title: Comparative community genomics in the Dead Sea: an increasingly extreme environment.
abstract: Owing to the extreme salinity ( approximately 10 times saltier than the oceans), near toxic magnesium levels (approximately 2.0 M Mg(2+)), the dominance of divalent cations, acidic pH (6.0) and high-absorbed radiation flux rates, the Dead Sea represents a unique and harsh ecosystem. Measures of microbial presence (microscopy, pigments and lipids) indicate that during rare bloom events after exceptionally rainy seasons, the microbial communities can reach high densities. However, most of the time, when the Dead Sea level is declining and halite is precipitating from the water column, it is difficult to reliably measure the presence of microorganisms and their activities. Although a number of halophilic Archaea have been previously isolated from the Dead Sea, polar lipid analyses of biomass collected during Dead Sea blooms suggested that these isolates were not the major components of the microbial community of these blooms. In this study, in an effort to characterize the perennial microbial community of the Dead Sea and compare it with bloom assemblages, we performed metagenomic analyses of concentrated biomass from hundreds of liters of brine and of microbial material from the last massive Dead Sea bloom. The difference between the two conditions was reflected in community composition and diversity, in which the bloom was different and less diverse from the residual brine population. The distributional patterns of microbial genes suggested Dead Sea community trends in mono- and divalent cation metabolisms as well as in transposable elements. This may indicate possible mechanisms and pathways enabling these microbes to survive in such a harsh environment.
authors.affiliation: Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Idan
authors.initials: I
authors.lastname: Bodaker
authors.forename: Itai
authors.initials: I
authors.lastname: Sharon
authors.forename: Marcelino T
authors.initials: MT
authors.lastname: Suzuki
authors.forename: Roi
authors.initials: R
authors.lastname: Feingersch
authors.forename: Michael
authors.initials: M
authors.lastname: Shmoish
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Andreishcheva
authors.forename: Mitchell L
authors.initials: ML
authors.lastname: Sogin
authors.forename: Mira
authors.initials: M
authors.lastname: Rosenberg
authors.forename: Michael E
authors.initials: ME
authors.lastname: Maguire
authors.forename: Shimshon
authors.initials: S
authors.lastname: Belkin
authors.forename: Aharon
authors.initials: A
authors.lastname: Oren
authors.forename: Oded
authors.initials: O
authors.lastname: Béjà
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics*; D044822:Biodiversity; D002412:Cations / Q000378:metabolism; D016000:Cluster Analysis; D004251:DNA Transposable Elements; D019641:DNA, Archaeal / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D020459:Genes, rRNA; D054892:Metagenome; D056186:Metagenomics; D008969:Molecular Sequence Data; D010802:Phylogeny; D019642:RNA, Archaeal / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D002412:Cations; D004251:DNA Transposable Elements; D019641:DNA, Archaeal; D004275:DNA, Ribosomal; D019642:RNA, Archaeal; D012336:RNA, Ribosomal, 16S