Question

What is the salinity of seawater?

Answer 1

Salinity is the term used to define the total content of dissolved salts in seawater. It is calculated as the amount of salt (in gm) dissolved in 1,000 gm (1 kg) of seawater. It is usually expressed as parts per thousand (%) or ppt. Salinity is an important property of seawater. The salinity of 24.7% has been considered as the upper limit to demarcate ‘brackish water’. Salinity changes with depth, but the way it changes depends upon the location of the sea. Salinity at the surface increases by the loss of water to ice or evaporation, or decreases by the input of freshwater, 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.’