How NYS is Combatting Harmful Algal Blooms

Algae are simple plants, usually found in wet environments, that can range in size from microscopic to giant kelp that can be more than 100 feet long. Generally beneficial, algae are found all over the planet, form the basis of many food webs, and produce about 70% of the world’s oxygen. Unfortunately, under certain conditions, algae can grow out of control. 

These overgrowths are known as harmful algal blooms (HABs) and they can have multiple detrimental effects. Drinking water may be contaminated due to algae clogging filters in water treatment plants or more directly by releasing toxins into the water. The cyanobacteria type of algae, also called blue-green algae, can also produce toxins that can kill fish, mammals, and birds. Other types of algae may be non-toxic but can still cause damage by clogging the gills of fish, depriving marine life of oxygen, smothering coral or other marine vegetation, and can make beaches unpleasant due to bad smells or discolored water. 

Algal blooms are caused by excess nutrients entering the water. This can come from agricultural runoff such as nitrogen or phosphorus from fertilizers, or urban runoff such as sewage. Wastewater runoff contains nitrogen, which is a major contributor to the formation of algal blooms. Traditional septic tanks and cesspools can allow wastewater to seep into the ground.

This is an especially severe problem on Long Island. More than 70% of Suffolk County residents use septic tanks.  This is more than the entire state of New Jersey. To help address this problem, Suffolk County recently established a plan to fight nitrogen pollution by upgrading and replacing aging septic systems with modern sewage systems. 

Algae are photosynthetic and thrive in warmer temperatures, so summer a common time for these blooms to occur. As climate change causes our environment to become warmer, these blooms are more likely to occur with increasing frequency and severity.

Many towns in New York State are currently suffering from harmful algal blooms. The season’s first HAB was detected in early August in Owasco Lake, in the Finger Lakes region. Canandaigua closed at least five beaches this summer due to algal overgrowth. Hemlock Lake, the source of Rochester’s drinking water had several small blooms. Babylon Town Hall Pond in Lindenhurst also had a bloom as did Poxabogue Pond in Southampton. 

New York State is working to combat HABs. Last year, the New York State Department of Environmental Conservation (DEC) announced that Governor Cuomo’s Regional Development Economic Council awarded $110 million in competitive grants to improve water quality, prevent harmful algal blooms, and insure drinking water quality across the state.

This led to the creation of an Action Plan to address the blooms in 12 lakes that were designated priority lakes because they are critical sources of drinking water and are vital tourism drivers. In May, the first 3 of these lakes, Owasco, Seneca, and Skaneateles Lakes, were given advanced monitoring technology developed by the U.S. Geological Survey in conjunction with DEC to detect HABs early and determine whether the blooms are harmful or simple algal overgrowths. The technology includes devices that allow the monitoring of light, temperature, nutrient density and fluorometers to measure algae and organic matter. Scientists were seeking to not only determine whether an algal bloom is harmful but to also understand which conditions lead to harmful blooms and which do not. Monitoring will be done by staff at the DEC Lake Classification and Inventory Program, Citizen Statewide Lake Assessment Program volunteers, and partner HAB monitoring programs. 

Each of the 12 priority lakes has an action plan that includes describing existing conditions, both physical and biological; identification of the factors potentially contributing to HABs; and specific suggestions to reduce the frequency and impact of HABs. Details of each lake’s action plan can be found here.

New York State is also focused on educating people about the harmful blooms and created a real-time map to allow the tracking of current blooms. DEC created a mobile-friendly, online form to allow for easy reporting of suspected blooms. If someone is unable to use the preferred form then they may send an e-mail to

NYLCV will continue to advocate for policies that reduce water contamination and combat harmful algal blooms.