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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:45 Percentile:91.3(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.
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:25 Percentile:73.46(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.
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:24 Percentile:67.66(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*; 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:11 Percentile:34.61(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.
Karasaki, Kenji*; Ito, Kazumasa*; Wu, Y.*; Shimo, Michito*; Sawada, Atsushi; Maekawa, Keisuke; Hatanaka, Koichiro
Proceedings of TOUGH Symposium 2009 (Internet), 9 Pages, 2009/09
Nomoto, Kosuke*; Matsui, Mikio*; Inoue, Hiroyuki*; Yoshino, Naoto; Karasaki, Kenji*; Ito, Kazumasa*
JNC TJ8400 2005-005, 94 Pages, 2005/02
In the safety assessment at geological disposal of High Level Nuclear Waste, it is necessary to understand several properties like hydrological, geological and chemical properties of the disposal site by site investigations. The investigation results should project to the ground water flow modeling, migration modeling and the parameter assignment of these models. Japan Nuclear cycle Development Institute is going to carry out two Underground Research Laboratory plans in order to push on with the project and help to make up the safety criteria of the geological disposal. Horonobe is one area of these plans. In Horonobe, following properties were identified./-There are saline and fresh water./-There is dissolved gas in the underground water./-The underground of some area has high water pressure./In this study, the analysis considering above properties were carried out for understanding of hydrological properties in sedimentary rock. In addition, the affection to the water flow and migration influenced by the results were examined.
Karasaki, Kenji*; Ito, Kazumasa*; Maekawa, Keisuke
no journal, ,
We have modeled laboratory experiments of saltwater intrusion using TOUGH2/EOS7. Matching laboratory and simulation results turned out to be quite challenging partly because of numerical dispersion and partly because the experiments were not very well controlled. In order to understand better the effects of numerical dispersion, we simulated the so-called Henry problem, in which a large dispersion coefficient is assumed, resulting in a wide transition zone between freshwater and saltwater. We imposed a sinusoidal boundary condition to see if a large transition zone can be created without explicitly modeling dispersion. However, for the parameters used we were not able to do so. It is still plausible that a wide transition zone is caused by formation heterogeneity and transient effects. Nonetheless, we question the validity of the use of a large dispersion coefficient where the velocity is very low, or where the flow is in the opposite direction of the concentration gradient.
Maekawa, Keisuke; Karasaki, Kenji*; Ito, Kazumasa*
no journal, ,
As a study to comprehend geological environment, we examined numerical analysis in order to understand the behavior of saltwater intrusion. This is an important study for safety assessment of high level radioactive waste geologic disposal. We made sense a relation between an extent of numerical dispersion and various grid spacing in analytical region. And the analytical code was verified with an experiment under the simple condition.
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.
Ito, Kazumasa*; Suzuki, Yohei*; Fukuda, Akari*; Kozuka, Mariko*; Mizuno, Takashi; Hagiwara, Hiroki
no journal, ,
no abstracts in English
Fukuda, Akari; Mizuno, Takashi; Aosai, Daisuke; Hagiwara, Hiroki; Yamamoto, Yuhei; Shingu, Shinya; Ito, Kazumasa*; Suzuki, Yohei*; Kozuka, Mariko*; Konno, Yuta*
no journal, ,
no abstracts in English
Ito, Kazumasa*; Haginuma, Masashi*; Uchida, Masahiro*; Seki, Yoji*; Takeno, Naoto*; Munakata, Masahiro
no journal, ,
Authors developed the regional geological model based on the existing data observed in the Horonobe Underground Research Center and the three-dimensional groundwater flow model taking account of spatial distribution of permeability and hydrological environment. And then, particle tracking analysis and wash-out analysis of salinity was performed. As the results, simulation results of groundwater flow explain the observed pressure data of groundwater as reasonable. It was founded that the independency between deep groundwater flow and shallow groundwater flow, the long residence time of deep groundwater, upward flow from deep stratum and the mixture of rainwater, seawater and other water estimated by the distribution of water quality and isotope data.
Togo, Yoko*; Suzuki, Yohei*; Fukuda, Akari; Mizuno, Takashi; Ito, Kazumasa*
no journal, ,
no abstracts in English
Fukuda, Akari; Iwatsuki, Teruki; Shingu, Shinya; Omori, Kazuaki; Hagiwara, Hiroki; Ito, Kazumasa*; Togo, Yoko*; Suzuki, Yohei*
no journal, ,
no abstracts in English
Ito, Kazumasa*; Togo, Yoko*; Hirota, Akinari*; Suzuki, Yohei*; Fukuda, Akari*; Omori, Kazuaki; Hasegawa, Takashi; Iwatsuki, Teruki
no journal, ,
Microbial metabolism and the chemical buffer capacity in deep groundwater were estimated at Mizunami underground research laboratory. The results show that sulfate reducing bacteria uses hydrogen gas. The sulfate consumption rate is important index to infer the redox buffer capacity in deep underground.
Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; Suzuki, Yohei*; Fukuda, Akari*; Konno, Yuta*; Tsunogai, Urumu*; Komatsu, Daiyu*; Nagao, Seiya*; Iwatsuki, Teruki
no journal, ,
Isotopic compositions of sulfate, sulfide ions were measured in deep groundwater of Mizunami URL to estimate microbial activity. The results show that relatively large isotopic fractionation between sulfate and sulfide by microbial reduction.
Hirota, Akinari*; Togo, Yoko*; Fukuda, Akari*; Ito, Kazumasa*; Suzuki, Yohei*; Tsunogai, Urumu*; Komatsu, Daiyu*; Iwatsuki, Teruki
no journal, ,
Microbial activity in deep groundwater at Mizunami URL was estimated based on isotopic composition. The result shows that sulfate reduction activity is higher at low-H gas condition.