Physical oceanographer Renato Castelao will work with another researcher to analyze data collected by the torpedo-shaped device, dubbed the Salty Dawg. The Salty Dawg will work in tandem with another submersible owned by North Carolina State University to record oxygen content, organic carbon, water temperature, chlorophyll, salinity, current speed and other measurements at varying depths in the eddies that form as the Gulf Stream flows northward along the Atlantic coast.
One of the great oceanic circulation systems, the warm, fast Gulf Stream flows from the southern tip of Florida north along the U.S. Atlantic coast before crossing the Atlantic Ocean toward Europe, where it is thought to keep the British isles warmer than they would otherwise be.
As the current flows along the relatively shallow waters of the continental shelf miles offshore, eddies form as bits of the Gulf Stream’s flow shear away.
Scientists believe these eddies are important places where nutrients flow into coastal waters, providing food for marine life as colder, nutrient-rich water from deep water mixes with warmer coastal waters, Castelao said.
Castelao will work with N.C. State University’s Ruoying He to analyze the data for information that might help them understand fish distributions, how eddies affect freshwater flows from rivers and other questions.
N.C. State named its submersible Salacia, for the Roman goddess of sea water. The data the two submersibles, called gliders, collect also can give scientists baseline information to see how coastal water characteristics may change as global climate change proceeds.
The Salty Dawg should dive into its first test voyage later this year. After a series of test voyages this fall, the two robots will go to work nearly full time beginning in 2014 and continuing into 2016.
The remotely controlled vehicles are designed to move slowly through the water in a kind of see-saw pattern, sinking as a chamber in its nose fills with sea water, then rising as the glider pushes water out of the chamber.
The machines are designed to move about 20 miles per day this way, staying out as long as a month at a time. They record data continuously, then transmit their measurements at six-hour intervals, Castelao said.
The scientists also will use data collected by satellites, which can detect slight variations in ocean water height, he said. The satellite data will help the researchers decide where to deploy the gliders.“Our main goal,” Castelao said, “is to understand what are the mechanisms that drive the water exchange.”