Lagoon Pond is in trouble. Island residents heard a familiar story on Wednesday from representatives of the Massachusetts Estuaries Project about another degraded coastal pond on the Island, but town officials say that they are determined to find a solution.

A joint venture of the Massachusetts Department of Environmental Protection and the University of Massachusetts at Dartmouth, the Massachusetts Estuaries Project aims to establish a scientific baseline for the health of 89 estuary systems in southeastern Massachusetts. So far estuaries project reports on Farm Pond, Sengekontacket Pond and Edgartown Great Pond all have implicated excess nitrogen as the chief villain of Vineyard estuaries, but unlike other contaminations such as oil, PCBs or heavy metals, nitrogen is supposed to be in the ponds.

“The problem with nitrogen is that it’s a part of all living things, it’s required for life,” said Brian Howes, technical director of the estuaries project in the presentation at the Oak Bluffs Public Library on Wednesday. “If there wasn’t any nitrogen there wouldn’t be any life in the bays and we wouldn’t be around either.”

The question then is how much nitrogen is too much, and it’s one that already has been answered in part by ecosystems throughout southeastern Massachusetts, where it has fueled explosive algae growth that has robbed both sensitive scallop and fish-rearing eelgrass beds of light and water columns of oxygen. Such malevolent growth within an ecosystem is known as eutrophication, a term that has become familiar to Islanders who have witnessed their coastal ponds degrade, with some spots nearly anoxic and barren of life after decades of development.

Excess nitrogen comes from a number of sources including runoff from impermeable surfaces such as pavement, lawn fertilizer and even agriculture, but by far the largest single source is from the classic title IV septic system which leaches nitrogen-rich wastewater into the watershed and eventually into the sensitive estuarine ecosystems. When turbid water starves eelgrass beds of light, killing them, and unsightly drift macroalgae comes to take their place, the effects are widespread.

“Without eelgrass there’s no scallops; blue crabs need it for part of their life cycle; certain birds use it for part of their life cycle; certain fish use it for part of their life cycle as well. So it’s a critical habitat within the bay,” said Mr. Howes.

In the past 50 years, as the project’s studies of the other Island ponds have uncovered, drastic die-offs of formerly robust eelgrass beds have occurred all over the Vineyard. On Wednesday Mr. Howes revealed that in Lagoon Pond a large stretch of eelgrass beds along the shore of the upper basin that was observed as recently as 1995 has vanished.

“That is the classic of pattern of nutrient loading, It’s sort of like male pattern baldness,” he said. “You see the pattern and you know what it is.”

While the area of Lagoon Pond closest to the bridge experiences occasional oxygen depletion events later in the summer, in the southernmost “upper” basin oxygen levels are almost always below those necessary to sustain life.

“This doesn’t bode well for the health of the habitat,” said Mr. Howes.

As a result the area is a near desert for marine life.

“Typically we’ll look for those animals that we know are indicative of stressful environments; we’ll look at the last animals that were living in Boston Harbor before the cleanup, we’ll look at animals at ocean outfalls where there’s a lot of organic matter being deposited. You find that the same species live in stressed environments and the same species live in healthy environments. This isn’t like that. There’s nothing living there.”

Mr. Howes’s team found 800 animals in the northernmost area of Lagoon Pond near the bridge and only four in the southernmost basin.

Although it took a half century of development to reach this point, profound changes to the pond could occur within a few years, Mr. Howes said, citing examples from Pleasant Bay in Orleans and the Boston Harbor.

“The reality is these systems recover really quickly in response to a lower load,” he said. “The story about Boston Harbor is when they just stopped sludge dumping in the inner harbor, immediately the next year the harbor exploded with all the bottom animals.”

To achieve an acceptable threshold for nitrogen Oak Bluffs and Tisbury could, under one scenario, sewer large areas of subdivisions on either side of the pond as well as increase the residence time of the water in the artificial man-made pond at the head of the pond. Freshwater ponds are effective at absorbing nitrogen, and MEP researchers cited the Lagoon’s freshwater pond as underperforming its nitrogen uptake potential. The MEP study also found that adding culverts along Beach Road would not significantly improve the pond’s condition.

To Vineyarders impatient with the inertia of the Island ponds’ recovery, Oak Bluffs selectmen said on Wednesday that they were working to find a solution.

“We’ve been working with the Lagoon Pond committee, we’ve been working with wastewater commissioners to look at sewering 450 some odd houses from the hospital to the fire house, from County Road down to the Lagoon,” said selectman Kathy Burton. But, she added, the revelation about the role of the freshwater pond in reducing nitrogen could redirect the town’s efforts.

“The plan was to ask for design monies from the wastewater enterprise fund at the annual town meeting,” she said. “Now I think we’re all questioning whether that’s our best bang for the buck. We certainly don’t want to ask the taxpayers to pay for something that may not necessarily solve the problem in the most efficient way.”

Selectman and wastewater commissioner Gail Barmakian said that the town currently had capacity at the wastewater plant but before any additional sewering the town would have to rethink its zoning.

“Any time you sewer you pave the way for even more intense development,” she said.

Selectman Ron DiOrio was the most optimistic about a start date, stating that work on the new sewers could begin within a year or two. At a recent selectmen’s meeting Mr. DiOrio advocated setting aside future bond money for sewering projects while the town begins to pay down its older capital projects.

“It’s got to be done in cooperation with Tisbury though,” he said. “They know it’s not a matter of one town or the other and it’s going to be a very expensive proposition no matter what the ultimate plan is.”

Mr. Howes says that the researchers at the Massachusetts Estuaries Project are charged with providing a scientific baseline for coastal towns and consulting with them as they embark on possible remedies but it is ultimately up to the towns themselves to implement the sometimes staggeringly expensive restoration of their ponds. While some communities including Chatham and Mashpee have embraced the recommendations of the MEP, others such as Orleans, he said, have all but refused to acknowledge the science behind eutrophication. To Mr. Howes the greatest fear is that people will forget what these habitats once were.

“When I started doing this there were a lot of old folks who really knew the environment and what it used to be like,” he said in a telephone conversation on Thursday. “To me the most horrifying thing was that one day my young daughter who’s 12 was helping me with monitoring in Popponessett Bay in Falmouth, one of the single most nitrogen saturated estuaries on the Cape. We were standing there getting off the boat and she says to me, ‘Dad why are we doing all this work? The bay looks great.’”