: Why is the Ocean Salty? 01.12.12

Question: Why is the Ocean Salty?

Answer: It's really easy to
understand why the ocean
is salty. The oceans have

been around a very long
time, so some of the salts
were added to the water
at a time when gases and
lava were spewing from
increased volcanic activity.

The carbon dioxide
dissolved in water from
the atmosphere forms
weak carbonic acid which
dissolves minerals. When
these minerals dissolve,
they form ions, which
make the water salty.

While water evaporates
from the ocean, the salt
gets left behind. Also,
rivers drain into the
oceans, bringing in
additional ions from rock
that was eroded by
rainwater and streams.

The saltiness of the ocean,
or its salinity, is fairly
stable at about 35 parts
per thousand. To give you
a sense of how much salt
that is, it is estimated that
if you took all the salt out
of the ocean and spread it
over the land, the salt
would form a layer more
than 500 feet (166 m)
deep! You might think the
ocean would become
increasingly salty over
time, but part of the
reason it does not is
because many of the ions
in the ocean are taken in
by the organisms that live
in the ocean. Another
factor may be the
formation of new
minerals.