Halomonas sulfidaeris‐dominated microbial community inhabits a 1.8 km‐deep subsurface Cambrian Sandstone reservoir

Abstract

SummaryA low-diversity microbial community, dominated by the γ-proteobacterium Halomonas sulfidaeris, was detected in samples of warm saline formation porewater collected from the Cambrian Mt. Simon Sandstone in the Illinois Basin of the North American Midcontinent (1.8 km/5872 ft burial depth, 50°C, pH 8, 181 bars pressure). These highly porous and permeable quartz arenite sandstones are directly analogous to reservoirs around the world targeted for largescale hydrocarbon extraction, as well as subsurface gas and carbon storage. A new downhole lowcontamination subsurface sampling probe was used to collect in situ formation water samples for microbial environmental metagenomic analyses. Multiple lines of evidence suggest that this H. sulfidaerisdominated subsurface microbial community is indigenous and not derived from drilling mud microbial contamination. Data to support this includes V1-V3 pyrosequencing of formation water and drilling mud, as well as comparison with previously published microbial analyses of drilling muds in other sites. Metabolic pathway reconstruction, constrained by the

Orenia metallireducens sp. nov. Strain Z6, a Novel Metal-Reducing Member of the Phylum Firmicutes from the Deep Subsurface

“…Genomic DNA for strain Z6 was extracted using the phenol-chloroform extraction method, as described previously (28). The genome was sequenced using the Roche 454 and Illumina HiSeq technologies, with average sequencing coverages of approximately 26ϫ and 140ϫ, respectively.…”

“…Our previous work identified indigenous microbial communities within different stratigraphic horizons in the Mt. Simon formation, and using this water, we successfully developed enrichment cultures capable of reducing ferric iron compounds (27,28). In this paper, we describe a bacterium isolated from these enrichments that is capable of reducing a broad suite of iron minerals.…”

Earth as a Microbial Habitat

“…As groundwater moves along flow paths from zones of recharge to discharge, its chemistry is altered by a range of geochemical and biogeochemical processes including the weathering and dissolution of rocks and minerals and by the products of microbial oxidation of organic matter and reduction of a range of electron acceptors. In response to increased levels of groundwater salinity, halotolerance has been observed in many bacterial strains isolated from deep terrestrial environments, including oil reservoirs (Tardy-Jacquenod et al, 1998), siltstone formations (Boone et al, 1995), sandstones (Dong et al, 2014), and granitic groundwater . Halophilic growth strategies are encountered in regions characterized by higher salinity concentrations, including ancient deep evaporite deposits (Schubert et al, 2009) and cryopegs in permafrost (Gilichinsky et al, 2003).…”

Fe-oxide grain coatings support bacterial Fe-reducing metabolisms in 1.7−2.0 km-deep subsurface quartz arenite sandstone reservoirs of the Illinois Basin (USA)

“…The deeply buried Mt. Simon Sandstone contains quartz grains with ubiquitous iron oxide cement coatings and porosity filled with briny water with high concentrations of dissolved ions (Bowen et al, 2010; Locke et al, 2013; Dong et al, 2014). …”

“…The studies on the Pennsylvanian Seelyville coal beds (95–100 m depth) on the eastern margin of the Illinois Basin in Indiana (Strapoć et al, 2009) revealed a microbial community dominated by Methanocorpusculum , which may utilize H 2 and CO 2 derived from biodegradation of coal organic matter for methane production (Strapoc et al, 2008). In addition, Dong et al (2014) identified a lowly diversified microbial community inhabiting in the significantly deeper (1.8 km) and more ancient subsurface of the Cambrian-age Mt. Simon Sandstone.…”