Salinity means the degree of dissolved salt content in water
Explanation:
In a world without global warming, water in seas or in oceans is salty or saline due to the influx or of rivers and various other sources that bring the water and other geomaterial from the landscapes like soils and various other clays and mud deposits. On an average the sea water consists of about 35 (ppt) part per thousand. mostly of Na and CL ions. More saline the water is more will be its density and less saline water is less is its density thus, freshwater has least density, as compared to the red sea and other sea with more than 37 ppt density. Rainfall is also an important factor in reducing the amount of saltiness.