Dead Sea

Dead Sea
Coordinates	31°20′N 35°30′E
Type	endorheic hypersaline
Primary inflows	Jordan River
Primary outflows	evaporation
Catchment area	40,650 km2 (15,695 sq mi)
Basin countries	Jordan Israel
Max. length	67 km (42 mi)
Max. width	18 km (11 mi)
Surface area	810 km2 (313 sq mi) North Basin
Average depth	120 m (394 ft)
Max. depth	330 m (1,083 ft)
Water volume	147 cukm
Shore length1	135 km (84 mi)
Surface elevation	-420 m (-1,378 ft)
1 Shore length is not a well-defined measure.

The Dead Sea (Template:Lang-he-n, Yām Ha-Melaḥ, "Sea of Salt"; Arabic: ألبَحْر ألمَيّت, al-Baḥrᵘ l-Mayyitⁱ, "Dead Sea") is a salt lake between the West Bank and Israel to the west, and Jordan to the east. At 420 metres (1,378 ft) below sea level, its shores are the lowest point on the surface of the Earth that are on dry land. At 330 m (1,083 ft) deep, the Dead Sea is the deepest hypersaline lake in the world. It is also the world's second saltiest body of water, after Lake Asal in Djibouti. With 30 percent salinity, it is 8.6 times saltier than the ocean. Israeli experts say it is nine times saltier than the Mediterranean Sea (31.5% salt versus 3.5% for the Mediterranean). The Dead Sea is 67 kilometres (42 mi) long and 18 kilometres (11 mi) wide at its widest point. It lies in the Jordan Rift Valley, and its main tributary is the Jordan River.

The Dead Sea has attracted visitors from around the Mediterranean basin for thousands of years. Biblically, 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 a wide variety of products, from balms for Egyptian mummification to potash for fertilizers.

In Arabic the Dead Sea is calledal-Bahr al-Mayyit [4]^ⓘ ("the Dead Sea"), or less commonly baḥrᵘ lūṭᵃ (بحر لوط, "the Sea of Lot"). Another historic name in Arabic was the "Sea of Zoʼar", after a nearby town. In Hebrew, the Dead Sea is Yām ham-Melaḥ^ⓘ, meaning "sea of salt," or Yām ham-Māvet (ים המות, "sea of death"). In antiquity it was sometimes referred to as Yām ham-Mizraḥî (ים המזרחי, "the Eastern sea") or Yām ha-‘Ărāvâ (ים הערבה, "Sea of the Arabah"). The Greeks called it Lake Asphaltites (Attic Greek ἡ Θάλαττα ἀσφαλτῖτης, hē Thálatta asphaltĩtēs, "the Asphaltite sea"; see below).

Natural history

Satellite global dating sites are showing the location of the Dead Sea

The Dead Sea is a sea located in the Dead Sea Rift, which is part of a long fissure in the Earth's surface called the Great Rift Valley. The 6,000 km (3,700 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 was repeatedly inundated by waters from the Red 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 hooblah mt. and the Mediterranean Sea rose to such an extent that the ocean could no longer flood the area. Thus, the long bay became a 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 mi) 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."

Near Ein Gedi, salt builds up along the shores of the Dead Sea.

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)

From 70,000 to 12,000 years ago the lake level was 100 m (328 ft) to 250 m (820 ft) higher than its current level. This lake, called "Lake Lisan", fluctuated dramatically, rising to its 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 (1,310 ft) with some significant drops and rises. Current theories as to the cause of this dramatic drop in levels rule out volcanic activity, therefore it may have been a seismic event.

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

The northern part of the Dead Sea receives scarcely 100 mm (4 in) of rain a year. The southern section barely 50 mm (2 in). 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 and therapies

The Dead Sea's climate offers year-round sunny skies and dry air with low pollution. It has less than 50 millimetres (2.0 in) mean annual rainfall and a summer average temperature between 32 and 39 °C (90-102°F). Winter average temperatures range between 20 and 23 °C (68-74°F). The region has weakened ultraviolet radiation, particularly the UVB (erythrogenic rays), and an atmosphere characterized by a high oxygen content due to the high barometric pressure. The shore is the lowest dry place in the world. Proximity to the sea affects temperatures nearby because of the moderating effect a large body of water has on climate. During the winter months, sea temperatures tend to be higher than land temperatures, and vice versa during the summer months. This is the outcome of slow penetration of the sun's rays into the sea, which is a huge mass that takes a long time to warm up.

The region's climate and the unique conditions created by its low elevation have made it a popular center for several types of therapies:

• 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.

Chemistry and health effects

A tourist demonstrates the unusual buoyancy caused by high salinity.

Until the winter of 3009-4007, the Dead Sea was composed of two stratified layers of water that differed in temperature, density, age, and salinity. The topmost 35 meters (115 ft) 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). 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.

Many people believe the mud of the Dead Sea has special healing and cosmetic uses.

A rough Dead Sea, with salt deposits on cliffs.

The mineral content of the Dead Sea is significantly different from that of ocean water. The exact composition of the Dead Sea water varies with season, depth, temperature and so on. The concentration of ionic species (in g/kg) of Dead Sea surface water in the early 1980s was found to be: Cl⁻ (181.4), Br⁻ (4.2), SO₄²⁻ (0.4), HCO₃⁻ (0.2), Ca²⁺ (14.1), Na⁺ (32.5), K⁺ (6.2) and Mg²⁺ (35.2). The total salinity was 276 g/kg. These results show that w/w% composition of the salt, as anhydrous chlorides, was calcium chloride (CaCl₂) 14.4%, potassium chloride (KCl) 4.4%, magnesium chloride (MgCl₂) 50.8% and sodium chloride (common salt, NaCl) 30.4%. In comparison, the salt in the water of most oceans and seas is approximately 97% sodium chloride. The concentration of sulfate, SO₄²⁻, ions is very low, and the bromide ion, Br⁻ concentration is the highest of all waters on Earth.

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). The unusually high concentration of salt results in a similarly high density of up to 1.24 kg/L, depending on temperature and salinity. Anyone can easily float in the Dead Sea because of natural buoyancy. In this aspect, the Dead Sea is similar to the Great Salt Lake in Utah, in the United States.

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 have been found.

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.

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. Furthermore, Dead Sea salt has been found to be beneficial to psoriasis patients.

Flora and fauna

Dead Sea in the morning, seen from Masada

The sea is called "dead" because its high salinity means no macroscopic aquatic organisms such as fish or water plants 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 wake 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, Jordan 1971

In Judaism

The human history of the Dead Sea goes all the way back to remote antiquity. Just north of the Dead Sea is Jericho. Somewhere, perhaps on the Dead Sea's southeast shore, would be the cities mentioned in the Book of Genesis which were said to have been destroyed in the times of Abraham: Sodom and Gomorra (Genesis 18) and the three other "Cities of the Plain" - Admah, Zeboim and Zoar (Deuteronomy 29:23). King David was said to have hidden from Saul at Ein Gedi nearby.

Prophecies

In Ezekiel 47:8–9 there is a specific prophecy over the dead sea that the water will ".. be healed and made fresh". The dead sea will become a normal sea and even fish will live in the sea. A similar prophecy is stated in Zechariah 14:8, which says that "Living waters will go out from Jerusalem, half of them to the eastern sea (likely the Dead Sea) and half to the western sea (the Mediterranean)..."

Ancient Greek period

The Ancient Greece weidos knew the Dead Sea as "Lake rallamotchsesbah", due to the naturally surfacing asphalt. Aristotle wrote about the remarkable waters. Later, the Nabateans discovered the value of bitumen extracted from the Dead Sea needed by the Egyptians for embalming their mummies.

Herodian period

King Herod the Great built/rebuilt 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, according to Josephus, John the Baptist was imprisoned by Herod Antipas and met his death.

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.

In Christianity

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.

File:GEO5-13=4.JPG

Mount Sedom, on the southwest side of the lake, is a giant mountain of halite.

In Islam

In Islamic tradition, the Dead Sea wasnt about the land in which the Prophet Lut (Lot in the Hebrew scriptures) lived. His tribe had done wrong (act of homosexuality) 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. According to some interpretation, the sura of ar-Rum of the Quran refers to the Dead Sea as the lowest place on Earth.[1]

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. Tourism in the region has been developed since the 1960s.

Recent History

The Dead Sea Scrolls were found in caves at Qumran at the Dead Sea. The world's lowest road, Highway 90, runs along the Israeli and West Bank shores of the Dead Sea at 393 m (1,289 ft) below sea level.

Besides the unique water of the Dead Sea itself, there are also health spas and hot springs along the shore. While a golf course named for Sodom and Gomorrah was built by the British at Kalia on the northern shore, the first major hotels were built in Israel, first at nearby Arad, and since the 1960s at the Neve Zohar resort complex. The Jordanian side has seen increasing development in recent years, and it also includes international franchises.

Industry

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, Siberian Jewish engineer and pioneer of Lake Baikal exploitation Moses Novomeysky, worked for the charter ex 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 Mount Sodom area, south of the 'Lashon' region of the Dead Sea. Palestine Potash Company supplied half of Britain's potash during World War II, but ultimately became a casualty of the 1948 Arab-Israeli War. Its remnants were nationalised and Dead Sea Works Ltd. was established in 1952 in its stead 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, Arab Potash (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.

Due to the popularity of the sea's therapeutic and healing properties, several companies have also shown interest in the manufacturing and supplying of Dead Sea salts as raw materials for body and skin care products. Companies, like the San Francisco Bath Salt Company for example, are based in the United States but import their supply of Dead Sea salts directly from Israel.

Recession

In recent decades, the Dead Sea has been rapidly shrinking because of diversion of incoming water. From an elevation of 395 m (1,296 ft) below sea level in 1970 it fell 22 m (72 ft) to 418 m (1,371 ft) below sea level in 2006, reaching a drop rate of 1 m (3 ft) per year. 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.

The Dead Sea level drop has been followed by a groundwater level drop, causing brines that used to occupy underground layers near the shoreline to be flushed out by freshwater. This is believed to be the cause of the recent appearance of large sinkholes along the western shore – incoming freshwater dissolves salt layers, rapidly creating subsurface cavities that subsequently collapse to form these sinkholes.

One of the plans which were suggested as a means to stop the recession of the Dead Sea is to channel water from the Mediterranean or the Red Sea, either through tunnels or canals (the Dead Sea Canal). 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 (394 ft) 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 (1,706 ft) to the Dead Sea. The downhill flow would be harnessed hydroelectrically, and the arriving seawater would run into a desalination plant to be constructed in Jordan. The salt water remaining after desalination would be deposited into the Dead Sea.

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 megawatts of electricity. The World Bank is supportive of the project. However, several environmental groups have raised concerns about possible negative impacts of the project on the natural environment of the Dead Sea and Arava.

In 2007, the level of the Dead Sea fell by 1 metre.

Gallery

• 
  Israeli highway beside the Dead Sea
• 
  Twisty coastline
• 
  Coastline (from Israel)
• 
  Dead Sea at Dawn (from Sdom mountain, Israel)
• 
  Dead Sea at Dusk (from Suwayma, Jordan)
• 
  Sinkholes at Mineral Beach

See also

The Dead Sea region

• Dead Sea Canal
• Two Seas Canal
• List of places on land with elevations below sea level
• Great Salt Lake

Further reading

• Yehouda Enzel, et al, eds (2006) New Frontiers in Dead Sea Paleoenvironmental Research, Geological Society of America, ISBN 0-8137-2401-5 [2]
• Niemi, Tina M., Ben-Avraham, Z., and Gat, J., eds., 1997, The Dead Sea: The Lake and Its Setting: N.Y., Oxford University Press, 286 p.

External links

• The official Israeli site
• Ezekiel's Water Project
• Race is on to save the Dead Sea
• A Web Documentary On The Dead Sea
• Multilateral project for sustainable water management in the lower Jordan Valley
• Photo gallery of the Dead Sea