ITHACA, N.Y. — Conditions have been right for Harmful Algal Blooms so far this summer, as blooms have begun popping up again on Cayuga Lake. But, as this has become a regular summer issue, the community has stepped up to closely monitor the blooms and report findings. About 80 volunteers called “HABs Harriers” patrol stretches of Cayuga Lake and send samples of any suspected bloom for local testing.

Three local environmental nonprofit organizations are leading efforts to monitor the blooms — the Community Science Institute, the Cayuga Lake Watershed Network and Discover Cayuga Lake.

More than 30 Harmful Algal Blooms — also called blue-green algae or cyanobacteria — have been reported since July 7 on Cayuga Lake, and a handful have been found to have some amount of toxin. Several blooms have been spotted in the southern stretch of Cayuga Lake, including at Taughannock Falls State Park, the Ithaca Yacht Club, and Bolton Point. Due to the blooms, some local beaches have closed periodically.

The Tompkins County Health Department is urging local residents to beware of blue-green algae, as they can produce toxins that are harmful to people and animals.

Out of caution when a bloom is spotted, the Tompkins County Health Department will close a beach. As Samantha Hillson, director of health promotion at the Tompkins County Health Department, explained, they will close a beach if the water appears to have a bloom — the surface of the water may look green or blue-green, or look like it’s streaked with paint — and then send the sample out for testing. If testing reveals the bloom to have over the allowable amount of toxin for recreation, the beach will stay closed.

As of Tuesday, July 23, Myers Park, the Ithaca Yacht Club, and the Girl Scout Camp, which the health department monitors, are open. And as of Monday, Taughannock Falls State Park is open.

What is a Harmful Algal Bloom? The Cayuga Lake Watershed Network defines it as such:

An algal bloom is a proliferation of cyanobacteria and algal cells in dense concentrations. Cyanobacteria are photosynthetic bacteria found on the surface of water bodies. These cyanobacteria can contain toxins that produce detrimental effects for humans and other animals, including Microcystins, a liver toxin, Anatoxins, a nerve toxin that is potentially fatal to dogs and Lipopolysacharides, an endotoxin that results in skin irritation.

Blooms can present in different ways, according to Nathaniel Launer, outreach coordinator at the Community Science Institute. They can appear blue-green, or white, or brown or bright green. Blooms can look like streaks on the water or dots or clumps. In cases of very dense blooms, it has been described as looking like pea soup. Though it’s unsettling when blooms appear, cyanobacteria is a natural part of the ecosystem, Nathaniel Launer, outreach coordinator at CSI said, and not always harmful.

“It’s present in lakes and ponds naturally. It’s just under certain conditions, that they multiply so rapidly that they form these big, concentrated blooms,” Launer said.

Water samples from Cayuga Lake awaiting testing at the Community Science Institute on July 10. (Kelsey O’Connor/The Ithaca Voice)
Water samples from Cayuga Lake awaiting testing at the Community Science Institute on July 10. (Kelsey O’Connor/The Ithaca Voice)

As HABs Harriers monitor the shores, the small staff at the Community Science Institute, based in Ithaca, tests samples that come in to see if they contain the toxin microcystin. On their map, which they keep updated on a rolling basis, CSI reports results down to the drinking water standard of 0.3 parts per billion. The limit for recreation is 4 ppb.

To view CSI’s Harmful Algal Bloom map, click here.

On the southern end of Cayuga Lake, several blooms have been spotted. However, only a couple — one by the Ithaca Yacht Club and another along the shore of Taughannock Boulevard — have been found to have a toxin concentration over the drinking water limit. None have exceeded the recreation limit yet this year.

Moving ahead, Harmful Algal Blooms will continue to be an issue that communities along Cayuga Lake will have to face, and it’s a serious one because of the public health concern, says Launer.

“(They’re) harmful because they do produce chemicals that are toxic and that presents a health concern both because the lake is used really widely for recreation and swimming … but also because Cayuga Lake is a drinking water supply for many different towns along the lake as well as private residents,” Launer said.

Bolton Point, which draws from Cayuga Lake to supply residents in Dryden, the Town of Ithaca, the villages of Lansing and Cayuga Heights, and some in the City of Ithaca, is closing monitoring cyanobacteria. Though Bolton Point draws water 400 feet from shore, at a depth of about 60 feet, cyanobacteria have been found a greater depths in the Finger Lakes, said Glenn Ratajczak, production manager at Bolton Point. Ratajczak is also HABs Harrier quadrant leader.

Glenn Ratajczak, production manager at Bolton Point, collects a water sample near Bolton Point on Monday, July 15, to check for HABs.

Ratajczak said staff are monitoring blooms in several ways – they check the shoreline visually every day, and if a HAB is present, they use a drone to see the extent of the bloom; staff also monitor reports from the HABs Harriers in real-time; and they have also installed a fluoroprobe to measure cyanobacteria’s chlorophyll continuously and monitor some key water quality parameters that may indicate the presence of a HAB.

“I believe HAB’s will be a problem that persists into the future for drinking water facilities on Cayuga Lake,” Ratajczak by email. “With increased awareness and monitoring we have more data than ever before on this subject, which has probably existed in the lake for a long time, we are just more aware now. With changing weather conditions and warmer weather the stage is set for blooms to continue well into the future.”

With blooms likely to continue to appear in Cayuga Lake, Bolton Point commissioned a study by Arcadis Engineering to learn how they can adjust their current treatment process and operation to handle blooms in raw water. Ratajczak  said they developed a report that provides “several layers of defense in treating for HABs.”

In 2018, Gov. Andrew Cuomo announced a $65 million initiative to “aggressively combat” HABs and is focusing on 12 priority lakes, including Cayuga Lake. According to a report published by the New York State Department of Environmental Conservation, the factors that cause HABs vary from lake to lake. But, the report states that phosphorus pollution from wastewater treatment plants, septic systems and fertilizer is a major contributor. Other factors they believe to cause an “uptick in HABs” include higher temperatures, increased precipitation and invasive species.

Anyone who spots what might be a Harmful Algal Bloom can report it here.

While the map on CSI is regularly updated, the best way to know if a beach is safe for swimming is to call the beach directly.

Local resources on HABs

Tips from the Tompkins County Health Department if you come into contact with suspicious blue-green algae

  • Rinse thoroughly with clean water to remove algae. Rinse dogs that may have gone in the water so they do not lick their coats.
  • Stop using water and seek medical attention immediately if symptoms such as vomiting, nausea, diarrhea, skin, eye or throat irritation, allergic reactions or breathing difficulties occur after drinking or having contact with blooms or untreated surface water.
  • For more information from the Tompkins County Health Department, visit

Kelsey O'Connor

Kelsey O'Connor is the managing editor for the Ithaca Voice. Questions? Story tips? Contact her at and follow her on Twitter @bykelseyoconnor.