Oceanography

Salinity and Chlorinity

Salinity

Salt content of water is the total quantity dissolved salts in 1.0Kg. of seawater. Most of the major constituents of sea water are not affected by biological and chemical reactions they are  called "conservative elements". Sea water maintains "Constancy of composition of sea water". Salinity of water varies with evaporation and fresh water precipitation.

Table 1- Range of salt contents in different water bodies

Marine Environments	Ranges of salts
Open ocean	32-38% average 35%
Shallow coastal water	27-30
Estuaries	0-30
Semi enclosed sea
Baltic Sea	<25
Hyper saline bodies (Red sea, Tropical coastal Lagoon)	>40

Chlorinity

Chlorinity is a measure of the chloride content, by mass, of seawater (grams per kilogram of seawater, or per cubic meter). Initially, chlorinity was defined as the weight of chlorine in grams per kilogram of seawater after the bromides and iodides had been replaced by chlorides. To make the definition independent of atomic weights, chlorinity is now defined as 0.3285233 times the weight of silver equivalent to all the halides present.