Seawater

Seawater is water from seas and oceans containing dissolved salts, gases, and other substances. Its composition varies with evaporation, rainfall, freshwater input, biological activity, and circulation.

Salinity: Salinity is the concentration of dissolved salts in water. It quantifies the salt content that distinguishes seawater from freshwater.
Evaporation: Evaporation is the transition of liquid water into water vapor at a surface. It removes water while leaving most dissolved salts behind, raising salinity.
Desalination: Desalination is the removal of dissolved salts from saline water to produce water with lower salinity. It makes seawater a source of freshwater where supplies are limited.
Dead Sea: The Dead Sea is a highly saline lake bordered by Jordan, Israel, and the West Bank. Its extreme salinity contrasts with ordinary ocean water and illustrates strong evaporation.
Sodium chloride: Sodium chloride is an ionic compound made of sodium and chloride ions. These ions account for most of the dissolved salts in seawater.
Ocean circulation: Ocean circulation is the movement of seawater through currents, tides, and mixing. It transports heat, dissolved substances, and water among ocean regions.
Reverse osmosis: Reverse osmosis uses pressure and a semipermeable membrane to separate water from dissolved substances. It is a widely used method for desalinating seawater.
Baltic Sea: The Baltic Sea is a brackish inland sea in northern Europe connected to the North Sea. Limited exchange and substantial freshwater input make its salinity unusually low.
Major ions in seawater: Major ions in seawater are the dissolved charged elements and compounds present at the highest concentrations. Their proportions give seawater a broadly consistent chemical signature.
Thermohaline circulation: Thermohaline circulation is large-scale ocean circulation driven by seawater density differences associated with temperature and salinity. It links seawater’s temperature and salt content to deep-ocean movement.

Linked from 12 pages