This graphic released by the National Geographic Society Tuesday Jan. 14, 1997 is part of oceanographic study by the U.S. and Russia on the Arctic Ocean. This cross-section Arctic Ocean map, combining U.S. and Russian data, represents a transect of Arctic waters, red line, showing an area in Greenland, left, where warmer surface water is pulled in and cooled, forming a mass of deep ocean water. By releasing the information, both nations hope to help scientists around the world who are investigating environmental questions such as global warming.

(AP Photo/National Geographic Society)