Benjamin Elazari Volcani (1915-1999): sixty-three years of studies of the microbiology of the Dead Sea.

On February 6, 1999, Benjamin Elazari Volcani died in La Jolla, CA, USA, from kidney failure at the age of 84 (Fig. 1). Volcani (born Wilkansky) will be remembered as the pioneer of the microbiological studies of the Dead Sea. In a short article published in Nature in 1936 [39], Volcani gave the first description of an indigenous microbial community adapted to the extremely harsh conditions of the Dead Sea with its high salt concentration and the unique ionic composition of its salts. His findings were further documented in his Ph.D. thesis submitted to The Hebrew University of Jerusalem in 1940 [5] and in a review article [38]. In 1939, Volcani became a member of the Sieff Institute in Rehovot, later renamed the Weizmann Institute of Science; he headed its laboratory of microbiology until 1959, when he joined the faculty of the Scripps Institution of Oceanography, University of San Diego, La Jolla, USA, where he remained as professor of marine biology until he retired in 1985. In his retirement, Volcani resumed his investigations of the Dead Sea biota. Bottles with old enrichment cultures, dating from the 1930s and stored in his laboratory at Scripps for more than 50 years, were opened, and these appeared still to contain a variety of viable microorganisms [1, 2, 37]. Volcani’s last publications on the forms of life in the Dead Sea appeared in the year of his death [2, 37]. The Dead Sea presents fascinating challenges to the biologist who attempts to understand the biological processes in the lake. Not only does the lake contain the highest salt concentration of all natural lakes inhabited by living organisms, but the peculiar ionic composition of the Dead Sea water, with high concentrations of divalent cations magnesium and calcium, is highly inhibitory even to those microorganisms best adapted to life in the lake. These organisms thus live at or near the upper limit of their tolerance toward high magnesium concentrations. Since the days of Volcani’s pioneering research on the biology of the Dead Sea our knowledge of the lake’s biota has increased tremendously (for reviews see e.g. [18, 21, 24, 35]). In the present essay we will attempt to assess the importance of Volcani’s work in the light of our present understanding of the biological processes in the Dead Sea. Physical and chemical properties of the Dead Sea and their long-time changes