What do you think is the cause of the "dip" (i.e., decrease) in salinity around the equator? Could it not be argued that higher temperature causes more evaporation from the ocean surface, which, in turn, results in higher salinity content?
Salinity is the measure of the concentration of dissolved salts in water, ocean water in this case. The measure of salinity directly correlates with surface temperature. While it can be argued that higher temperatures at the equator can cause more evaporation from the ocean surface, which, in turn, results in higher salinity ...
This discussion looks at the dip in the salinity in the ocean closer to the equator.