By Stephen. J. Kotz
There has been much talk about the need to reduce nitrogen in East End Bays and harbors to help restore healthy ecosystems. But the question remains how much nitrogen must be eliminated before harmful algal blooms can be controlled and eelgrass and shellfish stocks begin to rebound. On Thursday, scientists with the Research Foundation of Stony Brook University gave a presentation to the Southampton Town Board on a model they have developed, which should help guide future efforts to control nitrogen levels.
The presentation was given by Dr. Chris Gobler of Stony Brook University and Beth Lamoureaux and Raghav Narayanan of Anchor QEA, an environmental consulting firm, who told the board they had devised a model that simulates the amount of nitrogen seeping into portions of Shinnecock Bay and the time it takes to be flushed out, and the impact it has on algae growth.
While they stopped short of giving the board targets, they indicated that nitrogen levels would have to be halved before they would begin to have noticeable impacts on algal blooms.
“We know there is too much nitrogen,” Dr. Gobler said, adding the goal of the model was to determine “how much should we dial it back to make conditions better?”
“If you are going to make a huge effort you want to know when to say ‘when,’ so to speak,” he said.
While board members said they were pleased the research tool would be added to their arsenal, they expressed concerns about the broader task before them: Determining how to best spend the money the town is amassing in its Community Preservation Fund for water quality projects.
“We have resources,” said Supervisor Jay Schneiderman. “They still are finite, even though the CPF is decent.”
Before the town signs off on replacing hundreds or thousands of septic systems, Mr. Schneiderman said policymakers would want to “cross that threshold” where their efforts resulted in real dividends in terms of water quality.
“We don’t want to spend millions and million and million of dollars and not be able to measure what our level of success is,” said Councilman John Bouvier.
“If you got the nitrogen level to the right place doesn’t mean you are going to have a healthy ecosystem,” added Mr. Schneiderman. “There’s a whole bunch of characteristics that need to be there for it to be healthy.”
Dr. Gobler concurred that a multi-pronged approach, including restoring eelgrass beds and seeding shellfish, is necessary to help restore the environmental balance, but he said the modeling would prove a helpful tool nonetheless.
When Mr. Schneiderman asked if it would be possible to achieve targeted reductions in nitrogen by replacing all the private septic systems near the bays, Dr. Gobler said he believed it could have a major impact because 60 to 70 percent of the nitrogen entering the bays comes from either private septic systems or private wastewater treatment facilities.
Plus, he said, given Suffolk County’s own commitment to addressing water quality issues, there was a good chance portions of Southampton, particularly Quantuk Bay, where brown tide outbreaks have been frequent, would be targeted for funding.
He called Quantuk Bay “the epicenter” of brown tide and said if conditions were right, brown tide from that bay could spread throughout the rest of Shinnecock Bay.
Dr. Gobler told the board brown tide and other algal blooms had decimated the scallop industry, once the largest on the Eastern Seaboard, and also had devastating impacts on eelgrass and hard clams. He pegged the cost at $8 billion in lost revenue.
Mr. Bouvier cautioned that efforts to resuscitate the East End’s bays would not be an overnight success. He cited what scientists call a “legacy” problem: Much of the nitrogen that entered the groundwater years ago has yet to make its way to the bays.
“We’re not flipping a switch here,” he said. “It’s a long slog to get there.”