, swimming is prohibited in drinking water lakes), and some could be more vulnerable to blooms than others. Only through close monitoring can park managers gain a sense of which lakes may be on the brink.

The National Park Service has been sampling water quality in Acadia since 1981.

Fowler will add to this data collection with oxygen and temperature sensors at various depths in Jordan Pond (low nutrient levels and protected within the park), Witch Hole Pond (high nutrient levels but protected), and Seal Cove Pond (moderate nutrient levels and partially protected). She will create new, detailed maps of the lake beds (bathymetry). Combined with this information collected every two weeks (temperature and oxygen levels at depth), Fowler will also measure phycocyanin (an indicator of cyanobacteria) to identify potential early warning signs of algal blooms in Acadia lakes.

According to Acadia National Park biologist Bill Gawley, long-term monitoring has demonstrated that Acadia’s lakes are constantly changing. “This targeted study will help us understand which sites may develop conditions conducive to harmful algae blooms, and when these blooms are most likely to occur. With this knowledge we can proactively manage these lakes, communicate potential risk in a timely manner, and effectively protect visitor safety and ecological integrity,” said Gawley.

Fowler has been assisting the National Park Service with Jordan Pond sampling as an aquatic scientist with Friends of Acadia since 2016. Each spring, they install a sensor-equipped buoy in Jordan Pond. Follow the Jordan Pond Buoy Project on Twitter (@Jpbuoy) and Instagram (@jpbuoy), or look for Fowler at the Jordan Pond boat launch.