With Every Ferry Trip, New Data on Outer Banks
Monday, June 25, 2007
It's been almost four years since the night Hurricane Isabel washed away North Carolina Highway 12, along with homes, sand dunes, power lines and utility pipes on the Outer Banks. Pounding waves carried away a section of Hatteras Island, leaving behind a 2,000-foot-wide, 15-foot-deep gash in the banks. The open wound was later named Isabel Inlet.
On Sept. 18, 2003, no one who could flee the storm's wrath was around to watch Isabel Inlet's birth.
No one but FerryMon.
FerryMon (short for "ferry monitoring" program) is the name marine scientists gave to a set of oceanographic instruments installed on ferries in Pamlico Sound. FerryMon allows the ferries to take water samples every three minutes, monitoring changes in environmental conditions as they happen.
Although Pamlico Sound's ferries were the first in the United States to carry oceanographic instrumentation as extra passengers, the idea of using ferries as platforms to collect data for marine research originated more than a decade ago in the Baltic Sea. Equipment was placed on ferries running between Helsinki and Travemunde, Germany.
Now efforts are underway to install similar devices on ferries in Long Island Sound, Nantucket Sound, Delaware Bay, San Francisco Bay and Puget Sound. The water samplers are comparable to FerryMon.
The information that scientists gain from ferry-based instruments may be more valuable than Blackbeard's legendary Outer Banks treasure, says Hans Paerl of the University of North Carolina's Institute of Marine Sciences in Morehead City. Paerl and his colleagues developed the instrument package.
"FerryMon is the only source of continuous environmental information about the surface waters of the sound," said Paerl. "Except in fierce winds, ferries run 24-7-365."
On a map, a row of green dots arcs across the sound like a string of pearls. The dots represent the points where the ferries collected data about the sound's roiling waters and transmitted the information to the shore as they fought their way back and forth across the sound during Hurricane Isabel, taking samples for all but 36 hours of the storm's passage.
The resulting data gave scientists information important to decisions about recreational and commercial fishery openings and closings, nutrient pollution in local and regional waters, and significant beach erosion -- such as the cutting of Isabel Inlet.
"FerryMon tracked the opening and closing of the new inlet, for example, an event that spanned two months and affected lives both on and off the island," said Jack Cahoon, director of the North Carolina Department of Transportation's Ferry Division.
Salinity data collected by the Pamlico Sound ferries reflected the sudden opening of the new inlet and its closing two months later. "No other monitoring program was able to take that watch," Paerl said.