In five ponds across the Cape, high concentrations of blue-green algae blooms are raising concerns about dangerous levels of toxins they produce. Blue-green algae blooms, also known as cyanobacteria scums, can make the water of a pond look like pea soup, though usually, the growths are natural and harmless parts of ecosystems.
That is, until they dominate and release dangerous toxins, as they have at times this summer in Walkers Pond and Cliff Pond in Brewster; Mares Pond and Deep Pond in Falmouth; and Long Pond in Marstons Mills, according to the Association to Preserve Cape Cod (APCC).
“The concern is it’s early,” said Andrew Gottlieb, executive director of APCC. “Ponds have not really warmed up that much and yet we’re seeing toxic blooms in a number of different ponds and that gives concerns about … what we might see as the summer deepens and the warmth continues.”