Thursday, July 25, 2019

An ecological paradox: the Dead Sea is dying

The Dead Sea, also called Al-Bahr Al-Mayyit in Arabic, is the lowest point on Earth.  It receives as its unique source of water the Jordan river, which in turn is an outflow of the freshwater lake known as “Sea of Galilee”.
The upper basin of the Jordan-Galilee system encompass Syria, Lebanon, Israel, Jordan and Palestine. Important volumes of water from this basin is used for irrigation (mainly in Israel) and due to the very dry climate the Dead Sea has a continuous water deficit.
The Dead Sea has an average salt concentration of 33.7% which is almost ten times the ocean water salinity (approximately 3.5%)
Presently its surface and shores are 430.5 metres below sea level which is Earth's lowest elevation on land.
The Dead Sea is divided in two “pools” a larger northern basin about 50 kilometres (31 mi) long and 15 kilometres (9 mi) wide at its widest point and a smallest one at the South connected to the main one though a canal.  .
The level of the lake is continually decreasing at a rate of 1.5 meters per year and accelerating. It is expected that it may reach 500 meters below sea level around the year 2050. At the same time the area of the lake is decreasing. From more than 1,050 km2 in 1930 it has shrunk nowadays to less than 600 km2.
The political situation does not help. If the countries in the basin do not coordinate efforts and planning the Dead Sea will completely disappear by the turn of the century.
In spite of its name the Dead Sea is not a “dead” body of water.
While it’s true that higher organisms (fish, for example) can’t survive in the Dead Sea’s water, several microorganisms can. In fact, several bacteria and microscopic algae live in its waters. These microorganisms can survive because they are well adapted to hyper-salinity conditions. During very rainy periods or floods, the influx of fresh water changes the Dead Sea’s chemical makeup, thus increasing the volume and number of microorganisms living there. In such periods people have witnessed the water’s surface turning a bright red – indicating the presence of Dunaliella and other algae.
A little known fact is that the Dead Sea itself actually contains fresh water, which comes from freshwater springs that are found at its bottom. Near these springs more types of microorganisms can be found: single-celled algae, cyanobacteria and green sulfur bacteria. Other microorganisms that were found at the bottom of the Dead Sea are nearly 80 species of fungi. What’s even more interesting is that many of the microorganisms found in Dead Sea are very unique creatures, some of which have not been previously known to science.


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