Susan Lozier is having a busy year. From May to September, her oceanographic team is making five research cruises across the North Atlantic, hauling up dozens of moored instruments that track currents far beneath the surface. The data they retrieve will be the first complete set documenting how North Atlantic waters are shifting — and should help solve the mystery of whether there is a long-term slowdown in ocean circulation. “We have a lot of people very interested in the data,” says Lozier, a physical oceanographer at Duke University.
A similar string of moorings across the middle of the Atlantic, delving as deep as 3.7 miles from the Canary Islands to the Bahamas, has already detected a disturbing drop in this ocean’s massive circulation pattern. Since those moorings were installed in 2004, they have seen the Atlantic current wobble and weaken by as much as 30 percent, turning down the dial on a dramatic heat pump that transports warmth toward northern Europe. Turn that dial down too much and Europe will go into a deep chill.