Researchers mapping underwater landscape off Fire Island
A team of researchers from the University of Rhode Island is spending the summer piloting a small pontoon boat equipped with sonar to create a map of the underwater landscape near Sunken Forest on Fire Island.
The study is one of 17 ongoing projects the National Park Service and other agencies funded after superstorm Sandy on or near the Fire Island National Seashore to evaluate barrier islands and back bay areas.
The research -- focusing on undersea mapping, deer migration, water salinity, plankton levels, dune structures, salt marsh elevations and more -- will be used to help the park service decide whether to close a breach near Old Inlet that formed when Sandy hit in October 2012.
"Our main focus was to scientifically document what the response of the Great South Bay has been to . . . the Fire Island wilderness breach," said Charles Roman, a park service senior scientist overseeing the projects, some of which began soon after the storm.
The funding is $5.17 million, and some related research is taking place elsewhere, such as Chesapeake Bay, Maryland, and Cape Cod, Massachusetts.
"It's really to enhance our understanding of how barrier island ecosystems and back bay ecosystems respond to things like this breach," Roman said.
When Sandy hit Long Island, it tore breaches through Fire Island in three places. The cuts at Smith Point County Park and Cupsogue County Park were closed within two months by dredging in sand from offshore. But the third one, near Old Inlet, was in a wilderness area of the seashore where mechanical work is prohibited.
Seashore officials opted to monitor the breach and that presented researchers with a unique opportunity.
"There are very few studies that . . . document how these systems respond," Roman said. "That's due in part because when the breaches open they are often closed rather quickly."
Researchers from the park service, U.S. Geological Survey, Stony Brook University and elsewhere are doing the work, which should be completed by October 2016.
"All of this science is going to be compiled and used while we work on a management plan for the breach," Fire Island National Seashore biologist Jordan Raphael said.
Raphael, who helps coordinate visiting research teams, has been documenting vegetation and shoreline changes near the breach at Old Inlet, which was stable enough to allow shipping traffic from 1776 through 1836, according to "The Story of Old Inlet," written in 1952 by Paul Bigelow and William L. Hanaway.
The eastern edge of the breach is fairly stable while the western portion is eroding.
"It's almost doing the same exact thing the old inlet did a couple hundred years ago," Raphael said. "It looks as though it's following the same path.
"The University of Rhode Island team did underwater mapping near Otis Pike by the breach last year and is now focused on Sunken Forest by Sailors Haven marina.
Motoring at speeds of 2 to 3 miles per hour, the boat moves in straight lines as a side-scan sonar device in the water scans the seafloor out more than 80 feet in each direction.
"We're using sound to create a picture that basically looks like the seafloor," said Monique LaFrance Bartley, a marine research assistant at URI's Graduate School of Oceanography in Narragansett, Rhode Island.
As the boat moves, high- and low-resolution images are transmitted to a computer. Sea grass looks like tiny clumps of cauliflower while anchor marks or sailboat hull marks look like long scratches.
On another round of trips, a clawlike machine will extend from the boat to grab clumps of seafloor. Those samples will be compared to the sonar results in a sort of truth test to verify the interpretations of the scan.
In the end, an underwater map much like the kind used to mark points of interest on land will be created, marking out sea grass beds, shellfish sites and other locations. Knowing that, the park service can manage access or interpretive information for visitors.
"[The park service] . . . really haven't undertaken any serious underwater habitat mapping studies," Bartley said. "It's really more to help them better manage what they have."
Another research project is examining deer migration and vegetation regrowth in overwash spots in Otis Pike. In many spots, Sandy uprooted and scattered dune vegetation. Researchers are looking at how that vegetation returns and how deer feeding on it influence recovery, said H. Brian Underwood, an adjunct associate professor at SUNY College of Environmental Science and Forestry in Syracuse.
"The beach dune grass is coming back pretty quickly," he said. "We know a lot of things about deer on Fire Island but we know very little about the establishment of primary vegetation in overwash areas."