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An Undersea Waterfall

February 6, 2013

Greenland-Scotland Ridge looms like a great undersea dam, stretching from East Greenland to Iceland and the Faroe Islands and across to Scotland. Warm, salty Gulf Stream waters flow over it into the Nordic Seas, where they lose heat to the atmosphere in winter, become colder and denser, and sink to fill Nordic Seas basisns. The cold deep waters eventually pile up and spill over the Greenland-Scotland Ridge, and then flow southward underneath the lighter warmer waters flowing northward. More than one million gallons per second falls over the ridge—some 1,400 times the volume of water that goes over Niagara Falls.(Illustration by E. Paul Oberlander, Woods Hole Oceanographic Institution)