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Images: A Newfound Cog in the Ocean Conveyor

The newly confirmed ocean current is called the North Icelandic Jet. It feeds cold, dense water into the Deep Western Boundary Current, helping to drive the lower limb of the Ocean Conveyor, the global ocean circulation system that regulates Earth's climate. Warm water from the tropics eventually diverges south of Iceland, with one branch, the North Icelandic Irminger Current flowing west of the island. The current sheds eddies that dissipate into the Iceland Sea Gyre. The waters lose heat to the cold atmosphere in winter, become colder and denser, and sink. Cold, dense water  leaks out of the gyre, coalescing into the North Icelandic Jet, which pools behind the Greenland-Scotland Ridge. The cold, dense water flows over the ridge and feeds the Deep Western Boundary Current. (Illustration by Jack Cook, Woods Hole Oceanographic Institution)

A global system of currents, often called the Ocean Conveyor, carries warm surface waters from the tropics northward. At high latitudes, the waters cool, releasing heat to the atmosphere and moderating wintertime climate in the North Atlantic region. The colder (and denser) waters sink and flow southward in the deep ocean to keep the conveyor moving. (Illustration by Jack Cook, Woods Hole Oceanographic Institution)

The Greenland-Scotland Ridge is a tall undersea ridge that rises within 500 meters of the sea surface and extends from East Greenland to Iceland and across to Scotland. The ridge acts like a dam separating deeper ocean basins on either side. In some areas dense, cold water eventually flows over the dam in an undersea waterfall. (Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)