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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：91.8(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.
Miyakawa, Kazuya; Ishii, Eiichi; Hirota, Akinari*; Komatsu, Daisuke*; Ikeya, Kosuke*; Tsunogai, Urumu*
Applied Geochemistry, 76, p.218 - 231, 2017/01
Times Cited Count：14 Percentile：53.55(Geochemistry & Geophysics)no abstracts in English
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：66.62(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：35.78(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.
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.
reduction at deep granitic aquifer by anaerobic and high pressure culture experimentHirota, 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.
Miyakawa, Kazuya; Mizuno, Takashi; Hirota, Akinari*; Komatsu, Daisuke*; Tsunogai, Urumu*
no journal, ,
no abstracts in English
Miyakawa, Kazuya; Mizuno, Takashi; Ishii, Eiichi; Hirota, Akinari*; Komatsu, Daisuke*; Ikeya, Kosuke*; Tsunogai, Urumu*
no journal, ,
no abstracts in English
reduction continuing for millions years in Neogene mudstone resulting in extreme 
C-enrichmentMiyakawa, Kazuya; Ishii, Eiichi; Mizuno, Takashi; Hirota, Akinari*; Komatsu, Daisuke*; Ikeya, Kosuke*; Tsunogai, Urumu*
no journal, ,
no abstracts in English
