Toxic algae has bloomed in more Cape Cod ponds than usual at this time of year, triggering advisories in Barnstable, Brewster and Orleans.
Algae has been spotted in Bearse and Hamblin Ponds in Barnstable; Schoolhouse, Blueberry, and Seymore Ponds in Brewster; and Bakers Pond and Pilgrim Lake in Orleans. The Association to Preserve Cape Cod said it will continue to update its cyanobacteria map as conditions improve or deteriorate.
The unusually high number of early-season blooms was likely caused by recent heavy rains and a burst of warm weather, said Sophia Feuerhake, the Freshwater Science Coordinator at the Association to Preserve Cape Cod.
“A lot of the ponds froze over this winter, so we weren’t necessarily expecting to start the season with as many blooms as we have been seeing,” she said. But the late-May nor’easter that soaked the region fed nutrient-laden stormwater runoff into the ponds, she said, ”and that can fuel cyanobacteria blooms because they need nutrients to replicate and grow.”
Blue-green algae, or cyanobacteria, bloom in freshwater and can produce toxins that are harmful to humans and pets. Swimming in affected water can lead to stomach cramps and nausea, hay fever-like symptoms, or in extreme cases liver failure and death. Touching the water can also cause skin rashes.
The blooms are triggered by warm water and sunlight, and are expected to increase as the region warms with climate change.
The blooms often look like green scum on the water’s surface, but can also look like green paint, bright green strands or pea soup.
People should be cautious when walking dogs near affected ponds. When dogs swim, they often drink a lot of water, and also get algae in their fur and then lick it off.
There’s no statewide system to track blue-green algal blooms. The state Department of Public Health posts advisories when it receives them, but the list is not always comprehensive.
The Association to Preserve Cape Cod partners with towns and volunteers to monitor about 140 of the Cape’s nearly 900 freshwater ponds over the summer months. The group produces advisories and a map of blooms, and also run a cyanobacteria alert system.
On Cape Cod, septic tanks are a major source of nutrient pollution in bays and ponds. Towns are working to manage this pollution through sewers, advanced septic systems and other initiatives.
This article was originally published on WBUR.org. It was shared as part of the New England News Collaborative.
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