Topographic map of the Nordic Seas and Subpolar Basins, with schematic circulation of surface currents (solid curves) and deep currents (dashed curves) that form a portion of the Atlantic Meridional Overturning Circulation (MOC). The color of the curves depicts their approximate temperatures. Map inset shows the boundaries of the Nordic Seas and Subpolar Basins used in the analysis of water volume. Credit: Jack Cook, Woods Hole Oceanographic Institution.