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5J[Jt'1. 4) () / E;J-JWr !n (/)U- -00::-- r- « -1»0::r-aQ:mThe Ministry of National Infrastructuresr כ Xr--J ש - C : כ ט ט ,.0 " " U -JGEOLOGICAL SURVEY OF ISRAEL. נ oBIOLOGICAL SIMULATION EXPERIMENTS RELATED TOMIXING OF SEA WATER IN THE DEAD SEA(Implications for the future of the Dead Sea)Jointly funded by the Geological Survey of Israel,The Ministloy of Regional Coopeloation and Dead Sea WOloks Ltd.Oren A., Gavrieli I., Gavrieli J., Aharoni M., Lati J. and Kohen M.J erusalem, 2003GSII6/2003w ט
The Ministry of NationallnfrastmcturesGEOLOGICAL SURVEY OF ISRAELBIOLOGICAL SIMULATION EXPERIMENTS RELATED TOMIXING OF SEAWATER IN THE DEAD SEA(Implications for the future of the Dead Sea)Jointly funded by the Geological Survey of Israel,The Ministry of Regional Cooperation and Dead Sea Works Ltd.Oren A. 1, Gavrieli 1. 2 and Gavrieli J. 3 Aharoni M. 4 , Lati J. 4 and Kohen M. 41 Divisionof Microbial and Molecular Ecology, The Institute of Life Sciences,The Hebrew University of Jerusalem2Geological Survey of Israel3IMI (TAMI) Institute for Research and Development4Dead Sea Works LTD. המכון הג'אןלוגי הטפריה GEOLOGIC,A,L SURVEY OF ISRAEL ז HE LI8R נ ./ RYJerusalem,2003GSII6/2003
11. IntroductionAmong the factors to be taken into account when planning the "Peace Conduit" arebiological processes in the water column and the sediments. The mixing of seawater in theDead Sea will lead to several major changes in the limnology of the Dead Sea. The watercolumn will probably become stratified again, especially so during the filling period, whenthe surface layer will become diluted. The rate at which the salinity will decrease and thefinal density at the target level will be determined by the rates of inflow and lake level rise.Once the desired lake level has been attained the density of the upper water will increaseagain due to accumulation of seawater-derived salts.Its salinity will increase until itattains the salinity of the lower water column, and overtum will occur. From this point intime, prolonged periods of stratification are not expected. If stratification will develop, itwould be short-termed, probably with annual overtums (Gavrieli et al., 2002).An assessment of the biological processes that currently occur in the lake and the possibleeffect of the addition of water from the Gulf of Aqaba with the future implementation ofthe "Peace Conduit" is required.Therefore simulation experiments were set up inexperimental ponds on the grounds of the Dead Sea Works, Sedom. This study is part of ajoint project undertaken by the Geological Survey of Israel and the Ministry of RegionalCooperation to formulate a dynarnic limnological model for the Dead Sea that wouldmodel the mixing of seawater in Dead Sea brine. Preliminary results of these simulationexperiments are presented below.2. The Microbiology of the Dead Sea - Past and PresentIn spite of its extremely high salt concentration and its unusual ionic composition, a varietyof microorganisms have been shown to live in the Dead Sea. These include autotrophicunicellular green algae (Dunaliella sp.) and a number of aerobic heterotrophic prokaryotes.The dominant types are red halophilic Archaea belonging to the farnily Halobacteriaceae:Halojerax volcanii, Halorubrum sodomense, Halobaculum gomorrense, and others (Fig. 1)(for reviews see Nissenbaum, 1975; Oren, 1988, 1997, 1998,2000).
2. . . . . . . 'i 'נ -Figure 1. Dead Sea microorganisms. From left to right: Dunaliella parva, Haloarculamarismortui, and Halojerax volcanii (bar 10 I-tm).The Dead Sea is an exceptionally harsh environment, even for those microorganisms bestadapted to life at high salt concentrations. The water activity in Dead Sea brines (0.67calculated in 1979) (Krumgalz and Millero, 1982) is close to the lowest water activityknown to support life. In addition, molar concentrations of divalent cations are poorlytolerated even by the most halophilic organisms known.The pioneering studies of Benjarnin Elazari-Volcani (1915-1999) in the late 1930s - early1940s first showed that the Dead Sea is inhabited by an indigenous community ofmicroorganisms (Elazari-Volcani, 1940a, 1940b, 1943, 1944; Volcani, 1944; Wilkansky,1936). The first quantitative determinations of the sizes of the algal and archaeal/bacterialcommunities were performed only in 1963 (Kaplan and Friedmann, 1970). Only from1980 has a systematic monitoring program of the microbial communities in the Dead Seabeen operating. The results have shown that the Dead Sea is a highly dynarnic biotope,whose biological properties vary greatly from year to year.In the present holomictic state of the lake no growth of Dunaliella is possible, as the saltconcentration of the brine is too high. Algal blooms only appear when the upper waterlayers become significantly diluted (10-20% at least) by winter rain floods. Dunaliellablooms have been observed in 1980 and again in 1992, in both cases triggered by massivewinter floods that caused the formation of a diluted epilimnion, initiating a meromicticepisode. In the summer of 1980, algal population densities of up to 8.8xl03 cells/ml were
3observed (Oren and Shilo, 1982), and even higher numbers (up to 1.5xl04 Dunaliellacells/ml) were counted in the spring of 1992 (Oren, 1993, 1999; Oren et al., 1995a) (Fig.2). No algae were observed the water column during the monomictic periods (1983-1991and from 1996 onwards).The algal blooms probably develop from resting stages thatsurvive in the bottom sediments of the lake (Oren et al., 1995a). Analysis of the spatialdistribution of the 1992 bloom at its onset, using remote sensing, confirmed that the bloomoriginated in nearshore areas around the lake, wherever shallow sediments potentiallyharboring Dunaliella cysts came in contact with the diluted surface water (Oren and BenYosef, 1997). An additional factor essential for a Dunaliella bloom to develop in the lakeis phosphate, which is the limiting nutrient in the Dead Sea (Oren and Shilo, 1985).Levels of biologically available nitrogen in the Dead Sea are high.The averageconcentration of ammonium ions in the water column was reported to be 5.9 mg/l in 1960and 8.9 mg/l in 1991 (Nissenbaum et al., 1990; Stiller and Nissenbaum, 1999). Nitrate ispresent in low concentrations only (20 ן .tg N03--NIl in the 1960s, a value that had increasedto 200-500 ן .t g/l in 1981 as a result of anthropogenic pollution of the Jordan River) (Stillerand Nissenbaum, 1999). Phosphorus is not abundantly found in the Dead Sea, as itssolubility in the lake's brines is limited. Stiller and Nissenbaum (1999) reported dissolvedphosphorus levels of about 35 ן .tg P043--PIl. Particulate phosphorus was more variable at30-50 ן .tg/l.The sediments were suggested to contribute between 30 and 58% to thephosphate input in the Dead Sea water column, the remainder being derived from theJordan River and flood waters (Nissenbaum et al., 1990; Stiller and Nissenbaum, 1999.)Another source of phosphorus to the Dead Sea is dust from the atmosphere. Dustdeposition over a three-year period (1997-1999) varied between 25.5-60.5 g/m2.year. Theaverage phosphorus content of this dust was 1.2% (calculated as P205), present mainly asapatite.The value was esperically high in the winter months (average of 2.6% forDecember-February). Thus, between 4 and 10 mmoVm2 of phosphorus may be estimatedto enter the Dead Sea annually from atmospheric dust (Singer et al., 2003). Dissolvedoxygen levels in Dead Sea water are low: concentrations measured in the water column in1987-1989 averaged around 0.8 mlIkg (equivalent to 1 mVl or 1.4 mg/l) at all depths(Shatkay, 1991; Shatkay et al ,. 1993.)
4x1 סנ 151'810 ז c!5VJl0x10'-30i ו i20 .1100240"'i'- ן 220J3. 200:! ג 180180-r T חד ד 198019841988199219962000YearFig. 2. Population density of the unicellular green a1ga Dunaliella (upper panel) and thecommunity of prokaryotes (mainly Archaea) (middle panel) in the upper meters of the DeadSea water column, 1980-2002, as correlated with the salinity of the upper water layer (Iowerpanel). Salinity is expressed in sigma units, indicating the density excess (in kglm3) to thestandard reference density of 1000 kglm3 cr25 denotes the density in sigma units at 25 c.Concomitant with the algal blooms, red halophilic Archaea rapidly develop in highnumbers at the expense of organic material produced by Dunaliella. Glycerol may well bethe main organic compound on which the Archaea thrive as Dunaliella cells accumulateglycerol as osmotic stabilizer. We counted up to 1.9xl07 bacteria/ml in the surface layersin 1980 (Oren, 1983a), and up to3.5xl07 cells/ml in 1992 (Oren, 1999; Oren andGurevich, 1995) (Fig. 2). After the archaeal blooms in 1980 and 1992 had reached theirpeaks, the community density slowly declined. Bacteriophages may have been a cause forthe declines. Electron microscopic examination of water samples collected in 1994-1995
5showed large numbers of virus-like particles.Their numbers exceeded those of theprokaryotic cells ten-fold on the average (Oren et al., 1997).The bacterioruberin carotenoid pigments present in the cell membrane of the Archaeaimparted a reddish color to the Dead Sea water during the bloom periods. Another pigmentthat may have contributed to the red coloration of the Dead Sea water during these bloomsis bacteriorhodopsin (Oren and Shilo, 1981). Light energy absorbed by bacteriorhodopsinis converted into a pH gradient, which can be used as a source of energy. Halorubrumsodomense, isolated from the 1980 bloom, is one of the species able to synthesize purplemembrane with bacteriorhodopsin (Oren, 1983b).The bacterial blooms were case confined to the upper meters of the water column above thepycnocline. The vertical distribution of the bacteria in the water column could be used as asensitive tracer of stratification: when a new holomictic episode starts, the remainder of thearchaeal community that was previously confined to the upper water layers above thepycnocline and/or thermocline becomes distributed evenly over the entire water column(Anati et al., 1995; Oren, 1985, 1999; Oren and Anati, 1996). Densities of Archaea in thewater column during the holomictic episodes have been low (below 106 microscopicallyrecognizable cells/rnl) (Oren, 1992).Four Dead Sea Archaea have been described as new species: Haloarcula marismortui,Halojerax volcanii, Halorubrum sodomense, and Halobaculum gomorrense. Haloarculamarismortui - originally named Halobacterium marismortui (Volcani, 1944) andsubsequently lost - was reisolated in the 1960s (Ginzburg et al., 1970; Oren et al., 1990).The pleomorphic Halojerax volcanii was isolated in the early 1970s from sediments(Mullakhanbhai and Larsen, 1975). It tolerates high magnesium concentrations. The rodshaphed Halorubrum sodomense is also highly magnesium tolerant (Oren, 1983b).Halobaculum gomorrense is another rod-shaped isolate, obtained from the 1992 bloom(Oren et al., 1995b).Additional archaeal isolates have been isolated from the lake,including from the Jordanian side (Turki, 1992).
6The Dead Sea has also yielded a number of aerobic eubacterial isolates. Two of Volcani' sisolates have been preserved: Chromohalobacter marismortui (Elazari-Volcani, 1940a;Ventosa et al., 1989), and Halomonas halmophila (Dobson et al., 1990; Elazari-Volcani,1940a). Chromohalobacter israelensis was isolated from crude solar salt from a Dead Seaevaporation pond (Arahal et al., 2001; Huval et al., 1995; Rafaeli-Eshkol, 1968). Recentattempts to isolate bacteria from Volcani's old enrichments (Ventosa et al., 1999) haveyielded Salibacillus marismortui (Arahal et al., 1999).A variety of fungi were isolated from the lake, from surface waters as well as from deepwater samples (Buchalo et al., 1998; K.is-Papo et al., 2001). One isolate, described asGymnascella marismortui, is a true halophile that grows well in media containing 50%Dead Sea water and higher (Buchalo et al., 1998). Whether fungi are present as vegetativehyphae and may contribute to the heterotrophic activity in the lake remains to bedetermined. Protozoa probably do not play a role in the Dead Sea, although Volcani foundciliate and amoeboid protozoa in his enrichment cultures (Elazari-Volcani, 1943, 1944;Volcani, 1944).Anaerobic bacteria have been isolated from the bottom sediments of the Dead Sea. Theseinclude both non-halophilic endospore-forming species of the genus Clostridium (Lortet,1892) and truly halophilic bacteria. Isolates characterized are:- Halobacteroides halobius, a species of slender, flexible rods that ferment sugars toethanol, acetic acid, hydrogen, and carbon dioxide (Oren et al., 1984).-Sporohalobacter lortetii (basonym Clostridium lortetii), an endospore-formingbacterium producing gas vesicles adjacent to the developing endosporeThis speciespreferentially ferments amino acids (Oren, 1983c; Oren et al., 1987).Orenia marismortui, originally described as Sporohalobacter marismortui, anotherendospore-forming fermentative anaerobe (Oren et al., 1987; Rainey et al., 1995).- Selenihalanaerobacter shrijtii, a species that lives by anaerobic respiration, usingnitrate, trimethylamine N-oxide, and notably selenate as electron acceptors. Selenate isreduced to a mixture of selenite and elemental selenium. (Switzer Blum et al., 2001).
7It is unknown whether dissimilatory sulfate reduction presently occurs in the bottomsediments of the Dead Sea. Prior to the 1979 overtum, sulfide was found in the anaerobichypolimnion (Neev and Emery, 1967). This sulfide was enriched in light sulfur isotopes,suggesting bacterial sulfate reduction as its source (Nissenbaum and Kaplan, 1976). Themicroorganisms responsible for the formation of this sulfide have never yet been isolated,and attempts to quantify sulfate reduction in Dead Sea sediments by following theformation of H 235S from 35S042- did not give conclusive evidence for the occurrence of theprocess. The anaerobic sediments have a potential for methanogenesis. 14C was evolvedwhen sediment slurries were incubated with 14C-labeled methanol (Marvin DiPasquale etal., 1999). No methane formation was found on acetate, trimethylamine, dimethylsulfideor methionine.3. Possible Impact of The Proposed "Peace Conduit" on the Biology oftheDead Seaa. Algae and Bacteria in the aerobic water columnImplementation of the plans to construct the "Peace Conduit" between the Red Sea and theDead Sea is expected to drastically change the properties of the Dead Sea as an ecosystem.The massive inflow of sea water and/or reject brine will most probably cause theestablishment of a meromictic state of the Dead Sea with the formation of a dilutedepilimnion. This may possibly lead to mass development of unicellular algae and bacteria.A thorough understanding of the biological phenomena in the Dead Sea in its present state,supplemented with experiments simulating the effects of a reduction in salinity by additionof seawater are therefore necessary to allow predictions how the biological properties ofthe Dead Sea will change in the future (Gavrieli et al., 2002).In the past, outdoor simulation experiments were conducted at the Beit Ha'aravaexperimental station to simulate the possible effect of dilution (with Mediterranean water)and phosphate addition on the biological processes in Dead Sea water. These studies haveshown that dilution of Dead Sea water combined with the addition of phosphate may causethe formation of exceedingly turbid, reddish-green colored brines (for example: densities of105 Dunaliella cells ן ml and 108 bacterialml were obtained in 65% Dead Sea water
8supplemented with phosphate) (Oren and Shilo, 1985).A new serles of simulationexpel'iments has now been initiated on the gl'ounds of the Dead Sea Works Ltd. at Sedom.The experimental setup consists of 900 litel' ponds (Fig. 3), which are filled with different. concentl'ations of Dead Sea water and Red Sea water or Red Sea watel' concentrate,amended with different phosphate concentrations, to test the effect of different mixingscenarios and nutrient availability.Parameters monitol'ed are algal (Dunaliella) andbacterial numbers, total microbial biomass as particulate pl'otein, turbidity, quantitation ofbactel-ial and algal pigments, and othel-s. Figs. 4 and 5 present some of the first resultsobtained with this setup.Fig. 3. The expel'imental pond setup at Sedom.No algal and bacterial development was observed in unamended Dead Sea water .Similarly, no or very little biological activity occurred in mixtures of 85% Dead Sea waterand 15% seawater or twice concentrated seawater from the Gulf of Aqaba when nophosphate or 1 IlM phosphate was added. Moderately dense blooms of algae and bacteria(up to 7-14x103 and 1.6-2.3x107 cells/ml , numbers comparable to those monitored in thelake in 1980) developed when the added phosphate concentl-ation was increased to 10 IlM ;these blooms appeared relatively late (after 3-4 months) and declined dUl-ing the wintelmonths. Dramatic biological effects wel-e found in those ponds filled with a mixtl ן re of
970% Dead Sea water and 30% Gulf of Aqaba water. Even when no phosphate was added,algae and bacteria started to appear after 1.5-2 months, and reached peak densities of6.3xl03 Dunaliella cells/ml and 2.5xl07 bacterialml after 2-3 months. These blooms weresustained for many months.Here a siginificant decline was observed in the winter.Whether the phosphate required for the biota was derived from the water used to fill theponds or from atmospheric dust cannot be ascertain. When phosphate was added at theonset of the experiment (1 or 10 .M), dramatic increases in algal and bacterial densitieswere seen (up to 1.3xl04 and 8xl04 Dunaliella and 3xl07 and 9.7xl07 bacterialml,respectively). The water in the ponds became highly turbid, and the algal chlorophyll andthe bacterial bacterioruberin pigments imparted a brownish-green color to the water. Alsohere some decline was observed in the winter, but when the experiment was te ז minated inMarch 2003 after eight months, algal and bacterial numbers in the water still exceeded thehighest values monitored in the Dead Sea during the dramatic 1992 bloom, and the water inthe pond had a deep reddish-brown color.6
10111 'זכ 90c: 80 כ ,gt-70E60 ט 50.:i, !פ i40§30 וס ב C20100050100150200250Days from the onset of the experment160140120i. ם . 100 .cQ,e.2.cU808040200050100150200250Days from the onset of the experimentFig. 4. Algal development (population density of Dunaliella and chlorophyll) in selectedexperimental ponds at Sedom, July 23, 2002 (start of the experiment) - March 12, 2003.The ponds contained 100% Dead Sea water (0),85% Dead Sea water, 15% seawater fromthe Gulf of Aqaba 10 JJ.M phosphate (0), 85% Dead Sea water, 15% twice concentratedseawater from the Gulf of Aqaba 10 JJ.M phosphate (0), 70% Dead Sea water, 30%seawater from the Gulf of Aqaba without added phosphate (.) and with 1 JJ.M ( ) and 10JJ.M phosphate (.).
11120100;;.-80.!!.Eii 60't:Su" ומ 40200050100150200250Days from the onset of the experiment7060E'50 סו .;.c40j ו :. כ :0't:30"20SU ו a100050100150200250Days from the onset of the experimentFig. 5. Bacterial (archaeal) development, expressed as the community density of prokaryotesand the concentration of bacterioruberin carotenoids in selected experimental ponds atSedom, July 23, 2002 (start of the experiment) - March 12, 2003. The ponds contained100% Dead Sea water (0), 85% Dead Sea water, 15% seawater from the Gulf of Aqaba 10 phosphate ( », 85% Dead Sea water, 15% twice concentrated seawater from the Gulf ofAqaba 10 phosphate (0), 70% Dead Sea water, 30% seawater from the Gulf of Aqabawithout added phosphate (.) and with 1 ( ) and 10 phosphate (-).The .results of these simulation experiments show that the extent of the development ofmicrobial blooms in the Dead Sea will depend on factors such as the salinity of the upperwater layer and the availability of phosphate. Phosphate availability proved to be a criticalfactor. Some phosphate enters the lake from the Jordan river and with winter rainfloods.
12No quantiative estimates are available of the amounts of phosphorus thus added to the lake.From the data provided by Singer et al. (2003) it can be calculated that dust deposition willenrich the lake with 4-10 mmol/m2 annually.This phosphorus, if dissolved in theepilimnion above a pycnocline at a depth of 10 m, will enrich the upper water layers with0.4-1 of phosphate, a value high enough to stimulate the biota (Figs. 4, 5). Thepossible use of antiscalants to protect the membranes used in the reverse osmosis processhas also to be taken into account, as most of these antiscalants are based onpolyphosphates, which upon degradation yield inorganic phosphate.An important question is whether microbial blooms will be of short duration, followed by adecline, or whether dense communities of algae and bacteria will maintain the,mselves forprolonged periods. If the latter scenario will prevail, it willlead to increased surface waterturbidity, which will probably result in increased rate of evaporation due to light scattering.This implies that larger volume of seawater will be needed to raise, and later maintain, theDead Sea at the desired water level. Prolonged blooming periods is clearly not a desiredoutcome of the "Peace Conduit" as it implies a major change in the ecology of the DeadSea, the scenery around the lake and its attractiveness. These issues may be major factorswhen planning the "Peace Conduit".The pond simulation experiments at Sedom are being continued and extended, and we hopethus to obtain a more profound understanding of the possible biological effect of differentscenarios of short-term and long-term influx of seawater, seawater concentrates, andphosphate in the Dead Sea.b. Anaerobic processes in the lower water mass and the sedimentsThe development of density stratification in the Dead Sea will isolate its main water massfrom the atmosphere. This water mass may well develop anoxic conditions, similar to the situation that prevailed in the lake prior to the 1979 overtuffi, and it is well possible thatbacterial sulfate reduction will again cause the accumulation of H2S. In addition, under thereducing condition iron will becomes more mobile through its reduction to Fe2 . Presentlythere is no estimate for the rate at which the anoxic conditions will develop and what H2Sconcentrations should be expected in the lower water mass. Pumping of sulfide-containing
13brines to the surface by the Israeli and the Jordanian potash industries may haveenvironmental and industrial consequences: During the brine's flow in the feeding canalsand in the evaporation ponds, part of the H2S will become chemically oxidized and partwill evaporate. The disagreeable smell of H2S may decrease the attractiveness of the areain the vicinity of the canal and evaporation ponds. It is anticipated that by the time thebrine reaches the carnallite ponds it would contain no sulfide. If this assumption is wrong,the industries will need to cope with brine that is even more corrosive than the brine itpumps today from the lake. The iron in the anoxic brine will precipitate when exposed tooxygen as Fe-oxyhydroxides.Depending on the rate of oxidation, some of the ironprecipitation may occur in the carnallite ponds, in which case the industries will have tolearn how to separate this element and other trace elements from their products.Simulation experiments have been set up in March 2003 in which one-liter portions ofDead Sea, with or without dilution with distilled water or seawater from the Gulf of Aqaba,were amended with different potential electron donors (bacterial and algal biomass, lactate,acetate) and incubated under anaerobic conditions. Small amounts of anaerobic sedimentfrom the Dead Sea and from the Eilat saltem ponds were added as inoculum. We arecurrently monitoring the development of sulfide in these bottles to try to estimate whethersulfide may accumulate in the lower water mass, and if so, at what rate.4. Final CommentsDilution of the upper water layers of the Dead Sea is expected to have a profound effect onthe biology of the lake. Under certain circumstances dense microbial blooms may beexpected to develop, imparting a high turbidity and red-green colors to the brine.Biological simulation expertiments such as those presented above are therefore essential ,and biological parameters should be introduced in the comprehensive dynamiclimnological model that should enable a prediction of the impact of the "Peace Conduit יי ב project on the properties of this unique lake.
14AcknowledgmentsWe thank Dr. Jossi Lati, Moti Aharoni and their coworkers (the Dead Sea Works, Ltd.) formaintaining and sampling the experimental ponds at Sedom and for valuable discussions,and Tamar Arbel and her colleagues at IMI (TAMI), Haifa, for the pigment analyses.References ס :1 Anati, D.A., Gavrieli, 1. and Oren, A., 1995. The residual effect of the 1991-1993 rainywinters on the Dead Sea stratification. Isr. J. Earth Sci. 44: 63-70.Arahal, D.R., Marquez, M.C., Volcani, B.E., Schleifer, K.H., and Ventosa, A. 1999.Bacillus marismortui sp. nov., a new moderately halophilic species from the Dead Sea.Int. J. Syst. Bacteriol. 49: 521-530.Arahal, D.R., Garcia, M.T., Ludwig, W., Schleifer, K.-H., and Ventosa, A. 2001. Transferof Halomonas canadensis and Halomonas israelensis to the genus Chromohalobacter asChromohalobacter canadensis comb. nov. and Chromohalobacter israelensis comb.nov. Int. J. Syst. Evol. Microbiol. 51: 1443-1448.Buchalo, A.S., Nevo, E., Wasser, S.P., Oren, A., and Molitoris, H.P. 1998. Fungallife inthe extremely hypersaline water of the Dead Sea: first records. Proc. R. Soc. London B.265: 1461-1465.Dobson, S.J., James, S.R., Franzmann, P.D., and McMeekin, T.A. 1990. Emendeddescription of Halomonas halmophila (NCBM 1971 T ). Int. J. Syst. Bacteriol. 40: 462463.Elazari-Volcani, B. 1940a. Studies on the microflora of the Dead Sea. Ph.D. thesis, TheHebrew University of Jerusalem (in Hebrew).Elazari-Volcani, B. 1940b. Algae in the bed ofthe Dead Sea. Nature 145: 975.Elazari-Volcani, B. 1943. A dimastigamoeba in the bed ofthe Dead Sea. Nature 152: 301302.Elazari-Volcani, B. 1944. A ciliate from the Dead Sea. Nature 154: 335-336.Gavrieli, 1., Lanski, N., Yaari-Gazit, N., and Oren, A. 2002. The impact of the proposed"Peace Conduit" on the Dead Sea. Evaluation of current knowledge on Dead Sea seawater mixing. The Geological Survey of Israel, Report GSII23/2002, 42 pp.Ginzburg, M., Sachs, L., and Ginzburg, B.Z. 1970. Ion metabolism in a Halobacterium. 1.Influence of age of culture on intracellular concentrations. J. Gen. Physiol. 55: 187-207.Huval, J.H., Latta, R., Wallace, R., Kushner, D.J., and Vreeland, R.H. 1995. Description oftwo new species of Halomonas: Halomonas israelensis sp. nov. and Halomonascanadensis sp. nov. Can. J. Microbiol. 41: 1124-1131.Kaplan, I.R., and Friedmann, A. 1970. Biological productivity in the Dead Sea. Part 1.Microorganisms in the water column. Israel J. Chem. 8: 513-528.Kis-Papo, T., Grishkan, 1., Oren, A., Wasser, S.P., and Nevo, E. 2001. Spatiotemporaldiversity offilamentous fungi in the hypersaline Dead Sea. Mycol. Res. 105: 749-756.
15 בו 11Krumgalz, B.S., and Millero, F.J. 1982. Physico-chemical study of the Dead Sea waters. 1.Activity coefficients of major ions in Dead Sea water. Mar. Chem. 11: 209-222.Lortet, M.L. 1892. Researches on the pathogenic microbes of the Dead Sea. Palest. Expl.Fund 1892: 48-50.Marvin DiPasquale, M., Oren, A., Cohen, Y., and Oremland, R.S. 1999. Radiotracerstudies of bacterial methanogenesis in sediments from the Dead Sea and Solar Lake(Sinai). pp. 149-160 In: Oren, A. (Ed.). Microbiology and Biogeochemistry ofHypersaline Environments. CRC Press, Boca Raton, Florida.Mullakhanbhai, M.F., and Larsen, H. 1975. Halobacterium volcanii spec. nov., a Dead Seahalobacterium with a moderate salt requirement. Arch. Microbiol. 104: 207-214.Neev, D., and Emery, K.O. 1967. The Dead Sea. Depositional Processes and Environmentsof Evaporites. Bulletin No. 41, State of Israel, Ministry of Development, GeologicalSurvey, 147 pp.Nissenbaum, A. 1975. The microbiology and biogeochemistry of the Dead Sea. Microb.Ecol. 2: 139-161.Nissenbaum, A., and Kaplan, I., 1976. Sulfur and carbon isotopic evidence forbiogeochemical processes in the Dead Sea ecosystem. In J. Nriagu (ed.): Environmentalbiogeochemistry, Ann Arbor Sci., Publ., Ann Arbor, Michigan, 1,309-325.Nissenbaum, A., Stiller, M., and Nishri, A. 1990. Nutrients in pore waters from Dead Seasediments. Hydrobiologia 197: 83-90.Oren, A. 1983a. Population dynamics of halobacteria in the Dead Sea water column.Limnol. Oceanogr. 28: 1094-1103.Oren, A. 1983b. Halobacterium sodomense sp. nov., a Dead Sea halobacterium withextremely high magnesium requirement and tolerance. Int. J. Syst. Bacteriol. 33: 381386.Oren, A. 1983c. Clostridium lortetii sp. nov., a halophilic obligately anaerobic bacteriumproducing endospores with attached gas vacuoles. Arch. Microbiol. 136: 42-48.Oren, A. 1985. The rise and decline of a bloom of halobacteria in the Dead Sea. Limnol.Oceanogr. 30: 911-915.Oren, A. 1988. The microbial ecology of the Dead Sea, pp. 193-229 In: Marshall, K.C.(Ed.), Advances in microbial ecology, Vol. 10. Plenum Publishing Company, NewYork.Oren, A. 1992. Bacterial activities in the Dead Sea, 1980-1991: survival at the upper limitof salinity. Int. J. Salt Lake Res. 1: 7-20.Oren, A. 1993. The Dead Sea - alive again. Experientia 49: 518-522.Oren, A. 1997. Microbiological studies in the Dead Sea: 1892-1992, pp. 205-213 In:Niemi, T., Ben-Avraham, Z., and Gat, J.R. (Eds.), The Dead Sea - the lake and itssetting. Oxford University Press, Oxford.Oren, A. 1998. The rise and decline of a bloom of halophilic algae and Archaea in theDead Sea: 1992-1995. pp. 129-138 In: Oren, A. (ed.), Microbiology andbiogeochemi
of microorganisms have been shown to live in the Dead Sea. These include autotrophic unicellular green algae (Dunaliella sp.) and a number of aerobic heterotrophic prokaryotes. The dominant types are red halophilic Archaea belonging to the farnily Halobacteriaceae: . Another source of phosphorus to the
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2018 Accounting Higher Finalised Marking Instructions Scottish Qualifications Authority 2018 The information in this publication may be reproduced to support SQA qualifications only on a non-commercial basis. If it is reproduced, SQA should be clearly acknowledged as the source. If it is to be used for any other purpose, written permission must be obtained from permissions@sqa.org.uk. Where .
NORTH & WEST SUTHERLAND LOCAL HEALTH PARTNERSHIP Minutes of the meeting held on Thursday 7th December 2006 at 12:00 Noon in the Rhiconich Hotel, Rhiconich. PRESENT: Dr Andreas Herfurt Lead Clinician Dr Moray Fraser CHP Medical Director Dr Alan Belbin GP Durness Dr Anne Berrie GP Locum Dr Cameron Stark Public Health Consultant Mrs Sheena Craig CHP General Manager Mrs Georgia Haire CHP Assistant .
validated awards is a matter of prime importance to the OU. The OU will take any action it considers necessary under its Royal Charter to protect the quality of validated programmes of study and the standard of its validated awards. A1.6 Quality assurance As a UK University, the OU is subject to the requirements and expectations of UK higher education, as represented by the Quality Assurance .
Current International Banking Service monthly fee in other currencies Sterling US dollar Euro Australian dollar Canadian dollar Japanese yen New Zealand dollar South African rand Swiss franc 20.00 33.00 29.00 40.00 40.00 2,800.00 40.00 240.00 40.00. 3 General services Tariff Diarised statements Free Copy Statements Free Cheque books Free Cancelling a cheque Free Cheques you have paid in which .
Cambridge English: Business Higher is the highest of the three exams in the general Business English suite offered by Cambridge English Language Assessment. It can be taken in both paper-based and computer-based formats.
yle flyers Informazioni per i candidati 9 SestaParte(10Domande) ativonelqualemancanodieci parole .
Act CXXX of 2016 on the Code of Civil Procedure (as in force on 1 July 2018) This document has been produced for informational purposes only. 4 COURTS; DISQUALIFICATION 3. Proceeding courts Section 8 [The proceeding court] (1) The following courts shall proceed on first instance: a) the district courts, b) the administrative and labour courts, or c) the regional courts. (2) The following .
