Dead Sea
The Dead Sea (Hebrew ים המלח, Arabic البحر الميت) is an endorheic lake of saline water (area: ca. 1050 km² or 401 sq mi), fed by the Jordan River, surrounded by Jordan, Israel and the West Bank. The Dead Sea is the saltiest and deepest hypersaline lake in the world. The surface of the Dead Sea is the lowest point on the Earth's surface at an elevation of 417 m below sea level (2003 figure).
Since the Dead Sea is lower than its surroundings, the only outflow of water is by evaporation. The water level thus depends on whether the water flowing in balances the evaporative loss.
The Dead Sea is seriously threatened by diversion of water from the Jordan River and smaller tributaries to supply Israel and Jordan, and by an Israeli potash mine that increases evaporation. The water level has been dropping by as much as one meter per year, and the total surface area is now almost 1/3 less than it was 50 years ago. Plans to save the Dead Sea include the possibility of pumping sea water from the Red Sea, but there are many serious difficulties and no agreement has been reached.
The sea is called "dead" because its high salinity means no fish or macroscopic aquatic organisms can live in it, although bacteria and microbial fungi are present. The salinity of the Dead Sea varies according to depth with the surface water being approximately 15% saline (5 times the average ocean salinity) and water near the bottom being saturated, such that salt precipitates out of solution onto the sea floor. The mineral content of the Dead Sea is significantly different from that of ocean water, consisting of approximately 53% magnesium chloride, 37% potassium chloride and 8% sodium chloride (table salt) with the remainder comprised of various trace elements.
The Dead Sea area has become a major center for health research and treatment for several reasons. The mineral content of the waters, the very low content of pollens and other allergens in the atmosphere, the reduced ultraviolet component of solar radiation, and the higher atmospheric pressure at this great depth each have specific health effects. For example persons suffering reduced respiratory function from diseases such as cystic fibrosis, seem to benefit from the increased atmospheric pressure.
See also: brine, Dead Sea scrolls
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