Mild winters in northern Europe, rainfall in western Africa, hurricanes in North America -the energy transported around the world by the global ocean circulation affects the climate as well as regional weather phenomena. One of the key regions for the ocean circulation is the Labrador Sea between North America and Greenland. There warm, saline waters coming from the south near the sea surface cool down and sink to the depth. There the water masses flow back to the south along the continental margin. Thereby the area is one of the regions of crucial importance for the global ocean circulation.