12. Environment

The Dead Sea got its name because it was believed that life forms could not survive in the salty water. In 1936, Benjamin Elazari-Volcani of the Sieff Institute in Israel found evidence of microorganisms in the lake. He found one species of alga, the green Dunaliella, and several species of bacteria. The Dundaliella is usually found in fresh water or seawater but can adapt to a hyper saline environment by synthesizing glycerol, which increases the osmotic pressure inside the cell and prevents the entry of salt. Algae can only survive at the surface. Halotolerant red bacteria, which can survive in water with a moderate salt concentration (at least 150 grams of sodium chloride), are found at the northern end where fresh Jordan River mixes with Dead Sea water. The halobacterial cell contains a high concentration of potassium, and the cell membrane retains potassium rather than sodium. This feature allow the cell to survive in salty waters. Studies have found a high correlation between the physical and biological properties of the Dead Sea. One study found that the total number of bacteria decreased by a factor of 100 at a depth of 50 meters, and that there were no living alge below 100 meters. A 1970 study counted 40,000 Danaliella cells per milliliter at the surface, but only anaerobic bacteria below 50 meters.
Changes in salinity have an impact on the biological composition of the lake. Dilution in salt content causes the profusion of microorganisms. Heavy rains in the winter of 1980 (also in 1992) diluted the salt content of the lake and caused the number of microorganisms at the surface to multiply to some 19 million cells per milliliter. As a result, the color of the surface water changed from blue green to reddish blue. Scientists predict that a sudden inflow of fresh water, channeled in by a canal for example, could turn the sea first green, then bright pink.

Even though the southern basin is dry most of the year, the Dead Sea is not in danger of drying up any time soon. Water evaporates slowly because the vapor pressure over the surface is lowered by the water's dissolved salts. According to the current rate of evaporation, it would take hundreds of years for the lake to dry up because the northern basin is so deep. Nonetheless, if water levels continue to drop, the Dead Sea would see changes in landscape and biodiversity.

The Dead Sea's low surface level has caused changes in the biological, chemical and physical composition of the lake. The gradual recession of the shore may have negative effects on tourism and potash mining. A more pressing issue is that the low surface level is evidence of the water shortage throughout the region. Overuse and mismanagement of existing resources, in addition to massive development projects on both sides of the Jordan River, have caused water table levels throughout Israel to drop. Lake Tiberias, which supplies almost one-third of Israel's water requirements, is at its lowest level in 60 years. As a result, Israel and Jordan rank among the top 20 countries suffering from water scarcity, according to World Resources Water Stress Index, 1990. This index measures annual renewable water resources per capita available for agriculture, industry and domestic use. Renewable freshwater resources of 1,000 cubic meters have been accepted as an adequate minimum for development. Israel and Jordan are already far below that level. Using the same index to predict future water scarcity given low and high UN population growth predictions, the situation is expected to worsen. Although efficient management and modern technology can stretch scarce resources in some cases Israel, for example, supports agricultural, industrial and domestic needs with less than 500 cubic meters per person per year present water use may not be sustainable in the long run.


Table: Water Stress Index (cubic meters per capita) World Resources 1996-1997
1990:
Israel 461
Jordan 308

Projected water resources for 2050:
Israel 192-300
Jordan 68-90

Conservation efforts include reduced diversion of Jordan River water and more efficient use of water in agriculture. If a Med-Dead or Red-Dead Canal was constructed, Israel and Jordan could reduce the capacity of existing diversion projects. As it stands now, Israel spends nearly 20 percent of its energy resources to lift some 350 million cubic meters from Lake Kinneret, and pump it through the National Water Carrier each year. The canal would also reduce the need for additional diversion projects, since hydropower generated by the canal would provide a new supply of water for the region. Israeli water authorities have made efforts to promote efficient usage through cutbacks in subsidies to farmers. However, there needs to be an education campaign throughout the region on the value of using water efficiently.