Moh’d Wedyan, Ahmed El-Oqlah, Khalil Altif and Khalid Khlifate
Recently, the rapid drying out of the Dead Sea is one of the most challenging problems facing the scientists and governments of the region. Its level has dropped more than 20 m in the past decade. Massive precipitation of halite from the water column has led to a decrease in Na+ concentration, concomitant with an increase in Mg2+, making the lake supersaturated with NaCl. This situation presents a big challenge to the microbial life of the lake. However, despite these harsh conditions in the lake, several microorganisms, including members of the groups bacteria, unicellular algae, fungi, viruses, and Archaea, have been able to survive.
To understand the factors that affect the microbes in the Dead Sea and to predict the possible effects of the planned conveyance of Red Sea water to the Dead Sea, a series of experiments were performed in the field, as well as in the laboratory. The results of the laboratory experiments showed that the growth of the Dunaliella was possible only when Dead Sea water was diluted with a minimum of 10% (by volume) Red Sea water. Addition of phosphate was essential for the algae to grow and growth rates and yields increased with increasing phosphate concentration and decreasing salinity. Field experiments revealed that the growth of algae was rapidly followed by the development of dense blooms of red halophilic Archaea. Although it should be realized that the closed system formed by the shallow ponds differs from the conditions in the lake, the results suggest that a microbial bloom, once formed, can remain present in the Dead Sea for months to years. These observations are important when attempting to predict how the biological properties of the lake may change in the future and they have important implications for the planning of the Red Sea- Dead Sea conduit.
The “Peace Conduit”, a water carrier between the Red Sea and the Dead Sea, has been proposed to prevent the drying out of the lake and to restore the water level to a desired elevation. The present simulation experiments were designed at the Al Hussein bin Talal University (AHU) field station atMa’an to get information on the ecological impacts of the Dead Sea when the “Peace Conduit” plans are implemented and massive quantities of Red Sea water will enter the Dead Sea and lower the salinity of the upper water layers.
Preliminary analysis was carried out of Fluorescence In Situ Hybridization (FISH) and Polar lipid of Archaea and Bacteria collected from the experimental ponds containing different Dead Sea-Red Sea water ratios, in order to analyze how they affect the microbial communities of the ponds. The Archaea community changed significantly according to the water mixture, presenting the greatest diversity when 30% Red Sea water was added to Dead Sea water.