Dead Sea
| Dead Sea | |
|---|---|
 | |
| A view from the Israeli side looking across to Jordan | |
| Coordinates | 31°20′N 35°30′E / 31.333°N 35.5°ECoordinates: 31°20′N 35°30′E / 31.333°N 35.5°E |
| Lake type | endorheic hypersaline |
| Primary inflows | Jordan River |
| Primary outflows | none |
| Catchment area | 41,650 km2 (16,080 sq mi) |
| Basin countries | Jordan Israel |
| Max. length | 67 km (42 mi) |
| Max. width | 18 km (11 mi) |
| Surface area | 810 km2 (310 sq mi) North Basin |
| Average depth | 118 m (387 ft)[1] |
| Max. depth | 378 m (1,240 ft) |
| Water volume | 147 km3 (35 cu mi) |
| Shore length1 | 135 km (84 mi) |
| Surface elevation | -422 m (−1,385 ft)[2] |
| References | [1][2] |
| 1 Shore length is not a well- | |
al-Bahr al-Mayyit[3] (help·info), Hebrew: יָם הַמֶּלַח, Yām Ha-Melaḥ, "Sea of Salt"), also called the Salt Sea, is a salt lake bordering Jordan to the east, and Israel to the west. Its surface and shores are 422 metres (1,385 ft) below sea level,[2] the lowest elevation on the Earth's surface on dry land. The Dead Sea is 378 m (1,240 ft) deep, the deepest hypersaline lake in the world. It is also one of the world's saltiest bodies of water, with 33.7% salinity, though Lake Assal (Djibouti), Garabogazköl and some hypersaline lakes of the McMurdo Dry Valleys in Antarctica (such as Don Juan Pond) have reported higher salinities. It is 8.6 times more salty than the ocean.[4]
This salinity makes for a harsh environment where animals cannot
flourish, hence its name. 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. People also use the salt and the minerals from the Dead Sea to create cosmetics and herbal sachets. In 2009, 1.2 million foreign tourists visited on the Israeli side.
The sea has a density of 1.24 kg/L, making swimming difficult.
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Etymology
In Hebrew, the Dead Sea is Yām ha-Melaḥ (help·info), meaning "sea of salt" (Genesis 14,3). In prose sometimes the term Yām ha-Māvet (ים המוות, "sea of death") is used. In Arabic the Dead Sea is called al-Bahr al-Mayyit[3] (help·info) ("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 biblical times. The Greeks called it Lake Asphaltites (Attic Greek ἡ Θάλαττα ἀσφαλτῖτης, hē Thálatta asphaltĩtēs, "the Asphaltite[5] sea"). The Bible also refers to it as Yām ha-Mizraḥî (ים המזרחי, "the Eastern sea") and Yām ha-‘Ărāvâ (ים הערבה, "Sea of the Arabah")Geography
The Jordan River is the only major water source flowing into the Dead Sea, although there are small perennial springs under and around the Dead Sea, creating pools and quicksand pits along the edges.[6] There are no outlet streams.
Rainfall is scarcely 100 mm (3.9 in) per year in the northern part of the Dead Sea and barely 50 mm (2.0 in) in the southern part. 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.
To the west of the Dead Sea, the Judean Hills rise less steeply and are much lower than the mountains to the east. Along the southwestern side of the lake is a 210 m (690 ft) tall halite formation called "Mount Sodom".
[edit] Natural history
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 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 climate change. The lake that occupied the Dead Sea Rift, named "Lake Sodom", deposited beds of salt that eventually became 3 km (1.9 mi) thick.
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 mi) south of the current southern end of the Dead Sea and 100 km (62 mi) north, well above the present Hula Depression. As the climate became more arid, Lake Gomorrah shrank and became saltier. The large, saltwater predecessor of the Dead Sea is called "Lake Lisan."
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 a very wet climate in the Near East. 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.
Climate
The Dead Sea's climate offers year-round sunny skies and dry air. It has less than 100 millimetres (3.94 in) mean annual rainfall and a summer average temperature between 32 and 39 °C (90 and 102 °F). Winter average temperatures range between 20 and 23 °C (68 and 73 °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.[7] The sea affects temperatures nearby because of the moderating effect a large body of water has on climate. During the winter, sea temperatures tend to be higher than land temperatures, and vice versa during the summer months. This is the result of the water's mass and specific heat capacity.
Chemistry
Until the winter of 1978-79, when a major mixing event took place,[8] the Dead Sea was composed of two stratified layers of water that differed in temperature, density, age, and salinity. The topmost 35 metres (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 (99 °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).[citation 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 saltier than the lower layer. Nevertheless, the upper layer remained suspended above the lower layer because its waters were warmer and thus less dense. When the upper layer finally cooled down so its density was greater than the lower layer, the waters of the Dead Sea mixed (1978–79). For the first time in centuries, the lake was a homogeneous body of water. Since then, stratification has begun to redevelop.[8]
The mineral content of the Dead Sea is very different from that of ocean water. The exact composition of the Dead Sea water varies mainly with season, depth and temperature. In the early 1980s, the concentration of ionic species (in g/kg) of Dead Sea surface water was 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.[9] These results show that w/w%[clarification needed] 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 ions (SO42−) is very low, and the concentration of bromide ions (Br−) is the highest of all waters on Earth. The sea itself is abundant in minerals acclaimed to have therapeutic value.
The salt concentration of the Dead Sea fluctuates around 31.5%. This is unusually high and results in a nominal density of 1.24 kg/l. Anyone can easily float in the Dead Sea because of natural buoyancy. In this respect the Dead Sea is similar to the Great Salt Lake in Utah in the United States.
An unusual feature of the Dead Sea is its discharge of asphalt. From deep seeps, the Dead Sea constantly spits up small pebbles and blocks of the black substance.[10] Asphalt coated figurines and bitumen coated Neolithic skulls from archaeological sites have been found. Egyptian mummification processes used asphalt imported from the Dead Sea region.[11][12]
Health effects and therapies
The Dead Sea area has become a major center for health research and treatment for several reasons. The mineral content of the water, 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.[13]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.[14]
Thus, the region's climate and 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
Fauna and flora
In times of flood, the salt content of the Dead Sea can drop from its usual 35% salinity to 30% or lower. The Dead Sea temporarily comes to life in the wake of rainy winters. 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 caused 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 live in the mountains surrounding the Dead Sea. Hikers 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 fig 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. However, by the 19th century, Jericho's fertility had disappear
Human settlement
There are several small communities near the Dead Sea. These include the West Bank Israeli settlements in the Megilot Regional Council: Vered Yeriho, Kalya, Almog, Beit Ha'arava, Mitzpe Shalem and Avnat. There is a beautiful nature preserve at Ein Gedi, and several Dead Sea hotels with their resort-like atmosphere are located on the southwest end at Ein Bokek near Neve Zohar. Highway 90 runs north-south on the Israeli side for a total distance of 565 km from Metula on the Lebanese border in the north to its southern terminus at the Egyptian border near the Red Sea port of Eilat.
Potash City is a small community on the Jordanian side of the Dead Sea. Highway 65 runs north-south on the Jordanian side.
History
Biblical period
Just north of the Dead Sea is Jericho. Somewhere, perhaps on the southeast shore, would be the cities mentioned in the Book of Genesis which were said to have been destroyed in the time of Abraham: Sodom and Gomorra (Genesis 18) and the three other "Cities of the Plain" - Admah, Zeboim and Zoar (Deuteronomy 29:23). Zoar escaped destruction when Abraham's nephew Lot escaped to Zoar from Sodom (Genesis 19:21-22). Before the destruction, the Dead Sea was a valley full of natural tar pits, which was called the vale of Siddim. King David was said to have hidden from Saul at Ein Gedi nearby.In Ezekiel 47:8-9 there is a specific prophecy that the sea will ".. be healed and made fresh", becoming a normal lake capable of supporting marine life. 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)..."
Second Temple period
Dwelling in caves near the Dead Sea is recorded in the Hebrew Bible as having taken place before the Israelites came to Canaan, and extensively at the time of King David. Various sects of Jews settled in caves overlooking the Dead Sea. The best known of these are the Essenes of Qumran, who left an extensive library known as the Dead Sea Scrolls.[15] The town of Ein Gedi, mentioned many times in the Mishna, produced persimmon for the temple's fragrance and for export, using a secret recipe. "Sodomite salt" was an essential mineral for the temple's holy incense, but was said to be dangerous for home use and could cause blindness.[16] The Roman camps surrounding Masada were built by Jewish slaves receiving water from the towns around the lake. These towns had drinking water from the Ein Feshcha springs and other sweetwater springs in the vicinity.[17]Ancient Greek period
The Greeks knew the Dead Sea as "Lake Asphaltites", 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 or rebuilt several fortresses and palaces on the western bank of the Dead Sea. The most famous was Masada, where, in 70-73 CE, a small group of 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 died.[18]Also in Roman times, some Essenes 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 but contested 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 Islam
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Main article: Lut
According to the tradition of Islam, the Dead Sea was near the land in which the Prophet Lut lived. The people in this area were considered wicked for their acts of homosexuality, robbery and murder, and therefore Allah had ordained punishment to the people of Lut for these deeds. The punishment arrived when three angels
in the form of handsome men were sent down by Allah as guests for Lut
to host. When Lut's people heard of the men, they rushed to Lut's house
and said that those men were very handsome and they wanted to marry
them. This was the final test for the people of Lut in which they
failed, so the angel Jibrail
raised the land where the prophet's people lived, tipped it upside
down and threw it back on earth, causing the ground near the impact to
cave in. Thus, the lowest land on Earth was formed because of this
punishment. The non-believers (in the monotheism doctrine) were destroyed and the followers were saved.[edit] Modern times
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.
The first major hotels were built in nearby Arad, and since the 1960s at the Neve Zohar resort complex. On Jordanian side, three international franchises have opened seaside resort hotels near the King Hussein Bin Talal Convention Center along the eastern coast of the Dead Sea.[19]
Industry
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 ponds are separated by a central dike that runs—roughly north-south—along the international border. 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.
[edit] Recession and environmental concerns
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.[21]
In May 2009 at the World Economic Forum, Jordan announced its plans to construct the "Jordan National Red Sea Development Project" (JRSP). This is a plan to convey seawater from the Red Sea near Aqaba to the Dead Sea. Water would be desalinated along the route to provide fresh water to Jordan, with the brine discharge sent to the Dead Sea for replenishment. As of 2009, the project is in its early phases of planning, with developer and financier selection to be completed by year's end. The project is anticipated to begin detailed design in early 2010, with water delivery by 2017. Israel has expressed its support and will likely benefit from some of the water delivery to its Negev region. Some hydro-power will be collected near the Dead Sea from the dramatic change in elevation on the downhill side of the project.[citation needed] In October 2009, the Jordanians announced accelerated plans to extract around 300 million cubic meters of water per year from the Red Sea, desalinate it for use as fresh water and send the waste water to the Dead Sea by tunnel, despite concerns about inadequate time to assess the potential environmental impact.[22]
At a regional conference in July 2009, officials expressed increased concerns that water levels are dropping. Some suggested various industrial activities around the Dead Sea might need to be reduced. Others advised a range of possible environmental measures to restore conditions. This might include increasing the volume of flow from the Jordan River to replenish the Dead Sea. Currently, only sewage and effluent from fish ponds run in the river's channel. Experts also asserted a need for strict conservation efforts. They also said agriculture should not be expanded, sustainable support capabilities should be incorporated into the area and pollution sources should be reduced.[23]
[edit] Gallery
Israeli highway beside the Dead Sea
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Jordanian highway along the Dead Sea coast
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Twisty coastline
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Coastline (from Israel)
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A rough Dead Sea, with salt deposits on cliffs
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Dead Sea northern coast (Jordan)
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Located in Jordan, this sign diagrams the topography of Jordan, the West Bank, Israel, and the Mediterranean Sea.
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Dead Sea at dawn (from Sodom mountain, Israel)
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Dead Sea at dusk (from Suwayma, Jordan)
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Dead Sea at dusk (from Mövenpick Resort Dead Sea, Jordan)
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A tourist demonstrates the unusual buoyancy caused by high salinity
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Many people believe that the mud of the Dead Sea has special healing and cosmetic uses.
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Sinkholes at Mineral Beach
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Cobble encrusted with halite evaporated from the Dead Sea near Ein Gedi
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Dead Sea from Masada
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Line painted in 1900 (at top of image) by Robert A.S. Macalister of the Palestine Exploration Fund showing the level of the Dead Sea
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