For decades, oceanographers have embraced the idea that Earth’s ocean-overturning currents operate like a giant conveyor belt, continuously transporting deep, cold polar waters toward the equator and warm equatorial surface waters back toward the poles along narrow boundary currents. But Duke’s Susan Lozier, professor of physical oceanography and chair of the division of Earth and ocean sciences at the Nicholas School of the Environment, says it’s time to reconsider that hypothesis.
Lozier’s recent research on boundary currents has pointed to problems with the model. She says that other new scientific evidence that calls the conveyor-belt theory into question combined with technological innovations that allow for direct observation of the oceans have created a need for more studies. Much is still not known about how ocean currents operate at high latitudes, she says, or the effect of eddies and winds on currents. She is planning to lead a new five- to ten-year international research program that will coordinate studies in the North Atlantic to better understand these and other issues.