Thursday, July 23, 2015

Mapping shoreline loss

URI researchers map submerged areas of Fire Island National Seashore to monitor changing habitats

NARRAGANSETT, R.I. –A team of University of Rhode Island scientists and students is spending the summer using high-tech equipment to map submerged habitats along the coast of Fire Island National Seashore on Long Island. Their aim is to help the National Park Service better understand its holdings and how they are changing from the effects of major storms, sea level rise, warming waters and other factors.

The project, led by URI Oceanography Professor John King, was launched a year ago in response to damage caused by Hurricane Sandy, which created a breach in Fire Island’s 26-mile long barrier beach. The Park Service sought to gather baseline data about the submerged portions of the national seashore so it can monitor how it changes in the future.

“The Park Service is charged with protecting vast submerged areas, but it has little data about those habitats, making it difficult to manage and conserve them,” said King, a geological oceanographer at the URI Graduate School of Oceanography who studies coastal erosion, sedimentology and coastal marine habitats. “They will use the data we collect to develop management plans and monitoring programs.”


Fire Island National Seashore, which parallels the south coast of Long Island, is one of four coastal units of the National Park Service in the Northeast where similar studies are being conducted. Other universities are mapping coastal areas of the Cape Cod National Seashore in Massachusetts, Gateway National Recreation Area in New Jersey, and Assateague Island National Seashore in Virginia.

According to Monique LaFrance Bartley, a URI marine scientist leading the day-to-day fieldwork at Fire Island, the mapping is conducted in two parts. She and five graduate and undergraduate students use a 28-foot pontoon boat equipped with high-resolution, side-scan sonar to create acoustic maps of the submerged habitats from the shoreline out to about a mile into the Great South Bay. The sonar can detect and differentiate physical features on the seafloor like eelgrass, shellfish beds, boulders and sand. 

“Then we ‘ground-truth’ the maps to verify what the sonar says is true,” Bartley said. “We collect sediment samples, measure the grain size of the sediment, count and identify organisms, and use underwater cameras to image the samples.”

The Park Service has already noticed changes taking place as a result of the breach created by Hurricane Sandy. Water is clearer near the breach, fewer algae blooms occur there, and new eelgrass beds are growing to the east of the breach.

“When the breach first happened, there was a big question about what to do about it,” Bartley said. “A lot of people wanted it to be closed up again. But it’s a changing ecosystem, and the effects seem to be more good than bad.”

The research team spent nine weeks last summer mapping the submerged habitats near Fire Island’s Otis Pike Wilderness Area, where they found primarily sandy environments and eelgrass beds. This year they are spending July and August mapping the area near the Sunken Forest.

“We have no preconceived notions about what we’re going to find this year,” Bartley said. “We don’t know what to expect, and we have nothing to compare it to.”
Funding for the project comes from an $850,000 grant from the National Park Service.

Pictured above
URI Marine Scientist Monique LaFrance Bartley (right) and undergraduate Mitchell Kennedy prepare to deploy the sediment profile camera at Fire Island National Seashore. (Photo courtesy of Monique LaFrance Bartley)