Microalgae and cyanobacteria of the Dead Sea and its surrounding springs

Scientific exploration of the algal and cyanobacterial flora of the Dead Sea and its surroundings started in the 1930s. The unicellular green alga Dunaliella parva is the sole primary producer in the water column of the Dead Sea. The dynamics of the Dunaliella population and the interrelationships between the alga and the physical and chemical parameters in the lake are now well understood. Although cyanobacteria have occasionally been encountered in the Dead Sea as well, they are not known to contribute significantly to the microbial activities in the lake. Dense growth of cyanobacteria is found in various freshwater and saline, cold and warm springs in the Dead Sea area. Abundant cyanobacterial communities develop in the hot (up to 63°C) freshwater springs of Zerka Ma'in and Zara near the eastern shore of the lake. We here report data on the diversity of these communities, based both on microscopic observations and on molecular phylogeny techniques, and on their content of UV-absorbing pigments (mycosporine-like amino acids, scytonemin), which is of interest in view of the lowered levels of UV light reaching the Dead Sea shores.