A suggested mixing process between layers of saline and less saline water in the ocean. Where warm, saline water overlies cooler, less saline water, e.g. where the saline Mediterranean water flows out into the less saline Atlantic, mixing by this process is thought to take place. The vertical water movements between the water masses of different salinity occur in small columns or fingers a few milimetres across. These fingers penetrate only a small distance, producing a mixed layer. The mixing process may then be repeated at the two interfaces that are present, and a number of layers may develop.