The Dead Sea: the Lowest Place on Earth

Dead Sea Stats

Geography

The Dead Sea is the deepest hypersaline lake in the World, with a depth of 304 meters. It is one of the saltiest bodies of water on the Planet, with a salinity of 34.2%, which is 9 times as salty as the ocean. Only a handful of other lakes have a higher salinity, for example Lake Vanda with 35% on Antarctica, Lake Assal with 34.8% of Djibouti or the Lagoon Garavogazkol with 35% located in the Caspian Sea.

It is regarded as one of the first health spas in the World, first used by Herod the Great. The lake is also known as a supplier of a wide variety of products. In Ancient Times it provided the Egyptians with asphalt and now it’s famous for offering potash, mainly used for fertilizers. Its many minerals are also used for cosmetics.

The lake lies in the Jordan Rift Valley, with its main inflow, the mighty Jordan River. The left lateral moving transform fault can be found among the tectonic plate boundary which separates the African Plate from the Arab Plate. It runs between the Eastern Anatolian Fault Zone of Turkey and the Northern end of the Red Sea Rift. It is here that the Upper Jordan River System ends.

The Jordan River is the main tributary of the Dead Sea, although some other springs and creeks flow into the hypersaline lake, which mostly create quicksand and pools. The extreme aridity of the area is due to the proximity to the Judaean Mountains, which keep the lake in rain shadow. At the western end of the lake the Judaean Mountains rise less steep and at a much lower altitude than the mountains bordering it from the east. Mount Sodom, a 210 meter tall halite formation can be found at the southwestern side of the lake.

Hydrology

Besides the Jordan River the 4 most important inflowing streams are the Al-Uzagmi, the Zavqa, the Main and the Al-Mawjih. A few thermal sulphur springs also pour into the Dead Sea. The lake’s salinity, together with its high density, keeps bathers buoyant, floating atop of the water. The Dead Sea itself is actually a huge salt reserve. The excess of the mineral has been discovered in Ancient Times and salt has been exploited since the Antiquity on a small scale. Because of its location on the border between Jordan and Israel, navigation on the lake is insignificant.

Geology and Formation

The area of the lake was once part of a graben which was located between transform faults along a tectonic plate boundary, which ran from the Gulf of Suarez in the Red Sea to a convergent plate boundary in the Taurus Mountains. The Eastern fault, on the edge of the Moab Plateau can be clearly seen from the Dead Sea.

During the Jurassic and Cretaceous period, between 200 and 65 million years ago the Mediterranean Sea, which was much larger at the time, covered Syria and Palestine. In the time of the Miocene, between 23 and 5.3 million years ago the Arabian Tectonic Plate collided with the Eurasian Plate, which can be found to the north, which caused the upheaval of the seabed. This action upfolded the Transjordanian Highlands and the central range of Palestine, generating the fractures which allowed the Dead Sea graben to drop.

In the Pleistocene Epoch (2.6 million years to 11,700 years ago) the region rose 200 meters above its current altitude and formed a vast inland sea, which stretched 320 kilometers from the Hula Valley in the North, to 64 kilometers beyond the lake’s present southern limits.

Nearly 2.5 million years ago a heavy inflow into the lake deposited a thick layer of sediments made up mostly of sandstone, rock salt, gypsum, shale and clay, and which were dropped upon layers of sand and gravel. Because the lake’s waters evaporated quicker than the precipitation at the time the lake reached its current size. Also, the land between the Rift Valley and the Mediterranean Sea rose to an extend that the ocean couldn’t flood the sea anymore, so the whole area became landlocked, creating a long lagoon.

The first prehistoric lake which formed here was called the Sedom Lake or lagoon. The lake’s next names were Lake Amora then Lake Lisan and finally the Dead Sea. The level of the water and salinity has changed a lot during the past 2 million years, due to tectonic dropping of the valley bottom climate variation.

Approximately 10,000 years ago the lake level dropped drastically and never quite recovered. In the last several thousand years the Dead Sea fluctuated approximately 400 meters, witnessing significant rises and drops caused by seismic events.The Al Lisan Peninsula separating the lake in two was formed by a layer of clay, soft chalk, gypsum and marl, combined with sand and gravel.

Climate

The Dead Sea is located in a highly arid place, known for its year-round sunny skies and particularly dry air. The mean annual rainfall is less than 100 mm. The average summer temperature is between 32 and 39OC, whilst in the winter it’s between 20 and 23OC. Typical relative humidity ranges between 33 and 52%. August is the hottest month, whilst July is the driest. The coldest and also the most humid month is January.

The region is famous for its weakened ultraviolet radiation. Due to heavier atmospheric pressure the air also has slightly higher oxygen concentration as compared to oxygen density at sea level. The air temperature in the Dead Sea area changes with the arrival of Mediterranean breezes. In general, the air temperature above the water is colder by 0.5-1OC in the summer and by 1-2OC in the winter. The typical speed of winds is 4-6m/s. During the summer months winds are mostly northerly, whilst in winter one can witness an increase in southerly winds.

The Dead Sea affects nearby temperatures mainly due to the moderating effect a large body of water has over local climate. The region experiences an average 192 days of above 30 degrees Celsius temperatures each year.

Flora and Fauna

The high concentration of salinity that can be found in the lake prevents macroscopic organisms to live in its waters. At this day merely minuscule quantities of microbal fungi and bacteria live in the Dead Sea. When floods occur the salt content of the Dead Sea can fall from 35% to less than 30%. During one rainy winter the lake’s dark blue waters turned red because of a type of alga called Dunaliella, which contain red-pigmented halobacteria.

Since the 1980’s the lake basin has been relatively dry and the bacteria and algae haven’t returned to the lake in measurable numbers. A group of scientists from Germany and Israel have discovered fissures on the lake floor in 2011 during scuba diving and observations conducted from the surface. They allow fresh, brackish water to enter the Dead Sea.

Although the Dead Sea is somewhat literally dead, the surrounding areas, especially the mountains boast a myriad of animal ant plant life. Hikers can see animals like ibexes, hares, jackals, foxes and even leopards. Hundreds of bird species also roam the area. Around the delta of the Jordan River one can encounter jungles of papyrus and palm trees.

Flavius Josephus, the infamous Jewish historian once described Jericho as the “most fertile spot in Judea”.  During ancient Roman and Byzantine times the area was famous for sugarcane, henna and sycamore. One of the most valuable products of Jericho consisted of the sap of the balsam tree, which was made into perfume. The rich fertility of Jericho disappeared by the 19th century.

Water Chemistry

Before 1978 the Dead Sea was med up of 2 different stratification layers, which were dissimilar considering temperature, density, age and salinity. The top 35 meters of the lake consisted of water with temperature ranging between 19 and 37 degrees, depending on the weather and boasted 342 parts per thousand. The lower level was made up of waters with a consistent temperature of 22 degrees Celsius and complete saturation of sodium chloride. Because the water near the bottom of the lake is saturated, the salt usually precipitates out of solution and onto the sea floor.

At the beginning of the 1960s the water inflow from the Jordan River, the lake’s largest tribute was reduced because of a large-scale irrigation system built around the area and general low rainfall. This had devastating consequences: by 1975 the lake’s upper layer became saltier than the lower one. It remained suspended over the lower layer mainly because it was warmer, therefor less dense. Between 1978 and 1979 the upper water layer cooled down and became even more saltier. The two separate layers ended up mixing together, thus the lake became a homogenous body of water.

Although the water is salty, its mineral content is quite different from that of the ocean water. The waters’ exact composition differs according to the season, its depth and temperature. In 1980 the composition of salt was made up of 14.4% of calcium chloride, 4.4% of potassium chloride, 50% of magnesium chloride and the rest of sodium chloride. In comparison, the salt water of the oceans and seas is made up mostly of sodium chloride (over 85%). The lake’s concentration of sulfate ions is extremely low, however that of bromide ions is the highest of all waters on Planet Earth.

The lake’s salt concentration fluctuates at 31.5%, which is abnormalluy high, resulting in a nominal density of 1.24 kg/l. Because of the high concentration of salinity once can experience natural buoyancy similar like in the Great Salt Lake of Utah in the United States of America. The discharge of asphalt is similarly unusual for such a lake. The Dead Sea continuously spits up small pebbles and blocks of asphalt.

Therapeutic Effects

The Dead Sea is often referred to as the lowest health spa in the World, due to its low situation and its waters which boast beneficial, therapeutic effects. The mineral content of the water along with the low content of pollens and other allergens in the atmosphere, combined with the reduced ultraviolet component of solar radiation and higher atmospheric pressure all contribute to the specific health effects of the lake’s waters.

The low elevation and the region’s unique climate have made the Dead Sea a popular center for climatotherapy (treatment involving the features of local climate), heliotherapy (treatments using the biological effects of the radiation of the sun) and thalassotherapy (bathing in the mineral-rich water).

Climatotherapy is thought to be a kind of therapy for patients suffering of psoriasis. By sunbathing for long periods of time the UV rays, which are partially blocked by the increase of the clouds over the Dead Sea are said to be beneficial. Patients suffering from rhinosuinusitis receive saline nasal irrigation from the Dead Sea waters, while those suffering from osteoarthritis take advantage of local mud therapy to relieve their symptoms.

Chemical Industry

At the start of the 20th century a number of chemists and investors gained interest in the Dead Sea, mainly because of its natural deposit of potash and bromine. The Palestine Potash Company was created in 1929. Its founder, a Siberian Jewish engineer who was also a pioneer of the Lake Baikal exploitation, named Moses Novomeysky, worked for the charter for more than 10 years. The first plant was constructed next to the town of Kalya on the Northern shore of the lake, and produced potash by solar evaporation of the brine. The company quickly grew into the largest industrial site of the Middle East, after building a 2nd plant on the lake’s southwestern shore, close to Mount Sodom.

After the Arab-Israeli War in 1948 the plant was shut down. But operations restarted in 1952 at the Southern Sodom Plant. The remains of the Palestine Potash Plant were nationalized under Dead Sea Works Ltd, which was instituted in 1952. Its goal was to extract potash and useful minerals from the lake. In 1995 it was privatized and has been under the leadership of Israeli Chemicals.

On the Jordanian side of the lake the Arab Potash company was created in 1956 and produced more than 2 million tons of potash annually, along with sodium chloride and bromine. The company’s headquarters can be found at Safi in the South Aghwar Department.

The Palestinian part of the lake could not benefit of the lake’s chemicals and minerals due to issues regarding permits and the uncertainties of the investment climate surrounding the area.

The two primary companies working in the area use extensive salt evaporation pans to succeed in their extraction process, which have diked the southern end of the Dead Sea entirely with the aim of producing carnallite, potassium magnesium chloride, processed further to potassium chloride. The plant on the Israeli side also produces magnesium metal.

Human History

Around the Dead Sea numerous dwellings in various caves can be seen, which have been documented in the Hebrew Bible. According to the Bible, the dwellings took place even before the Israelites arrived in Canaan and during the reign of the infamous King David. The city of Jericho can be found close to the northern end of the lake. According to the Book of Genesis, the cities Sodom and Gomorra, which were destroyed in the time of Abraham, along with Admah, Zeboim and Zoar were once located at the southeastern shore of the Dead Sea. Before the destruction, the Dead Sea was made up mostly of tar pits and was referred to as the Vale of Siddim. In Ezekiel one can encounter a prophecy referring to the lake, which will “be healed and made fresh”, referring to the fact that it would became a normal lake.

Aristotle was one of the first people to write about the lake and its remarkable healing powers. The Nabateaans were the ones who first came across the value of the globs of natural asphalt which can be encountered by the lake. The globs of natural asphalt floated atop of the water and were collected by them with the help of nets. The Egyptians were their most faithful costumers, since they actually used the asphalt in the embalming process of mummies.

The ancient Romans referred to the lake as Asphalt Lake. It was King Herod the Great who first started to develop the area by building fortresses and castles on the Western bank of the Dead Sea. Masada was by far the most famous one, where in 70 CE a group of Jewish zealots fled. Macherus was located on the Eastern bank and it was the place where John the Baptist was imprisoned, and where he eventually perished. Essenes was also found on the Western shore of the lake. Josephus claimed that the lake was in the proximity of the ancient Biblical city of Sodom.

Sects of Jews have moved into the caves which overlook the lake, such as the Essenes of Qumran, which left behind an immense library known today as the Dead Sea Scrolls. The town of Ein Gedi had an important role: they were the ones responsible for producing persimmon which was used as the fragrance of the temples, and also for export. “Sodomite salt” was also an important product back then, used for the temple’s incest but was deemed dangerous for home use.

During the Byzantine period, because of the lake’s closeness to the Judean wilderness to the northwest and the west, the area was a place of refuge for the many Greek Orthodox monks, who later built monasteries which are now places of pilgrimage (such as the St. George in Wadi Kelt and the Mak Saba in the Judean Desert).

In the times of the modern explorations the Dead Sea and the River Jordan were first explored by boat by Christopher Costigan in 1835, then Thomas Howasrd Molyneux in 1847, Francis Lynch in 1848 and John McGregor in 1869. The shores of the lake were explored as early as 1817 and 1818 by Charles Leonard Irby and James Mangles, but they didn’t actually explore its waters by boat.

Archaeological Finds

On a plateau located east of the Dead Sea a so-called “Moabite Stone” was found in 1868 by Moses Wilhelm Shapira and Salim al-Khouri who were famous for forging and eventually selling a whole series of “Moabite antiques”. In 1883 Shapira showcased a collection of ancient scrolls written on leather strips which he named the “Shapira Strips” and which he claimed he came across near the shores of the Dead Sea. After they were deemed fakes, Shapira took his own life in disgrace.

Between the late 1940’s and the early 1950’s hundreds of documents dating back between 150 BCE and 70 CE were discovered in the caves near Qumran, a mile inland from the northwestern shore of the lake and were named the Dead Sea Scrolls.

Human Settlements

Numerous small communities can be found on the shores of the Dead Sea, including Ein Gedi, Neve Zohar and some Israeli settlements in the Megliot Regional Council Area, such as Kalya, Mitzpe Shalem and Avnat. A nature preserve can be found next to Ein Gedi. Potash City is a small community on the Jordanian side of the Dead Sea.

Etymology and Toponymy

The name of the Dead Sea in Hebrew can be roughly translated as “the sea of salt”. In the Bible it appeared often under the names Salt Sea, Sea of Arabah and En Sea. In Arabic the lake is referred to asa “al-Bahr al-Mayyit” or “the Sea of Lot”. Sea of Zo’ar is another historic Arabic name of the Dead Sea. The Greeks simply referred to it as “Lake Asphaltites”.

Environmental Issues

The Dead Sea has been continuously monitored as early as the 1930s. In the past couple of decades its rapid shrinking was caused mainly by the diversion of its main tributary, the Jordan River. The lake’s surface at the beginning of the surveillance in 1930 was at 395 meters. By 1970 its surface was 22 meters below sea level and by 2006 it fell to 418 meters below sea level with an average drop rate of 1 meter per year.

After the level of the Dead Sea dropped the groundwater level also lowered, causing brines which once occupied underground layers near the lakeshore, which were flushed out by freshwater. Because of this sinkholes appeared on the western shore. The freshwater now dissolves salt layers, creating subsurface cavities.

In 2009, Jordan presented its plan to initiate the Jordan National Red Sea Development Project, which would convey sea water from the Red Sea. The plan was to desalinate the water to provide the Jordan River with fresh water. The brine discharge was to be sent to the Dead Sea for replenishment. The plan was redesigned in more detail in 2010 and is expected to deliver water by 2017. Israel supports the cause and will benefit of its own water delivery into the much-needed Negev region.

A regional conference was held in 2009in which there were talks of reducing the industrial activities polluting the area and various other environmental propositions with the aim of restoring the lake’s condition. They agreed upon the need of 3 important efforts: agriculture should not be expanded in the future, sustainable support should be considered and the many sources of pollution should be decreased.

In December of 2013 Israel, Jordan and the Palestinian Authority all signed an agreement which involved implementing a 180 kilometer long water pipeline which would link the Red Sea to the Dead Sea.

According to specialists, the surface level of the Dead Sea is expected to further drop in the next 500 years. This was predicted by a couple of different models.

Tourism and Leisure

On the Jordan part of the lake 6 international franchises have opened seaside resorts on the eastern shore of the lake, near the King Hussein Bin Talal Convention Center. 4-5 star luxury hotels can be found further to the south. People can explore the Dead Sea Panorama Road on Google Street View, which went live at the end of November in 2015.

In the Israeli side of the Dead Sea the first major hotels have been built since the 1960s. Most hotels on this part of the lake can be found on a 6 kilometer long stretch of the Southern Shore.

On the Palestinian coast of the Dead Sea, which is approximately 40 kilometers long, is still underdeveloped. The World Bank estimated that it could generate whopping $290 million revenue each year and would create nearly 3000 jobs in the area through the help of tourism. But the Palestinians are unable to get the necessary permits needed for construction works.