The news that barreled through the East End’s waterways last summer was never pleasant. From Shinnecock Bay to Marratooka Pond in Mattituck, it seemed not a week went by that there wasn’t a tale of a new harmful algae bloom wreaking havoc on our waters.
Dr. Chris Gobler, whose laboratory at Stony Brook Southampton conducts a great deal of the research on algae blooms on the East End, said at his “State of the Bays” lecture at the campus Friday night that last year saw “a series of impairments in nearly every water body” on Long Island.
“The state is not great in many places,” he said, adding that most of the problems can be linked back to high nitrogen levels in the water, which have several sources, including, most prominently, human wastewater and agricultural fertilizer.
“The nitrogen cycle is way outside of the safe area for humanity worldwide,” he said, adding that the nitrogen level in groundwater on Long Island increased 40 percent in the upper glacial aquifer between 1987 and 2005, while in the Magothy aquifer, it increased 200 percent.
He also pointed out that studies by Suffolk County and the state Department of Environmental Conservation show the current level of nitrogen loading will destroy all the eelgrass beds left here by 2030.
Graduate students in his program have also been studying the effect of nitrogen on the roots of spartina grass in salt marshes. When there is too much nitrogen in the water, he said, the grasses don’t need to grow strong, deep roots in order to tap nutrients, and the marshes begin “calving,” or breaking apart as their roots weaken.
Dr. Gobler pointed out that work on reducing nitrogen in the western Long Island Sound, begun in 1994, had reduced the nitrogen levels in the sound by 20 percent by 2007, giving him hope that people who care about Long Island’s bays can help turn around the water quality here.
Students in his program have also been studying the synergistic effect of both low oxygen levels, caused by decomposing masses of algae that grew because of nitrogen loading, and acidification of the waters, which is also caused by the decay of the algae.
His students have found that the synergistic effect of both low oxygen levels and acidity is far more toxic to shellfish and algae-eating filter feeding fish than either of those factors alone.
He also pointed out that his students have been finding higher levels of dinophysis, the algae that causes diarrhetic shellfish poisoning, every year in Long Island’s bays.
His students have found that, if nitrogenous compounds are added to samples of dinophysis, they become far more toxic than if they’d been growing under controlled conditions.
“That’s a very clear story with this organism,” he said.
Blue-green algae has also become a problem in ponds on Long Island, including Lake Agawam in Southampton, Mill Pond in Water Mill and Marratooka Pond in Mattituck.
While many blue-green algae blooms aren’t toxic, Marratooka Pond saw an especially toxic strain of blue-green algae last summer.
Dr. Gobler said the CDC has found 368 cases throughout the country where they know dogs have died after drinking water from a pond with toxic blue-green algae in it, including one dog on Long Island in 2012. He said that, while most pond algae blooms are caused by excess phosphorous, the toxic strains are prompted by excess nitrogen.
“More nitrogen makes those cells more toxic,” he said. “And the biggest culprit is wastewater-derived nitrogen.”
The only silver lining in his report was the breach into Moriches Bay at Cupsogue Beach created by Superstorm Sandy, which he said has improved the water quality there. Throughout the island, areas with better tidal flushing had less chance of algae blooms, he said.
“East Hampton has some of the cleanest water, with one exception,” he said. That exception is Three Mile Harbor, which had some elevated levels of rust tide and dinophysis last year. Dr. Gobler said a part of that problem could be the sand bar extending down the west side of the jetty at the entrance to the harbor at Sammy’s Beach.
“There’s plenty of development around Accabonac Harbor and Three Mile Harbor, but only Three Mile Harbor had a problem,” he said.
Dr. Gobler applauded Suffolk County Executive Steve Bellone’s recent commitment to clean water, including a plan to spend about $750 million hooking up western Suffolk County to the Southwest Sewer District. He said, though, that he didn’t think sewers were the right solution for the East End, in part because the houses here are too far apart to make it economically feasible to build sewers, and the zoning here already doesn’t permit any more housing density than we already have, which is in itself a limiting factor on how much nitrogen will end up in the bays.
“I don’t think we’ll ever be to the point where we have large-scale sewering on the East End,” he said.