Book excerpt: The 'perpetual salt fountain' can occur in an area of the ocean where the water is vertically stable. Warm, saline water overlies cold, relatively fresh water. A tube is placed in the water from just beneath the ocean surface to just beneath the halocline. Water is pumped up the tube to initiate the flow. As the water in the tube is warmed, it becomes less dense than (and thus buoyant with respect to) the surrounding water, and the flow will continue after pumping is stopped. The effect of the vertical conduction of heat by turbulent mixing on the velocity of flow in the 'perpetual salt fountain' is investigated. Temperature and salinity profiles with depth from hydrographic soundings are considered to determine flow velocities in the ocean. The calculations show that vertical heat conduction has a negligible effect on the rate of flow in the presence of horizontal heat conduction, the salinity-depth profile is the primary factor influencing the rate of flow, and the temperature-depth profile has a negligible effect on flow velocity. (Author).