Life at High Salt Concentrations

Oren, Aharon

doi:10.1007/978-3-642-30123-0_57

Cited by 90 publications

(95 citation statements)

References 163 publications

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“…In both LI and UI, expression of the NhaC Na þ /H þ antiporter was similar, but a substantial increase in expression of the NhaP and Mnh systems was observed in the LI, as was expression of all K þ transport systems, particularly Kdp (Supplementary Figures S4A and B). This implies that LI communities adapt to hypersalinity using the 'salt-in', rather than 'salt-out' adaptation strategy, consistent with generally accepted statements about energetic constraints associated with life at high salinity (Oren, 2013). Ion concentrations are two to four times higher than in sea water in the UI, and seven-to eight-fold higher in the LI.…”

Section: Ion Transporterssupporting

confidence: 81%

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

et al. 2014

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Deep-sea hypersaline anoxic basins (DHABs) in the Eastern Mediterranean Sea are considered some of the most hostile environments on Earth. Little is known about the biochemical adaptations of microorganisms living in these habitats. This first metatranscriptome analysis of DHAB samples provides significant insights into shifts in metabolic activities of microorganisms as physicochemical conditions change from deep Mediterranean sea water to brine. The analysis of Thetis DHAB interface indicates that sulfate reduction occurs in both the upper (7.0-16.3% salinity) and lower (21.4-27.6%) halocline, but that expression of dissimilatory sulfate reductase is reduced in the more hypersaline lower halocline. High dark-carbon assimilation rates in the upper interface coincided with high abundance of transcripts for ribulose 1,5-bisphosphate carboxylase affiliated to sulfuroxidizing bacteria. In the lower interface, increased expression of genes associated with methane metabolism and osmoregulation is noted. In addition, in this layer, nitrogenase transcripts affiliated to uncultivated putative methanotrophic archaea were detected, implying nitrogen fixation in this anoxic habitat, and providing evidence of linked carbon, nitrogen and sulfur cycles.

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Section: Ion Transporterssupporting

confidence: 81%

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

et al. 2014

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“…The two main factors that determine whether a microorganism can live anaerobically at extreme salinity (4250 g l − 1 ) are (i) the amount of energy it can generate through dissimilatory metabolism and (ii) the mode of maintaining osmotically balanced functional cytoplasm (haloadaptation) (Oren, 2011;2013;Andrei et al, 2012). Haloadaptation has high energetic costs, thus limiting the number of prokaryotes that can thrive in these environments.…”

Section: Discussionmentioning

confidence: 99%

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

et al. 2015

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Archaea domain is comprised of many versatile taxa that often colonize extreme habitats. Here, we report the discovery of strictly anaerobic extremely halophilic euryarchaeon, capable of obtaining energy by dissimilatory reduction of elemental sulfur using acetate as the only electron donor and forming sulfide and CO 2 as the only products. This type of respiration has never been observed in hypersaline anoxic habitats and is the first example of such metabolic capability in the entire Archaea domain. We isolated and cultivated these unusual organisms, selecting one representative strain, HSR2, for detailed characterization. Our studies including physiological tests, genome sequencing, gene expression, metabolomics and [ 14 C]-bicarbonate assimilation assays revealed that HSR2 oxidized acetate completely via the tricarboxylic acid cycle. Anabolic assimilation of acetate occurred via activated glyoxylate bypass and anaplerotic carboxylation. HSR2 possessed sulfurtransferase and an array of membrane-bound polysulfide reductase genes, all of which were expressed during the growth. Our findings suggest the biogeochemical contribution of haloarchaea in hypersaline anoxic environments must be reconsidered.

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“…We recovered multiple osmoprotectant strategies from all genomes (Supplementary Table 6 and Supplementary Discussion). Our metabolite data show that, of the known osmoprotectants 14 , glycine betaine (GB) was present in the fluids, but mannitol, sorbital, ecotine and trehalose were not detected (Supplementary Table 1). Consistent as a response to salinity, GB was below detection in the input and early Marcellus shale fluids, but reached a maximum concentration at day 82 that was maintained at day 328 (Fig.…”

Section: Glycine Betaine and Chemical Additives Fuel Methanogenesismentioning

confidence: 99%

Microbial metabolisms in a 2.5-km-deep ecosystem created by hydraulic fracturing in shales

et al. 2016

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Hydraulic fracturing is the industry standard for extracting hydrocarbons from shale formations. Attention has been paid to the economic benefits and environmental impacts of this process, yet the biogeochemical changes induced in the deep subsurface are poorly understood. Recent single-gene investigations revealed that halotolerant microbial communities were enriched after hydraulic fracturing. Here, the reconstruction of 31 unique genomes coupled to metabolite data from the Marcellus and Utica shales revealed that many of the persisting organisms play roles in methylamine cycling, ultimately supporting methanogenesis in the deep biosphere. Fermentation of injected chemical additives also sustains long-term microbial persistence, while thiosulfate reduction could produce sulfide, contributing to reservoir souring and infrastructure corrosion. Extensive links between viruses and microbial hosts demonstrate active viral predation, which may contribute to the release of labile cellular constituents into the extracellular environment. Our analyses show that hydraulic fracturing provides the organismal and chemical inputs for colonization and persistence in the deep terrestrial subsurface. S hale gas accounts for one-third of natural gas energy resources worldwide. It has been estimated that shale gas will provide half of the natural gas in the USA, annually, by 2040, with the Marcellus shale in the Appalachian Basin projected to produce three times more than any other formation 1 . Recovery of these hydrocarbons is dependent on hydraulic fracturing technologies, where the high-pressure injection of water and chemical additives generates extensive fractures in the shale matrix. Hydrocarbons trapped in tiny pore spaces are subsequently released and collected at the wellpad surface, together with a portion of the injected fluids that have reacted with the shale formation. The mixture of injected fluids and hydrocarbons collected is referred to as 'produced fluids'.Microbial metabolism and growth in hydrocarbon reservoirs has both positive and negative impacts on energy recovery. Whereas stimulation of methanogens in coal beds enhances energy recovery 2 , bacterial hydrogen sulfide production ('reservoir souring') decreases profits and contributes to corrosion and the risk of environmental contamination 3 . Additionally, biomass accumulation within newly generated fractures may reduce their permeability, decreasing natural gas recovery. Despite these potential microbial impacts, little is known about the function and activity of microorganisms in hydraulically fractured shale.Initial work by our group and others 4-9 used single marker gene analyses to identify microorganisms from several geographically distinct shale formations. These analyses showed similar halotolerant taxa in produced fluids several months after hydraulic fracturing. To assign functional roles to these organisms, we conducted metagenomic and metabolite analyses on input and produced fluids up to a year after hydraulic fracturing (HF) from two Appala...

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Life at High Salt Concentrations

Cited by 90 publications

References 163 publications

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

Unveiling microbial activities along the halocline of Thetis, a deep-sea hypersaline anoxic basin

Elemental sulfur and acetate can support life of a novel strictly anaerobic haloarchaeon

Microbial metabolisms in a 2.5-km-deep ecosystem created by hydraulic fracturing in shales

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