DEAD SEA

The 'Dead Sea' (, '', "Sea of Salt"; , '', "Dead Sea") is a salt lake between the West Bank and Israel to the west, and Jordan to the east. It is said to be the lowest point on Earth, at below sea level;² its shores are actually the lowest point on dry land, as there are deeper points on Earth under water or ice. At 330m deep (1,083 feet), 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 ^[3]. 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 long and 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 called ("the Dead Sea"), or less commonly '' (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 '', meaning "sea of salt," or '' (ים המות, "sea of death"). In antiquity it was sometimes referred to as '' (ים המזרחי, "the Eastern sea") or '' (ים הערבה, "Sea of the Arabah").
The Greeks called it ''Lake Asphaltites'' (Attic Greek , '', "the Asphaltite ^[4] sea"; see below).

Contents

Natural history

Climatic features and therapies

Chemistry and health effects

Flora and fauna

Human history

Potash and salt works

Recession of the Dead Sea

Water attractions

See also

Further reading

References

External links

Natural history

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 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 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 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."

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 to 250 m 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 with some significant drops and rises.
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 50mm mean annual rainfall and a summer average temperature between 32 and 39 °C. Winter average temperatures range between 20 and 23 °C. 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.^[5]
Proximity to the sea affects the temperature of a place because the sea temperature changes due to the penetration of the sun in the summer. During winter months, sea temperatures tend to be much higher than summer temperature and vice versa during summer months, this is the outcome of slow penetration from the sun into the sea as it is a huge mass and 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.

★ Balneotherapy: Treatment that exploits black mineral mud of the Dead Sea.^[6]

Chemistry and health effects

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). 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.^[7]
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), SO₄^2– (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 ^[8] 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, SO₄^2–, 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). 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.

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.^[9]
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.^[10]

Flora and fauna

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 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 color 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

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 (Genesis 18) and the three other "Cities of the Plain" - Admah, Zeboim and Zoar (Deuteronomy 29:23). 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 (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.
The world's lowest road, Route 90 (Israel), runs along the Israeli and Palestinian (West Bank) shores of the Dead Sea at 393 m below sea level.

Potash and salt works

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, 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.

Recession of the Dead Sea

In recent decades, the Dead Sea has been rapidly shrinking because of diversion of incoming water. From an elevation of 395 m below sea level in 1970 ^[11] it fell 22 m to 418 m below sea level in 2006, reaching a drop rate of 1 m 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.^[12]
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 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 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.

Water attractions

Besides the unique water of the Dead Sea itself, there are also health spas and hot springs along the shore. On the Jordanian side there are the Dead Sea Marriott and The Movenpick resorts. Both are equipped with spas and multiple restaurants, etc. 2007 saw a Kempinski Hotel under construction alongside. There is also the Israeli Atractziah Water Park (across from Kalia Kibbutz) and swimming pools in the large Hotel Resort.

See also

★ 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.

References

1. Dead Sea Data Summary. ''International Lake Environment Committee Foundation''.
2. Monitoring of the Dead Sea. ''Israel Marine Data Center (ISRAMAR)''.
3. Goetz, P.W. (ed.) ''The New Encyclopaedia Britannica'' (15th ed.). Vol. 3, p. 937. Chicago, 1986
4. See Bitumen and asphalt for more about ''asphaltite''.
5. Lowest Elevation: Dead Sea
6. DAV school magazine vol.IV (March-April 2005)
7. http://www.american.edu/TED/deadsea.htm
8. I. Steinhorn, ''In Situ Salt Precipitation at the Dead Sea'', Limnol. Oceanogr. 28(3),1983, 580-583
9. Asthma, Cystic Fibrosis, Chronic Obstructive Lung Disease
10. S. Halevy et al. ''Dead sea bath salt for the treatment of psoriasis vulgaris: a double-blind controlled study''. Journal of the European Academy of Dermatology and Venereology, Volume 9, Issue 3: 237-242.
11. C. Klein, A. Flohn, Contribution to the Knowledge in the Fluctuations of the Dead Sea Level. Theoretical and Applied Climatology, vol. 38, p. 151–156, 1987
12. M. Abelson, Y. Yechieli, O. Crouvi, G. Baer, D. Wachs, A. Bein, V. Shtivelman. "Evolution of the Dead Sea Sinkholes", in ''New Frontiers in Dead Sea Paleoenvironmental Research'', Geological Society of America, special paper 401, p. 241–253, 2006

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