Metagenomic investigation of a low diversity, high salinity offshore oil reservoir

Gabrielle Scheffer, Casey R. J. Hubert*, Dennis R. Enning, Sven Lahme, Jaspreet Mand, Júlia R. de Rezende

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)
52 Downloads (Pure)


Oil reservoirs can represent extreme environments for microbial life due to low water availability, high salinity, high pressure and naturally occurring radionuclides. This study investi-gated the microbiome of saline formation water samples from a Gulf of Mexico oil reservoir. Meta-genomic analysis and associated anaerobic enrichment cultures enabled investigations into metabolic potential for microbial activity and persistence in this environment given its high salinity (4.5%) and low nutrient availability. Preliminary 16S rRNA gene amplicon sequencing revealed very low microbial diversity. Accordingly, deep shotgun sequencing resulted in nine metagenome-as-sembled genomes (MAGs), including members of novel lineages QPJE01 (genus level) within the Halanaerobiaceae, and BM520 (family level) within the Bacteroidales. Genomes of the nine organisms included respiratory pathways such as nitrate reduction (in Arhodomonas, Flexistipes, Geotoga and Marinobacter MAGs) and thiosulfate reduction (in Arhodomonas, Flexistipes and Geotoga MAGs). Genomic evidence for adaptation to high salinity, withstanding radioactivity, and metal acquisition was also observed in different MAGs, possibly explaining their occurrence in this extreme habitat. Other metabolic features included the potential for quorum sensing and biofilm formation, and genes for forming endospores in some cases. Understanding the microbiomes of deep biosphere environments sheds light on the capabilities of uncultivated subsurface microorganisms and their potential roles in subsurface settings, including during oil recovery operations.

Original languageEnglish
Article number2266
Issue number11
Early online date31 Oct 2021
Publication statusPublished - Nov 2021


  • Formation water
  • Gulf of Mexico
  • Halophiles
  • Marine subsurface
  • Metagenomics
  • Metal acquisition
  • Microbial adaptation
  • Microbial persistence
  • Polyextremophiles
  • Radionuclide resistance

ASJC Scopus subject areas

  • Microbiology
  • Microbiology (medical)
  • Virology


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