Changing Geography of the Dead Sea

| |

We’ve all seen the pictures- tourists floating in a picturesque lake surrounded by a mountainous desert environment, calmly reading flipping the pages of a newspaper with no fear of sinking. What is this strange phenomenon? This geographic anomaly is the Dead Sea, located between the countries of Israel and Jordan in the Middle East- a hypersaline lake that is rapidly disappearing.

How the Dead Sea Was Formed

Located 427 meters (1,401 feet) below sea level in the Jordan Rift Valley, the Dead Sea is 306 meters (1,004 feet) deep and has 34.2% salinity; compare this to the ocean’s approximate 3.5% salinity and you have a recipe for a very salty swim! Fed primarily by the Jordan River and the Sea of Galilea further north in addition to few inflows from smaller valleys along its length, the Dead Sea was formed by the Dead Sea Transform (DST) which runs from the East Anatolian Fault in Turkey south to the Red Sea Rift, located in the ocean off the southern edge of the Sinai Peninsula. This transform fault line is microscopically moving left-lateral and lies along the African and Arabian Tectonic Plates.

Biodiversity and the Dead Sea

True to its name the Dead Sea contains no life; rather, it has an incredibly intricate chemical makeup and is surrounded by a unique biosphere that is home to many endangered species of plants and animals. Until 1979 the Dead Sea had two layers of water that were stratified; approximately the top 35 meters (115 feet) were colder and less saline than the bottom layer, which was completely saturated with sodium chloride and had salt precipitate leeching into the lake bed. In 1979 the layers mixed due to a reduction of inflow, low rainfall, and a change in the salinity of the two layers. Currently the layers are beginning to form again after the mix up.

The false-color images above of the Dead Sea were captured by the Landsat 1, 4, and 7 satellites. The Multispectral Scanner System on Landsat 1 acquired the top image on September 15, 1972. The middle image was acquired on August 27, 1989, by the Thematic Mapper on Landsat 4. The third image is from the Enhanced Thematic Mapper Plus on Landsat 7 on October 11, 2011. On a hot dry summer day, the 1,035-square-kilometer (405-square-mile) surface of the Dead Sea can drop as much as two to three centimeters (one inch) from evaporation, making the remaining water increasingly salty. In the past, the Dead Sea has been deep at the northern end and shallow at the south. Diversion of the water flowing in to the sea for agriculture in modern times has caused the Sea to separate into two separate lobes. The southern part is mostly dry except for ponds that are used to extract potash (a potassium-based salt) and other salts. Source: NASA.
The false-color images above of the Dead Sea were captured by the Landsat 1, 4, and 7 satellites. The Multispectral Scanner System on Landsat 1 acquired the top image on September 15, 1972. The middle image was acquired on August 27, 1989, by the Thematic Mapper on Landsat 4. The third image is from the Enhanced Thematic Mapper Plus on Landsat 7 on October 11, 2011.
On a hot dry summer day, the 1,035-square-kilometer (405-square-mile) surface of the Dead Sea can drop as much as two to three centimeters (one inch) from evaporation, making the remaining water increasingly salty. In the past, the Dead Sea has been deep at the northern end and shallow at the south. Diversion of the water flowing in to the sea for agriculture in modern times has caused the Sea to separate into two separate lobes. The southern part is mostly dry except for ponds that are used to extract potash (a potassium-based salt) and other salts. Source: NASA.

The Dead Sea produces asphalt as one of its many strange characteristics. Ancient artifacts from the region such as bones and small statues have been found covered in asphalt from the depths of the sea- small bits of rock and larger chunks of asphalt are routinely found as well that have popped up from the depths of the sea.

The geography around the Dead Sea is unique in its features and life forms thriving in this strange environment. To the west and east of the Dead Sea mountains and higher hills are common; the Judean Hills in Israel cause a rain shadow effect from the Mediterranean climate to the very arid regions around the Dead Sea. The mountainous region to the west (in Israel) receives more rainfall than reaches the Dead Sea, contributing to the falling water levels. There are two theories regarding the Dead Sea’s lack of physical elevation; one is that is lies in a true rift zone as part of the Turkey/Sinai rift line, and the other is that the Dead Sea is a “step over” discontinuity along the DST. This means it is functioning as an extension of the tectonic plate crusts.

Preserving the Dead Sea’s Unique Environment

In Jordan a preserve called the Mujib Nature Reserve was set up by the Royal Society for the Conservation of Nature. The reserve studies the biosphere and ecological zones of the Dead Sea from its surface to the valleys and mountains around it. The preserve covers approximately 212 square kilometers around the Dead Sea and protects not only one of the Dead Sea’s most consistent inflows, but a variety of flora and fauna as well. Studies by local and international biologists have estimates that the Mujib Nature Reserve contains about 300 species of plants including palm trees, wild fig trees, Tamarix trees and Oleander bushes, 10 species of animals (like the Rock Hyrax, the Eurasian Badger, the Caracal and the rare Nubian Ibex as well as a few rare Arabian Leopards) and a variety of birds that are local to the region and migratory (White and Black Storks, Honey Buzzards, the Barbary Falcon and Dead Sea Sparrow Hawks).

Changing geography, both man-made and natural, is playing a key role in the disappearing Dead Sea. Factories and resorts built along the Dead Sea on the Israeli and Jordanian sides are taking water and replacing it with waste products; the decreased inflow of the Jordan River for the same reasons mentioned above is not able to replenish the Dead Sea quickly enough to maintain water levels. The increased sedimentation from the water has clogged former inflows and evaporation due to increased temperatures has caused the Dead Sea water levels to decrease at an estimated 1 meter (3 feet) per year. Newly exposed seashores and cliff sides erode back into the Sea causing water displacement.

The Dead Sea is a unique geographical formation, essential for study and preservation.

References

Mujib Biosphere Reserve; 2008; http://www.rscn.org.jo/orgsite/RSCN/HelpingNature/ProtectedAreas/MujibBiosphereReserve/tabid/94/Default.aspx

Disappearing Dead Sea: Tyler Nichols. November 9th, 2013. http://greatecology.com/disappearing-dead-sea/

The Dead Sea: A Dying Lake. World Wildlife Foundation. http://wwf.panda.org/about_our_earth/teacher_resources/best_place_species/top_10_scary_destinations/dead_sea.cfm

Project: Dead Sea. Friends of the Earth Middle East. 2012. http://foeme.org/www/?module=projects&record_id=21

Monitoring of the Dead Sea. Israel Oceonographic and Limnological Research. 2004. http://isramar.ocean.org.il/isramar2009/DeadSea/

Share:


Enter your email to receive the Geography Realm newsletter:
Previous

Geography of the Himalayas

Aquatic Dead Zones

Next