The force exerted on the surface by the column of air above it is called atmospheric pressure or air pressure. It is measured by means of an instrument called barometer.
Salinity is directly positively related to seawater density.On an average, seawater density increases with increasing salinity and vice versa.E.g. Density of pure water is 1.00 g/cm3 and density of water with 35% salinity is 1.028 g/cm3.