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Sep 14, 2018 12:11 PMPublication: The Southampton Press

Lake Agawam Coated By Worst Algae Bloom Ever Recorded On Long Island

An aerial view of the blue-green algae bloom in Lake Agawam in Southampton Village on Monday.
Sep 19, 2018 10:52 AM

Scientists from Stony Brook University said this week that a toxic algae bloom in Southampton Village’s Lake Agawam was the densest growth ever recorded in a Long Island water body.

The incredibly dense blooms of the blue-green algae microcystis exploded to hundreds of times the Environmental Protection Agency’s thresholds for harmful conditions.

The EPA sets the threshold for a harmful algae bloom as 25 micrograms of algae per 1 liter of water. In August, the levels in Agawam were about 80 micrograms per liter, or mpl. By Labor Day weekend, spurred by high water temperatures and regular rainfall, the levels had leaped to over 10,000 mpl.

This week, the Stony Brook team measured levels of 76,000 mpl in Lake Agawam—more than 3,000 times the EPA threshold.

“When we took samples this week, it was 80 to 90 percent solid, and only 10 percent liquid—it was that dense,” said Dr. Christopher Gobler, a Stony Brook University researcher who leads the team of marine biologists that oversees water testing and algae monitoring throughout Long Island. “This breaks all records of anything we’ve ever observed anywhere on Long Island in the last 15 years of monitoring.”

The algae species microcystis that has taken over Lake Agawam naturally emits a toxin, known as microcystin, that can be harmful or even fatal to humans and animals if ingested. In 2012, a dog died after drinking water in Georgica Pond in East Hampton that contained a blue-green algae bloom at far lower levels than what is found in Lake Agawam currently.

The Stony Brook scientist said that people should keep animals away from the pond’s shoreline and should avoid contact with the water. Even if not ingested, the algae can cause skin irritations.

Algae blooms have been shown to feed on nitrogen and other nutrients carried into water bodies by groundwater flow contaminated with residential septic system waste and rain runoff that carries fertilizers and other chemicals from lawns and roadways.

The blooms are helped along by warm summer temperatures, and this summer’s conditions were optimal. Dr. Gobler noted that while the summer did not feature exceptional high temperatures, the low temps at night were higher than usual, so waters did not cool during overnight hours.

“In a normal summer, at night it gets into the low 60s, but in July and August this year, it rarely got below 70,” Dr. Gobler said. “So we had some of the warmest water temperatures we’ve seen—at or above 80 degrees for most of July and August, which is unusual.”

Dr. Gobler said that the current health threat posed by the dense algae bloom was not the only concern for the lake. When temperatures cool and the algae begins to die off, the decaying process will suck oxygen from the surrounding water and could cause a fish kill, as occurred in 1997, 2002 and 2006.

Lake Agawam has a long history of being impacted by dense blooms, thanks to being the end point for drainage from dozens of streets around the village’s business district, up to a mile away.

Despite years of study and concern about the health of the lake, village officials have been unable to identify and mobilize a solution to the pond’s chronic woes.

Multiple calls seeking a reaction to the density of the bloom from Southampton Village Mayor Michael Irving were not returned.

Sean O’Neill, the Peconic Baykeeper, said the big issue with Lake Agawam is drainage. “You have this giant conveyance from the village, of stormwater coming from the village, and the lake basically acts as a sump,” he said last week. “Think of the whole village draining to a confined space.”

On top of that, Lake Agawam is not tidal, so there is no flushing effect. Mr. O’Neill said when the lake is about to flood, a valve opens to allow the lake to drain into the ocean, but that removes only what is on the surface of the water.

Mr. O’Neill said the village should continue to push for alternative wastewater systems that reduce nitrogen loading into the groundwater, along with buffers to help rain runoff from yards. He also said diverting some of the water that drains from the village to other area ponds instead of just Lake Agawam could help lessen the blow.

In 2016, village officials began discussing a sewer system in the business district, but that has been put on the back burner as the technology evolves.

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Yucky! There are fewer and fewer ponds/lakes that are fiahable/swimable on the South fork and the problem is going to get worse. A municipal wastewater treatment plant is badly needed, just don't put it anywhere I'll ever see it ; /
By Aeshtron (431), Southampton on Sep 14, 18 2:24 PM
Sewer district is desperately needed.
By Mouthampton (439), Southampton on Sep 14, 18 2:38 PM
Too much duck poop.
By V.Tomanoku (790), southampton on Sep 14, 18 3:27 PM
2 members liked this comment
Nuke the hamptons
By greenmonster (20), southampton on Sep 14, 18 5:17 PM
1 member liked this comment
This has been an ongoing problem for over sixty years. I remember a
substantial fish kill in the lake back in the late 50’s.
By Jimion (129), Hampton Bays on Sep 14, 18 5:20 PM
What an honor.
By even flow (1023), East Hampton on Sep 14, 18 5:54 PM
1 member liked this comment
Hmmm raining all the time and duck poop. Sounds like massive runoff from Hill st, but know the idiots will blame septic systems. They need drainage and to drain the lake.
By chief1 (2800), southampton on Sep 14, 18 7:40 PM
1 member liked this comment
Chlorinate it.
By chief1 (2800), southampton on Sep 15, 18 9:36 AM
if you think the pond is polluted because of lawns you are insane. Millions of gallons of street runoff end up in there. The whole village runs down into the lake.
By chief1 (2800), southampton on Sep 16, 18 5:24 PM
I'm sure that there is plenty of other pollution running into the lake from street runoff, however, heavy metals and other pollutants wouldn't cause these types of algal blooms. There is no doubt that the nitrogen leaching from the septic systems and lawn fertilizer runoff are playing a major role in the blue-green algae blooms.
By Enviro Guy (55), Southampton on Sep 19, 18 4:30 PM
The latest culinary trend...vegan algae/pond-scum burger on rye. It’s absolutely killer!
By SDG1776 (114), Southampton on Sep 17, 18 6:08 AM
1 member liked this comment
The member is the Southampton Association who live on the lake and have done this insist they care about the village and are not self centered hypocrites
By SlimeAlive (1181), Southampton on Sep 17, 18 7:34 AM
Google earth Agawam lake and take a good look at the lawns around the lake. Take notice of Charles Stevensons over view of the lake, a natural landscape 200 - 300ft from the lake east to the house and other buildings. A man that thinks a lot of our lake and ecosystem...
Others should take notice...
By knitter (1941), Southampton on Sep 17, 18 8:05 PM
The water is nitrate that was from road runoff of Hill St. The lawns and houses have been there for a century.
By chief1 (2800), southampton on Sep 21, 18 12:30 AM
You don't know what you're talking about. First of all, "the water is nitrate" makes no sense. There is nitrate in the water, yes. However, major sources of nitrogen pollution, including nitrate,
come from many sources, as stated by the EPA here:


"...lawn and garden fertilizers, pet waste, leaking septic tanks, and aerially-deposited nitrogen from ...more
By Enviro Guy (55), Southampton on Sep 21, 18 8:09 AM
2 members liked this comment
This is natures revenge on all the Mr. and Mrs. Thurston Howells who maintain gold course like lawns, which are no doubt being heavily fertilized. Same thing is happening in Georgica, Wainscot, and now Sagg Pond.

They wanted green grass, and now they have lovely poisonous green lakes and ponds to match. The problem with fining anyone property owner in this area is that the penalty is less than the cost of a weekly visit from the lawn company. It's a no win situation. You can't fight with ...more
By Harbor Master (114), Sag Harbor on Sep 24, 18 6:05 PM
"golf" course like lawns
By Harbor Master (114), Sag Harbor on Sep 24, 18 6:06 PM
The obvious Canary in the coal mine?
By clamdigger (85), Quogue on Sep 26, 18 7:51 PM