Atlantic ocean currents defied the ice age

The state of the North Atlantic Ocean during the last ice age remains debated. A pair of independent geochemical measures shows that a cold, salty and dense deep-ocean current, known as the North Atlantic Deep Water, continued to form and remained relatively warm, instead of being close to freezing as was assumed previously. Geochemical analyses of marine sediments suggest that a major deep-water current remained active when the world was much colder.