Ocean conveyor belt theory, which posits that warm surface water flows poleward from the tropics and cools, where it then sinks and flows back to the equator, is incorporating some surprising twists and turns.
The water that fills the oceans doesn't stay in the same place from year to year — huge ocean-wide patterns of circulation slowly cycle that water around the world over the course of thousands of years.
Until now, oceanographers have subscribed to the overarching view that a conveyor belt-like system circulates the ocean waters from the poles to the equator and back again. Scientists have known that this was an oversimplification, and new research is showing where the ocean superhighway takes some unexpected twists and turns.
Scientists have found evidence that the ocean currents move on different pathways than previously thought, said M. Susan Lozier of Duke University in Durham, N.C., and author of a review of ocean circulation research detailed in the June 18 issue of the journal Science.
The basic global conveyor belt theory works like this: Warm surface water flows poleward from the tropics and cools, becoming denser and eventually sinking when it reaches the North Atlantic. The cooled water then returns along the bottom of the ocean to the tropics. It's this circulation that is thought to help redistribute heat around the planet.