Figure 4. Horizontal Distribution of temperature of oceans around the world

1.5. Salinity

Salinity is used to define the total content of dissolved salts in sea water. 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 sea water. Salinity of 24.7 ppt has been considered as the upper limit to demarcate brackish water(saltier than fresh water, but not as salty as seawater).