Despite a cool spring, yet another noxious brown tide has returned to the Great South Bay, as it has every year since superstorm Sandy cut a breach in Fire Island.
There might be a possible cause and effect between the bloom and the breach, according to a Stony Brook University scientist.
The bay-to-ocean channel has won praise from fishermen and environmentalists for cleansing nearby water.
However, the breach might aid algae blooms by reducing water circulation in the west, said Chris Gobler, a professor at Stony Brook’s School of Marine and Atmospheric Sciences.
“The new inlet is a big plus for water quality along the eastern part of the bay and the western Moriches,” said Gobler, who also co-directs Stony Brook University’s Center for Clean Water Technology that aims to improve septic systems.
Yet “Certain areas at the center of the bay are a little more stagnant; they don’t flush out quite as well,” he said.
“And that may be just enough,” he said, for brown tide to have already taken hold a little early — and possibly setting the stage for a repeat of last year’s record-setting densities.
Resembling cocoa, brown tides kill marshes and the eelgrass fish need for food, breeding and their young. And baby clams die off, checkmating efforts to restore them to improve water quality.
The blooms have occurred off and on since the 1980s, but this year’s bloom will be the sixth in a row, a new record, dating from the year after Sandy opened the breach.
Long Island’s brown tide algae “usually grows fastest between 20C and 25C,” said Gobler, which works out to 68 to 77 degrees on the Fahrenheit scale. The sunlight-choking algae can stick around until the water climbs to above 80 degrees Fahrenheit.
Scientists cannot say how long the breach will stay open.
“I think we are clearly heading toward closure, and sooner rather than later,” wrote Charles Flagg, a professor at Stony Brook University’s School of Marine and Atmospheric Sciences, who analyzes the breach, on his website.
“In the past, the nor’easters have been able to clear out the channels but that has not happened during the recent storms. In fact the storms seem to be depositing more sand.”
The main cause of brown tides and other blooms has been known for decades: too much nitrogen, mainly from people and fertilizers.
More than two-thirds of Suffolk’s home rely on septic systems that do little or nothing to remove nitrogen. The county hopes to entice homeownes to upgrade to advanced systems and is working on a limited number of sewer connections.
Nassau’s Bay Park Sewage Treatment Plant, undergoing a multiyear upgrade, has been releasing 52 million gallons of treated sewage daily into Reynolds Channel, which feeds into the Great South Bay to the east.
Some locations elsewhere, like Florida’s Tampa Bay, have made considerable progress in curbing nitrogen.
Since the 1970s, “We’ve seen a precipitous drop” in algae blooms, said Ed Sherwood, executive director, Tampa Bay Estuary Program.
Developers, localities, farmers, industries and the like devised more than 400 solutions, from strict zoning laws to requiring wastewater treatment plants to either use advanced systems or re-use 100 percent of their water for irrigation, for instance, he said.
With the clear water, “We actually exceed all historic levels of sea grass,” he said, citing data going back to the 1950s.