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 designed a study 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 added 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 created new, detailed maps of the lake beds (bathymetry). Combined with this information collected every two weeks (temperature and oxygen levels at depth), Fowler also measured phycocyanin (an indicator of cyanobacteria) to identify potential early warning signs of algal blooms in Acadia lakes.

Fowler assisted the National Park Service and Friends of Acadia with Jordan Pond sampling as an aquatic scientist with Friends of Acadia beginning in 2016.

Read more:

Final Report: HABs on the Horizon (2024)

Tracking the Health of Acadia’s Lakes,” Maine Boats, Homes & Harbors (2022)