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MethanoperedenaceaeNishimura, Hiroki*; Kozuka, Mariko*; Fukuda, Akari*; Ishimura, Toyoho*; Amano, Yuki; Beppu, Hikari*; Miyakawa, Kazuya; Suzuki, Yohei*
Environmental Microbiology Reports (Internet), 15(3), p.197 - 205, 2023/06
Times Cited Count：1 Percentile：59.23(Environmental Sciences)The family Methanoperedenaceae archaea mediate anaerobic oxidation of methane (AOM). We newly developed a high-pressure laboratory incubation system and investigated groundwater from 214- and 249-m deep boreholes at Horonobe Underground Research Laboratory, Japan, where the high and low abundances of Methanoperedenaceae archaea have been revealed, respectively. We incubated the samples amended with or without amorphous Fe(III) and 
C-labelled methane at an in-situ pressure of 1.6 MPa. After three to seven-day incubation, AOM activities were not detected from the 249-m sample but from the 214-m sample. The AOM rates were 93.7
40.6 and 27.737.5 nM/day with and without Fe(III) amendment. Suspended particulates were not visible in the 249-m sample on the filter, while they were abundant and contained amorphous Fe(III) and Fe(III)-bearing phyllosilicates in the 214-m sample. This supports the in-situ activity of Fe(III)-dependent AOM in the deep subsurface borehole.
Mizuno, Takashi; Suzuki, Yohei*; Milodowski, A. E.*; Iwatsuki, Teruki
Applied Geochemistry, 150, p.105571_1 - 105571_11, 2023/03
Times Cited Count：1 Percentile：62.05(Geochemistry & Geophysics)Anaerobic oxidation of methane (AOM) affects both the redox conditions and carbon cycle in groundwater. However, examples of studies on crystalline rock deep in terrestrial subsurface as well as the potential host rock for geological disposal are few. Therefore, we conducted a paleohydrogeological study on fracture-filling calcite in the Toki Granite. The 
O
value (-32.7 to -0.59 permil) revealed that the groundwater that precipitated the calcite was groundwater derived from hydrothermal fluid, freshwater that came from the surface, and seawater that penetrated during marine transgression. On the other hand, C (-56.6 to 6.0 permil) was wider than the isotopic range of DIC that originated from hydrothermal, freshwater, and seawater sources (-25 to 2 permil). Calcite with C that was lighter than -25 permil was believed to have precipitated DIC, which was provided by AOM. In contrast to previous studies, the Mizunami AOM calcite was precipitated in a freshwater environment, indicating that various processes could have generated AOM in crystalline rocks deep in the terrestrial subsurface.
Ino, Kohei*; Hernsdorf, A. W.*; Konno, Yuta*; Kozuka, Mariko*; Yanagawa, Katsunori*; Kato, Shingo*; Sunamura, Michinari*; Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; et al.
ISME Journal, 12(1), p.31 - 47, 2018/01
Times Cited Count：49 Percentile：91.33(Ecology)In this study, we found the dominance ofanaerobic methane-oxidizing archaea in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.
and metal transformations associated with novel bacteria and archaea in deep terrestrial subsurface sedimentsHernsdorf, A. W.*; Amano, Yuki; Miyakawa, Kazuya; Ise, Kotaro; Suzuki, Yohei*; Anantharaman, K.*; Probst, A. J.*; Burstein, David*; Thomas, B. C.*; Banfield, J. F.*
ISME Journal, 11, p.1915 - 1929, 2017/03
Times Cited Count：89 Percentile：95.92(Ecology)To evaluate the potential for interactions between microbial communities and disposal systems, we explored the structure and metabolic function of a sediment-hosted subsurface ecosystem associated with Horonobe Underground Research Center, Hokkaido, Japan. Overall, the ecosystem is enriched in organisms from diverse lineages and many are from phyla that lack isolated representatives. The majority of organisms can metabolize H, 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 H metabolism are also predicted to catalyze carbon, nitrogen, iron, and sulfur transformations. Notably, iron-based metabolism was predicted in a bacterial lineage where this function has not been predicted previously and in an ANME-2d archaeaon that is implicated in methane oxidation. We infer an ecological model that links microorganisms to sediment-derived resources and predict potential impacts of microbial activity on H accumulation and radionuclide migration.
Togo, Yoko*; Takahashi, Yoshio*; Amano, Yuki; Matsuzaki, Hiroyuki*; Suzuki, Yohei*; Terada, Yasuko*; Muramatsu, Yasuyuki*; Ito, Kazumasa*; Iwatsuki, Teruki
Geochimica et Cosmochimica Acta, 191, p.165 - 186, 2016/10
Times Cited Count：28 Percentile：73.1(Geochemistry & Geophysics)Iodine distribution, speciation, and isotope ratio (
I/
I) in both rock and groundwater phases were determined to investigate long-term migration of iodine in diatomaceous and siliceous shale. It was suggested that I
is released to the ground water during the progress of the maturation of organic matter. Dissociated I could move toward the surface because of the upward water flow driven by the compaction during burial diagenetic process. Thus, iodine rich brine is created by integration of iodine released from underlying formations. Because of low affinity of I to solid phase, released I remains in solution phase, and the concentration of the iodine in the solution has been possibly increasing during sedimentation history.
Hug, L. A.*; Baker, B. J.*; Anantharaman, K.*; Brown, C. T.*; Probst, A. J.*; Castelle, C. J.*; Butterfield, C. N.*; Hernsdorf, A. W.*; Amano, Yuki; Ise, Kotaro; et al.
Nature Microbiology (Internet), 1(5), p.16048_1 - 16048_6, 2016/05
Times Cited Count：1209 Percentile：99.97(Microbiology)The tree of life is one of the most important organizing principles in biology. Gene surveys suggest the existence of an enormous number of branches, but even an approximation of the full scale of The Tree has remained elusive. Here, we use newly available information from genomes of uncultivated organisms, along with other published sequences, to present a new version of the Tree of life, with Bacteria, Archaea and Eukaryotes included. The depiction is both a global overview and a snapshot of the diversity within each major lineage. The results imply the predominance of bacterial diversification and underline the importance of organisms lacking isolated representatives, with substantial evolution concentrated in a major radiation of such organisms.
Ino, Kohei*; Konno, Yuta*; Kozuka, Mariko*; Hirota, Akinari*; Togo, Yoko*; Fukuda, Akari*; Komatsu, Daisuke*; Tsunogai, Urumu*; Tanabe, Akifumi*; Yamamoto, Satoshi*; et al.
Environmental Microbiology Reports (Internet), 8(2), p.285 - 294, 2016/04
Times Cited Count：26 Percentile：68.59(Environmental Sciences)To understand the subsurface biosphere, borehole investigation was conducted for 300-m deep granitic rocks at the Mizunami underground research laboratory, Japan. The initial biomass was the highest with the flourish of aerobic H-oxidizing Hydrogenophaga spp., whereas an uncultivated lineage of the phylum Nitrospirae became predominant after three years with decreasing biomass. The common occurrence of many species of Nitrospirae and Chlorobi phyla at the geographically distinct sites and the exclusive detection of their phylogenetically related environmental sequences from deep groundwaters and terrestrial hot springs, suggest that these bacteria are indigenous and potentially adapted to the deep terrestrial subsurface.
Suzuki, Yohei*; Mukai, Hiroki*; Ishimura, Toyoho*; Yokoyama, Takatomi*; Sakata, Shuhei*; Hirata, Takafumi*; Iwatsuki, Teruki; Mizuno, Takashi
Scientific Reports (Internet), 6, p.22701_1 - 22701_6, 2016/03
Times Cited Count：14 Percentile：49.58(Multidisciplinary Sciences)The stimulation of bacterial activities that convert hexavalent uranium to tetravalent uranium appears to be feasible for cost-effective remediation of contaminated aquifers. However, U(VI) reduction typically results in the precipitation of U(IV) particles less than 5 nanometers in diameter. Here we show that U(IV) nanoparticles of coffinite formed in fracture-filling calcium carbonate in a granitic aquifer. As the microbiologically induced precipitation of calcium carbonate in aquifer systems worldwide is extremely common, we anticipate simultaneous stimulation of microbial activities for precipitation reactions of calcium carbonate and U(IV) nanoparticles, which leads to long-term sequestration of uranium and other radionuclides in contaminated aquifers and deep geological repositories.
Suzuki, Yohei*; Konno, Yuta*; Fukuda, Akari*; Komatsu, Daisuke*; Hirota, Akinari*; Watanabe, Katsuaki*; Togo, Yoko*; Morikawa, Noritoshi*; Hagiwara, Hiroki; Aosai, Daisuke*; et al.
PLOS ONE (Internet), 9(12), p.e113063_1 - e113063_20, 2014/12
Times Cited Count：12 Percentile：34.33(Multidisciplinary Sciences)We present multi-isotopic evidence of microbially mediated sulfate reduction in a granitic aquifer, a representative of the terrestrial crust habitat. Deep groundwater of meteoric origin was collected from underground boreholes drilled into the Cretaceous Toki granite, central Japan. A large sulfur isotopic fractionation of 20-60 permil diagnostic to microbial sulfate reduction is associated with the investigated groundwater containing sulfate below 0.2 mM. In contrast, a small carbon isotopic fractionation (
30 permil) is not indicative of methanogenesis. Our results demonstrate that the deep biosphere in the terrestrial crust is metabolically active and playing a crucial role in the formation of reducing groundwater even under low energy fluxes.
Saito, Takumi*; Suzuki, Yohei*; Mizuno, Takashi
Colloids and Surfaces A; Physicochemical and Engineering Aspects, 435(Sp.IAP2012), p.48 - 55, 2013/10
Times Cited Count：20 Percentile：47.03(Chemistry, Physical)Nano colloids in granitic groundwater obtained from a borehole located at the -300-m stage of the Mizunami Underground Research Laboratory were studied in terms of their size distributions by flow-field flow fractionation. In order to deal with relatively low concentrations of colloids, colloids were enriched first by ultrafiltration, and then by in-situ enrichment using a large injection loop and the slot flow technique. The size distributions of organic and inorganic constituents of colloids were measured by UV/Vis, fluorescence and inductively coupled plasma mass spectrometry, from which possible association of trace elements with host colloidal phases consisting of major elements and organic materials was discussed. Trace elements, namely, Sr, lanthanides (La, Ce, Eu, Lu), actinide elements (U, Th) and heavy metals (Cu, Zn and W), exhibited distinct size distributions, reflecting their preferential association with certain host colloidal phases.
Nagao, Seiya*; Niibori, Yuichi*; Tanaka, Tadao; Sasaki, Takayuki*; Saito, Takumi*; Kirishima, Akira*; Yoshikawa, Hideki; Iijima, Kazuki; Hama, Katsuhiro; Iwatsuki, Teruki; et al.
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 20(1), p.3 - 14, 2013/06
This paper shows a current status of groundwater colloids studies on the performance assessment of geological disposal of radioactive wastes in Japan, and summaries realistic approach of the colloids studies at a substantial research network for Japanese universities and institutes.
Fukuda, Akari*; Hagiwara, Hiroki; Ishimura, Toyoho*; Kozuka, Mariko*; Ioka, Seiichiro*; Amano, Yuki; Tsunogai, Urumu*; Suzuki, Yohei*; Mizuno, Takashi
Microbial Ecology, 60(1), p.214 - 225, 2010/05
Times Cited Count：29 Percentile：65.76(Ecology)To better understand the geochemical and microbiological relationships, we characterized granitic groundwater collected from a 1,148 to 1,169 -m deep borehole interval at the Mizunami Underground Research Laboratory site, Japan, in 2005 and 2008. Geochemical analyses of the groundwater samples indicated that major electron acceptors, such as NO
and SO
, were not abundant, while dissolved organic carbon (not including organic acids), CH and H were moderately rich. The most common phylotypes were both related to 
spp., the cultivated members of which can utilize minor electron donors, such as aromatic and aliphatic hydrocarbons. Geomicrobiological results suggest that deep granitic groundwater has been stably colonized by spp. probably owing to the limitation of O, NO and organic acids.
Fukuda, Akari*; Suzuki, Yohei*; Ito, Kazumasa*; Mizuno, Takashi; Amano, Yuki; Hagiwara, Hiroki; Hama, Katsuhiro
no journal, ,
This study was aimed to understand the control system and the process of redox system in deep groundwater. As the result of chemical study of groundwater, it is revealed that succniate was highly enriched in groundwater from Toki Formation (up to 81 mg/L). This result suggests that succinate is one of major electron donors that can fuel metabolic activities.
Mizuno, Takashi; Suzuki, Yohei*; Fukuda, Akari*; Hagiwara, Hiroki; Ito, Kazumasa*
no journal, ,
JAEA and AIST has been conducting collaborative work on hydrochemical study at MIU construction site. The aim of this collaborative study is to establish the methodology for investigation, analysis and evaluation of colloid/organics/microbes study. This paper reports that the colloid study. As the result, it is suggested that some metal components are existing as non-dissolved solid.
Fukuda, Akari*; Hagiwara, Hiroki; Ishimura, Toyoho*; Kozuka, Mariko*; Ito, Kazumasa*; Tsunogai, Urumu*; Suzuki, Yohei*; Mizuno, Takashi
no journal, ,
JAEA and AIST have been conducting collaborative work on hydrochemical study at MIU construction site. The aim of this collaborative study is to establish the methodology for investigation, analysis and evaluation of colloid/organics/microbes study. This paper reports the biogeochemical study. As the result, it is suggested that groundwater taken from deeper part (1150m depth) is relatively oxidized.
Suzuki, Yohei*; Fukuda, Akari*; Kozuka, Mariko*; Ishimura, Toyoho*; Tsunogai, Urumu*; Hagiwara, Hiroki; Mizuno, Takashi
no journal, ,
no abstracts in English
Ito, Kazumasa*; Suzuki, Yohei*; Fukuda, Akari*; Kozuka, Mariko*; Mizuno, Takashi; Hagiwara, Hiroki
no journal, ,
no abstracts in English
Uyama, Masao*; Noda, Masatoshi*; Noda, Masaru*; Hasegawa, Hiroshi*; Matsui, Hiroya; Suzuki, Yohei*; Hamako, Tadashi*; Tanaka, Yuji*
no journal, ,
Dynamic injection method increase the penetration of grout material and apply the grouting of small and low permeable crack in rock mass. This paper report the results of in-situ dynamic injection under high water pressure condition by using of the developed system reported Part1. This test used the borehole drilled in collaboration study between JAEA and AIST and the budget is a part of contract study from NISA.
Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi; Watanabe, Katsuaki*; Kogure, Toshihiro*; Suzuki, Yohei*
no journal, ,
no abstracts in English
Fukuda, Akari; Kozuka, Mariko*; Aosai, Daisuke; Hagiwara, Hiroki; Mizuno, Takashi; Suzuki, Yohei*
no journal, ,
no abstracts in English
