The Broecker [1987] and Gordon [1986] descriptions of the thermohaline circulation as a conveyor belt graphically emphasized the interconnections amongst the waters of the world's oceans. The thermohaline circulation in the Atlantic consists of two parts: 1) northward flow of warm water (the upper limb) (some of this water contributes to the production of new deep water in the high latitudes of the North Atlantic); and 2) southward export of newly formed deep water (Figure 1) (the lower limb). The thermohaline circulation differs from the wind-driven circulation in that the former is forced by density differences that are controlled by changes in temperature and salinity. An example of such an induced circulation occurs when the top of a container of water is cooled. The cooled water at the top of the container becomes unstable (cold water is more dense than hot water) and begins to convect, i.e., it sinks and the net result is substantial vertical mixing. This can be compared with what happens in the high latitudes of the North Atlantic. In winter the water column becomes unstable due to a combination of intensive cooling at the ocean surface from passage of winter storms, and northward transport of salty surface water from lower latitudes (both increase the density). As a consequence, the water column convects, and mixes vertically. This newly formed water is carried southward at great depths along the western boundary in the lower limb of the thermohaline circulation.