Gobler Lab Monitors Algae-Hungry Bacteria In Long Island Waters

Christopher Gobler, endowed chair of coastal ecology and conservation in the School of Marine and Atmospheric Sciences, presented the annual State of the Bays Symposium at The Avram at Stony Brook Southampton April 24. Photos by J.D. Allen.

Several Long Island bays and waterways are closed to shellfishing due to bacteria linked to rare flesh-eating infections.

Researchers at Stony Brook Southampton and state regulators are monitoring Southold Bay and Shinnecock Bay due to the presence of saxitoxin, a marine biotoxin produced by algal blooms that causes paralytic shellfish poisoning (PSP).

In recent years, algal blooms have also become fertile grounds for high concentrations of Vibrio vulnificus, an opportunistic and potentially harmful bacterium found in warming, brackish waters, according to Stony Brook University's State of the Bays Symposium April 24 at The Avram Theatre.

"Our surface waters are not something to fear, but something to be a great resource for us all to enjoy responsibly," said Christopher Gobler, endowed chair of coastal ecology and conservation in the School of Marine and Atmospheric Sciences (SoMAS) and director of the NYS Center for Clean Water Technology.

"We are at the forefront of marine research on Long Island," said Wendy Pearson, the University's vice president for strategic initiatives and executive director of Stony Brook Southampton. "Research from the Gobler Lab and his students is critical to ensure water quality and marine conservation."

Warm temperatures and low salinity following heavy rains create favorable conditions for the Vibrio bacteria to thrive, Gobler said. His research team also found that organic matter from dying algae acts as an accelerant for bacterial growth. In controlled experiments, adding lysed algae cells to water produced a 200-fold increase in Vibrio concentration in a single day.

Earlier this month, algae that synthesize saxitoxin led to the state Department of Environmental Conservation closure of Jockey Creek, Town Creek and Goose Creek in Southold and the western portion of Shinnecock Bay. Temporary shellfishing closures are common in the spring, but the intensity of some of the events in regional waterways is cause for concern, Gobler said.

Warming waters due to climate change and high levels of nitrogen pollution from Long Island's aging cesspools and septic systems have intensified algal blooms in recent decades - and in 2025, the most intense paralytic shellfish poisoning bloom occurred in Southold, setting records for New York state. Warming waters have also increased Vibrio concentrations, and an estimated three local people have died from bacterial infections in 2023.

A Gobler Lab researchers poster session preceded the State of the Bays symposium.

Despite the potential severity of infections, especially for immunocompromised individuals, the risk to the average beachgoer remains low. Gobler described the danger as "a one in 10 million outcome for people who are going to the beach," and noted that a person is 50 times more likely to drown than to contract the infection.

Basic precautions - covering open wounds before entering summer waters - go a long way. Gobler said he plans to swim in Shinnecock Bay again this summer barring a major flood event. Gobbler also mentioned that shellfish in New York are extremely well-regulated allowing anyone to know precisely where an oyster or clam was harvested; he mentioned he regularly enjoys Long Island oysters.

"Hundreds of thousands of people enjoy the resources from our public waters," Gobler said. "Let's protect the water bodies that are most sensitive, including the ones here on the South Shore."

Nitrogen pollution from fertilizers and wastewater underlies nearly all of these threats. Groundwater nitrogen levels have climbed 60% since the late 20th century.

Suffolk County has responded with a dedicated wastewater fund to help homeowners replace aging septic systems, and the university is now testing nitrogen-removing biofilters - systems that use sand and wood chips to filter contaminants before they reach the bays - to protect both drinking water and coastal habitats. State and town grants cover the full cost of those commercial upgrades.

"There is no time to waste for us to adopt solutions to deal with nitrogen overloading and climate change and their impacts," Gobler said.