Natural Mineral Salt content of Seawater

The salinity of seawater is usually 35 parts per thousand  in most marine areas. This salinity measurement is a total of all the salts that are dissolved in the water. Although 35 parts per thousand is not very concentrated (the same as 3.5 parts per hundred, o/o, or percent) the water in the oceans tastes very salty. The interesting thing about this dissolved salt is that it is always made up of the same types of salts and they are always in the same proportion to each other (even if the salinity is different than average). The majority of the salt is the same as table salt (sodium chloride) but there are other salts as well. The table below shows these proportions:


Chemical Ion Contributing
to Seawater Salinity
Concentration
(parts per thousand)
in average seawater
Proportion of Total Salinity
(no matter what the salinity)

Chloride 19.345 55.03 %

Sodium 10.752 30.59 %

Sulfate 2.701 7.68 %

Magnesium 1.295 3.68 %

Calcium 0.416 1.18 %

Potassium 0.390 1.11 %

Bicarbonate 0.145 0.41 %

Bromide 0.066 0.19 %

Borate 0.027 0.08 %

Strontium 0.013 0.04 %

Fluoride 0.001 0.003 %

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