Salt water of saline water is water that
contains a significant concentration of dissolved
The reason why salt water is salty is because
when rain falls on terrestrial rock (mountains,
etc.) it contains some dissolved carbon dioxide
from the surrounding air. This causes the
rainwater to be slightly acidic due to carbonic
acid (which forms from carbon dioxide and water).
The rain erodes the rock and the acid breaks down
the component parts of the rock and carries it
along in a dissolved state. The ions in the
runoff are carried to the streams, rivers, and
estuaries to the ocean. Many of the
dissolved ions are used by organisms in the ocean
and are removed from the water. Others are not
reactive and are not used up and are left for long
periods of time where their concentrations
increase over time. The two ions that reside in
greatest quantity and are removed most slowly of
the major ions in seawater are chloride (Cl-) and
sodium (Na+). These two make up over 90% of all
dissolved ions in seawater.
River water has higher concentrations of
bicarbonate, potassium, calcium, and sulfates.
These elements however are used or absorbed by
organisms or react with other things in the water
so that they are no longer present in the ocean in
large quantities. On the other hand, river water
contains almost no sodium or chloride ions, but
these do not get removed by organisms or by
chemical reaction, so they just keep on building
up and getting more concentrated.
ocean water contains the following ions in the
indicated concentrations. These make up over
99.3% of everything dissolved in seawater.
values listed are grams per kilogram of seawater
(g/kg) at a salinity of 35 parts per thousand
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