The World War II-era theme of “Keep Calm and Carry On” seemed incongruous with the barrage of dire environmental statistics, but the 2025 State of the Bays report on Long Island’s waterways, delivered by Christopher Gobler of Stony Brook University’s School of Marine and Atmospheric Sciences on April 2 at the university’s Southampton campus, did include some encouraging, albeit smaller scale, developments with respect to mitigation.
It is widely accepted that Earth has entered the Anthropocene, an era in which human activity is the dominant influence on climate and the environment, overwhelming the forces of nature. Dr. Gobler’s presentation offered ample evidence of this, while noting that he and a colleague had just been asked to redact the words “climate change” from a grant proposal, a sign of the federal government’s denial of, and hostility to, science.
“But we do need to think about it,” Dr. Gobler said of climate change, “if we’re going to manage coastal ecosystems.”
The signs “are everywhere,” he said. Temperatures in 2024 were the highest ever, by 1.5 degrees centigrade, “and that was despite the fact that the Pacific Ocean had transitioned to a climate phase called La Niña, which is an extreme cooling phase.” June 21, 2024, was the planet’s warmest day since records have been kept, eclipsing the record set on the previous day. The cold winter experienced on the South Fork belied the fact that January was the planet’s warmest ever, he said, “again, despite the fact that we’re in a La Niña phase.”
Since 2002, summer water temperatures around Long Island have warmed at three times the global rate, he said, “and when we have warmer water, in some cases that can lead to more rainfall.” The National Oceanic and Atmospheric Administration has documented that since the mid-20th century, the Northeastern United States has been experiencing a 71-percent increase in the amount of heavy rainfall. “These are like tropical deluges, the rainfall falling all at once.” Such rainfall closes shellfish beds, sometimes for extended periods, and can cause severe damage to infrastructure.
What was a “one in a thousand year” rainfall can no longer be classified as such, he said, citing three of them between 2014 and last year, and modeling predicts that “we’re in the bull’s-eye for these events. . . . We need to think about this, because it’s not just that dams break, but with more rainfall comes more nutrient loading.”
He referred to a colleague’s study that concluded that eutrophication — excessive nutrients in a water body, often related to runoff from the land — “will increase during the 21st century as a result of precipitation changes,” which shows that “this rainfall alone is going to increase nitrogen loading by more than 33 percent.”
This, in turn, promotes harmful algal blooms. There were more than two dozen blooms of cyanobacteria, or toxic blue-green algae, in fresh or brackish water bodies across Long Island last year, along with multiple other marine algal blooms and low-oxygen zones, which often result in fish kills. “The research is in,” Dr. Gobler said. “We’ve done many, many studies where, when there’s more nitrogen, these organisms either grow faster or in some cases they can make more toxins.”
Levels of Dinophysis, a genus of dinoflagellates, spiked in Accabonac Harbor in 2024 and were measured at the highest-ever level in Three Mile Harbor, Dr. Gobler had told the East Hampton Town Trustees in a March 24 presentation. Dinophysis acuminata, which produces okadaic acid, which in turn can cause diarrhetic shellfish poisoning, is present throughout the year, usually at low levels, he said, but it is becoming more abundant.
“If I was giving this talk 10, 15 years ago, I would say we’ve never had a [diarrhetic shellfish poisoning] event in the U.S.,” he said, but since then there have been such incidents on the East, West, and Gulf Coasts.
In local waters, temperature and chlorophyll levels have significantly increased in the 11 years he has been monitoring waterways under trustee jurisdiction, Dr. Gobler told the trustees. Along with Dinophysis, Alexandrium, which makes a saxitoxin that can cause paralytic shellfish poisoning, set a record in East Hampton Town in 2024. “We’ve never seen a density this high” in Three Mile Harbor.
He told the trustees that chlorophyll-a concentrations have also increased since he has been monitoring these waterways, particularly in Three Mile Harbor, Hog Creek, and Accabonac Harbor. “In some places, if chlorophyll levels get too high, oxygen levels get too low. This is a real trend.”
“We’re going to need some big nutrient reductions to limit these blooms,” Dr. Gobler said in the State of the Bays presentation. “In many of these places, you need about a 60-percent or more reduction in nitrogen.”
Along with the hazard to marine life, evidence is mounting of a link between excessive nitrate and cancer, Dr. Gobler said. The World Health Organization has classified nitrate as a probable carcinogen, and studies are “looking at the links between nitrate in drinking water and potential epidemiological links to cancer.” There are also links to potential adverse birth outcomes. “Having low nitrogen in our groundwater and in our drinking water is an optimal outcome, both for human health but also for environmental health.”
Another emerging concern is microplastics, he said, with studies finding “a quarter-million microplastic particles per liter of bottled water. This might have medical effects as well.”
Yet another worrisome manifestation of a warming world is the migration of the bacteria Vibrio vulnificus, which “seems to like warm water, brackish water,” Dr. Gobler said. In 2023, three people died in the tristate area from Vibrio vulnificus infection, one of them in Suffolk County. It infects open wounds, and can accumulate in shellfish. Immunocompromised people are the most vulnerable, and infections lead to necrotizing fasciitis, an infection in which the flesh around the open wound dies.
A warming climate is expected to result in Vibrio vulnificus infections increasing in North America. “With Hurricanes Helene and Milton last year, it triggered a bunch of these infections in the South.”
In keeping with the theme, Dr. Gobler concluded his State of the Bays report on a positive note. Efforts to reduce nitrogen loading by upgrading sewage treatment plants in New York and Connecticut have sharply reduced the size of a “dead zone” of low oxygen in Long Island Sound since the mid-1990s. “This is, I would say, one of the great examples in this country of people saying, ‘Let’s address nitrogen loading’ and effecting a great outcome.”
Despite President Trump’s margin of 11 percent in Suffolk in the 2024 election, and the county’s congressional representatives being re-elected by greater margins, voters also overwhelmingly supported Proposition 2, which is projected to raise, via a sales tax increase, $4 billion to modernize wastewater infrastructure and an additional $2 billion to protect clean drinking water.
Concurrently, “kelp can help,” he said, referring to the emerging field of kelp and other seagrass farming. “Kelp is photosynthetic,” he said, “it takes up carbon dioxide, so it’s combating some of our climate change issues; it takes up nitrogen, producing oxygen that is in short supply, and is active against harmful algal blooms.” There is emerging evidence that kelp itself is a food source for bivalves like oysters and clams.
“I call this the halo effect,” Dr. Gobler said. “We are not solving climate change with seaweeds. We are not going to get rid of harmful algal blooms with seaweeds. But, they can be used in a targeted way on shellfish farms and specific areas to have positive outcomes for shellfish against ocean acidification and against harmful algal blooms.”
