At high latitudes, such as near Antarctica and the Arctic Circle, the ocean’s surface waters are cooled by frigid temperatures and become so dense that they sink a few thousand meters into the ocean’s abyss.Ocean waters are thought to flow along a sort of conveyor belt that transports them between the surface and the deep in a never-ending loop. However, it remains unclear where the deep waters rise to the surface, as they ultimately must. This information would help researchers estimate how long the ocean may store carbon in its deepest regions before returning it to the surface.