New Algal Bloom in Ft. Pond

Concerned Citizens of Montauk on Friday confirmed a new bloom of cyanobacteria, or blue-green algae, in the northern part of Montauk’s Fort Pond, and has urged people to avoid contact with the water and to keep their pets away from it “due to potential health concerns.”

The latest bloom was detected in sampling the organization did on Sept. 12. This follows confirmation the previous week of a harmful algal bloom detected in the southern part of the pond. At that time — on Sept. 5 — the northern part of the pond showed an elevated risk of a bloom.

“Blue-green algal blooms produce toxins that can cause health risks to people and animals,” C.C.O.M. wrote in a release on Friday.

Cyanobacteria are naturally present in low numbers in streams and lakes, but the microcystin toxins it produces in higher concentrations can cause nausea, vomiting, or diarrhea; skin, eye, or throat irritation, and allergic reactions or breathing difficulties. Those who have come in contact with the water in affected ponds have been advised to rinse with clean water and seek medical attention if they experience any of those symptoms.

C.C.O.M. is monitoring the pond in partnership with Christopher Gobler of Stony Brook University’s School of Marine and Atmospheric Sciences.

While concentrations of the microcystin toxin at the northern and southern testing sites in Fort Pond are below both the drinking water and recreational use guidelines, “caution should still be taken around the pond,” C.C.O.M. said on Friday.

In its release, the organization also noted that the Fort Pond blooms would not be listed on the New York State Department of Environmental Conservation’s harmful algal bloom notifications web page because the D.E.C. “uses a slightly higher threshold for bloom status . . . than that used by the Gobler lab,” which is based at Stony Brook Southampton.