What is the reason for the difference in the salinity of sea water at different latitudes

The temperature and evaporation rates determine the salinity of seawater and its variations at different latitudes.

Explanation:

The seawater is saline. This basically means that it contains salt in it in amounts that are high enough to make it salty. The water in the sea is saline because of the enormous amounts of salt on the rocks that are covered with seawater, so the salt dissolves into the water, mixes with it, and gives its salinity. The salinity is not the same everywhere though and there are great variations.

The seawater tends to have the highest salinity near the in the lower latitudes, thus at the tropical areas, while the salinity is the smallest at the high latitudes, thus around the poles. This is due to the difference in temperature and based on it, rates of evaporation. At the lower latitudes, the temperatures are constantly high so the evaporation rates are constantly high as well. This leads to a higher concentration of salt in the water. In the higher latitudes, the temperature is very low so the evaporation is very low as well. This leads to a smaller concentration of salt in the water.