GEOLOGY

Detailed explanation-1: -As a result the highest salinities are found in the so-called sub-tropical central gyre regions centered at about 20° to 30° North and South, where evaporation is extensive but rainfall is minimal. The highest surface salinities, other than evaporate basins, are found in the Red Sea.

Detailed explanation-2: -The saltiest ocean water is in the Red Sea and in the Persian Gulf region (around 40‰) due to very high evaporation and little fresh water inflow.

Detailed explanation-3: -There are parts of the ocean where hardly any rain falls but warm dry winds cause lots of evaporation. This evaporation removes water – when water vapour rises into the atmosphere, it leaves the salt behind, so the salinity of the seawater increases. This causes the seawater to become denser.

Detailed explanation-4: -Temperature is highest at the surface, and decreases with depth. Salinity is lowest at the surface, and decreases with depth. Both temperature and salinity are high at the surface, and decrease with depth.

Detailed explanation-5: -The density of seawater (salinity greater than 24.7) increases as temperature decreases at all temperatures above the freezing point. The density of seawater is increased by increasing pressure. Density changes about 2% because of the pressure difference between the surface and the deep seafloor.