Oceanography

Salinity of Sea water

It is well known that sea water is salty. The reason for the oceans to be salty or saline is that all salts and other mineral elements have been washed away from the land to sea by rain over billions of years. All the rivers on the earth contribute to the oceans large quantities of dissolved solids every year. The total amount of salts in the oceans is estimated to be about 5 x 10¹⁹ kg.

Table 2. Different salts in seawater

Constituent	g/kg of sea water	Percentage of dissolved material
Chloride	19.353	55.0
Sodium	10.760	30.6
Sulphate	2.712	7.7
Magnesium	1.294	3.7
Calcium	0.413	1.6
Potassium	0.387	1.1
Bicarbonate	0.142	0.4
Bromide	0.067	0.189
Strontium	0.013	0.038
Boron	0.026	0.075
Fluoride	0.001	0.003