Blue-green algae pops up in the Finger Lakes region

Steve Orr
Democrat and Chronicle
Blue-green algae bloom along the southeastern shore of Conesus Lake on June 29.

With summer heating up, blue-green algae blooms have begun to appear on New York water bodies, including three of the 11 Finger Lakes.

Blooms have reported in recent days on Conesus, Honeoye and Hemlock, three of the western-most Finger Lakes. A swimming beach had been closed at Honeoye Lake in Ontario County but is now reopened.

This is the first year that blooms have been reported on multiple Finger Lakes by June 30, state data show.

Blue-green algae, a naturally occurring form of photosynthetic bacteria, can proliferate wildly, or bloom, under the right conditions. Some forms of the organism release toxins that can be harmful to the health of people, pets and other animals that drink or come in contact with the water.

The weather in recent weeks has been favorable for algal blooms. The conventional wisdom is that blooms can result from heavy rainfalls that wash nutrients into the water, followed by hot, sunny weather that encourage growth.

Blooms at Hemlock Lake are always noteworthy because it is a long-time source of drinking water for the city of Rochester. The undeveloped lake, surrounded by a state forest about 30 miles south of the city, has had a number of small blooms in recent years.

None have threatened the drinking water supply. This bloom, detected by city workers, was along the eastern shore about 1,500 feet from the point where the city draws Hemlock water into the treatment plant.

It had dissipated a few days later, city spokesman Justin Roj said.

New York state has tracked algal blooms for more than a decade, relying on employees, volunteer observers and citizens to make reports. The state Department of Environmental Conservation describes New York's monitoring and reporting program as the most comprehensive in the country.

Thirty-two New York lakes and ponds had reported blooms through June 30, a lower total than in each of the last three years, according to data compiled by the DEC.

People can report suspected blooms to the DEC via an online form.