   #copyright

Dead Sea

2007 Schools Wikipedia Selection. Related subjects: General Geography

   Dead Sea
   Dead Sea - Dead Sea at Sunset (from Suwayma, Jordan)

                  Dead Sea at Sunset (from Suwayma, Jordan)

   Coordinates 31°20′N 35°30′E
   Lake type endorheic
   hypersaline
   Primary sources Jordan River
   Primary outflows Evaporation
   Catchment area 40,650 km² (25,258 mi²)
   Basin countries Jordan
   Israel
   Max-length 67 km (42 mi)
   Max-width 18 km (11 mi)
   Surface area 810 km² (North Basin)
   Average depth 120 m (394 ft)
   Max-depth 330 m (1,083 ft)
   Water volume 147 km³ (91 mi³)
   Shore length^1 135 km (84 mi)
   Surface elevation -418 m (-1,371 ft)
   ^1 Shore length is an imprecise measure which may not be standardized
   for this article.

   The Dead Sea (Arabic: البحر الميت‎; Hebrew: ים המלח) is both the lowest
   point on the Earth at 418 metres (1,371 ft) below sea level and
   falling, and the deepest hypersaline lake in the world at 330 m (1,083
   ft) deep and 799 m (2,621 ft) below sea level. It is also one of the
   saltiest bodies of water on Earth with a salinity of about 30 %. This
   is about 8.6 times greater than the average ocean salinity. It measures
   67 kilometres (42 mi) long, up to 18 kilometres (11 mi) wide, and is
   located on the border between the West Bank, Israel, and Jordan, and
   lies in the Jordan Rift Valley. The main tributary is the Jordan River.

   The Dead Sea has attracted interest and visitors from around the
   Mediterranean basin for thousands of years. It was a place of refuge
   for King David, it was one of the world's first health resorts for
   Herod the Great, and it has been the supplier of products as diverse as
   balms for Egyptian mummification to potash for fertilizers.

   In Arabic the Dead Sea is called Al Bahr al Mayyit  meaning "the Dead
   Sea", or less commonly Bahr Lūţ meaning "the Sea of Lot". Historically,
   another Arabic name was the "Sea of Zoar", after a nearby town. In
   Hebrew the Dead Sea is called the Yam ha-Melakh  - meaning "sea of
   salt", or Yam ha-Mavet - meaning "sea of death". In past times it was
   the "Eastern Sea" or the "Sea of Arava". To the Greeks, the Dead Sea
   was "Lake Asphaltites" (see below).

Natural history

   Satellite photograph showing the location of the Dead Sea
   Enlarge
   Satellite photograph showing the location of the Dead Sea

   The Dead Sea is located in the Dead Sea Rift, which is part of a long
   fissure in the Earth's surface called the Great Rift Valley. The 6000
   km (3700 mile) long Great Rift Valley extends from the Taurus Mountains
   of Turkey to the Zambezi Valley in southern Africa. The Great Rift
   Valley formed in Miocene times as a result of the Arabian Plate moving
   northward and then eastward away from the African Plate.

   Around three million years ago what is now the valley of the Jordan
   River, Dead Sea, and Wadi Arabah/Nahal Arava was repeatedly inundated
   by waters from the Mediterranean Sea. The waters formed in a narrow,
   crooked bay which was connected to the sea through what is now the
   Jezreel Valley. The floods of the valley came and went depending on
   long scale climatic change. The lake that occupied the Dead Sea Rift,
   named " Lake Sodom", deposited beds of salt, eventually coming to be 3
   km (2 miles) thick.

   According to geological theory, approximately two million years ago the
   land between the Rift Valley and the Mediterranean Sea rose to such an
   extent that the ocean could no longer flood the area. Thus, the long
   bay became a long lake.

   The first such prehistoric lake is named "Lake Gomorrah". Lake Gomorrah
   was a freshwater or brackish lake that extended at least 80 km (50
   miles) south of the current southern end of the Dead Sea and 100 km (60
   miles) north, well above the present Hula Depression. As the climate
   turned more arid, Lake Gomorrah shrank and became saltier. The large,
   saltwater predecessor of the Dead Sea is called "Lake Lisan".
   Mount Sedom, on the southwest side of the lake, is a giant mountain of
   halite.
   Enlarge
   Mount Sedom, on the southwest side of the lake, is a giant mountain of
   halite.

   In prehistoric times great amounts of sediment collected on the floor
   of Lake Gomorrah. The sediment was heavier than the salt deposits and
   squeezed the salt deposits upwards into what are now the Lisan
   Peninsula and Mount Sedom (on the southwest side of the lake).
   "Geologists explain the effect in terms of a bucket of mud into which a
   large flat stone is placed, forcing the mud to creep up the sides of
   the pail". When the floor of the Dead Sea dropped further due to
   tectonic forces the salt mounts of Lisan and Mount Sedom stayed in
   place as high cliffs. (see salt domes)

   During 70,000 to 12,000 years ago the lake level was a 100-250 m higher
   than its current level. This lake was termed "Lake Lisan", which
   fluctuated dramatically with rising to highest level around 26,000
   years ago, indicating very wet climate in the Near East. Sometime
   around 10,000 years ago the lake level dropped dramatically, probably
   to levels even lower than today. During the last several thousand years
   the lake has fluctuated approximately 400 m with some significant drops
   and rises.

   The Jordan River is the only major stream flowing into Dead Sea. There
   are no outlet streams.

   The northern part of the Dead Sea receives scarcely 100 mm (4 inches)
   of rain a year. The southern section barely 50 mm (2 inches). The Dead
   Sea zone's aridity is due to the rainshadow effect of the Judean Hills.
   The highlands east of the Dead Sea receive more rainfall than the Dead
   Sea itself.

   The mountains of the western side, the Judean Hills, rise less steeply
   from the Dead Sea than do the mountains of the eastern side. The
   mountains of the eastern side are also much higher. Along the
   southwestern side of the lake is a 210 m (700 ft) tall halite formation
   called " Mount Sedom".

Climatic features

     * Year-round sunny skies
     * Dry, low polluted air
     * Less then 50mm mean annual rainfall
     * Summer average temperature: 32-39 degree celsius
     * Winter average temperature: 20-23 degree celsius
     * Weakened UV radiation, particularly the UVB (erythrogenic rays)
     * High oxygen content due to the high barometric pressure.

Therapies popular at Dead Sea

     * Climatotherapy:- Treatment which exploits local climatic features
       such as temperature, humidity, sunshine, Barometric pressure and
       special Atmospheric constituents.
     * Heliotherapy:- Treatment that exploits the biological effects of
       the sun's radiation.
     * Thalassotherapy:- Treatment that exploits bathing in Dead Sea
       water.
     * Balneotherapy:- Treatment that exploits black mineral mud of the
       Dead Sea.

Chemistry and health effects

   A tourist demonstrates the unusual buoyancy caused by high salinity.
   Enlarge
   A tourist demonstrates the unusual buoyancy caused by high salinity.

   Until the winter of 1978-1979, the Dead Sea was composed of two
   stratified layers of water that differed in temperature, density, age,
   and salinity. The topmost 35 meters or so of the Dead Sea had a
   salinity that ranged between 300 and 400 parts per thousand and a
   temperature that swung between 19 °C (66 °F) and 37 °C (98 °F).
   Underneath a zone of transition, the lowest level of the Dead Sea had
   waters of a consistent 22 °C (72 °F) temperature and complete
   saturation of sodium chloride (NaCl).^[ citations needed] Since the
   water near the bottom is saturated, the salt precipitates out of
   solution onto the sea floor.

   Beginning in the 1960s water inflow to the Dead Sea from the Jordan
   River was reduced as a result of large-scale irrigation and generally
   low rainfall. By 1975 the upper water layer of the Dead Sea was
   actually saltier than the lower layer. The upper layer nevertheless
   remained suspended above the lower layer because its waters were warmer
   and thus less dense. When the upper layer finally cooled down so that
   its density was greater than the lower layer the waters of the Dead Sea
   mixed. For the first time in centuries the lake was a homogeneous body
   of water. Since then stratification has begun to redevelop.^[ citations
   needed]

   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 (common salt)
   with the remainder comprised of various trace elements.

   The concentration of sulfate, SO[4]^2-, ions is very low, and the
   bromide ion concentration is the highest of all waters on Earth.
   Chlorides neutralize most of the calcium ions in the Dead Sea and its
   surroundings. While in other seas sodium chloride is 97% of the salts,
   in the Dead Sea the quantity of NaCl is only 12-18%.

   Comparison between the chemical composition of the Dead Sea to other
   lakes and oceans show that the salt concentration in the Dead Sea is
   31.5% (the salinity fluctuates somewhat). Because of its unusually high
   concentration of salt, anyone can easily float in the Dead Sea because
   of natural buoyancy as a result of the higher density of the water. In
   this aspect, the Dead Sea is similar to the Great Salt Lake in Utah, in
   the United States.

   The water of the Dead Sea has a greasy feel to it. The water stings
   cuts, and causes pain if it comes in contact with the eyes.^[ citations
   needed]

   One of the most unusual properties of the Dead Sea is its discharge of
   asphalt. From deep seeps, the Dead Sea constantly spits up small
   pebbles of the black substance. After earthquakes, chunks as large as
   houses may be produced.

   The Dead Sea area has become a major centre 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.

   Sufferers of the skin disorder Psoriasis also benefit from the ability
   to sunbathe for long periods in the area due to its position below sea
   level and subsequent result that many of the sun's harmful UV rays are
   reduced.

Flora and fauna

   Dead Sea in the morning, seen from Masada
   Enlarge
   Dead Sea in the morning, seen from Masada

   The sea is called "dead" because its high salinity means no fish or
   macroscopic aquatic organisms can live in it, though minuscule
   quantities of bacteria and microbial fungi are present.

   In times of flood the salt content of the Dead Sea can drop from its
   usual 35% salinity to 30% or lower. In the wakes of rainy winters the
   Dead Sea temporarily comes to life. In 1980, after one such rainy
   winter, the normally dark blue Dead Sea turned red. Researchers from
   Hebrew University found the Dead Sea to be teeming with a type of algae
   called Dunaliella. The Dunaliella in turn nourished
   carotenoid-containing (red-pigmented) halobacteria whose presence is
   responsible for the colour change. Since 1980 the Dead Sea basin has
   been dry and the algae and the bacteria have not returned in measurable
   numbers.

   Many animal species make their homes in the mountains surrounding the
   Dead Sea. A hiker can see camels, ibex, hares, hyraxes, jackals, foxes,
   and even leopards. Hundreds of bird species inhabit the zone as well.
   Both Jordan and Israel have established nature reserves around the Dead
   Sea.

   The delta of the Jordan river was formerly a veritable jungle of
   papyrus and palm trees. Flavius Josephus described Jericho as "the most
   fertile spot in Judea". In Roman and Byzantine times sugarcane, henna,
   and sycamore all made the lower Jordan valley quite wealthy. One of the
   most valuable products produced by Jericho was the sap of the balsam
   tree, which could be made into perfume.

   By the nineteenth century Jericho's fertility was a thing of the past.

Human history

   World's lowest (dry) point, 1971
   Enlarge
   World's lowest (dry) point, 1971

   The human history of the Dead Sea goes all the way back to remote
   antiquity. Just north of the Dead Sea is Jericho, the oldest
   continually occupied town in the world. Somewhere, perhaps on the Dead
   Sea's southeast shore, are the cities mentioned in the Book of Genesis
   which were destroyed in the times of Abraham: Sodom and Gomorra and the
   three other "Cities of the Plain". King David hid from Saul at Ein Gedi
   nearby.

   The Greeks knew the Dead Sea as "Lake Asphaltites", due to the
   naturally surfacing asphalt. Aristotle wrote about the remarkable
   waters. During the Egyptian conquest it is said that Queen Cleopatra
   obtained exclusive rights to build cosmetic and pharmaceutical
   factories in the area. Later, the Nabateans discovered the value of
   bitumen extracted from the Dead Sea needed by the Egyptians for
   embalming their mummies.

   Prominent personages linked with the Dead Sea and its surroundings are
   Herod the Great, Jesus of Nazareth, and John the Baptist. Also in Roman
   times some Essenes had settled on the Dead Sea's western shore; Pliny
   the Elder identifies their location with the words, "on the west side
   of the Dead Sea, away from the coast ... [above] the town of Engeda"
   (Natural History, Bk 5.73); and it is therefore a hugely popular though
   not uncontested hypothesis today, that same Essenes are identical with
   the settlers at Qumran and that "the Dead Sea Scrolls" discovered
   during the 20th century in the nearby caves had been their own library.

   King Herod the Great built/re-built several fortresses and palaces on
   the Western Bank of the Dead Sea. The most famous was Masada, where, in
   66-70 AD, a small group of rebellious Jewish zealots held out against
   the might of the Roman Legion, and Machaerus where, it has been argued
   from the Gospel according to Luke 3:20, that John the Baptist had been
   imprisoned by Herod Antipas and met his death.

   The remoteness of the region attracted Greek Orthodox monks since the
   Byzantine era. Their monasteries such as Saint George in Wadi Kelt and
   Mar Saba in the Judean Desert are places of pilgrimage.

   In Islamic tradition, the Dead Sea was about the land in which the
   Prophet Lut ( Lot in the Hebrew scriptures) lived. His tribe had done
   wrong and had therefore been given a punishment for such deeds. The
   punishment arrived when angels were sent down by Allah to Lut. The
   angels raised the land where the prophet's tribe lived and threw it
   back into the ground, causing the ground near the impact to cave in.
   Thus, the lowest land on Earth was formed because of this punishment.
   The sinners were destroyed and the followers were saved.

   Bedouin tribes have continuously lived in this area, and more recently
   explorers and scientists arrived to analyze the minerals and conduct
   research into the unique climate. Since the 1960s, tourists from all
   the over world have also explored the Dead Sea region.

Potash and salt works

   View of salt evaporation pans on the Dead Sea, taken in 1989 from the
   Space Shuttle Columbia. The southern half is now separated from the
   northern half at what used to be the Lisan Peninsula because of the
   fall of the level of Dead Sea.
   Enlarge
   View of salt evaporation pans on the Dead Sea, taken in 1989 from the
   Space Shuttle Columbia. The southern half is now separated from the
   northern half at what used to be the Lisan Peninsula because of the
   fall of the level of Dead Sea.

   In the early part of the 20th century, the Dead Sea began to attract
   interest from chemists who deduced that the Sea was a natural deposit
   of potash and bromine. The Palestine Potash Company was chartered in
   1929 (after its founder, Moses Novomeysky, a Jewish engineer from
   Siberia, worked for the charter for over ten years). The first plant
   was on the north shore of the Dead Sea at Kalia and produced potash, or
   potassium chloride, by solar evaporation of the brine. Employing Arabs
   and Jews, it was an island of peace in turbulent times. The company
   quickly grew into the largest industrial site in the Middle East and in
   1934 built a second plant on the southwest shore, in the Sodom area,
   south of the 'Lashon' region of the Dead Sea. The Dead Sea Works Ltd.
   was established in 1952 as a state-owned company to extract potash and
   other minerals from the Dead Sea.

   From the Dead Sea brine, Israel produces (2001) 1.77 million tons
   potash, 206,000 tons elemental bromine, 44,900 tons caustic soda,
   25,000 tons magnesium metal, and sodium chloride. On the Jordanian side
   of the Dead Sea, the Arab Potash Co. (APC), formed in 1956, produces
   2.0 million tons of potash annually, as well as sodium chloride and
   bromine. Both companies use extensive salt evaporation pans that have
   essentially diked the entire southern end of the Dead Sea for the
   purpose of producing carnallite, potassium magnesium chloride, which is
   then processed further to produce potassium chloride. The power plant
   on the Israeli side allows production of magnesium metal (by a
   subsidiary, Dead Sea Magnesium Ltd.). The salt evaporation pans are
   visible from space.

Saving the Dead Sea

   Dead Sea at Dusk (from Suwayma, Jordan)
   Enlarge
   Dead Sea at Dusk (from Suwayma, Jordan)

   The Dead Sea is rapidly shrinking because of diversion of incoming
   water. Between 1930 and 1997 it fell 21 m . Although the Dead Sea may
   never entirely disappear, because evaporation slows down as surface
   area decreases and salinity increases, it is feared that the Dead Sea
   may substantially change its characteristics.

   Since it is not realistic to cease using the Jordan River for human
   needs, one idea to save the Dead Sea is to channel water from the
   Mediterranean or the Red Sea, either through tunnels or canals.
   Although a Mediterranean structure would be shorter, Israel is now
   committed to building a Red Sea canal in deference to Jordan's needs.
   The plan is to pump water 120 m up the Arava/Arabah from Aqaba or
   Eilat, tunnel under the highest point of the Arava/Arabah valley, and
   then canalize the river of seawater as it falls 520 m to the Dead Sea.
   The desalination plant would be constructed in Jordan.

   On May 9, 2005, Jordan, Israel, and the Palestinian Authority signed an
   agreement to begin feasibility studies on the project, to be officially
   known as the " Two Seas Canal". The scheme calls for the production of
   870 million cubic metres of fresh water per year and 550 mega watts of
   electricity. The World Bank is supportive of the project.

   Overpumping and mineral extraction by Israeli and Jordanian companies
   are drying up the Dead Sea with the result that the shoreline is
   receding three feet a year. The southern third of the lake has
   vanished, and Friends of the Earth Middle East doubts the famously
   salty lake can ever be rehabilitated. One woman in the Israeli resort
   of Ein Gedi stated that when she moved to the area from South Africa in
   1978, the shoreline was just 30 feet from the road. As of September
   2006, the spa has to drive its guests a mile to the water. Visitors
   flock there to sightsee and bathe in mineral-rich waters. People who
   believe the Dead Sea is good for them will still go there on vacation.
   Nobody can say how much longer the sea will exist for tourists.

The road to the Dead Sea

   The world's lowest road runs along the Israeli shores of the Dead Sea
   at 393 m (1,289 ft) below sea level. This road was also made famous in
   Naomi Shemer's song Jerusalem of Gold.

Water attractions

   Besides the unique water of the Dead Sea itself, there are also health
   spas and hot springs along the shore. There is also the Israeli
   Atractziah Water Park (across from Kalia Kibbutz) and swimming pools in
   the large Hotel Resort.

Miscellanea

     * West Antarctica's Don Juan Pond has a greater salinity than the
       Dead Sea, at 18 times ocean salinity.
     * The deepest point on the Earth's crust is the Mariana Trench, a
       submarine trench in the western Pacific Ocean.
     * There are ice-covered depressions on the continent of Antarctica
       that are deeper than the Dead Sea (such as the Bentley Subglacial
       Trench).
     * The world's deepest lake is Lake Baikal in Siberia, Russia.

   Retrieved from " http://en.wikipedia.org/wiki/Dead_Sea"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
