u2_web_seawater

16 | Seawater MEDCLIC
A.2.1.
EL MEDITERRÁNEO: UN MAR DE MARES
Wait, watch and think...
What do you see when no more salt will dissolve? What appears in the bottom
of the glass?
A certain amount of water can only dissolve a certain amount of salt, the
rest cannot be dissolved. At the point beyond which the solute no longer dissolves
it starts to appear at the bottom of the container, this is called the saturation
point. The solutions, which under these conditions have reached the maximum
concentration of solute, are called saturated solutions. Solutions which
have more solute (salt) than that held by a saturated solution (salt appears at
the bottom) are called oversaturated solutions. Solutions which contain less
solute than can be dissolved are called dilute solutions.
Besides even though the sea receives salts continuously it also rids itself of salt
in many ways before becoming oversaturated, for example in salt marshes and
salt pans.
Mediterranean salt marshes
Coastal salt marshes are wetlands
of incalculable ecological and
cultural value. They are located in low,
flat coastal areas, at sea level or below,
allowing water to enter freely. They appear
to be divided into various connected
reservoirs, which allow water to pass
through floodgates. The structure of the
salt marsh is closed so that the seawater
collects, and, due to the sun and warm
dry winds, the water evaporates and a
salt deposit remains.
Coastal salt marshes have been
exploited historically by the various civilizations
which settling in the Mediterranean.
Since the Phoenicians up until
today the salt marshes have been used to
obtain salt.
In the Balearics we find salt
marshes on the east coast of Mallorca,
in the municipalities of Ses Salines and
Campos; and in Ibiza and Formentera the
coastal lagoons of s’Estany d’es Peix and
Estany Pudent are the most prominent.