Algae Blooms Continue To Wreak Havoc, But Kelp And Shellfish Provide Potential Elixirs, Report Says

A concerted effort by Stony Brook University scientists to boost clam populations in western Shinnecock Bay appears to have stanched chronic blooms of the infamous “brown tide,” and growing long fronds of kelp on the ropes of oyster growing racks can both soak up pollutants from water and reverse the harmful effects of ocean acidification on the growing shellfish, scientists found.

Those hopeful revelations were the bright spots in the work by SBU researchers this year as they labored to track and find solutions to the water quality woes that have beset local bays over the last four decades.

The darker other side of the coin, the leader of the university’s water quality research team, Dr. Christopher Gobler, told an audience at the Stony Brook Southampton campus earlier this month, is that Long Island’s tidal and freshwaters continued to be plagued by a still expanding catalog of detrimental conditions.

New species of invasive and destructive algae blooms are finding footholds in Long Island’s waters, blooms of algae that have established are growing more toxic and lasting longer than in the past, warming water temperatures that create optimal conditions for destructive blooms and other stresses to the marine ecosystems, and the acidification of seas as they absorb more carbon dioxide from a saturated atmosphere.

Two of the most destructive algae blooms, one that flourishes in saltwater and one in freshwater, saw widespread and dense outbreaks in 2021, again putting Suffolk County in the ignominious position at the top of the list of counties with “impaired” water bodies.

Two new species of toxic algae cemented their foothold in local waters, bringing the total number of harmful algae species that are now established here to six.

One of the new species, a stringy red seaweed that was identified in the United States for the first time by Stony Brook scientists in 2017, has spread from Great South Bay to Shinnecock Bay and now into the Peconics.

During his annual “State of the Bays” symposium at the Stony Brook University Southampton campus, Gobler, an SBU School of Marine and Atmospheric Sciences professor, put up two photos of shorelines in Shinnecock Bay and Great South Bay where thick mats of the seaweed, known as Dasysiphonica japonica, or Dasy for short, stained the water a brownish red.

“When you see water like this, you don’t need a scientist to tell you that something is amiss,” Gobler said. “It is not water you would want to swim in.”

Dasy’s spread brings the total number of toxic aquatic blooms that have now anchored themselves in East End waters to eight. Between the 1950s and late 1980s, there were none.

A new species of algae also joined the Dasy seaweed on the list of newly normalized plagues in 2021, one that biologists have dubbed “mahogany tide” in keeping with the dour practice of differentiating blooms for the layperson by nicknaming them according to the varying shades they tint the waters they infest — joining the infamous brown tide, two species of red tide and the now perennial rust tide.

Regardless of color, the blooms have all proven to be destructive additions to the local environment. Brown tide starved shellfish in the 1980s and 1990s by crowding out other algae and killed native aquatic vegetation by blocking out sunlight. The mahogany tide and rust tide are both toxic to marine species and has been blamed for fish kills and a widespread die-off of bay scallops in 2017. Red tides, one of which blooms in the spring, pose a direct health threat to humans if they were to eat shellfish infested with its toxins.

And blue-green algae, which blooms in dozens of freshwater lakes and ponds around the island, can be toxic to humans if ingested and has killed pets that drank water from local ponds. Even the Dasy seaweed emits noxious fumes when it decays that have sent hundreds to hospitals following especially large die-offs in other countries.

Gobler’s annual presentation — which he dedicated this year to the memory of Springs resident Nancy Kelley, who was director of the Long Island chapter of The Nature Conservancy for more than two decades — has long focused on tracing the connections between the emergence of these destructive blooms and the nutrients leaking into groundwater and eventually bays and ponds from the toilets of homes, particularly in Suffolk County, where most homes are not connected to sewers that pump waste to treatment plants.

Suffolk County had the highest number of water bodies afflicted by blue-green algae blooms in the state last year, by half again as many as the next hardest hit county. Nassau County, which is far more densely populated, but is sewered to waste treatment plants, had none.

The scientists from Stony Brook, who track algae blooms around the island for the state Department of Environmental Conservation and on the East End under contracts with local governments and citizens groups like the Friends of Georgica Pond, have shown that high nitrogen levels seen in local waters can boost the toxicity of the algae blooms.

A study of the specific source of nitrogen being absorbed by the Dasy seaweed by one of the scientists from the Gobler Laboratory, Craig Young, showed that it draws more than 75 percent of the nitrogen it has used to fuel its spread from the nitrogen in residential wastewater, as opposed to fertilizers or other sources of the pollution, Gobler said.

Adding to the woes of the algae blooms are the warming water temperatures, which have risen more in our small corner of the Atlantic than anywhere else — driven by record warmth in two of the last three summers.

Warming waters have been blamed, in part, for the nearly complete die-off of bay scallops in three consecutive summers. High water temperatures, which are already starting to approach the maximum a scallop is known to be able to survive in, also hold less dissolved oxygen than cooler water, adding to the stresses taxing the scallops.

“We’re warming much faster here on Long Island than the rest of the globe,” Gobler said, “particularly in summer. Our springs aren’t warmer, but our summers are. The warmer it gets, the less oxygen is in the water, and that’s especially true for shellfish, which are on the bottom, where oxygen is the lowest.”

The warmer waters have created a Goldilocks scenario for some of the most destructive algae blooms. The rust tide, in particular, now has two to three months when waters in the local bays are within the temperature window it thrives in. Twenty years ago, that window could be just a matter of days or weeks — a clear waypoint in the search for the cause of blooms.

The solution to reversing the fortunes of the bays in the face of climate change and rising CO2 levels is clear, Gobler said: reducing nitrogen. Suffolk County has adopted one of the nation’s best long-term plans for dialing back nitrogen “loading” into groundwater — which can also have health effects for humans — and bays and ponds by connecting homes to more efficient septic systems that scrub out nitrogen from flushed waste.

But the county’s plan relies on the replacement of hundreds of thousands of individual septic systems and will take decades to unfurl entirely.

In the meantime, scientists are uncovering tactics to help fight the ill-effects of the man-made and natural world around us.

The growing of kelp is emerging as a potential major tool in removing nitrogen from tidal waters. An added benefit, Gobler noted, is that new research this year showed that the kelp seems to have a “halo effect” on the waters around where it grows, reducing toxins in shellfish, destroying harmful algae cells and reducing CO2 levels in the water in its immediate vicinity, reversing the effects of ocean acidification, one of the most dire threats to shellfish species.

There have been other signs of hope. Since the Shinnecock Bay Restoration Project began in 2016, the millions of clams that the project has deposited in the western side of the bay have snuffed out the brown tides that had stained waters there for years, and native eelgrass, which once carpeted the bays and provided important habitat for scallops and other marine species, is starting to grow back in some areas.

Gobler concluded his assessment of the situation facing the bays with one made by Martin Luther King Jr., who called on all men to see that their behavior is inextricably tied to the lives of all those around them: be it contributions to the national consciousness of civil rights or a regional awareness of the ill-effects of one’s inaction on lessening their role in worsening water quality.

“In a real sense, all life is interrelated,” King wrote in a letter penned while he was in a Birmingham, Alabama jail in 1962. “All men are caught in an inescapable network of mutuality, tied in a single garment of destiny. Whatever affects one directly, affects all indirectly … This is the interrelated structure of reality.”