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7 Aug 07
Mumford Cove's eelgrass recovery a scientific marvel
By Judy Benson
Groton -- Usually the phrase “canary in the coal mine” is used to describe a danger sign, often of something going wrong in the environment.
But marine scientist Jamie Vaudrey talks about a metaphoric canary that's singing loud and sweet in one of southeastern Connecticut's scenic coastal inlets on Long Island Sound, signaling not danger but an environmental success story of international significance.
This harbinger of ecosystem health — the waist-high, sinuous green blades called eelgrass — grows in abundance at the bottom of Mumford Cove, forming a perpetually swaying underwater meadow where young scallops, crabs, winter flounder, and other juvenile fish and shellfish like to live and grow, and older fish like to feed.
Such was not the case 20 years ago, and the story of how the eelgrass that had historically flourished in the cove fell into a 40-year decline, then regenerated from a few surviving shoots to its current lushness is one Vaudrey loves to tell.
It's also one without parallel in the Northeast, and very rare worldwide.
“When I present this information to the scientific community, people get very excited about it,” said Vaudrey, who's been studying the recovery of eelgrass beds in the cove for the last seven years from her base in the Marine Sciences Department at the University of Connecticut's Avery Point campus, just a few miles from the cove.
“This is definitely a big issue.”
Worldwide, many types of seagrass have been in a long decline, and along much of the East and West coasts of the United States, eelgrass is the once-dominant species that many environmental managers would love to see recover.
Mumford Cove is one of only a handful of places worldwide where natural recovery of seagrass has been documented, Vaudrey said.
The process began when the town moved its sewer outfall pipe out of the cove in 1987, and has continued unabated through the present as the cove continues to cleanse itself of the high levels of nitrogen and other nutrients from the effluent.
“Eelgrass is used as the canary in the mine, as an indicator of the kind of system we want to see, and that's why as ecosystem managers we focus on it,” said Vaudrey one morning last week aboard a small power boat she and research assistant Kaitlyn Shaw took out into the cove.
They were collecting some fresh eelgrass samples, pulling them up roots and all with a special long-handled scoop and a six-pronged hook.
That same day Vaudrey, who holds a doctorate in oceanography from UConn, submitted a research paper on the eelgrass recovery in Mumford Cove to “Estuaries and Coasts,” a leading academic journal in her field. She co-wrote the paper with James Kremer, who lives near the cove and is a marine sciences professor at Avery Point, and Brett Branco, who did earlier research on the cove while he was a student at Avery Point and who now teaches at the University of Western Australia.
In the conclusion, the authors say: “Mumford Cove has undergone a distinct transformation. ... Not only is there a need to highlight the success stories, but also a need to understand why mitigation efforts at a particular site were successful in order to increase the likelihood of future success.”
Town Councilor Paulann Sheets was a relatively new resident of the Mumford Cove neighborhood in 1982, when the town was still putting more than 3 million gallons a day of effluent into the cove.
She led an effort of homeowners to bring a lawsuit that ultimately forced the town to move the pipe, which now empties into the Thames River near Electric Boat.
“In 1982,” Sheets said, “you did not swim in the cove. That body of water had turned into spinach soup, and there was an atrocious stench in August.”
But once the pipe was moved in 1987, the water started becoming cleaner. The eelgrass leaves that now wash onshore provide fertilizer for gardens, Sheets said. She and many of her neighbors once again enjoy swimming there, and Mumford Cove became a very desirable address.
“It transformed summer life here,” she said. “There was an explosion of development here.”
The fact that Mumford Cove now supports vigorous eelgrass beds isn't as significant to most residents as the fact that they can now enjoy clean, swimmable water, said Howard Root, president of the Mumford Cove Homeowner's Association.
But since the two go hand-in-hand, managers who figure out how to bring back eelgrass are achieving something that is both good for wildlife and humans, Vaudrey said.
Eelgrass not only provides critical habitat for many marine animals, it also helps stabilize the sediment where it grows, keeping the water clearer, said Paul Stacey, division director at the state Department of Environmental Protection's Water Bureau.
Stacey has been working with Vaudrey on another eelgrass research project. Historically, Stacey said, eelgrass flourished in the eastern half of Long Island Sound beginning at Clinton harbor, but the only remaining beds are in the far eastern end starting at the Thames River.
A fungal disease attacked the beds in the 1930s, and they were unable to recover to their former prominence because nitrogen and other nutrients flooded into the Sound from sewage-treatment plant discharges.
Also, increasing development created more polluted runoff that made its way into the Sound.
“For a long time we've been grappling with the issue of what's going on with our eelgrass beds in Long Island Sound,” Stacey said. “Eelgrass beds are a key part of the near-shore ecosystem, but we're continuing to lose them. “
Mumford Cove, he noted, is the only place in the Sound — and in all of New England — where the opposite is true.
Determining how and why the recovery occurred there naturally could provide key information for restoration projects elsewhere.
Clearly, removing the sewage effluent was key, but other details need to be understood, he said. How clean does the water have to be for eelgrass? What range of nitrogen levels can it do well in? What role does water temperature play? What about levels of tidal flushing and salinity? Development and the polluted runoff that comes from it is another factor, Stacey said.
Mumford Cove has an advantage over many other coastal areas, because one side is part of the Bluff Point Coastal Reserve and so remains undeveloped.
“It would be great if the recovery just required nitrogen removal,” he said, because the technology to improve sewer-plant effluent exists.
Curtailing polluted runoff from myriad driveways, roads and lawns is a much more complicated task.
Eelgrass grows best in clean, clear water uncluttered by the thick algae blooms that thrive in nutrient-rich waters and block light from reaching young eelgrass shoots.
Vaudrey's research documents the changeover of Mumford Cove from one smothered in green algae to one dominated by eelgrass beds, with data showing the extent and volume of seagrass and the algae at four different parts of the cove over the last decade.
The lesson of Mumford Cove, she said, is that “if you fix the root of the problem, nature will help you along to get you where you want to be.”
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