Freshwater fish do the opposite by not drinking but excreting copious amounts of urine while losing little of their body salts.
This world map shows how the salinity of the oceans changes slightly from around 32ppt (3.2%) to 40ppt (4.0%).
It features 24 hours of battery life and claims to be a 'mini-disco on the move'.
In order to understand the sea, some of its chemical properties are important.
This page details the chemical composition of sea water, salinity, density, its dissolved gases, carbon dioxide and p H as limiting factor.
Chemical elements in sea water do not exist on their own but are attracted to preferential ions of opposite charge: sulphur will occur mainly as sulphate, sodium as sodium chloride, and so on.