Salinity of ocean water refers to the amount of dissolved solids in the ocean water. Ocean water consists of various kinds of chemical elements and minerals. Of these constituents, sodium chloride is the most important constituent of ocean water. The other constituents or salts like magnesium chloride, magnesium sulphate, calcium sulphate, potassium sulphate, etc.
Are also present in the ocean or sea water. The ocean water is saline by the rivers which bring huge amount of mineral salt dissolved in water. Another reason for salinity is the evaporation of sea water, by which mineral salt in the sea or ocean water increase every year. Salinity is measured in gram per kg of sea water and it is expressed as part per thousands for examples: 35% it means 35gram of salt in 1000 gram of sea water.
Factors affecting the salinity in the ocean water are: Evaporation, Precipitation, and Fresh water mixing with ocean water, ground water and glaciers increase the percentage of salt content in the ocean. The trade winds drive away saline water to less saline areas resulting the variation of salt content.
Latitudes, precipitation, mixing of fresh water etc. influence on the horizontal and vertical distribution of salinity. The regions near Tropic of ** and Capricorn record high salinity due to high temperature, more evaporation, low rainfall and extensive arid and semi-arid areas. While the equatorial region record low sanity because of high temperature and high rainfall. The polar region record least salinity due to very low temperature, evaporation and less rainfall.
