Last summer, Sam Look of the Vineyard Conservation Society collected a cup of water from Tisbury Great Pond, and another from Look’s Pond just upstream on the Tiasquam River, and delivered them to Jesse Ausubel of The Rockefeller University in New York city.
Before long, the samples revealed a colorful snapshot of that part of the great pond ecosystem, with 13 fish species, three mammal species (including humans), frogs and Canada geese — all based on remnant DNA in the water. The process cost about $50.
“The results from Tisbury Great Pond and Look’s Pond are just fantastic,” said Mr. Ausubel, director of the Program for the Human Environment at Rockefeller, whose current work focuses on environmental DNA (eDNA), which he believes could revolutionize the way scientists and laypeople alike understand the natural environment.
Overlooking the orchards and fruit bushes on his property in Oak Bluffs, Mr. Ausubel recently described eDNA monitoring, where animals shed bits of DNA like dandruff, or leave it behind in their waste, creating an invisible signature in the environment that scientists can decipher using equipment that fits on a kitchen table.
Mr. Ausubel will talk about his work with eDNA at the Vineyard Conservation Society’s annual meeting at 5 p.m. next Tuesday at the West Tisbury Library. In addition to his work at Rockefeller and as an adjunct scientist at the Woods Hole Oceanographic Institution, Mr. Ausubel has long served as an advisor to the VCS.
DNA sequencing has come a long way since the early 1990s, with its applications expanding from the courtroom to the high seas and beyond. Scientists have known since around 2000 that loose DNA can be found in seawater, but only in the last two or three years has eDNA testing such as the kind done for Tisbury Great Pond become possible. A large library of DNA sequences, maintained by GenBank in Maryland, serves as a reference for eDNA testing.
“Part of what is so exciting about this method is you can imagine a time in the not too distant future, a bit like the days when you used to send rolls of film to a developer,” Mr. Ausubel. DNA sequencers are available for as little as a few hundred dollars online, and Mr. Ausubel expected to see much broader applications in the next five or 10 years.
New York has been something of a hotbed of eDNA research in recent years, with about a half dozen groups, including Rockefeller and Monmouth universities, conducting experiments in New York Harbor, the Hudson and East rivers and elsewhere.
A study by Rockefeller scientists published in PLOS ONE in April showed a correlation between eDNA testing results and conventional monitoring data in the Lower Hudson River, including when it came to species abundance and seasonal changes.
“If this turns out to be a method for improving estimates of abundance, then that would be very, very important,” Mr. Ausubel said, noting that species abundance can be hard to pin down, and is often a point of contention when it comes to regulations for commercial and recreational fishing.
Unlike conventional monitoring, he said, eDNA can be collected with little effort, and for a fraction of the price. Conventional methods for ocean monitoring can range from around $10,000 to $150,000 per day, depending on the location. And because ocean life tends to wax and wane, it’s easy to miss things using nets and sonar. (The decade-long Census of Marine Life that Mr. Ausubel and others led from 2000 to 2010 helped foster the development of eDNA monitoring, largely by contributing to the reference library.)
Under the right conditions, eDNA can last for millennia, but it usually lingers in salt or fresh water for just a day or two. Mr. Ausubel calls this the Goldilocks effect: not too long and not too short. “This is from our point of view just right, because it tells you what’s around,” he said. “It tells you what was there really recently, which is what we want to know.”
The samples from Tisbury Great Pond and Look’s Pond show entirely different animal communities, although human DNA showed up in both samples. Mr. Ausubel said the difference was likely the result of salty versus fresh water, but he also said the results might change throughout the year. He hoped to set up continued monitoring on the Island in the coming months.
On the Vineyard, eDNA could help monitor the success of stream restoration, including along the Tiasquam River, where a dam just downstream from Look’s Pond was removed in 2015, allowing a small pond there to revert to marshland. The state Division of Marine Fisheries later helped install a fish ladder at Look’s Pond to help herring and other diadromous fish make their way upstream.
The method could also enhance monitoring for initiatives such as the Billion Oyster Project, which aims to restore the historic oyster beds that once existed in New York Harbor, and for dredging projects such as the one in Menemsha that are halted by the migration of rare species.
Mr. Ausubel did see one potential downside to the technology. “There is the risk that people will use this to find things and remove them, rather than to find things and conserve them,” he said, knocking on the weathered table where he sat. But he added that people have taken such a heavy toll on the oceans in general that not pursuing new technologies could be even more harmful.
“Something has to be done,” he said.
This summer, Mr. Ausubel will be studying the eDNA of sharks and rays, along with marine mammals, in the New York area. He noted a recent string of sightings of humpback whales in New York Harbor (the first sightings there in a century), including near the George Washington Bridge — possibly the result of improved water quality and more herring and other fish in the area.
One goal is to determine whether endangered blue whales have returned to the area outside the harbor, where they haven’t been documented in decades. Mr. Ausubel said one colleague at the Wildlife Conservation Society may have recently spotted one within sight of the Verrazano Bridge. Such a large animal could still elude conventional monitoring, he said, but its DNA could be easier to find.
October will mark Mr. Ausubel’s 40th year as an environmental scientist. Over that time, he said, what has surprised him the most is simply the fact that eDNA testing appears to work as well as it does.
“Just the idea that that amount of water — the water in your glass on the table — can tell me basically as much as I used to learn by going on a ship at sea with nets and sonars for weeks at a time, it’s astonishing,” he said.
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