microbial-diversity-of-soda-lakes

B.Jochimsenetal.:Stetteriahydrogenophila191Extremophiles(1998)2:191–200©Springer-Verlag1998REVIEWBrianE.Jones·WilliamD.GrantAndrewW.Duckworth·GeraldG.OwensonMicrobialdiversityofsodalakesReceived:January22,1998/Accepted:February16,1998AbstractSodalakesarehighlyalkalineextremeenviron-mentsthatformincloseddrainagebasinsexposedtohighevaporationrates.BecauseofthescarcityofMg2�andCa2�inthewaterchemistry,thelakesbecomeenrichedinCO32�andCl�,withpHsintherange8to�12.AlthoughthereisacleardifferenceinprokaryoticcommunitiesbetweenthehypersalinelakeswhereNaClconcentrationsare�15%w/vandmoredilutewaters,i.e.,NaClconcentrationsabout5%w/v,photosyntheticprimaryproductionappearstobethebasisofallnutrientrecycling.Inboththeaerobicandanaerobicmicrobialcommunitiesthemajortrophicgroupsresponsibleforcyclingofcarbonandsulfurhaveingeneralbeenidentified.Systematicstudieshaveshownthatthemi-crobesarealkaliphilicandmanyrepresentseparatelin-eageswithinacceptedtaxa,whileothersshownostrongrelationshiptoknownprokaryotes.Althoughalkaliphilesarewidespreaditseemsprobablethattheseorganisms,es-peciallythoseuniquetothehypersalinelakes,evolvedseparatelywithinanalkalineenvironment.Althoughpresent-daysodalakesaregeologicallyquiterecent,theyhaveprobablyexistedsincearchaeantimes,permittingtheevolutionofindependentcommunitiesofalkaliphilessinceanearlyperiodintheEarth’shistory.Presentaddress:1FossilFuelsandEnvironmentalGeochemistry,UniversityofNewcastle,NewcastleuponTyne,NE17RU,UK2DepartmentofBiologicalSciences,UniversityofWarwick,Coventry,CV47AL,UKCommunicatedbyK.HorikoshiB.E.Jones(�)GenencorInternationalBV,POBox642,2600AP,Delft,TheNetherlandsTel.�31-15-284-3084;Fax.�31-15-284-3076e-mail:bjones@genencor.comW.D.Grant·A.W.Duckworth1·G.G.Owenson2DepartmentofMicrobiologyandImmunology,UniversityofLeicester,MauriceShockBuilding,UniversityRoad,Leicester,LE19HN,U.K.KeywordsAlkaliphile·Diversity·ScreeningAlkalineenvironmentsAlkalineenvironmentscanbeplacedintoseveralbroadcategoriesdependingonthenatureoftheprocessgenerat-in