Jordan Times
Wednesday, March 22, 2000
Lowest point on earth is getting lower
By Batir Wardam
We are privileged in Jordan to have the lowest point on earth here. However, it seems we are overenthusiastic about that record to the point where we are trying to stretch it even further by making the lowest point even lower! The Dead Sea, one of the world's most prestigious and magnificent ecological and geographical localities is suffering from a gradual progressive decline in its level and a decrease in its surface area. The end result could be obliteration!
Several factors contribute to the decline of the Dead Sea level, most of which are anthropogenic and caused by non-sustainable modes of developmental activities mainly from industry, agriculture and tourism. The main cause is the increased rate of evaporation of the Dead Sea water compared to the decrease in feeding water influx from adjacent natural tributaries.
In 1920 the Dead Sea water level was at 392 m below sea level. In 1990 it was at 407 m below and in 2000 it has decreased further to 420. This corresponded to a parallel decrease in the surface area from 1,050 sq. km in 1920, 600 sq. km in 1990 to 515 sq. km in 2000. About 76 per cent of the total surface area of the Dead Sea is found in its northern half or “lake.” The southern half constitutes 24 per cent with a maximum depth of 10 m.
Actually the southern half of the Dead Sea is currently few patches of evaporation lagoons used by the Arab Potash Company to extract Potash and other minerals. The remaining is salty brine resulting from the industrial process. The Arab Potash Company contributes to 30 per cent of Dead Sea water evaporation annually from the Jordanian side. It is a great surprise to see some halotolerant (salt adapted) vegetation species growing inside the salt giving an explicit example on resilience.
The high rate of water evaporation from the Dead Sea is a result of the high temperature of the Jordan River Valley. To add to this, the quantity of feeding freshwater that drains into the sea is witnessing gradual decrease also. The main tributary, the Jordan River has been diverted for agricultural use for a long time by Jordan, Syria and Israel. The eastern tributaries also are decreasing in volume especially the Mujib River which lost half of its volume reaching the Dead Sea after the construction of the Mujib Dam for agricultural uses.
Water budget studies of the Dead Sea have shown that the total quantity of feeding freshwater to the Dead Sea from all tributaries does not exceed 375 million cubic metres while the evaporation rate is 1,250 million cubic metres. This leaves us with a water deficit of 900 million cubic metres. This is a huge number by any standards and the gap is never likely to be closed. This is most evident with the gradual loss of the hope to establish the dream Red-Dead Seas Canal that was proposed in conjunction with the development in the peace process. The multi-billion project was proposed to energise the development of the Wadi Araba area and to help increasing the Dead Sea level. However, hopes for this project are now evaporating just as fast as the Dead Sea water itself.
Ecologically, the Dead Sea is considered a hypersaline lake where its proportions of salts are drastically different from normal sea water.
The Dead Sea water is more saline than any other sea in the world. The average salinity is about 290 gm/L for the surface water, and 326 gm/L at 100 m depth. In comparison, a regular ocean contains about 33 gm/L, the Red Sea in he Gulf of Aqaba has about 40 gm/L, and the Great Salt Lake has 230 gm/L.
Dead Sea water is also much denser than any other sea. The density of the Dead Sea water has been measured over the past 150 years, and the results have ranged from 1.164 to 1.236 gm cm3. The density is affected by fluctuation of the Dead Sea level, and the high rate of evaporation for different seasons. The high rate of evaporation during summer causes an increase in salinity, and subsequently increases the density.
The Dead Sea is a host for a unique set of halophilic (salt loving) bacteria and one species of algae. These organisms possess peculiar characteristics that allow them to survive in such a harsh environment.
Although the utilisation of halophilic bacteria for man's needs and prosperity through biotechnology and applied microbiology is still at its beginning, many attempts were and still are made, worldwide, in this regard. Yet, so far, little attempts have been made in Jordan.
Certainly, halophilic bacteria can play a major role in reclamation of saline environments that normally have very low microbial activities, especially in nitrogen fixation and cellulose decomposition. Such bacteria may be applied in wastewater treatment, and to utilise saline agricultural wastes to obtain microbial products.
Such bacteria can be also applied in the biodegradation of hydrocarbons in hypersaline environments and for the production of the polymers of biotechnological interest.
The fact that research into the biodiversity of the Dead Sea is far from complete, calls for further programmes to collect, identify and determine the biochemical characteristics of organisms which live in this very unique and very saline environment.
Further studies are needed for the determination of various possible uses of halophilic microorganisms for certain economic enterprises i.e. the industrial and commercial utilisation of some of their enzymes, other metabolites and perhaps the use of whole organisms for soil reclamation and water treatment. Some of such organisms may have a medical value and certainly, most of them provide excellent genetic material for genetic engineering.
In spite of all this, it is very sad to say that little is being done in Jordan towards reaching any of these objectives, some of which are of prime importance and must be given first priority.
Apart from the Dead Sea proper, its shores and the oasis in its vicinity preserve a rare collection of desert species including relics that have survived in isolation from the surrounding desert and many other endemic species. The Mujib basin has been identified as an important bird and wetland area in the Middle East.
Jordanian research on the Dead Sea future has not been extensive or conclusive. In contrast Israeli research is more oriented and open to public, except for a mysterious submarine mission which was launched from the Israeli side late last year. Speculation about the objective ranges from the study of deep sea currents to excavations for the mythical city of Sodom and Gommorah.
One interesting recent study made in Israel proposed a scenario of the future of the Dead Sea. The study projects that the natural characteristics of the Dead Sea will prevent it from disappearing and will eventually reach an equilibrium between evaporation and recharge. Based on the progressive decline in its level, the salinity of the water will accordingly increase thus decreasing evaporation rates until reaching a balance with natural recharge. Based on that the final stable Dead Sea water level will be 510 m below sea level in the year 2400 with a final surface area of 455 sq. km.
The writer is the Programme Developmental Officer in the World Conservation Union ( IUCN) National Office in Jordan