Evaporation
Density currents also result from increased salinity of ocean water due to evaporation. The eastern Mediterranean's dry north-west wind and sunny days lead to an annual excess of evaporation compared to the amount of precipitation. As the water evaporates, salt is left behind, raising the salinity of the remaining water, making the water denser than the Atlantic.
conveyor belt
In a simplified model of ocean circulation, warm water in the oceans upper layers flow toward the poles, making the temperature drop and its salinity increases, making it more dense. It sinks and moves toward the equator, eventually becoming cold, deep water that upwells, completing the circuit. This "conveyor belt" influences global climate by changing warm water into cold water and releasing heat to the atmosphere.