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

195 On Feb ua y 6, 1999, Benjamin Elaza i Volcani died in La Jolla, CA, USA, om kidney ailu e a he age o 84 (Fig. 1). Volcani (bo n Wilkansky) will be emembe ed as he pionee o he mic obiological s udies o he Dead Sea. In a sho a icle published in Na u e in 1936 [39], Volcani ga e he i s desc ip ion o an indigenous mic obial communi y adap ed o he ex emely ha sh condi ions o he Dead Sea wi h i s high sal concen a ion and he unique ionic composi ion o i s sal s. His indings we e u he documen ed in his Ph.D. hesis submi ed o The Heb ew Uni e si y o Je usalem in 1940 [5] and in a e iew a icle [38]. In 1939, Volcani became a membe o he Sie Ins i u e in Reho o , la e enamed he Weizmann Ins i u e o Science; he headed i s labo a o y o mic obiology un il 1959, when he joined he acul y o he Sc ipps Ins i u ion o Oceanog aphy, Uni e si y o San Diego, La Jolla, USA, whe e he emained as p o esso o ma ine biology un il he e i ed in 1985. In his e i emen , Volcani esumed his in es iga ions o he Dead Sea bio a. Bo les wi h old en ichmen cul u es, da ing om he 1930s and s o ed in his labo a o y a Sc ipps o mo e han 50 yea s, we e opened, and hese appea ed s ill o con ain a a ie y o iable mic oo ganisms [1, 2, 37]. Volcani’s las publica ions on he o ms o li e in he Dead Sea appea ed in he yea o his dea h [2, 37]. The Dead Sea p esen s ascina ing challenges o he biologis who a emp s o unde s and he biological p ocesses in he lake. No only does he lake con ain he highes sal concen a ion o all na u al lakes inhabi ed by li ing o ganisms, bu he peculia ionic composi ion o he Dead Sea wa e , wi h high concen a ions o di alen ca ions magnesium and calcium, is highly inhibi o y e en o hose mic oo ganisms bes adap ed o li e in he lake. These o ganisms hus li e a o nea he uppe limi o hei ole ance owa d high magnesium concen a ions. Since he days o Volcani’s pionee ing esea ch on he biology o he Dead Sea ou knowledge o he lake’s bio a has inc eased emendously ( o e iews see e.g. [18, 21, 24, 35]). In he p esen essay we will a emp o assess he impo ance o Volcani’s wo k in he ligh o ou p esen unde s anding o he biological p ocesses in he Dead Sea. Physical and chemical p ope ies o he Dead Sea and hei long- ime changes In he la e 1930s, when Volcani pe o med he i s mic obiological s udies o he Dead Sea, he salini y o he lake’s wa e was lowe han a p esen . Volcani s a ed ha a he ime he o al sal concen a ion a he lake su ace was 269 g/l, inc easing o 327 g/l a 50 m dep h [38]. A su ey pe o med in 1959–1960 showed he lake o be me omic ic, wi h a “pe manen ” pycnocline a a dep h o abou 40 m [17]. Since he beginning o his cen u y he wa e balance o he Dead Sea has been nega i e [12]. The dec ease in wa e le el, due in pa o clima ic changes and in ensi ied by he di e sion o esh wa e om he Jo dan i e , has led o an inc ease in he salini y o he uppe wa e laye s. This esul ed in he disappea ance o he pycnocline, ollowed by an o e u n o he wa e column a he beginning o 1979. P esen ly he sal Aha on O en1 An onio Ven osa2 1The Ins . o Li e Sciences and The Moshe Shilo Mine a Cen e o Ma ine Biogeochemis y, The Heb ew Uni e si y o Je usalem, Is ael 2Dep . o Mic obiology and Pa asi ology, Fac. o Pha macy, Uni e si y o Se illa, Spain Co espondence o: Aha on O en. Di ision o Mic obial and Molecula Ecology. The Ins i u e o Li e Sciences. The Heb ew Uni e si y o Je usalem. 91904 Je usalem. Is ael. Tel: +972-2-6584951. Fax: +972-2-6528008. E-mail: [email p o ec ed] PERSPECTIVES INTERNATL MICROBIOL (1999) 2:195–198 © Sp inge -Ve lag Ibé ica 1999 Benjamin Elaza i Volcani (1915–1999): Six y– h ee yea s o s udies o he mic obiology o he Dead Sea Fig. 1 Benjamin Elaza i Volcani (1915–1999). Pho og aph aken by A. Ven osa in Alican e, Spain, in Sep embe 1989 con en o he Dead Sea wa e is a ound 340 g/l a all dep hs. The mean alues o he ionic concen a ions in 1996 we e (in mol/l): Mg2+, 1.887; Na+, 1.594; Ca22+, 0.436; K+, 0.199; Cl–, 6.335; B –, 0.068; and SO42–, 0.005. The lake is now holomic ic, bu me omic ic egimes ha e occu ed om 1979–1982 and om 1992–1995 as a esul o massi e in low o esh wa e du ing unusually ainy win e s [12]. The chemical p ope ies o he lake ha e changed beyond a simple inc ease in he o al ionic concen a ions. A he ime o Volcani’s ea ly s udies p ecipi a ion o CaCO3we e occasionally obse ed, causing whi ening o he wa e [3, 38]. No such e en s ha e been documen ed in ecen yea s; howe e , due o he nega i e wa e balance, massi e amoun s o NaCl now p ecipi a e om he wa e column o he lake bo om as hali e c ys als. The weigh o hali e ha has p ecipi a ed be ween 1976 and 1992 was es ima ed o be o e abou 2.550 ×106 on [11]. The p ecipi a ion o hali e has caused an addi ional inc ease in he al eady ex emely high a io o di alen o mono alen ca ions o he Dead Sea wa e . Pho osyn he ic mic oo ganisms in he Dead Sea F om en ichmen cul u es se up wi h Dead Sea wa e and sedimen samples, Volcani succeeded in g owing a a ie y o pho osyn he ic mic oo ganisms. These include euka yo ic lagella e algae (Dunaliella sp.), well adap ed o he high salini ies p e ailing a he ime in he uppe wa e laye s, and an uniden i ied g een lagella e wi h a single lagellum ha g ew a 1–27% sal , wi h sligh g ow h a 30% [5, 6, 38]. Di e en ypes o cyanobac e ia we e also ound ha g ow a lowe sal concen a ions (up o abou 18%) [38]. Al hough indigenous li e was disco e ed in he Dead Sea as ea ly as 1936, he i s quan i a i e assessmen s o he mic obial communi y densi ies in he lake we e made only as la e as 1963–1964 [14]. I is now clea ha a small Dunaliella species (designa ed in he pas as Dunaliella i idis o Dunaliella pa a) is he main o only p ima y p oduce in he lake. The g een lagella e wi h a single lagellum isola ed by Volcani ha e ne e been obse ed in he lake since, no ha e been cyanobac e ia epo ed o occu in signi ican numbe s. Cyanobac e ia, howe e , can nowadays be ound in abundance in hype saline sp ings on he lake’s sho e, such as Hamei Mazo (a sp ing wi h a salini y o abou 169 g/l ha was subme ged a he ime o Volcani’s s udies, when he wa e le el was highe han a p esen ) [22]. Dunaliella was eco ded o occu in su ace wa e in high numbe s in 1964 (up o 4 ×104cells/ml). F om 1980 onwa ds a comp ehensi e sampling and moni o ing p og am has been ca ied ou , esul ing in an ex ensi e da a se co e ing algal densi ies o e he seasons a di e en dep hs. Blooms o Dunaliella cells we e obse ed du ing he pe iod 1980–1981 and again in 1992–1994: up o 8.8 ×103cells/ml we e coun ed in 1980 [27] and 1.5 ×104 cells/ml and maybe e en highe densi ies in 1992 [23, 30]. The appea ance o Dunaliella in he Dead Sea was igge ed by he massi e ain loods in he win e s o 1979–1980 and 1991–1992 ha caused a signi ican dilu ion o he uppe wa e laye s, and ini ia ed a me omic ic s a e o he lake. Dunaliella cells we e ound only in he mixed epilimnion abo e he pycnocline. In mos samples examined, he dis ibu ion o he algae was uni o m om he wa e su ace down o he pycnocline. Howe e , du ing he pe iod Augus –Oc obe 1992 cells we e ound concen a ed as a “deep chlo ophyll maximum” a a dep h o 7–10 m nea he pycnocline [30]. Labo a o y simula ions ha e shown ha a dilu ion o he uppe wa e laye s wi h mo e han 10% esh wa e is equi ed o ini ia e a mass de elopmen o he alga, p o ided ha all essen ial nu ien s a e a ailable. Inpu o su icien phospha e is also necessa y, as phospha e is he limi ing nu ien in he Dead Sea. When he salini y becomes oo high o he Dunaliella cells, hey apidly disappea om he wa e column. Du ing he decline o he dense algal bloom in he summe o 1992, Dunaliella cells we e obse ed o o m cys s ha sank o he bo om o he lake [30]. Halophilic A chaea Among he mic oo ganisms isola ed by Volcani ha a e bes adap ed o he ex emely high sal concen a ions o he Dead Sea a e a numbe o ed halophilic A chaea belonging o he amily Halobac e iaceae. Haloa cula ma ismo ui, i s desc ibed by Volcani as Fla obac e ium (o Halobac e ium) ma is-mo ui, was epo ed o g ow a NaCl concen a ions om 18% up o sa u a ion [5, 10, 38]. The gene ic name Halobac e ium was i s used by Volcani in his Ph.D. hesis, and he consolida ed he nomencla u e o he genus in his con ibu ion o he 7 h edi ion o Be gey’s Manual o De e mina i e Bac e iology in 1957 [10]. The o iginal cul u e o Halobac e ium ma ismo ui has no been p ese ed, bu a simila s ain now desc ibed as Haloa cula ma ismo ui was isola ed om he lake in he la e 1960s [13], and a o mal desc ip ion o he species was based on his isola e [29]. In addi ion, Volcani also isola ed a “ ed mic ococcus”, p obably being a Halococcus s ain [5, 38]. Addi ional no el halophilic A chaea ha e been isola ed om he Dead Sea by o he in es iga o s; hese include Halo e ax olcanii, named a e Volcani [16], Halo ub um sodomense [20], and Halobaculum gomo ense [21]. Recen ly a numbe o bo les con aining en ichmen cul u es, da ing om he 1930s and s o ed in Volcani’s labo a o y a he Sc ipps Ins i u ion o Oceanog aphy in La Jolla o mo e han 50 yea s, we e opened, and he mic oo ganisms hey con ained we e analyzed. Molecula analysis showed ha hese cul u es con ained a a ie y o a chaeal species, some o hem no el [1, 37]. This sugges ha ou unde s anding o he biodi e si y o he lake is s ill a om comple e. Quan i a i e assessmen s o he a chaeal communi y in he Dead Sea showed ha halophilic A chaea a e o en p esen in 196 INTERNATL MICROBIOL Vol. 2, 1999 O en, Ven osa e y high concen a ions: be ween 2.3 ×106and 8.9 ×106cells/ml we e coun ed in 1963–1964 [14]; up o 1.9 ×107cells/ml we e ound in he lake’s su ace laye s in he summe o 1980 [19], and in he sp ing o 1992 a maximum communi y densi y o 3.5 ×107cells/ml was eached [26]. The dense communi ies o he A chaea ich in ca o enoid pigmen s impa ed a eddish colo o he Dead Sea wa e bo h in 1980 and in 1992 [19, 23, 26], and a eddish hue had been also obse ed in 1964 [14]. De elopmen o a chaeal blooms is co ela ed wi h he occu ence o la ge numbe s o Dunaliella, he p ima y p oduce in he lake, which supplies he necessa y o ganic ma e ial. Glyce ol, p oduced and accumula ed by Dunaliella as an osmo ic s abilize , is p obably one o he main sou ces o ca bon ha suppo he de elopmen o he a chaeal communi y. Li le is known on he con ibu ion o he di e en gene a and species o halophilic A chaea o he communi y in he Dead Sea. Du ing he 1992 bloom, pola lipid analyses we e pe o med o ob ain in o ma ion on he ypes o A chaea p esen . The lake’s biomass con ained one majo glycolipid ( he sul a ed diglycosyl die he lipid S-DGD-1), whe eas he die he de i a i e o phospha idylglyce osul a e (PGS) was absen [25]. These obse a ions may sugges ha he dominan A chaeon in he Dead Sea a he ime belonged o he genus Halo ub um o o Halobaculum. No signi ican amoun s o hose speci ic glycolipids we e ound ha would ha e indica ed a massi e p esence o Haloa cula ma ismo ui in he biomass a he ime. Halophilic and halo ole an ae obic Bac e ia In addi ion o halophilic A chaea, Volcani isola ed a numbe o halophilic o halo ole an Bac e ia om he Dead Sea. Two o hese ha e been p ese ed and desc ibed as new species: Ch omohalobac e ma ismo ui [36] (o iginally desc ibed as Ch omobac e ium ma is-mo ui [5, 38]), and Halomonas halmophila [4] (o iginally Fla obac e ium halmephilum [5, 38]). Ano he in e es ing isola e, which un o una ely was no p ese ed, is Pseudomonas hales o gus [5, 38]. F om he old en ichmen cul u es, a new halophilic Bacillus species, Bacillus ma ismo ui, was ecen ly isola ed [2]. Non-halophilic ep esen a i es o he genus Bacillus we e also ound in he Dead Sea [5, 38]. These we e e med “halo esis an ” by Volcani. These o ganisms p obably su i ed exposu e o he hype saline b ines o he Dead Sea in he o m o esis an endospo es, and canno be conside ed o belong o he indigenous mic obio a o he lake. To hono Volcani’s achie emen s in he ield o halophilic Bac e ia, he bac e ial genus Volcaniella was named a e him [33]. Anae obic mic oo ganisms in he sedimen s F om he bo om sedimen s o he Dead Sea, Volcani isola ed a numbe o halophilic anae obic bac e ia [7, 38]. These include e men a i e bac e ia— hey e men glucose o lac ose and g ow a 25% sal —and deni i ie s. Se e al ae obic halophilic A chaea, including Haloa cula ma ismo ui, can g ow by deni i ica ion. Un o una ely, he e men a i e isola es ob ained by Volcani we e no p ese ed. Only in he ea ly 1980s we e new isola es o halophilic e men a i e Bac e ia ob ained om he Dead Sea and om o he hype saline lakes, and he g oup (o de Haloanae obiales) appea ed o be an ex emely in e es ing one [34]. Dead Sea isola es belonging o his o de a e Halobac e oides halobius [32], O enia ma ismo ui, and Spo ohalobac e lo e ii [34]. Spo ohalobac e lo e ii was named a e he F ench mic obiologis M. L. Lo e , who in he las decade o he 19 h cen u y isola ed a numbe o pa hogenic non-halophilic ep esen a i es o he genus Clos idium om Dead Sea mud [15]. These p obably had su i ed as esis an endospo es, and should hus be designa ed halo esis an bac e ia acco ding o Volcani’s classi ica ion. P o ozoa In en ichmen cul u es incuba ed o e y long pe iods (mon hs o yea s), Volcani ound wo ypes o p o ozoa: a cilia e and a dimas igamoeba [8, 9, 38]. La e s udies ha e ne e asce ained he p esence o p o ozoa in he Dead Sea ecosys em o hei possible impo ance in egula ing communi y densi ies o mic oo ganisms in he lake. Vi uses, howe e , may be implica ed in he decline o a chaeal and algal blooms: many i us-like pa icles we e obse ed upon examina ion o wa e samples in he elec on mic oscope [28]. Cilia e and amoeboid p o ozoa we e abundan in he hype saline (169 g/l o al sal ) sul u sp ing o Hamei Mazo , which, a he ime o Volcani’s s udies, was subme ged below he lake su ace, and now is exposed on he sho e [22]. Thus, he p o ozoa cul u ed by Volcani migh ha e de i ed om less saline ecosys ems in he Dead Sea a ea. Epilogue The apidly changing Dead Sea can be conside ed an in e es ing la ge-scale expe imen in mic obial e olu ion and adap a ion wi h espec o highe and highe di alen ca ion concen a ions. A he ime o w i ing, a chaeal communi y densi ies in he lake we e e y low, and no Dunaliella cells we e obse ed a all. The A chaea and he es ing s ages o he algae in he bo om sedimen s we e wai ing o hei oppo uni y o mul iply when condi ions would become sui able again. Li e in he Dead Sea in i s p esen s a e hus depends p ima ily on hose a e e en s o abundan ain all in he ca chmen a ea ha lead o he o ma ion o an epilimnion su icien ly dilu ed. The e e inc easing salini y o he Dead Sea wa e and he concomi an ly inc easing 197 B. E. Volcani (1915–1999) INTERNATL MICROBIOL Vol. 2, 1999 ela i e concen a ions o inhibi o y di alen ca ions, along wi h he inc easing ex en in which excess ainwa e in he ca chmen a ea is di e ed o ag icul u al use, sugges ha such mic obial bloom e en s may become a e and a e . Volcani’s s udies in he la e 1930s p o ide us wi h aluable in o ma ion on he ypes o mic oo ganisms ound in he Dead Sea du ing a pe iod in which he o e all salini y was much lowe han oday, and he uppe wa e laye had less han 80% o i s p esen -day sal concen a ion. Un o una ely, no quan i a i e in o ma ion was collec ed by Volcani, and almos 30 yea s had o pass un il he i s enume a ions o mic oo ganisms in he lake we e pe o med [14]. Ne e heless, he in o ma ion o be ound in Ben Volcani’s legacy, consis ing bo h o his publica ions and o hose bo les o en ichmen cul u es p ese ed om he 1930s, is o he u mos impo ance o unde s and he mic obial ecology o he Dead Sea, no only in he pas bu also in he p esen . Re e ences 1. A ahal DR, Dewhi s FE, Pas e BJ, Volcani BE, Ven osa A (1996) Phylogene ic analysis o some ex emely halophilic A chaea isola ed om Dead Sea wa e , de e mined on he basis o hei 16S RNA sequences. Appl En i on Mic obiol 62:3779–3786 2. A ahal DR, Má quez MC, Volcani BE, Schlei e KH, Ven osa A (1999) Bacillus ma ismo ui sp. no ., a new mode a ely halophilic species om he Dead Sea. In J Sys Bac e iol 49:521–530 3. Bloch MR, Li man HZ, Elaza i-Volcani B (1944) Occasional whi eness o he Dead Sea. Na u e 154:402–403 4. Dobson SJ, James SR, F anzmann PD, McMeekin TA (1990) Emended desc ip ion o Halomonas halmophila (NCMB 1971T). In J Sys Bac e iol 40:462–463 5. Elaza i-Volcani B (1940) S udies on he mic o lo a o he Dead Sea. Ph.D. hesis, The Heb ew Uni e si y o Je usalem (in Heb ew). 6. Elaza i-Volcani B (1940) Algae in he bed o he Dead Sea. Na u e 145:975 7. Elaza i-Volcani B (1943) Bac e ia in he bo om sedimen s o he Dead Sea. Na u e 152:274–275 8. Elaza i-Volcani B (1943) A dimas igamoeba in he bed o he Dead Sea. Na u e 152:301–302 9. Elaza i-Volcani B (1944) A cilia e om he Dead Sea. Na u e 154:335–336 10. Elaza i-Volcani B (1957) Genus XII. Halobac e ium Elaza i-Volcani, 1940. In: B eed RS, Mu ay EGD, Smi h NR (eds) Be gey’s Manual o De e mina i e Bac e iology, 7 h ed. Bal imo e: The Williams & Wilkins Company, pp 207–212 11. Ga ieli I (1997) Hali e deposi ion om he Dead Sea: 1960–1993. In: Niemi T, Ben-A aham Z, Ga JR (eds) The Dead Sea—The Lake and i s Se ing. Ox o d: Ox o d Uni e si y P ess, pp 161–170 12. Ga ieli I, Bey h M, Yechieli Y (1998) The Dead Sea—A e minal lake in he Dead Sea i : a sho o e iew. In: O en A (ed) Mic obiology and Biogeochemis y o Hype saline En i onmen s. Boca Ra on: CRC P ess, pp 121–127 13. Ginzbu g M, Sachs L, Ginzbu g BZ (1970) Ion me abolism in a halobac e ium. I. In luence o age o cul u e on in acellula concen a ions. J Gen Physiol. 55:187–207 14. Kaplan IR, F iedmann A (1970) Biological p oduc i i y in he Dead Sea. Pa 1. Mic oo ganisms in he wa e column. Is ael J Chem 8:513–528 15. Lo e ML (1892) Resea ches on he pa hogenic mic obes o he mud o he Dead Sea. Pales Expl Fund 1892:48–50 16. Mullakhanbhai ML, La sen H (1975) Halobac e ium olcanii spec. no ., a Dead Sea halobac e ium wi h a mode a e sal equi emen . A ch Mic obiol 104:207–214 17. Nee D, Eme y KO (1967) The Dead Sea. Deposi ional P ocesses and En i onmen s o E apo i es. Bulle in No. 41, S a e o Is ael, Minis y o De elopmen , Geological Su ey 18. Nissenbaum A (1975) The mic obiology and biogeochemis y o he Dead Sea. Mic ob Ecol 2:139–161 19. O en A (1983) Popula ion dynamics o halobac e ia in he Dead Sea wa e column. Limnol Oceanog 28:1094–1103 20. O en A (1983) Halobac e ium sodomense sp. no ., a Dead Sea halobac e ium wi h ex emely high magnesium equi emen and ole ance. In J Sys Bac e iol 33:381–386 21. O en A (1988) The mic obial ecology o he Dead Sea. In: Ma shall KC (ed) Ad ances in Mic obial Ecology. Vol. 10. New Yo k: Plenum Publishing Company, pp 193–229 22. O en A (1989) Pho osyn he ic and he e o ophic ben hic bac e ial communi ies o a hype saline sul u sp ing on he sho e o he Dead Sea (Hamei Mazo ). In: Cohen Y, Rosenbe g E (eds) Mic obial Ma s. Physiological Ecology o Ben hic Mic obial Communi ies. Washing on, D.C.: Ame ican Socie y o Mic obiology, pp 64–76 23. O en A (1993) The Dead Sea - ali e again. Expe ien ia 49:518–522 24. O en A (1997) Mic obiological s udies in he Dead Sea: 1892–1992. In: Niemi T, Ben-A aham Z, Ga , JR (eds) The Dead Sea - The Lake and i s Se ing. Ox o d: Ox o d Uni e si y P ess, pp 205–213 25. O en A, Gu e ich P (1993) Cha ac e iza ion o he dominan halophilic A chaea in a bac e ial bloom in he Dead Sea. FEMS Mic obiol Ecol 12:249–256 26. O en A, Gu e ich P (1995) Dynamics o a bloom o halophilic A chaea in he Dead Sea. Hyd obiologia 315:149–158 27. O en A, Shilo M (1982) Popula ion dynamics o Dunaliella pa a in he Dead Sea. Limnol Oceanog 27:201–211 28. O en A, B a bak G, Heldal M (1997) Occu ence o i us-like pa icles in he Dead Sea. Ex emophiles 1:143–149 29. O en A, Ginzbu g M, Ginzbu g BZ, Hochs ein LI, Volcani BE (1990) Haloa cula ma ismo ui (Volcani) sp. no ., nom. e ., an ex emely halophilic bac e ium om he Dead Sea. In J Sys Bac e iol 40:209–210 30. O en A, Gu e ich P, Ana i DA, Ba kan E, Luz B (1995) A bloom o Dunaliella pa a in he Dead Sea in 1992: biological and biogeochemical aspec s. Hyd obiologia 297:173–185 31. O en A, Gu e ich P, Gemmell RT, Teske A (1995) Halobaculum gomo ense gen. no ., sp. no ., a no el ex emely halophilic a chaeon om he Dead Sea. In J Sys Bac e iol 45:747–754 32. O en A, Weisbu g WG, Kessel M, Woese CR (1984) Halobac e oides halobius gen. no ., sp. no ., a mode a ely halophilic anae obic bac e ium om he bo om sedimen s o he Dead Sea. Sys Appl Mic obiol 5:58–70 33. Quesada E, Valde ama MJ, Beja V, Ven osa A, Gu ie ez MC, Ruiz- Be aque o F, Ramos-Co menzana A (1990) Volcaniella eu ihalina gen. no ., sp. no ., a mode a ely halophilic nonmo ile G am-nega i e od. In J Sys Bac e iol 40:261–267 34. Rainey FA, Zhilina TN, Boulygina ES, S ackeb and E, Tou o a TP, Za a zin, GA (1995) The axonomic s a us o he e men a i e halophilic anae obic bac e ia: desc ip ion o Haloanae obiales o d. no ., Halobac e oidaceae am. no ., O enia gen. no . and u he axonomic ea angemen s a he genus and species le el. Anae obe 1:185–190 35. Ven osa A, A ahal DR (1999) Mic obial li e in he Dead Sea. In: Seckbach J (ed) Enigma ic Mic oo ganisms and Li e in Ex eme En i onmen s. Do d ech : Kluwe Academic Publishe s, pp 357–368 36. Ven osa A, Gu ie ez MC, Ga cia MT, Ruiz-Be aque o F (1989) Classi ica ion o “Ch omobac e ium ma ismo ui” in a new genus, Ch omohalobac e gen. no ., as Ch omohalobac e ma ismo ui comb. no ., nom. e . In J Sys Bac e iol 39:382–386 37. Ven osa A, A ahal DR, Volcani BE (1999) S udies on he mic obio a o he Dead Sea —50 yea s la e . In: O en A (ed) Mic obiology and Biogeochemis y o Hype saline En i onmen s. Boca Ra on: CRC P ess, pp 139–147 38. Volcani BE (1944) The mic oo ganisms o he Dead Sea. In: Pape s Collec ed o Commemo a e he 70 h Anni e sa y o D . Chaim 198 INTERNATL MICROBIOL Vol. 2, 1999 O en, Ven osa Weizmann. Collec i e olume: 71–85. Reho o h: Daniel Sie Resea ch Ins i u e 39. Wilkansky B (1936) Li e in he Dead Sea. Na u e 138:467 199 B. E. Volcani (1915–1999) INTERNATL MICROBIOL Vol. 2, 1999