title: Potential for microbial H2and metal transformations associated with novel bacteria and archaea in deep terrestrial subsurface sediments.
abstract: Geological sequestration in deep underground repositories is the prevailing proposed route for radioactive waste disposal. After the disposal of radioactive waste in the subsurface, H2may be produced by corrosion of steel and, ultimately, radionuclides will be exposed to the surrounding environment. To evaluate the potential for microbial activities to impact disposal systems, we explored the microbial community structure and metabolic functions of a sediment-hosted ecosystem at the Horonobe Underground Research Laboratory, Hokkaido, Japan. Overall, we found that the ecosystem hosted organisms from diverse lineages, including many from the phyla that lack isolated representatives. The majority of organisms can metabolize H2, often via oxidative [NiFe] hydrogenases or electron-bifurcating [FeFe] hydrogenases that enable ferredoxin-based pathways, including the ion motive Rnf complex. Many organisms implicated in H2metabolism are also predicted to catalyze carbon, nitrogen, iron and sulfur transformations. Notably, iron-based metabolism is predicted in a novel lineage of Actinobacteria and in a putative methane-oxidizing ANME-2d archaeon. We infer an ecological model that links microorganisms to sediment-derived resources and predict potential impacts of microbial activity on H2consumption and retardation of radionuclide migration.
authors.affiliation: Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
authors.forename: Alex W
authors.identifier: 0000-0002-3737-380X
authors.initials: AW
authors.lastname: Hernsdorf
authors.affiliation: Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan.|Horonobe Underground Research Center, Japan Atomic Energy Agency, Horonobe, Hokkaido, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Amano
authors.affiliation: Horonobe Underground Research Center, Japan Atomic Energy Agency, Horonobe, Hokkaido, Japan.
authors.forename: Kazuya
authors.identifier: 0000-0002-5306-5014
authors.initials: K
authors.lastname: Miyakawa
authors.affiliation: Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, Tokai, Ibaraki, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Ise
authors.affiliation: Graduate School of Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Yohey
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Earth and Planetary Sciences, Berkeley, CA, USA.
authors.forename: Karthik
authors.initials: K
authors.lastname: Anantharaman
authors.affiliation: Department of Earth and Planetary Sciences, Berkeley, CA, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Probst
authors.affiliation: Department of Earth and Planetary Sciences, Berkeley, CA, USA.
authors.forename: David
authors.identifier: 0000-0002-6219-1880
authors.initials: D
authors.lastname: Burstein
authors.affiliation: Department of Earth and Planetary Sciences, Berkeley, CA, USA.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Thomas
authors.affiliation: Department of Earth and Planetary Sciences, Berkeley, CA, USA.|Department of Environmental Science, Policy, and Management, Berkeley, CA, USA.
authors.forename: Jillian F
authors.initials: JF
authors.lastname: Banfield
mesh_terms: D001105:Archaea / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism; D006859:Hydrogen / Q000737:chemistry / Q000378:metabolism*; D006864:Hydrogenase; D008670:Metals / Q000737:chemistry / Q000378:metabolism*; D008697:Methane / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010084:Oxidation-Reduction; D011850:Radioactive Waste; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D013455:Sulfur / Q000378:metabolism; D064091:Waste Disposal Facilities
chemical_list: D008670:Metals; D011850:Radioactive Waste; D012987:Soil; D013455:Sulfur; D002244:Carbon; D006859:Hydrogen; C043296:nickel-iron hydrogenase; D006864:Hydrogenase; D009584:Nitrogen; D008697:Methane