The distribution of salinity depends upon the amount of evaporation as well as the position of the water bodies. Solar energy has a major role to play in evaporation.
Water bodies located near the equator have a much greater salinity compared to those located near the poles.
Additionally, there is much difference in salinity with depth. The vertical distribution of salinity depends upon whether a water body is landlocked or located in an ocean.
Salinity at the surface increases by the loss of water to ice or evaporation, or decreased by the input of fresh waters, such as from the rivers.
Salinity at depth is very much fixed, because there is no way that water is ‘lost’, or the salt is ‘added There is a marked difference in the salinity between the surface zones and the deep zones of the oceans.
The lower salinity water rests above the higher salinity dense water.
