2021/04/09 更新

写真a

ツノガイ ウルム
角皆 潤
TSUNOGAI Urumu
所属
大学院環境学研究科 地球環境科学専攻 物質循環科学 教授
職名
教授
連絡先
メールアドレス

学位 1

  1. 博士(理学) ( 1996年3月   東京大学 ) 

研究キーワード 16

  1. 森林

  2. 海洋

  3. 大気

  4. 生物地球化学

  5. 陸水

  6. 一次生産

  7. 硝酸

  8. メタン

  9. 炭素循環

  10. 窒素循環

  11. 温室効果気体

  12. 分析化学

  13. 同位体

  14. 極限環境

  15. 水素

  16. 火山学

研究分野 3

  1. 環境・農学 / 環境動態解析  / 同位体地球化学

  2. 自然科学一般 / 大気水圏科学  / 生物地球化学・大気化学・海洋化学

  3. 自然科学一般 / 固体地球科学  / 火山学

現在の研究課題とSDGs 4

  1. 同位体を指標に用いた海域・陸域の生物地球化学的研究

  2. 同位体を指標に用いた大気化学研究

  3. 極限環境下における微生物活動

  4. 深海底および地殻内部におけるメタンの挙動と起源

経歴 5

  1. 名古屋大学   大学院環境学研究科   教授

    2012年4月 - 現在

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    国名:日本国

  2. 北海道大学   大学院理学研究科   准教授

    2000年4月 - 2012年3月

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    国名:日本国

  3. 東京工業大学   大学院総合理工学研究科   講師

    1999年4月 - 2000年3月

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    国名:日本国

  4. 科学技術振興事業団・研究員(名古屋大学大気水圏科学研究所・東京工業大学大学院総合理工学研究科)

    1997年3月 - 1999年3月

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    国名:日本国

  5. 日本学術振興会・特別研究員(東京大学理学部)

    1996年4月 - 1997年2月

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    国名:日本国

学歴 3

  1. 東京大学   理学系研究科   化学専攻

    1993年4月 - 1996年3月

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    国名: 日本国

  2. 東京大学   理学系研究科   化学専攻

    1991年4月 - 1993年3月

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    国名: 日本国

  3. 東京大学   理学部   化学科

    1987年4月 - 1991年3月

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    国名: 日本国

所属学協会 17

  1. 日本地球化学会

    1994年3月 - 現在

  2. 日本地球惑星科学連合

    2005年5月 - 現在

  3. 日本海洋学会

    1995年12月 - 現在

  4. American Geophysical Union

    1995年8月 - 現在

  5. 日本大気化学会

    1999年6月 - 現在

  6. 日本火山学会

    2012年4月 - 現在

  7. ASLO Association for the Sciences of Limnology and Oceanography

    2012年2月 - 現在

  8. IAVCEI (International Association of Volcanology and Chemistry of the Earth's Interior)

    2009年8月 - 現在

  9. 大気環境学会

    2003年10月 - 現在

  10. 日本分析化学会

    2002年2月 - 現在

  11. 日本質量分析学会同位体比部会   世話人

    2001年1月 - 現在

  12. Geochemical Society

  13. IAVCEI International Association of Volcanology and Chemistry of the Earth's Interior

  14. IAVCEI International Association of Volcanology and Chemistry of the Earth's Interior

  15. Geochemical Society

  16. ASLO Association for the Sciences of Limnology and Oceanography

  17. American Geophysical Union

▼全件表示

委員歴 7

  1. 日本地球化学会   理事  

    2017年11月 - 現在   

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    団体区分:学協会

  2. 科学研究費補助金新学術領域研究専門委員会   委員  

    2014年4月 - 2015年3月   

  3. 東京大学大気海洋研究所陸上共同研究部会   委員  

    2013年4月 - 現在   

  4. 三重大学大学院生物資源学研究科附属練習船共同利用運営協議会   委員  

    2012年4月 - 現在   

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    団体区分:その他

  5. 科学研究費補助金新学術領域研究専門委員会   委員  

    2012年4月 - 2013年3月   

  6. 日本学術会議・環境学委員会・地球惑星科学委員会合同IGAC小委員会   委員  

    2009年1月 - 2014年12月   

  7. 日本学術会議・環境学委員会・地球惑星科学委員会合同SOLAS小委員会   委員  

    2002年1月 - 現在   

▼全件表示

受賞 5

  1. 日本地球化学会賞

    2017年9月   日本地球化学会   軽元素安定同位体比の高感度分析に基づく地球環境科学研究の新展開

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

  2. 第31回海洋化学学術賞(石橋賞)

    2016年4月   一般財団法人海洋化学研究所  

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    受賞国:日本国

  3. 昭和シェル石油環境研究課題賞

    2005年9月   (財)昭和シェル石油環境財団  

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    受賞国:日本国

  4. 日本地球化学会奨励賞

    2000年9月   日本地球化学会  

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    受賞国:日本国

  5. 第13・14回村尾育英会学術賞

    1997年3月   財団法人村尾育英会  

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    受賞国:日本国

 

論文 160

  1. Dual stable isotope characterization of excess methane in oxic waters of a mesotrophic lake 査読有り

    Tsunogai Urumu, Miyoshi Yuko, Matsushita Toshiyuki, Komatsu Daisuke D., Ito Masanori, Sukigara Chiho, Nakagawa Fumiko, Maruo Masahiro

    LIMNOLOGY AND OCEANOGRAPHY   65 巻 ( 12 ) 頁: 2937 - 2952   2020年7月

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    担当区分:筆頭著者, 責任著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/lno.11566

    Web of Science

    Scopus

  2. Development of a drone-borne volcanic plume sampler

    Shingubara R.

    Journal of Volcanology and Geothermal Research   412 巻   2021年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Volcanology and Geothermal Research  

    DOI: 10.1016/j.jvolgeores.2021.107197

    Scopus

  3. Variation of volcanic gas composition at a poorly accessible volcano: Sakurajima, Japan

    Shinohara H., Kazahaya R., Ohminato T., Kaneko T., Tsunogai U., Morita M.

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   407 巻   2020年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Journal of Volcanology and Geothermal Research  

    DOI: 10.1016/j.jvolgeores.2020.107098

    Web of Science

    Scopus

  4. Gas-geochemical studies of gas fields and increased metal concentrations in the East Siberian Sea 国際共著

    Shakirov R. B., Sorochinskaja A. V, Syrbu N. S., Tsunogai Urumu, Tran Hoang Yen

    VIETNAM JOURNAL OF EARTH SCIENCES   42 巻 ( 4 ) 頁: 395 - 410   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Vietnam Journal of Earth Sciences  

    DOI: 10.15625/0866-7187/42/4/15492

    Web of Science

    Scopus

  5. Influence of warm-core eddy on dissolved methane distributions in the southwestern Canada basin during late summer/early fall 2015

    Oanh Thi Ngoc Bui, Kameyama Sohiko, Kawaguchi Yusuke, Nishino Shigeto, Tsunogai Urumu, Yoshikawa-Inoue Hisayuki

    POLAR SCIENCE   22 巻   2019年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.polar.2019.100481

    Web of Science

    Scopus

  6. Stable hydrogen and oxygen isotopic compositions of water vapor in volcanic plumes sampled in glass bottles using cavity ring-down spectroscopy

    Takahashi Koji U., Tsunogai Urumu, Nakagawa Fumiko, Sukigara Chiho

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   384 巻   頁: 232-240   2019年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.jvolgeores.2019.07.020

    Web of Science

    Scopus

  7. Time Variation in the Chemical and Isotopic Composition of Fumarolic Gasses at Kusatsu-Shirane Volcano, Japan

    Ohba Takeshi, Yaguchi Muga, Nishino Kana, Numanami Nozomi, Tsunogai Urumu, Ito Masanori, Shingubara Ryo

    FRONTIERS IN EARTH SCIENCE   7 巻   2019年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.3389/feart.2019.00249

    Web of Science

    Scopus

  8. Time variations in the chemical and isotopic composition of fumarolic gases at Hakone volcano, Honshu Island, Japan, over the earthquake swarm and eruption in 2015, interpreted by magma sealing model

    Ohba Takeshi, Yaguchi Muga, Nishino Kana, Numanami Nozomi, Daita Yasushi, Sukigara Chiho, Ito Masanori, Tsunogai Urumu

    EARTH PLANETS AND SPACE   71 巻 ( 1 )   2019年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1186/s40623-019-1027-5

    Web of Science

    Scopus

  9. Export flux of unprocessed atmospheric nitrate from temperate forested catchments: a possible new index for nitrogen saturation

    Nakagawa Fumiko, Tsunogai Urumu, Obata Yusuke, Ando Kenta, Yamashita Naoyuki, Saito Tatsuyoshi, Uchiyama Shigeki, Morohashi Masayuki, Sase Hiroyuki

    BIOGEOSCIENCES   15 巻 ( 22 ) 頁: 7025-7042   2018年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.5194/bg-15-7025-2018

    Web of Science

    Scopus

  10. Variation of geochemical environments associated with whale-fall biomass mineralization processes in the sediment during the mobile scavenger, enrichment opportunist, and sulfophilic stages

    Onishi Yuji, Shimamura Sho, Yamanaka Toshiro, Nakayama Rei, Ozaki Ken-Ichi, Miyazaki Masayuki, Tsunogai Urumu, Fujiwara Yoshihiro

    MARINE BIOLOGY   165 巻 ( 9 )   2018年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/s00227-018-3398-8

    Web of Science

  11. Estimates of methane emissions from the Southern Ocean from quasi-continuous underway measurements of the partial pressure of methane in surface seawater during the 2012/13 austral summer

    Oanh Thi Ngoc Bui, Kameyama Sohiko, Yoshikawa-Inoue Hisayuki, Ishii Masao, Sasano Daisuke, Uchida Hiroshi, Tsunogai Urumu

    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY   70 巻   2018年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1080/16000889.2018.1478594

    Web of Science

  12. Clay Mineral Suites in Submarine Mud Volcanoes in the Kumano Forearc Basin, Nankai Trough: Constraints on the Origin of Mud Volcano Sediments

    Ijiri Akira, Iijima Koichi, Tsunogai Urumu, Ashi Juichiro, Inagaki Fumio

    GEOSCIENCES   8 巻 ( 6 )   2018年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.3390/geosciences8060220

    Web of Science

  13. Deep-biosphere methane production stimulated by geofluids in the Nankai accretionary complex

    Ijiri Akira, Inagaki Fumio, Kubo Yusuke, Adhikari Rishi R., Hattori Shohei, Hoshino Tatsuhiko, Imachi Hiroyuki, Kawagucci Shinsuke, Morono Yuki, Ohtomo Yoko, Ono Shuhei, Sakai Sanae, Takai Ken, Toki Tomohiro, Wang David T., Yoshinaga Marcos Y., Arnold Gail L., Ashi Juichiro, Case David H., Feseker Tomas, Hinrichs Kai-Uwe, Ikegawa Yojiro, Ikehara Minoru, Kallmeyer Jens, Kumagai Hidenori, Lever Mark A., Morita Sumito, Nakamura Ko-ichi, Nakamura Yuki, Nishizawa Manabu, Orphan Victoria J., Roy Hans, Schmidt Frauke, Tani Atsushi, Tanikawa Wataru, Terada Takeshi, Tomaru Hitoshi, Tsuji Takeshi, Tsunogai Urumu, Yamaguchi Yasuhiko T., Yoshida Naohiro

    SCIENCE ADVANCES   4 巻 ( 6 )   2018年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1126/sciadv.aao4631

    Web of Science

  14. Triple oxygen isotopes indicate urbanization affects sources of nitrate in wet and dry atmospheric deposition

    Nelson David M., Tsunogai Urumu, Ding Dong, Ohyama Takuya, Komatsu Daisuke D., Nakagawa Fumiko, Noguchi Izumi, Yamaguchi Takashi

    ATMOSPHERIC CHEMISTRY AND PHYSICS   18 巻 ( 9 ) 頁: 6381-6392   2018年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.5194/acp-18-6381-2018

    Web of Science

  15. Quantifying nitrate dynamics in a mesotrophic lake using triple oxygen isotopes as tracers

    Tsunogai Urumu, Miyauchi Takanori, Ohyama Takuya, Komatsu Daisuke D., Ito Masanori, Nakagawa Fumiko

    LIMNOLOGY AND OCEANOGRAPHY   63 巻   頁: S458-S476   2018年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/lno.10775

    Web of Science

  16. Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment

    Ino Kohei, Hernsdorf Alex W., Konno Uta, Kouduka Mariko, Yanagawa Katsunori, Kato Shingo, Sunamura Michinari, Hirota Akinari, Togo Yoko S., Ito Kazumasa, Fukuda Akari, Iwatsuki Teruki, Mizuno Takashi, Komatsu Daisuke D., Tsunogai Urumu, Ishimura Toyoho, Amano Yuki, Thomas Brian C., Banfield Jillian F., Suzuki Yohey

    ISME JOURNAL   12 巻 ( 1 ) 頁: 31-47   2018年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1038/ismej.2017.140

    Web of Science

  17. Flux and distribution of methane (CH4) in the Gunsan Basin of the southeastern Yellow Sea, off the Western Korea

    Lee Jun-Ho, Woo Han Jun, Son Seung-Kyu, Kim Moonkoo, Lee Dong-Hun, Tsunogai Urumu, Jeong Kap-Sik

    JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH PART A-TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING   53 巻 ( 5 ) 頁: 457-466   2018年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1080/10934529.2017.1409026

    Web of Science

  18. 軽元素安定同位体比の高感度分析に基づく地球惑星科学研究・地球環境科学研究の新展開

    角皆 潤

    地球化学   52 巻 ( 3 ) 頁: 107-129   2018年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    By using the hydrogen isotope exchange equilibrium between molecular hydrogen (H2) and water vapor, a new method called HIReTS (Hydrogen Isotopes Remote Temperature Sensing) was proposed for remote sensing of fumarole outlet temperatures. In this method, the hydrogen isotopic composition (D) of fumarolic H2 is obtained remotely from observation in a volcanic plume, and the outlet temperature is then derived from the obtained D of fumarolic H2. The HIReTS method can be used to obtain the fumarolic temperature remotely in active volcanoes when the actual fumaroles are inaccessible. Recent advances in using the 17O-excess (Δ17O) of nitrate were summarized as well. Within the possible sources of nitrate in the natural environment, only atmospheric nitrate that is produced from atmospheric NO through photochemical reactions can be characterized by the anomalous enrichment in 17O, reflecting the transfer of an oxygen atom from ozone. In addition, Δ17O is stable during partial metabolism̶such as denitrification and assimilation, so by using these characteristics of Δ17O, the author and coworkers were able to trace the fate of atmospheric nitrate deposited onto surface ecosystems. This also allowed the author and co-workers to propose a new method to quantify nitrate dynamics̶production rate through nitrification and metabolic rate through assimilation and denitrification̶in aquatic environments, using the Δ17O of nitrate. The Δ17O method is considered to offer an alternative to the traditional artificial tracer techniques for the determination of nitrate dynamics, including temporal variations.

    DOI: 10.14934/chikyukagaku.52.107

    CiNii Article

  19. Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment 査読有り

    Suzuki, Y., K. Ino, A. Hernsdorf, U. Konno, M. Kouduka, K. Yanagawa, M. Sunamura, A. Hirota, Y. Togo, K. Ito, A. Fukuda, T. Iwatsuki, T. Mizuno, D. Komatsu, U. Tsunogai, T. Ishimura, Y. Amano, B. Thomas, J. Banfield, and S. Kato

    The ISME Journal     2017年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1038/ismej.2017.140

  20. 高感度安定同位体質量分析に基づく海洋地球化学の革新(第31回海洋化学学術賞石橋賞受賞記念論文) 招待有り

    角皆 潤

    海洋化学研究   30 巻 ( 1 ) 頁: 3-17   2017年4月

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    担当区分:筆頭著者   記述言語:日本語  

  21. Formation of gas discharging from Taketomi submarine hot spring off Ishigaki Island in the southern Ryukyu Islands, Japan

    Toki Tomohiro, Iwata Daigo, Tsunogai Urumu, Komatsu Daisuke D., Sano Yuji, Takahata Naoto, Hamasaki Hiroshi, Ishibashi Jun-ichiro

    JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH   330 巻   頁: 24-35   2017年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.jvolgeores.2016.11.018

    Web of Science

  22. The role of low-temperature organic matter diagenesis in carbonate precipitation within a marine deposit

    Miyakawa Kazuya, Ishii Eiichi, Hirota Akinari, Komatsu Daisuke D., Ikeya Kosuke, Tsunogai Urumu

    APPLIED GEOCHEMISTRY   76 巻   頁: 218-231   2017年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.apgeochem.2016.11.001

    Web of Science

  23. Methanogens in H2-rich hydrothermal fluids resulting from phase separation in a sediment-starved, basalt-hosted hydrothermal system 査読有り

    Toki, T., A. Hamamoto, M. Tawata, J. Miyazaki, K. Nakamura, M. Abe, K. Takai, Y. Sano, N. Takahata, U. Tsunogai, J. Ishibashi

    Chemical Geology   447 巻   頁: 208-218   2016年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.chemgeo.2016.11.004

  24. Geochemical characteristics of hydrothermal fluids at Hatoma Knoll in the southern Okinawa Trough 査読有り

    Toki, T., M. Itoh, D. Iwata, S. Ohshima, R. Shinjo, J. Ishibashi, U. Tsunogai, N. Takahata, Y. Sano, T. Yamanaka, A. Ijiri, N. Okabe, T. Gamo, Y. Muramatsu, Y. Ueno, S. Kawagucci, and K. Takai

    Geochemical Journal   50 巻 ( 6 ) 頁: 493-525   2016年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.2343/geochemj.2.0449

  25. Mass occurrence of the enigmatic gastropod Elmira in the Late Cretaceous Sada Limestone seep deposit in southwestern Shikoku, Japan 査読有り

    Nobuhara, T., D. Onda, T. Sato, H. Aosawa, T. Ishimura, A. Ijiri, U. Tsunogai, N. Kikuchi, Y. Kondo, and S. Kiel

    Paläontologische Zeitschrift   90 巻 ( 4 ) 頁: 701–722   2016年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/s12542-016-0326-4

  26. Remote determinations on fumarole outlet temperatures in an eruptive volcano 査読有り

    Tsunogai, U., L. Cheng, M. Ito, D. D. Komatsu, F. Nakagawa, and H. Shinoara

    Geophysical Research Letters   43 巻 ( 22 ) 頁: 11620-11627   2016年11月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/2016GL070838

  27. Geochemical imprints of genotypic variants of Globigerina bulloides in the Arabian Sea 査読有り

    Sadekov, A., K. Darling, T. Ishimura, C. Wade, K. Kimoto, A. Singh, P. Anand, D. Kroon, S. Jung, G. Ganssen, R. Ganneshram, U. Tsunogai, and H. Elderfield

    Paleoceanography   31 巻 ( 10 ) 頁: 1440-1452   2016年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/2016PA002947

  28. Spatial and temporal variations of gas geochemistry at Mt. Ontake, Japan 査読有り

    Kagoshima, T., Y. Sano, N. Takahata, A. Ishida, Y. Tomonaga, E. Roulleau, D. L. Pinti, T. P. Fischer, T. Lan, Y. Nishio and U. Tsunogai

    Journal of Volcanology and Geothermal Research   325 巻   頁: 179-188   2016年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.jvolgeores.2016.06.013

  29. Helium and methane sources and fluxes of shallow submarine hydrothermal plumes near the Tokara Islands, Southern Japan 査読有り

    Wen, H.-Y., Y. Sano, N. Takahata, Y. Tomonaga, A. Ishida, K. Tanaka, T. Kagoshima, K. Shirai, J. Ishibashi, H. Yokose, U. Tsunogai, and T.F. Yang

    Scientific Reports   6 巻   頁: doi:10.1038/srep34126   2016年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1038/srep34126

  30. A 150-year variation of the Kuroshio transport inferred from coral nitrogen isotope signature 査読有り

    Yamazaki, A., T. Watanabe, U. Tsunogai, F. Iwase, H. Yamano

    Paleoceanography   31 巻 ( 6 ) 頁: 838-846   2016年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1002/2015PA002880

  31. Accurate and precise quantification of atmospheric nitrate in streams draining land of various uses by using triple oxygen isotopes as tracers 査読有り

    Tsunogai, U., T. Miyauchi, T. Ohyama, D.D. Komatsu, F. Nakagawa, Y. Obata, K. Sato, and T. Ohizumi

    Biogeosciences   13 巻   頁: 3441-3459   2016年6月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.5194/bg-2015-627

  32. Deep Microbial Life in High-Quality Granitic Groundwater from Geochemically and Geographically Distinct Underground Boreholes 査読有り

    Ino, K., U. Konno, M. Kouduka, A. Hirota, Y. Togo, A. Fukuda, D. Komatsu, U. Tsunogai, A.S. Tanabe, S. Yamamoto, T. Iwatsuki, T. Mizuno, K. Ito, Y. Suzuki

    Environmental Microbiology Reports   8 巻 ( 2 ) 頁: 285-294   2016年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1111/1758-2229.12379

  33. 安定同位体組成を指標に用いた窒素酸化物の起源解析と窒素循環定量への応用 招待有り 査読有り

    角皆 潤, 中川 書子

    エアロゾル研究   31 巻 ( 1 ) 頁: 5-14   2016年3月

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.11203/jar.31.5

  34. The GEOTRACES Intermediate Data Product 2014 査読有り

    The GEOTRACES Group

    Marine Chemistry   177 巻 ( 1 ) 頁: 1-8   2015年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.marchem.2015.04.005

  35. Chemical composition of Hydrothermal fluids in the central and southern Mariana trough backarc basin 査読有り

    Ishibashi, J. U. Tsunogai, T. Toki, N. Ebina, T. Gamo, Y. Sano, H. Masuda, H. Chiba

    Deep-Sea Research Part II   121 巻   頁: 126-136   2015年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.dsr2.2015.06.003

  36. Hydrothermal plumes in the Gulf of Aden, as characterized from light transmission, Mn, Fe, CH4 and δ13C-CH4 anomalies 査読有り

    Gamo, T., K. Okamura, H. Hatanaka, H. Hasumoto, D. Komatsu, M. Chinen, M. Mori, J. Tanaka, A. Hirota, U. Tsunogai, K. Tamaki

    Deep-Sea Research Part II   121 巻   頁: 62-70   2015年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.dsr2.2015.06.004

  37. The coral δ15N record of terrestrial nitrate loading varies with river catchment land use 査読有り

    Yamazaki, A., T. Watanabe, U. Tsunogai, H. Hasegawa, H. Yamano

    Coral Reefs   34 巻 ( 1 ) 頁: 353-362   2015年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/s00338-014-1235-1

  38. Biogeochemical Signals from Deep Microbial Life in Terrestrial Crust 査読有り

    Suzuki, Y., U. Konno, A. Fukuda, D.D. Komatsu, A. Hirota, Y. Togo, N. Morikawa, H. Hagiwara, D. Aosai, T. Iwatsuki, U. Tsunogai, S. Nagao, K. Ito, T. Mizuno

    PLoS ONE   9 巻 ( 12 ) 頁: e113063   2014年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1371/journal.pone.0113063

  39. Chemical and Isotopic Compositions of Hydrothermal Fluids at Snail, Archaean, Pika, and Urashima Sites in the Southern Mariana Trough 招待有り 査読有り

    Toki, Tomohiro, Jun-ichiro Ishibashi, Takuroh Noguchi, Miki Tawata, Urumu Tsunogai, Toshiro Yamanaka, Kentaro Nakamura

    Subseafloor Biosphere Linked to Hydrothermal Systems     頁: 587-602   2014年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/978-4-431-54865-2_45

  40. Tarama Knoll: Geochemical and Biological Profiles of Hydrothermal Activity 査読有り

    Yamanaka, T., H. Nagashio, R. Nishio, K. Kondo, T. Noguchi, K. Okamura, T. Nunoura, H. Makita, K. Nakamura, H. Watanabe, K. Inoue, T. Toki, K. Iguchi, U. Tsunogai, R. Nakada, S. Ohshima, S. Toyoda, J. Kawai, N. Yoshida, A. Ijiri, and M. Sunamura

    Subseafloor Biosphere Linked to Hydrothermal Systems     頁: 497-504   2014年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/978-4-431-54865-2_40

  41. Origin and transport of pore fluids in the Nankai accretionary prism inferred from chemical and isotopic compositions of pore water at cold seep sites off Kumano 査読有り

    Toki, T., R. Higa, A. Ijiri, U. Tsunogai and J. Ashi

    Earth Planets and Space   66 巻   頁: doi:10.1186/s40623-014-0137-3   2014年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1186/s40623-014-0137-3

  42. Quantifying the effects of clear-cutting and strip-cutting on nitrate dynamics in a forested watershed using triple oxygen isotopes as tracers 査読有り

    Tsunogai, U., Komatsu, D. D., Ohyama, T., Suzuki, A., Nakagawa, F., Noguchi, I., Takagi, K., Nomura, M., Fukuzawa, K., Shibata, H.

    Biogeosciences   11 巻 ( 19 ) 頁: 5411–5424   2014年10月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.5194/bg-11-5411-2014

  43. 同位体環境科学:安定同位体比によるプロセス解析 招待有り 査読有り

    角皆 潤, 中川書子

    大気環境学会誌   49 巻 ( 5 ) 頁: A63-A72   2014年9月

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    担当区分:筆頭著者   記述言語:日本語  

  44. Electrochemical Stimulation of Microbial Reductive Dechlorination of Pentachlorophenol Using Solid-State Redox Mediator (Humin) Immobilization 査読有り

      164 巻   頁: 232–240   2014年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.biortech.2014.04.071

  45. Tracing geologically constrained fluid flow pathways using a combination of heat flow measurements, pore water chemistry, and acoustic imaging near the deformation front of the Nankai Trough off the Muroto Peninsula, Japan 査読有り

      618 巻   頁: 121-137   2014年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.tecto.2014.01.035

  46. High-Resolution Measurement of Volatile Organic Compounds Dissolved in Seawater Using Equilibrator Inlet-Proton Transfer Reaction-Mass Spectrometry (EI-PTR-MS) 査読有り

        頁: 89-115   2014年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.5047/w-pass.a02.001

  47. Leakage of magmatic-hydrothermal volatiles from a crater bottom formed by a submarine eruption in 1989 at Teishi Knoll, Japan 査読有り

    Notsu, K., R. Sohrin, H. Wada, T. Tsuboi, H. Sumino, T. Mori, U. Tsunogai, P.A. Hernandez, Y. Suzuki, R. Ikuta, K. Oorui, M. Koyama, T. Masuda, N. Fujii

    Journal of Volcanology and Geothermal Research   270 巻   頁: 90-98   2014年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.jvolgeores.2013.11.017

  48. 熊野泥火山における間隙水の起源 査読有り

    土岐知弘, 比嘉良作, 棚原朗, 井尻暁, 角皆潤, 芦寿一郎

    地球化学   47 巻 ( 4 ) 頁: 221-236   2013年12月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  49. Occurrence and potential activity of denitrifiers and methanogens in groundwater at 140 m depth in Pliocene diatomaceous mudstone of northern Japan 査読有り

    Katsuyama, C., Nashimoto, H., Nagaosa, K., Ishibashi, T., Kinoshita, T., Yoshikawa, H., Aoki, K., Asano, T., Sasaki, Y., Sohrin, R., Komatsu, D., Tsunogai, U., Kimura, H., Suwa, Y., Kato, K.

    FEMS Microbiology Ecology   86 巻 ( 3 ) 頁: 532–543   2013年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1111/1574-6941.12179

  50. HIReTS法を用いた火山噴気の遠隔温度測定:薩摩硫黄島における検証 査読有り

    角皆 潤, 小松大祐, 中川書子

    火山   58 巻 ( 3 ) 頁: 443-459   2013年9月

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  51. Strong relationship between dimethyl sulfide and net community production in the western subarctic Pacific 査読有り

    Kameyama, S., H. Tanimoto, S. Inomata, H. Y. Inoue, U. Tsunogai, A. Tsuda, M. Uematsu, M. Ishii, D. Sasano

    Geophysical Research Letters   40 巻 ( 15 ) 頁: 3986-3990   2013年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Although much attention has been paid to describing the distribution of oceanic dimethyl sulfide (DMS) concentrations, establishing robust relationships between DMS concentrations and biological, physical, and chemical variables is still challenging. Previous studies have proposed semiempirical parameterizations by combining multiple physical and biogeochemical parameters to better understand and reproduce the global distribution of sea surface DMS. However, none of these parameterization schemes could reconcile regionally elevated DMS peaks found in high-resolution DMS measurements made in the western subarctic Pacific. Here we found that DMS concentrations are highly correlated with the net community production, a parameter that integrates biological activity over time. We anticipate that this elationship may be exportable to other regions with high primary productivity, such as the Southern Ocean or upwelling regions, and can be used as an important parameterization scheme, combined with solar radiation dose relationship.

    DOI: 10.1002/grl.50654

  52. Nitrogen isotopes in intra-crystal coralline aragonites 査読有り

    Yamazaki, A., T. Watanabe, N. Takahata, Y. Sano, U. Tsunogai

    Chemical Geology   351 巻   頁: 276–280   2013年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.chemgeo.2013.05.024

  53. Tracing atmospheric nitrate in groundwater using triple oxygen isotopes: Evaluation based on bottled drinking water 査読有り

    Nakagawa, F., A. Suzuki, S. Daita, T. Ohyama, D.D. Komatsu, U. Tsunogai

    Biogeosciences   10 巻   頁: 3547-3558   2013年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.5194/bg-10-3547-2013

  54. Shallow submarine hydrothermal activity with abundant magmatic water producing talc chimneys in the Wakamiko Crater of Kagoshima Bay, southern Kyushu, Japan 査読有り

    Journal of Volcanology and Geothermal Research   258 巻   頁: 74–84   2013年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.jvolgeores.2013.04.007

  55. Validity of otolith delta18O of Pacific bluefin tuna (Thunnus orientalis) as an indicator of ambient water temperature 査読有り

    Kitagawa, T., T. Ishimura, R. Uozato, K. Shirai, Y. Amano, A. Shinoda, T. Otake, U. Tsunogai, S. Kimura

    Marine Ecology Progress Series     2013年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.3354/meps10202

  56. Novel microbial populations colonized in deep granitic groundwater from Grimsel Test Site, Switzerland 査読有り

    Konno, U., M. Kouduka, D.D. Komatsu, K. Ishii, A. Fukuda, U. Tsunogai, K. Ito, Y. Suzuki

    Microbial Ecology   65 巻 ( 3 ) 頁: 626-637   2013年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/s00248-013-0184-5

  57. Megacities and large urban agglomerations in the Coastal Zone: Interactions between atmosphere, land and marine ecosystems 査読有り

    von Glasow, R., T. Jickells, A. Baklanov, G.R. Carmichael, T. Church, L. Gallardo, C. Hughes, M. Kanakidou, P. Liss, L. Mee, R. Raine, P. Ramachandran, R. Ramesh, K. Sundseth, U. Tsunogai, M. Uematsu, T. Zhu

    AMBIO   42 巻 ( 1 ) 頁: 13-28   2013年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1007/s13280-012-0343-9

  58. Contribution of methane to total gas pressure in deep waters at lakes Nyos and Monoun (Cameroon, West Africa) 査読有り

    Issa, T. Ohba, F. Wilson, Y. Yoshida, F. Alain, M. Kusakabe, U. Tsunogai, Y. Oginuma, C. T. Boris, G. Tanyileke, S. Nkamdjou, H. Satake J.V. Hell

    Geochemical Journal   47 巻 ( 3 ) 頁: 349-362   2013年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  59. Coseimic massive methane release from a submarine mud volcano 査読有り

    Tsunogai, U., K. Maegawa, S. Sato, D.D. Komatsu, F. Nakagawa, T. Toki, and J. Ashi

    Earth and Planetary Science Letters   341-344 巻   頁: 79-85   2012年8月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We report here the discovery of two methane-enriched plumes in a water column above the Kumano Knoll 5 submarine mud volcano (KK-5) in Nankai Trough during 2004; a slight methane enrichment was observed in this region in 2000 and 2010. The deeper of the two plumes spread horizontally at depths near the top of KK-5, whereas a shallow plume spread at a height of 300 m from the top of KK-5. The end-member d13C values of methane in both plumes, -46.1+-4.8 per mil and -51.4+-5.8 per mil in the deep and shallow plumes, respectively, and methane extracted from sediment in KK#5 (-52+-2 per mil) are statistically indistinguishable. We conclude that the plumes were created by massive release of methane from KK#5 and that this event probably occurred in response to the large earthquakes (Mw 7.5) that occurred shortly before our observation in 2004. The discharge rates from submarine mud volcanoes (SMVs) in subduction zones may be highly variable in response to major earthquakes.

    DOI: 10.1016/j.epsl.2012.06.004

  60. Biogeochemical processes involving acetate in sub-seafloor sediments from the Bering Sea shelf break 査読有り

    Ijiri, A., N. Harada, A. Hirota, U. Tsunogai, N.O. Ogawa, T. Itaki, B.-K. Khim, M. Uchida

    Organic Geochemistry   48 巻   頁: 47-55   2012年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.orggeochem.2012.04.004

  61. Iron-based microbial ecosystem on and below the seafloor: a case study of hydrothermal fields of the Southern Mariana Trough 査読有り

    Kato, S., K. Nakamura, T. Toki, J. Ishibashi, U. Tsunogai, A. Hirota, M. Ohkuma, A. Yamagishi

    Frontiers in Microbiology   3 巻   2012年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.3389/fmicb.2012.00089

  62. Disturbance of deep-sea environments induced by the M9.0 Tohoku Earthquake 査読有り

    Kawagucci, S., Y.T. Yoshida, T. Noguchi, M.C. Honda, H. Uchida, H. Ishibashi, F. Nakagawa, U. Tsunogai, K. Okamura, Y. Takaki, T. Nunoura, J. Miyazaki, W. Lin, H. Kitazato, and K. Takai

    Scientific Reports   2 巻   2012年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The impacts of the M9.0 Tohoku Earthquake on deep-sea environment were investigated 36 and 98 days after the event. The light transmission anomaly in the deep-sea water after 36 days became atypically greater (similar to 35 %) and more extensive (thickness similar to 1500 m) near the trench axis owing to the turbulent diffusion of fresh seafloor sediment, coordinated with potential seafloor displacement. In addition to the chemical influx associated with sediment diffusion, an influx of C-13-enriched methane from the deep sub-seafloor reservoirs was estimated. This isotopically unusual methane influx was possibly triggered by the earthquake and its aftershocks that subsequently induced changes in the sub-seafloor hydrogeologic structures. The whole prokaryotic biomass and the development of specific phylotypes in the deep-sea microbial communities could rise and fall at 36 and 98 days, respectively, after the event. We may capture the snap shots of post-earthquake disturbance in deep-sea chemistry and microbial community responses.

    DOI: 10.1038/srep00270

  63. First measurements of methane and its carbon isotope ratio in the Japan Sea (East Sea) 査読有り

    Gamo, T., U. Tsunogai, A. Hirota, N. Nakayama, D.-J. Kang, K.-R. Kim

    MARINE CHEMISTRY   128 巻   頁: 92-99   2012年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We measured dissolved methane (CH4) and its carbon isotope ratio (C-13/C-12 or delta C-13) from surface to bottom seawaters (maximum depth: 3574 m) for the first time in three major offshore areas of the Japan Sea (East Sea): the eastern Japan Basin, Yamato Basin, and Ulleung Basin. Seawater samples were taken during the KT-07-24 cruise of the R/V Tansei Maru in 2007 as part of a Japan-Korea collaborative study. The CH4 concentration and its delta C-13(PDB) were obtained by continuous flow isotope ratio mass spectrometry. While the CH4 concentrations of surface seawater were 2.6-3.8 nmol kg(-1), which was 43( +/- 22) % supersaturated compared to the atmospheric equilibrium values, those in the subsurface (D=30-150 m) showed much higher values up to 9.7 nmol kg(-1) (similar to 300 % supersaturation). This subsurface CH4 had the minimum delta C-13 value of -54.3 parts per thousand (less than the atmospheric CH4 value of -47 parts per thousand), implying a contribution from in situ microbial CH4 production in some anoxic microenvironments. The CH4 concentration decreased with depth toward minimum values of similar to 1 nmol kg(-1) (delta C-13, -30 to -40 parts per thousand.) at 1500-2000 m depth. Below a depth of 2000 m, we found a clear difference in CH4 profiles among the three basins; in the eastern Japan Basin the CH4 concentration remained almost constant down to the seafloor, while it gradually increased with depth up to > 2.0 nmol kg(-1) in the Yamato and Ulleung basins. This CH4 increase toward the bottom was accompanied by a decrease of delta C-13-CH4 to less than -50 parts per thousand, suggesting a microbial CH4 supply from bottom sediment in the Yamato and Ulleung basins. We observed a local CH4 plume over a deep channel east of the Yamato Basin, indicating unknown submarine CH4 seepage with a microbial delta C-13 value of about -60 parts per thousand.

    DOI: 10.1016/j.marchem.2011.10.006

  64. Methane production and accumulation in the Nankai accretionary prism: Results from IODP Expeditions 315 and 316 査読有り

    Geochemical Journal   46 巻 ( 2 ) 頁: 89-106   2012年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  65. Variation in stable carbon and oxygen isotopes of individual benthic foraminifera: tracers for quantifying the magnitude of isotopic disequilibrium 査読有り

    Ishimura, T., Tsunogai, U., Hasegawa, S., Nakagawa, F., Oi, T., Kitazato, H., Suga, H., Toyofuku, T.

    Biogeosciences   9 巻   頁: 4353-4367   2012年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.5194/bg-9-4353-2012

  66. 琉球諸島周辺の地殻内部流体中のメタンの起源 査読有り

    土岐 知弘,本田 龍太郎,大嶺 一希,岩田 大吾,角皆 潤,小松 大祐,佐野 有司,高畑 直人,石橋 純一郎,木下 正高,山城 秀之

    地球化学   46 巻 ( 4 ) 頁: 257-274   2012年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  67. Stable hydrogen isotopic analysis of nanomolar molecular hydrogen by automatic multi-step gas chromatographic separation 査読有り

    Komatsu, Daisuke D., Tsunogai, Urumu, Kamimura, Kanae, Konno, Uta, Ishimura, Toyoho, Nakagawa, Fumiko

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   25 巻 ( 21 ) 頁: 3351-3359   2011年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We have developed a new automated analytical system that employs a continuous flow isotope ratio mass spectrometer to determine the stable hydrogen isotopic composition (delta D) of nanomolar quantities of molecular hydrogen (H2) in an air sample. This method improves previous methods to attain simpler and lower-cost analyses, especially by avoiding the use of expensive or special devices, such as a Toepler pump, a cryogenic refrigerator, and a special evacuation system to keep the temperature of a coolant under reduced pressure. Instead, the system allows H2 purification from the air matrix via automatic multi-step gas chromatographic separation using the coolants of both liquid nitrogen (77 K) and liquid nitrogen + ethanol (158 K) under 1 atm pressure. The analytical precision of the delta D determination using the developed method was better than 4 parts per thousand for >5 nmol injections (250 mL STP for 500 ppbv air sample) and better than 15 parts per thousand for 1 nmol injections, regardless of the delta D value, within 1 h for one sample analysis. Using the developed system, the delta D values of H2 can be quantified for atmospheric samples as well as samples of representative sources and sinks including those containing small quantities of H2, such as H2 in soil pores or aqueous environments, for which there is currently little delta D data available. As an example of such trace H2 analyses, we report here the isotope fractionations during H2 uptake by soils in a static chamber. The delta D values of H2 in these H2-depleted environments can be useful in constraining the budgets of atmospheric H2 by applying an isotope mass balance model.

    DOI: 10.1002/rcm.5231

  68. Nitrogen isotopes of organic nitrogen in reef coral skeletons as a proxy of tropical nutrient dynamics 査読有り

    Yamazaki, Atsuko, Watanabe, Tsuyoshi, Tsunogai, Urumu

    GEOPHYSICAL RESEARCH LETTERS   38 巻   2011年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Understanding tropical nutrient dynamics is essential for quantifying marine productivity. In tropical and subtropical oceans, however, the spatial and continuous observation of nutrients has been scarce because of low nutrient concentration. The nitrogen isotopes of organic nitrogen in coral skeletons (delta15Ncoral) could be used to record nitrogenous nutrient origins at oceanic surfaces. Here, we show the intra- and inter-reef variations of delta15Ncoral in the western Pacific. The zonal distribution of delta15Ncoral was found inside a coral reef corresponding with delta15N of seawater nitrate (δ15N(nitrate)). The extended analysis of delta15Ncoral among various coral reefs also shows a latitudinal gradient from tropical to temperate in the western Pacific. The delta15Ncoral records high-resolution dynamics of nitrogenous nutrients through the geologic time scale.

    DOI: 10.1029/2011GL049053

  69. Hydrogen isotopes in volcanic plumes: Tracers for remote temperature sensing of fumaroles 査読有り

    Tsunogai, U., K. Kamimura, S. Anzai, F. Nakagawa, D.D. Komatsu

    GEOCHIMICA ET COSMOCHIMICA ACTA   75 巻 ( 16 ) 頁: 4531-4546   2011年8月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In high-temperature volcanic fumaroles (>400 degrees C), the isotopic composition of molecular hydrogen (H2) reaches equilibrium with that of the fumarolic H2O. In this study, we used this hydrogen isotope exchange equilibrium of fumarolic H2 as a tracer for the remote temperature at volcanic fumaroles. In this remote sensing, we deduced the hydrogen isotopic composition (delta D value) of fumarolic H2 from those in the volcanic plume. To ascertain that we can estimate the delta D value of fumarolic H2 from those in a volcanic plume, we estimated the values in three fumaroles with outlet temperatures of 630 degrees C (Tarumae), 203 degrees C (Kuju), and 107 degrees C (E-san). For this we measured the concentration and delta D value of H2 in each volcanic plume, along with those determined directly at each fumarole. The average and maximum mixing ratios of fumarolic H2 within a plume's total H2 were 97 % and 99 % (at Tarumae), 89 % and 96 % (at Kuju), and 97 % and 99 % (at E-san). We found a linear relationship between the depletion in the delta D values of H2, with the reciprocal of H2 concentration. Furthermore, the estimated end-member delta D value for each H2-enriched component (260 +/- 30 parts per thousand vs. VSMOW in Tarumae, 509 +/- 23 parts per thousand in Kuju, and 437 +/- 14 parts per thousand in E-san) coincided well with those observed at each fumarole (-247.0 +/- 0.6 parts per thousand in Tarumae, -527.7 +/- 10.1 parts per thousand in Kuju, and -432.1 +/- 2.5 parts per thousand in E-san). Moreover, the calculated isotopic temperatures at the fumaroles agreed to within 20 degrees C with the observed outlet temperature at Tarumae and Kuju. We deduced that the dD value of the fumarolic H2 was quenched within the volcanic plume. This enabled us to remotely estimate these in the fumarole, and thus the outlet temperature of fumaroles, at least for those having the outlet temperatures more than 400 degrees C. By applying this methodology to the volcanic plume emitted from the Crater 1 of Mt. Naka-dake (the volcano Aso) where direct measurement on fumaroles was impractical, we estimated that the dD value of the fumarolic H2 to be -172 +/- 16 parts per thousand and the outlet temperature to be 868 +/- 97 degrees C. The remote temperature sensing using hydrogen isotopes developed in this study is widely applicable to many volcanic systems.

    DOI: 10.1016/j.gca.2011.05.023

  70. A geochemical study on mud volcanoes in the Junggar Basin, China 査読有り

    Nakada, Ryoichi, Takahashi, Yoshio, Tsunogai, Urumu, Zheng, Guodong, Shimizu, Hiroshi, Hattori, Keiko H.

    APPLIED GEOCHEMISTRY   26 巻 ( 7 ) 頁: 1065-1076   2011年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A comprehensive study was performed to characterize, for the first time, the mud, water, and gases released from onshore mud volcanoes located in the southern margin of the Junggar Basin, northwestern China. Chemical compositions of mud, along with the geology of the basin, suggest that a source of the mud is Mesozoic or Cenozoic shale. Oxygen and H isotope compositions of the released water suggest a local meteoric origin. Combined with the positive Eu anomalies of the water, a large (18)O shift of the water suggests extensive interaction with rocks. Gases discharged from the mud volcanoes are predominantly thermogenic hydrocarbons, and the high delta13C values (>+20 parts per thousand VPDB) for CO2 gases and dissolved carbonate in muddy water suggest secondary methanogenesis with CO2 reduction after oil biodegradation. The enrichments of Eu and (18)O in water and the low thermal gradient of the area suggest that the water-rock interactions possibly occur deeper than 3670 +/- 200 m. On the other hand, considering the relationship to the petroleum reservoir around the mud volcanoes, the depth of the gases can be derived from about 3600 m, a depth that is greater than that generally estimated for reservoirs whose gas is characterized by 13C-enriched CO2. Oil biodegradation with CO2 reduction likely occurs at a shallower depth along the seepage system of the mud volcano. The results contribute to the worldwide data set of gas genesis in mud volcanoes. Moreover, they further support the concept that most terrestrial mud volcanoes release thermogenic gas produced in very deep sediments and may be early indicators of oil biodegradation, an important problem in the petroleum industry.

    DOI: 10.1016/j.apgeochem.2011.03.011

  71. Geophysical and geochemical evidence of large scale fluid flow within shallow sediments in the eastern Gulf of Mexico, offshore Louisiana 査読有り

    Gay, A., Takano, Y., Gilhooly, III, W. P., Berndt, C., Heeschen, K., Suzuki, N., Saegusa, S., Nakagawa, F., Tsunogai, U., Jiang, S. Y., Lopez, M.

    GEOFLUIDS   11 巻 ( 1 ) 頁: 34-47   2011年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We analyse the fluid flow regime within sediments on the Eastern levee of the modern Mississippi Canyon using 3D seismic data and downhole logging data acquired at Sites U1322 and U1324 during the 2005 Integrated Ocean Drilling Program (IODP) Expedition 308 in the Gulf of Mexico. Sulphate and methane concentrations in pore water show that sulphate-methane transition zone, at 74 and 94 m below seafloor, are amongst the deepest ever found in a sedimentary basin. This is in part due to a basinward fluid flow in a buried turbiditic channel (Blue Unit, 1000 mbsf), which separates sedimentary compartments located below and above this unit, preventing normal upward methane flux to the seafloor. Overpressure in the lower compartment leads to episodic and focused fluid migration through deep conduits that bypass the upper compartment, forming mud volcanoes at the seabed. This may also favour seawater circulation and we interpret the deep sulphate-methane transition zones as a result of high downward sulphate fluxes coming from seawater that are about 5-10 times above those measured in other basins. The results show that geochemical reactions within shallow sediments are dominated by seawater downwelling in the Mars-Ursa basin, compared to other basins in which the upward fluid flux is controlling methane-related reactions. This has implications for the occurrence of gas hydrates in the subsurface and is evidence of the active connection between buried sediments and the water column.

    DOI: 10.1111/j.1468-8123.2010.00304.x

  72. Stable carbon isotope ratios of ethane over the North Pacific: Atmospheric measurements and global chemical transport modeling 査読有り

    Saito, Takuya, Stein, Olaf, Tsunogai, Urumu, Kawamura, Kimitaka , Nakatsuka, Takeshi, Gamo, Toshitaka, Yoshida, Naohiro

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   116 巻   2011年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The atmospheric mixing ratios of ethane and its stable carbon isotope ratios (delta13C) were measured over the North Pacific (2 degrees N to 38 degrees N, 140 degrees E to 90 degrees W) during oceanographic cruises in summer and autumn. The measured mixing ratios were relatively low (mostly < 1 ppbv) over the North Pacific, whereas elevated ethane levels (> 1 ppbv) were observed over the western North Pacific near Japan, with lower delta13C values (approximately -25 parts per thousand), suggesting recent emissions from neighboring source regions. The most 13C-enriched values of ethane (approximately -16 parts per thousand) were observed over the western equatorial Pacific rather than the central and eastern equatorial Pacific. This is likely caused by the kinetic isotope effect (KIE) for the removal of ethane during the atmospheric transport from potential upwind source regions to the most remote region under the prevailing trade easterly winds. The measurements were compared with the results of a global chemical transport model including two ethane isotopologues ((12)C(2)H(6) and 13C(2)H(6)). The model-estimated delta13C values were too high compared with the observations. It is likely that this discrepancy is partly due to an approximately 40 % overestimation of the reported KIE for the reaction between ethane and OH radicals.

    DOI: 10.1029/2010JD014602

  73. Application of PTR-MS to an incubation experiment of the marine diatom Thalassiosira pseudonana 査読有り

    Kameyama, Sohiko, Tanimoto, Hiroshi, Inomata, Satoshi, Suzuki, Koji, Komatsu, Daisuke D., Hirota, Akinari, Konno, Uta, Tsunogai, Urumu

    GEOCHEMICAL JOURNAL   45 巻 ( 5 ) 頁: 355-363   2011年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Emission of trace gases from the marine diatom Thalassiosira pseudonana (CCMP 1335) was continuously monitored with a proton transfer reaction-mass spectrometry (PTR-MS) in an axenic batch culture system under a 13:11-h light:dark cycle. Substantial increases in the signals at m/z 49, 63, and 69, attributable to methanethiol, dimethyl sulfide (DMS), and isoprene, respectively, were observed in response to increases in cell density. Signals at m/z 69 showed diurnal variations throughout the experiment whereas those at m/z 49 were more pronounced at the beginning of the incubation. Interestingly, the signals at m/z 49 and 69 changed immediately following the light-dark and dark-light transitions, suggesting that light plays a crucial role in the production of methanethiol and isoprene. However, in the latter half of the experiment, methanethiol showed negligible diurnal variations regardless of light conditions, suggesting the production of methanethiol from enzymatic cleavage of DMS. The trend ill signals at m/z 63 was similar to that of the abundance of senescent cells plus cell debris rather than vegetative cells. The results suggest that aging or death of phytoplankton cells could also substantially control DMS production in natural waters along with the other microbial processes related to bacteria and zooplankton.

  74. Quantifying nitrate dynamics in an oligotrophic lake using Δ17O 査読有り

    Tsunogai, U., Daita, S., Komatsu, D. D., Nakagawa, F., Tanaka, A.

    BIOGEOSCIENCES   8 巻 ( 3 ) 頁: 687-702   2011年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The stable isotopic compositions of nitrate, including the 17O anomalies (Delta17O), were determined twice in 1 yr (June and August 2007) in the oligotrophic water column of Lake Mashu, Japan. These data were then used to quantify the geochemical dynamics of nitrate in the lake, by using the deposition rate of the atmospheric nitrate onto the entire catchment area of the lake. The total amount of nitrate in the lake water decreased from 4.2 to 2.1 Mmol during the period between the observations, while the average Delta17O values remained uniform at + 2.5 parts per thousand. The Delta17O values corresponded to an small and uniform mixing ratio of atmospheric nitrate to total nitrate of 9.7 +/- 0.8 %. These results indicate that 0.52 +/- 0.34 Mmol of the remineralized nitrate was fed into the water column through nitrification, while 2.6 +/- 0.4 Mmol of nitrate was simultaneously removed from the water column by assimilation, during the period between the observations. The lake water dissolved nitrate was characterized by rapid removal through assimilation during summer until it was almost completely removed from the euphotic layer, as well as continuous feeding into the lake through nitrification (3.2 +/- 0.3 Mmol a(-1)) and deposition (0.35 +/- 0.2 Mmol a(-1)), regardless of the seasons. The 15N-depleted nitrogen isotopic compositions of nitrate were as low as -6.5 parts per thousand in June, which also indicates that in-lake nitrification is the major source of nitrate in the lake and suggests that there is low potential for denitrification in and around the lake. Atmospheric nitrate deposited into the lake will be assimilated quickly, having a mean residence time of 1.2 +/- 0.1 yr. In addition, more than 90 % of the assimilated nitrate will be remineralized to nitrate and re-assimilated via active nitrogen cycling in the lake.

    DOI: 10.5194/bg-8-687-2011

  75. Diversity and Function of Epibiotic Microbial Communities on the Galatheid Crab, Shinkaia crosnieri 査読有り

    Watsuji, Tomo-o, Nakagawa, Satoshi, Tsuchida, Shinji, Toki, Tomohiro, Hirota, Akinari, Tsunogai, Urumu, Takai, Ken

    MICROBES AND ENVIRONMENTS   25 巻 ( 4 ) 頁: 288-294   2010年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The galatheid crab, Shinkaia crosnieri (Decapoda: Galatheidae), forms dense colonies in the Iheya North and Hatoma Knoll deep-sea hydrothermal fields and has numerous setae covered with filamentous epibiotic microorganisms. Molecular phylogenetic analyses revealed that the epibiotic communities in S. crosnieri consisted mainly of yet-uncultivated phylotypes within Epsilonproteobacteria and Gammaproteobacteria in both hydrothermal vent fields. Uptake experiments using 13C-labeled tracers clearly demonstrated that both H13CO(3)(-) and 13CH4 were assimilated into not only the epibiotic microbial communities associated with the setae, but also the epibiont-free tissue of living S. crosnieri. In addition, the incorporation of H13CO(3)(-) into the microbial cells was strongly stimulated by the presence of reduced sulfur compounds but not by H2. In conclusion, the uptake experiments suggested that sulfur-oxidizing chemolithoautotrophic and methanotrophic production by the epibionts provides the nutrition for S. crosnieri.

    DOI: 10.1264/jsme2.ME10135

  76. High-resolution measurement of multiple volatile organic compounds dissolved in seawater using equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS) 査読有り

    Kameyama, Sohiko, Tanimoto, Hiroshi, Inomata, Satoshi, Tsunogai, Urumu, Ooki, Atsushi, Takeda, Shigenobu, Obata, Hajime, Tsuda, Atsushi, Uematsu, Mitsuo

    MARINE CHEMISTRY   122 巻 ( 40912 ) 頁: 59-73   2010年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We developed an equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS) system for high-resolution measurement of the concentrations of multiple volatile organic compounds (VOCs) dissolved in seawater. The equilibration of five VOCs (isoprene, propene, acetone, acetaldehyde, and methanol) between seawater samples and the carrier gas, and the response time of the system, were evaluated by means of a series of laboratory experiments. Although equilibrium between the seawater sample and the carrier gas in the equilibrator was not achieved for isoprene and propene (likely because of their low water solubility), the other species did reach equilibrium. The EI-PTR-MS system was deployed during a research cruise in the western North Pacific Ocean. Evaluation of several seawater sampling methods indicated that there was no significant contamination from the sampling apparatus for the target VOCs. For isoprene, comparison of EI-PTR-MS measurements with measurements obtained with a membrane equilibrator-gas chromatography/mass spectrometry system showed generally good agreement (R(2)=0.79). EI-PTR-MS captured the temporal variations of dissolved VOCs, including small-scale variability, which demonstrates that the performance of the EI-PTR-MS system was sufficient for simultaneous and continuous measurements of multiple VOCs of environmental importance in seawater.

    DOI: 10.1016/j.marchem.2010.08.003

  77. Geomicrobiological Properties of Ultra-Deep Granitic Groundwater from the Mizunami Underground Research Laboratory (MIU), Central Japan 査読有り

    Fukuda, Akari, Hagiwara, Hiroki, Ishimura, Toyoho, Kouduka, Mariko, Ioka, Seiichiro, Amano, Yuki, Tsunogai, Urumu, Suzuki, Yohey, Mizuno, Takashi

    MICROBIAL ECOLOGY   60 巻 ( 1 ) 頁: 214-225   2010年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Although deep subterranean crystalline rocks are known to harbor microbial ecosystems, geochemical factors that constrain the biomass, diversity, and metabolic activities of microorganisms remain to be clearly defined. 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 (3) (-) and SO (4) (2-) , were not abundant, while dissolved organic carbon (not including organic acids), CH4 and H2, was moderately rich in the groundwater sample collected in 2008. The total number of acridine orange-stained cells in groundwater samples collected in 2005 and 2008 were 1.1 x 10(4) and 5.2 x 10(4) cells/mL, respectively. In 2005 and 2008, the most common phylotypes determined by 16S rRNA gene sequence analysis were both related to Thauera spp., the cultivated members of which can utilize minor electron donors, such as aromatic and aliphatic hydrocarbons. After a 3-5-week incubation period with potential electron donors (organic acids or CH4 + H2) and with/without electron acceptors (O(2) or NO (3) (-) ), dominant microbial populations shifted to Brevundimonas spp. These geomicrobiological results suggest that deep granitic groundwater has been stably colonized by Thauera spp. probably owing to the limitation of O(2), NO (3) (-) , and organic acids.

    DOI: 10.1007/s00248-010-9683-9

  78. Simultaneous determination of delta15N and delta18O of N2O and delta13C of CH4 in nanomolar quantities from a single water sample 査読有り

    Hirota, A., Tsunogai, U., Komatsu, D. D., Nakagawa, F.

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   24 巻 ( 7 ) 頁: 1085-1092   2010年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We have developed a rapid, sensitive, and automated analytical system to simultaneously determine the concentrations and stable isotopic compositions (delta15N, delta(18)O, and delta13C) of nanomolar quantities of nitrous oxide (N(2)O) and methane (CH4) in water, by combining continuous-flow isotope-ratio mass spectrometry and a helium-sparging system to extract and purify the dissolved gases. Our system, which is composed of cold traps and a capillary gas chromatograph that use ultra-pure helium as the carrier gas, achieves complete extraction of N(2)O and CH4 in a water sample and separation among N(2)O, CH4, and the other component gases. The flow path following exit from the gas chromatograph was periodically changed to pass the gases through the combustion furnace to convert CH4 and the other hydrocarbons into CO2, or to bypass the combustion furnace for the direct introduction of eluted N(2)O into the mass spectrometer, for determining the stable isotopic compositions through monitoring the ions of m/z 44, 45, and 46 of CO2(+) and N(2)O(+). The analytical system can be operated automatically with sequential software programmed on a personal computer. Analytical precisions better than 0.2 parts per thousand and 0.3 parts per thousand and better than 1.4 parts per thousand and 2.6 parts per thousand were obtained for the delta15N and delta(18)0 of N(2)O, respectively, when more than 6.7 nmol and 0.2 nmol of N(2)O, respectively, were injected. Simultaneously, analytical precisions better than 0.07 %, and 2.1 parts per thousand were obtained for the delta13C of CH4 when more than 5.5 nmol and 0.02 nmol of CH4, respectively, were injected. In this manner, we can simultaneously determine stable isotopic compositions of a 120 mL water sample with concentrations as low as 1.7 nmol/kg for N(2)O and 0.2 nmol/kg for CH4.

    DOI: 10.1002/rcm.4483

  79. Archaeal Diversity and Distribution along Thermal and Geochemical Gradients in Hydrothermal Sediments at the Yonaguni Knoll IV Hydrothermal Field in the Southern Okinawa Trough 査読有り

    Nunoura, Takuro, Oida, Hanako, Nakaseama, Miwako, Kosaka, Ayako , Ohkubo, Satoru B., Kikuchi, Toru, Kazama, Hiromi, Hosoi-Tanabe, Shoko, Nakamura, Ko-ichi, Kinoshita, Masataka, Hirayama, Hisako, Inagaki, Fumio, Tsunogai, Urumu, Ishibashi, Jun-ichiro, Takai, Ken

    APPLIED AND ENVIRONMENTAL MICROBIOLOGY   76 巻 ( 4 ) 頁: 1198-1211   2010年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A variety of archaeal lineages have been identified using culture-independent molecular phylogenetic surveys of microbial habitats occurring in deep-sea hydrothermal environments such as chimney structures, sediments, vent emissions, and chemosynthetic macrofauna. With the exception of a few taxa, most of these archaea have not yet been cultivated, and their physiological and metabolic traits remain unclear. In this study, phylogenetic diversity and distribution profiles of the archaeal genes encoding small subunit (SSU) rRNA, methyl coenzyme A (CoA) reductase subunit A, and the ammonia monooxygenase large subunit were characterized in hydrothermally influenced sediments at the Yonaguni Knoll IV hydrothermal field in the Southern Okinawa Trough. Sediment cores were collected at distances of 0.5, 2, or 5 m from a vent emission (90 degrees C). A moderate temperature gradient extends both horizontally and vertically (5 to 69 degrees C), indicating the existence of moderate mixing between the hydrothermal fluid and the ambient sediment pore water. The mixing of reductive hot hydrothermal fluid and cold ambient sediment pore water establishes a wide spectrum of physical and chemical conditions in the microbial habitats that were investigated. Under these different physico-chemical conditions, variability in archaeal phylotype composition was observed. The relationship between the physical and chemical parameters and the archaeal phylotype composition provides important insight into the eco-physiological requirements of uncultivated archaeal lineages in deep-sea hydrothermal vent environments, giving clues for approximating culture conditions to be used in future culturing efforts.

    DOI: 10.1128/AEM.00924-09

  80. 北日本における亜硝酸ガス濃度と窒素酸化物由来成分の挙動 査読有り

    野口泉, 林健太郎, 加藤拓紀, 山口高志, 秋山雅行, 大塚英幸, 酒井茂克, 高木健太郎, 深澤達矢, 柴田英昭, 藤沼康実, 三枝信子, 下鳥稔, 家合浩明, 松田和秀, 角皆潤, 原宏

    大気環境学会誌   45 巻   頁: 153-165   2010年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  81. Sources of pore water in a Tanegashima mud volcano inferred from chemical and stable isotopic studies 査読有り

    Nakayama, Noriko, Ashi, Juichiro, Tsunogai, Urumu, Gamo, Toshitaka, Tanahashi, Michiro

    GEOCHEMICAL JOURNAL   44 巻 ( 6 ) 頁: 561-569   2010年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Pore waters at the depths of 0-590 cm below seafloor (bsf) were collected from four core samples at four different sites in a mud volcano off Tanegashima Island between Ryukyu trench and Ryukyu arc of Japan Concentrations of Cl(-), SO(4)(2-), CH4 C(2)H(6) and stable isotopic composition of delta13C(CH4), delta(18)O(H2O) delta D(H2O) in the pore waters vary as a function of distance from seafloor This paper reports and discusses the pore waters collected at the summit (CV) site The concentration, of Cl(-) decrease from 540 at the seafloor to 375 mmol/kg at a depth of similar to 200 cm and remain constant at around 350 mmol/kg (64 % of the concentration of seawater) below the depth The concentrations of CH4 are two to three orders of magnitude higher than those at other sites and have a maximum value of 715 mu mol/kg at around 120-140 cm bsf Core samples collected at depths deeper than 180 cm bsf show collapsing gas bubbles and empty voids when they were split open It was also observed that liquid seeped out from the surface of the split core Considering the physical condition is favorable for the, formation of methane hydrate, the observations suggest the existence of methane hydrates High concentration of C2H6 which had similar depth profile to that of CH4 was also observed C(2)H(6)/CH4 ratio remained larger than 10(-3) and delta13C(CH4) also remained around -45 parts per thousand below 180 cm bsf The data suggest presence of thermogenic methane in the CV site delta(18)O(H2O) and delta D(H2O) profiles exhibited an opposite depth dependence and only delta D(H2O) showed a decreasing depth profile similar to the concentration profile of Cl- They were inversely correlated with the concentration of Cl- The data of these two isotope compositions suggest a dilute fluid originates mainly from clay mineral dehydration but meteoric water A simple mixing model of fluids from three sources (ambient seawater water dissociated from methane hydrates and diagenetic water ascending from deeper depth) with isotopic fraction during methane hydrate dissociation was applied for the observation result below 280 cm bsf to constrain ranges of delta(18)O(H2O) and delta D(H2O) of diagenetic water Using the observed depth profile of Cl(-) as a conservative component of ambient seawater contribution of ambient seawater is estimated to be 64 % whereas 36 % from other two sources Considering an isotopic fractionation during methane hydrate dissociation and using the estimated source fractions and observed isotopic composition of pore water delta(18)O(H2O) and delta D(H2O) of the diagenetic water were estimated to range from +15 to +22 parts per thousand and from -103 to -43 parts per thousand respectively which are in good agreement with isotopic compositions of water formed from clay minerals during their dehydration but quite different from those of meteoric water, supporting negligible contribution of meteoric water in the Tanegashima mud volcano fluid.

  82. Tracing the fate of atmospheric nitrate deposited onto a forest ecosystem in Eastern Asia using Δ17O 査読有り

    Tsunogai, U., Komatsu, D. D., Daita, S., Kazemi, G. A., Nakagawa, F., Noguchi, I., Zhang, J.

    ATMOSPHERIC CHEMISTRY AND PHYSICS   10 巻 ( 4 ) 頁: 1809-1820   2010年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The stable isotopic compositions of nitrate in precipitation (wet deposition) and groundwater (spring, lake, and stream water) were determined for the island of Rishiri, Japan, so as to use the 17O anomalies (Δ17O) to trace the fate of atmospheric nitrate that had deposited onto the island ecosystem, which is a representative background forest ecosystem for eastern Asia. The deposited nitrate had large 17O anomalies with Δ17O values ranging from +20.8 parts per thousand to +34.5 parts per thousand (n = 32) with +26.2 parts per thousand being the annual average. The maximum Δ17O value of + 34.5 parts per thousand, obtained for precipitation on the 23rd to 24th of February 2007, was an extraordinarily large value among values for all samples of precipitation in Rishiri. Most nitrate in the sample might have been produced via NO(3) radical in a highly polluted air mass that had been supplied from megacities on the eastern coast of the Asian continent. On the other hand, nitrate in groundwater had small Δ17O values ranging from + 0.9 parts per thousand to 3.2 parts per thousand (n = 19), which corresponds to an mixing ratio of atmospheric nitrate to total nitrate of (7.4 +/- 2.6) %. Comparing the inflow and outflow of atmospheric nitrate in groundwater within the island, we estimated that the direct drainage accounts for (8.8 +/- 4.6) % of atmospheric nitrate that has deposited on the island and that the residual portion has undergone biological processing before being exported from the forest ecosystem.

    DOI: 10.5194/acp-10-1809-2010

  83. 三酸素同位体組成を指標に用いた大気沈着窒素ー森林生態系間相互作用の定量的評価法 査読有り

    角皆 潤, 小松 大祐, 代田 里子, 中川 書子, 野口 泉, 張 勁

    低温科学   68 巻   頁: 107-120   2010年

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    担当区分:筆頭著者   記述言語:日本語  

  84. Gas geochemical characteristics of hydrothermal plumes at the HAKUREI and JADE vent sites, the Izena Cauldron, Okinawa Trough 査読有り

    Kawagucci, Shinsuke, Shirai, Kotaro, Lan, Tefang Faith, Takahata, Naoto, Tsunogai, Urumu, Sano, Yuji, Gamo, Toshitaka

    GEOCHEMICAL JOURNAL   44 巻 ( 6 ) 頁: 507-518   2010年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hydrothermal plumes above the HAKUREI and JADE sites two high-temperature hydrothermal vent sites in the Izena Cauldron at the mid-Okinawa Trough were investigated in order to gain a preliminary understanding of gas geochemical characteristics at underlying hydrothermal vent sites Three geochemical tracers, H2, CH4 and delta(3)He covary with each other above the HAKUREI site but only CH4 and delta(3)He are correlated above the JADE site The carbon isotope ratio of methane within the Izena Cauldron can be accounted by a combination of the fluid dilution by ambient seawater and microbial consumption with the kinetic carbon isotope effect (KIE) of 1 007 An estimated endmember delta13C value of -32 parts per thousand in the HAKUREI fluid was obtained Both the plumes above the HAKUREI and JADE sites showed C(1)/C(2) ratios between 10(3)similar to 10(4) Only the bottom water around the HAKUREI site showed significant N(2)O excess with isotopically light delta15N and delta(18)O, suggesting N(2)O input from microbial activity in the sediment A linear con elation between H2 and CH4 in the HAKUREI plume gives a H2/CH4 ratio of the HAKUREI fluid of more than 0 022 The estimated H2/CH4 ratio in the HAKUREI fluid is significantly higher than that of the JADE fluid comparable with those of fluids venting at other sediment related hydrothermal systems, and also comparable with those of thermogenic gases produced by hydrothermal sediment experiments These facts suggest that fluid sediment interaction during fluid upwelling appears to modify gas geochemical characteristics at the HAKUREI site but have little influence at the JADE site This study demonstrates the availability of the Izena Cauldron hydrothermal field and the HAKUREI and JADE sites as a natural laboratory for investigating the fluid-sediment interaction during fluid upwelling.

  85. Origin and fate of deep-sea seeping methane bubbles at Kuroshima Knoll, Ryukyu forearc region, Japan 招待有り 査読有り

    Tsunogai, U., Kosaka, A., Nakayama, N., Komatsu, D. D., Konno, U., Kameyama, S., Nakagawa, F., Sumino, H., Nagao, K. , Fujikura, K., Machiyama, H.

    GEOCHEMICAL JOURNAL   44 巻 ( 6 ) 頁: 461-476   2010年

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Seafloor sec ping methane bubbles were successfully sampled on the summit area of the Kuroshima Knoll (depth of ca 640 m) using the gas-tight sampler WHATS attached to the Shinkai 2000 To evaluate the origin of the bubbles and verify that the dissociation of methane hydrate was actually in progress the chemical and isotopic composition of the samples wen analyzed The major component of the gas bubbles was methane (C(1)) with traces of CO2 (67 +/- 16 ppmv) and helium (11 +/- 1 ppmv (4)He/(20)Ne = 320) having a moderate (3)He/(4)He ratio (0 44R(a)) C(1) was enriched relative to other hydrocarbons (C(1)/(C(2)+C(3)) > 3000) The delta13C values for C(1) (-40 1 parts per thousand(VPDB)) C(2) (-28 3 parts per thousand(VPDB)) and C(5) (-28 0 parts per thousand(VPDB)) were similar to those of hydrocarbons produced by thermal decomposition of organic matter The contribution of the mantle derived (3)He enriched component in coexisting helium also supports thermogenic generation On the other hand the other light hydrocarbons showed an unusual 13C enrichment in C(3) (-19 1 parts per thousand(VPDB)) ISO-C(4) (-22 4 parts per thousand(VPDB)) and n-C(4) (-19 9 parts per thousand(VPDB)) C(3) and C(4) had been fractionated both chemically and isotopically through subsequent microbial destruction during the long storage from Miocene in the gas reservoir In addition the anaerobic oxidation of CH4 within shallow sediments removed about 20 % of CH4, until seepage into ocean water column Regarding the contribution of gases originating from hydrate dissociation to the bubbles observed helium amount in the bubbles suggests that methane hydrate is considered to be a minor contributor to the bubbles at least at present Direct leakage of gases from deep reservoirs is a more plausible for the source Regarding the fate of the hydrocarbons in the bubbles in the water column, all rising bubbles at Kuroshima Knoll dissolved within 140 m of the seafloor After the dissolution the plume spreads horizontally along with the surface of equal density in the water column, while the concentrations decrease through dilution by eddy diffusion rather than by oxidation.

  86. Microbial carbon isotope fractionation to produce extraordinarily heavy methane in aging hydrothermal plumes over the southwestern Okinawa Trough 査読有り

    Gamo, Toshitaka, Tsunogai, Urumu, Ichibayashi, Shinsuke, Chiba, Hitoshi, Obata, Hajime, Oomori, Tamotsu, Noguchi, Takuro, Baker, Edward T., Doi, Takashi, Maruo, Masahiro, Sano, Yuji

    GEOCHEMICAL JOURNAL   44 巻 ( 6 ) 頁: 477-487   2010年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Within neutrally buoyant hydrothermal plumes derived from the Yonaguni Knoll IV hydrothermal field (24 degrees 51' N, 122 degrees 42' E D = 1 370-1 385 m) in the southwestern Okinawa Trough back arc basin we obtained profiles of dissolved manganese (Mn), helium isotopes ((3)He/(4)He) methane (CH4) and its stable carbon isotope ratio (delta13C(PDB)) in young to old plume waters We first mapped the spatial distribution of hydrothermal plumes by towing a fixed array of optical sensors (Miniature Autonomous Plume Recorders MAPRs) above the field We then made water column observations and samplings using a CTD (Conductivity Temperature and Depth sensors)-Carousel package with a transmissometer and Niskin-X bottles at five locations with distances between 0 6 and 6 1 km horn the hydrothermally active center so far discovered Vertical profiles of light transmission and chemical tracers indicated triple-layered plumes the centers of which were at depths of 700-800 m similar to 1 050 m and similar to 1 200 m The CH4 concentrations and delta13C value for the 1 200-m plume ranged between 1,026 and 10 nmol/kg, and between -22 4 and +40 4 parts per thousand (the highest delta13C value yet reported for oceanic CH4) respectively indicating active microbial CH4 oxidation accompanied by the delta13C increase for residual CH4 The delta13C(CH4) was shown to be useful for tracing such a ``microbial plume whose CH4 concentration has already fallen to almost the background level By applying the Rayleigh distillation equation for a closed system we estimated the kinetic isotope fractionation factor of 1.012 for the CH4 oxidation process occurring within the hydrothermal plumes deeper than 1 000 m.

  87. Determination of total N2 fixation rates in the ocean taking into account both the particulate and filtrate fractions 査読有り

    Konno, U., Tsunogai, U., Komatsu, D. D., Daita, S., Nakagawa, F., Tsuda, A., Matsui, T., Eum, Y. -J., Suzuki, K.

    BIOGEOSCIENCES   7 巻 ( 8 ) 頁: 2369-2377   2010年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Using the 15N(2) tracer method and high-sensitivity delta15N analytical systems, we determined N(2) fixation rates for ocean samples by dividing them into particulate (> 0.7 mu m) and filtrate (< 0.7 mu m) fractions. While N(2) fixation in the filtrate fraction had been ignored in previous studies, we found a significant N(2) fixation rates in the filtrate fraction in our study. The areal N(2) fixation rates in the western North Pacific Ocean estimated from the particulate fraction varied from < 1 to 160 mu mol N m(-2) d(-1), and those rates estimated from the filtrate fraction ranged from < 0.5 to 54 mu mol N m(-2) d(-1). Thus, N(2) fixation in the filtrate fraction accounts for on average 50 % (ranging from < 10 % to 84 %) of the total N(2) fixation rates. If these results are confirmed generally in the ocean, the new total N(2) fixation flux, which includes fixation in the filtrate fraction, possibly doubles the original estimates; therefore, the revised influx may reduce the imbalance in the global oceanic fixed nitrogen budget.

    DOI: 10.5194/bg-7-2369-2010

  88. Unique distribution of deep groundwater bacteria constrained by geological setting 査読有り

    Kato, Kenji, Nagaosa, Kazuyo, Kimura, Hiroyuki, Katsuyama, Chie , Hama, Katsuhiro, Kunimaru, Takanori, Tsunogai, Urumu, Aoki, Kazuhiro

    ENVIRONMENTAL MICROBIOLOGY REPORTS   1 巻 ( 6 ) 頁: 569-574   2009年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    P>We collected groundwater samples at depths of up to 482 m from three boreholes drilled into sedimentary rock within two formations in Hokkaido, Japan. The prokaryotic community in each subsurface groundwater sample was analysed by microscopic counts and cloning-sequencing the 16S rRNA genes. On total direct counts, there were between 4.61 x 104 and 5.06 x 106 prokaryote cells ml-1 in the samples, which is similar to the numbers observed at the marine subsurface. However, the vertical distribution of the prokaryotes did not show a simple decrease in abundance with increasing depth. A high abundance of cells with significant amounts of RNA was identified in the domain Bacteria using fluorescence in situ hybridization, with a high frequency of dividing cells at the transition zone between the two sedimentary rock formations. Cloning-sequencing analysis showed the predominance of gamma-Proteobacteria at this transition zone at 281-312 m. The horizontal heterogeneity of the microbial distribution in the subsurface environment was also demonstrated by a relatively high density of members of the domain Archaea in borehole HDB-4, drilled only 1.5 km northeast of HDB-6 and in the same formation.

    DOI: 10.1111/j.1758-2229.2009.00087.x

  89. Enrichment of nitrous oxide in the water columns in the area of the Bering and Chukchi Seas 査読有り

    Hirota, A., Ijiri, A., Komatsu, D. D., Ohkubo, S. B., Nakagawa, F., Tsunogai, U.

    MARINE CHEMISTRY   116 巻 ( 40912 ) 頁: 47-53   2009年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We found N2O enrichment of up to 157% saturation in continental shelf water columns in the Bering and Chukchi Seas at water depths less than 66 m. The N2O enrichment exhibited a linear relationship with N* depletion. We also observed that the stable isotopic characteristics of N2O are an enrichment of 18O and a depletion of 15N relative to atmospheric N2O. We conclude that N2O in the area is primarily produced through denitrification in sediments. By using the observed instantaneous N2O emission rate, we estimated the annual emission rate from the surface to the atmosphere in the area to be 0.097 +/- 0.065 Tg N year-1, which corresponds to 0.6% to 10% of the total oceanic emission. The area of the Bering and Chukchi Seas could be very important in understanding global oceanic N2O emission.

    DOI: 10.1016/j.marchem.2009.09.001

  90. Molecular Characterization of Potential Nitrogen Fixation by Anaerobic Methane-Oxidizing Archaea in the Methane Seep Sediments at the Number 8 Kumano Knoll in the Kumano Basin, Offshore of Japan 査読有り

    Miyazaki, Junichi, Higa, Ryosaku, Toki, Tomohiro, Ashi, Juichiro, Tsunogai, Urumu, Nunoura, Takuro, Imachi, Hiroyuki , Takai, Ken

    APPLIED AND ENVIRONMENTAL MICROBIOLOGY   75 巻 ( 22 ) 頁: 7153-7162   2009年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The potential for microbial nitrogen fixation in the anoxic methane seep sediments in a mud volcano, the number 8 Kumano Knoll, was characterized by molecular phylogenetic analyses. A total of 111 of the nifH (a gene coding a nitrogen fixation enzyme, Fe protein) clones were obtained from different depths of the core sediments, and the phylogenetic analysis of the clones indicated the genetic diversity of nifH genes. The predominant group detected (methane seep group 2), representing 74 % of clonal abundance, was phylogenetically related to the nifH sequences obtained from the Methanosarcina species but was most closely related to the nifH sequences potentially derived from the anoxic methanotrophic archaea (ANME-2 archaea). The recovery of the nif gene clusters including the nifH sequences of the methane seep group 2 and the subsequent reverse transcription-PCR detection of the nifD and nifH genes strongly suggested that the genetic components of the gene clusters would be operative for the in situ assimilation of molecular nitrogen (N(2)) by the host microorganisms. DNA-based quantitative PCR of the archaeal 16S rRNA gene, the group-specific mcrA (a gene encoding the methyl-coenzyme M reductase alpha subunit) gene, and the nifD and nifH genes demonstrated the similar distribution patterns of the archaeal 16S rRNA gene, the mcrA groups c-d and e, and the nifD and nifH genes through the core sediments. These results supported the idea that the anoxic methanotrophic archaea ANME-2c could be the microorganisms hosting the nif gene clusters and could play an important role in not only the in situ carbon (methane) cycle but also the nitrogen cycle in subseafloor sediments.

    DOI: 10.1128/AEM.01184-09

  91. Equilibrator Inlet-Proton Transfer Reaction-Mass Spectrometry (EI-PTR-MS) for Sensitive, High-Resolution Measurement of Dimethyl Sulfide Dissolved in Seawater 査読有り

    Kameyama, Sohiko, Tanimoto, Hiroshi, Inomata, Satoshi, Tsunogai, Urumu, Ooki, Atsushi, Yokouchi, Yoko, Takeda, Shigenobu, Obata, Hajime, Uematsu, Mitsuo

    ANALYTICAL CHEMISTRY   81 巻 ( 21 ) 頁: 9021-9026   2009年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We developed an equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS) method for fast detection of dimethyl sulfide (DAIS) dissolved in seawater. Dissolved DMS extracted by bubbling pure nitrogen through the sample was continuously directed to the PTR-MS instrument. The equilibration of DMS between seawater and the carrier gas, and the response time of the system, were evaluated in the laboratory. DMS reached equilibrium with an overall response time of 1 min. The detection limit (50 pmol L(-1) at 5 s integration) was sufficient for detection of DMS concentrations in the open ocean. The EI-PTR-MS instrument was deployed during a research cruise in the western North Pacific Ocean. Comparison of the EI-PTR-MS results with results obtained by means of membrane tube equilibrator-gas chromatography/mass spectrometry agreed reasonably well on average (R(2) = 0.99). EI-PTR-MS captured temporal variations of dissolved DMS concentrations, including elevated peaks associated with patches of high biogenic activity. These results demonstrate that the EI-PTR-MS technique was effective for highly time-resolved measurements of DMS in the open ocean. Further measurements will improve our understanding of the biogeochemical mechanisms of the production, consumption, and distribution of DMS on the ocean surface and, hence, the air-sea flux of DMS, which is a climatically important species.

    DOI: 10.1021/ac901630h

  92. Enrichment of adsorbed methane in authigenic carbonate concretions of the Japan Trench 査読有り

    Ijiri, Akira, Tsunogai, Urumu, Gamo, Toshitaka, Nakagawa, Fumiko, Sakamoto, Tatsuhiko, Saito, Saneatsu

    GEO-MARINE LETTERS   29 巻 ( 5 ) 頁: 301-308   2009年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Substantial amounts of adsorbed methane were detected in authigenic carbonate concretions recovered from sedimentary layers from depths between 245 and 1,108 m below seafloor during Ocean Drilling Program Leg 186 to ODP sites 1150 and 1151 on the deep-sea terrace of the Japan Trench. Methane contents were almost two orders of magnitude higher in the concretions (291-4,528 nmol/g wet wt) than in the surrounding bulk sediments (5-93 nmol/g wet wt), whereas methane/ethane ratios and stable carbon isotopic compositions were very similar. Carbonate content of surrounding bulk sediments (0.02-3.2 wet wt %) and methane content of the surrounding bulk sediments correlated positively. Extrapolation of the carbonate contents of bulk sediments suggests that 100 wt % carbonate would correspond to 1,886 +/- 732 nmol methane per g bulk sediment, which is similar to the average value observed in the carbonate concretions (1,321 +/- 1,067 nmol/g wet wt, n = 13). These data support the hypothesis that, in sediments, adsorbed hydrocarbon gases are strongly associated with authigenic carbonates.

    DOI: 10.1007/s00367-009-0143-9

  93. Theoretical and experimental evaluation of the isotope effect of NDIR analyzer on atmospheric CO2 measurement 査読有り

    Tohjima, Yasunori, Katsumata, Keiichi, Morino, Isamu, Mukai, Hitoshi, Machida, Toshinobu, Akama, Isao, Amari, Taketo, Tsunogai, Urumu

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   114 巻   2009年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nondispersive infrared (NDIR) CO2 analyzer could produce erroneous CO2 mole fraction measurements for an air sample when CO2-in-air mixtures having different isotopic compositions than atmospheric CO2 are used as the NDIR calibration gases. This is because (1) an optical band-pass filter equipped in a typical NDIR analyzer to minimize the interference effect from the other infrared-active species is basically designed to transmit only the absorption band of (12)C(16)O(2) and (2) absorption bands for the other CO2-related isotopologues, for example, 13C(16)O(2), are shifted to lower wave numbers depending on their isotope effects. To evaluate the effect of the isotopic composition on the NDIR response, we computed the theoretical relative molar response of the instrument to each isotopologue based on the infrared absorptance by the individual isotopologues. We then prepared a gravimetric 13CO2-in-air mixture with CO2 mole fraction of 380 ppm to experimentally determine the optical filter property. The apparent mole fractions of the 13CO2-in-air mixture determined by three NDIR analyzers used in this study were 46, 94, and 27 ppm, indicating that the optical filters in these instruments substantially reduced the response to 13C(16)O(2). Based on these theoretical and experimental analyses, we evaluated the apparent difference in the CO2 mole fraction determined by the three NDIR analyzers from the true value when isotopically lighter CO2-in-air mixtures (delta13C = -32.4 parts per thousand and delta(18)O = +11.7 parts per thousand), as compared to atmospheric CO2 (delta13C = similar to -8 parts per thousand and delta(18)O = similar to +40 parts per thousand), are used as calibration gases. The estimated difference varied with NDIR analyzers, ranging from -0.04 to -0.08 ppm for air samples with 380 ppm CO2.

    DOI: 10.1029/2009JD011734

  94. Enrichment of alkanes within a phytoplankton bloom during an in situ iron enrichment experiment in the western subarctic Pacific 査読有り

    Kameyama, Sohiko, Tsunogai, Urumu, Nakagawa, Fumiko, Sasakawa, Motoki, Komatsu, Daisuke D., Ijiri, Akira, Yamaguchi, Junko, Horiguchi, Takeo, Kawamura, Hiroshi, Yamaguchi, Aika, Tsuda, Atsushi

    MARINE CHEMISTRY   115 巻 ( 40910 ) 頁: 92-101   2009年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    During the Subarctic Pacific Iron Experiment for Ecosystem Dynamics Study II (SEEDS-II), we monitored variations in the concentrations of non-methane hydrocarbons (NMHCs), CH(3)Cl. N(2)O. and CH4 within a phytoplankton bloom. Stable isotopic compositions were also determined to evaluate the sources of the variations. Although there was little variation in either the concentrations or the stable isotopic compositions of alkenes, CH(3)Cl, N(2)O. and CH4 during the 23-day observation period, alkane concentrations increased substantially as the phytoplankton bloomed. The column-integrated quantities of alkanes increased to 3 times pre-bloom levels for C(2)H(6), 5 times for C(3)H(8). and 20 times for n-C(4)H(10). The delta13C values of both C(2)H(6) and C(3)H(8) remained almost constant while concentrations increased, whereas that of n-C(4)H(10) increased by about 12 parts per thousand. To evaluate the sources of the alkanes produced during the bloom, we compared their delta13C values with those of alkanes produced in axenic phytoplankton cultures in our laboratory. We concluded that during the SEEDS-II experiment the major portions of C(2)H(6) and C(3)H(8) were produced during the autolysis of diatoms cells, whereas n-C(4)H(10) was produced during autolysis of other phytoplankton cells such as cryptophytes and dinoflagellates.

    DOI: 10.1016/j.marchem.2009.06.009

  95. Photochemical histories of nonmethane hydrocarbons inferred from their stable carbon isotope ratio measurements over east Asia 査読有り

    Saito, Takuya, Kawamura, Kimitaka, Tsunogai, Urumu, Chen, Tai-Yih, Matsueda, Hidekazu, Nakatsuka, Takeshi, Gamo, Toshitaka, Uematsu, Mitsuo, Huebert, Barry J.

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   114 巻   2009年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The first airborne measurements of stable carbon isotope ratios (delta13C) of nonmethane hydrocarbons (NMHCs) were made over east Asia and its downwind regions as part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The measured delta13C values for ethane, n-butane, and n-pentane varied from approximately -30 parts per thousand to -20 parts per thousand. In contrast, acetylene showed much higher delta13C with a wide variation (-10 parts per thousand to +20 parts per thousand). These are consistent with the high delta13C values of combustion-derived acetylene and a significant isotopic fractionation due to photochemical removal process. Vertical profiles of delta13C-derived photochemical ages of NMHCs differed from one NMHC to another: less reactive ethane and acetylene showed linear increases in age with altitude (similar to 8 days below 1 km to similar to 20 days at about 6 km altitude), whereas more reactive n-butane and n-pentane (similar to 4 days) had no age gradient. This suggests that less reactive NMHCs in high-altitude air are transported from upwind source regions and mixed with fresh emissions from east Asia, while reactive NMHCs, even in the free troposphere, have recently been emitted. Thus vertical profiles are caused by the mixing of fresh emissions with aged air masses containing reactivity-determined amounts of photochemically aged NMHCs. This mixing causes the difference in the photochemical ages calculated by two methods (the ``hydrocarbon clock'' method using n-butane/ethane ratios and the ``isotopic hydrocarbon clock'' method using delta13C values of ethane).

    DOI: 10.1029/2008JD011388

  96. The living triserial planktic foraminifer Gallitellia vivans (Cushman): Distribution, stable isotopes, and paleoecological implications 査読有り

    Kimoto, Katsunori, Ishimura, Toyoho, Tsunogai, Urumu, Itaki, Takuya, Ujiie, Yurika

    MARINE MICROPALEONTOLOGY   71 巻 ( 40910 ) 頁: 71-79   2009年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Gallitellia vivans (Cushman) is the only triserial coiling species among modern planktic foraminifera. Although previous studies suggested that G. vivans is a planktic species, it was unreported for a long time because of its small test and its low abundance in the water column and deep-sea sediments. Therefore, its distribution and ecology are poorly understood. In November 2006 we collected numerous specimens of living G. vivans by towed plankton net at three stations in the Tsushima Strait, located between the East China Sea and Japan Sea, and we performed faunal assemblage and isotopic analyses. G. vivans were commonly observed in the water column, and this species accounted for 1.4-63.1 % of all living planktic foraminifera, but plankton tow samples contained both living and resuspended shells. Stable oxygen isotopic values of G. vivans ranged from -1.14 parts per thousand to -2.85 parts per thousand. VPDB and indicated that their habitat is definitely planktic and that they may live at the surface. On the other hand, carbon isotope ratios ranged from -2.4 parts per thousand to -3.2 parts per thousand, distinctly lower than values for other planktic species. This may indicate isotopic disequilibrium between ambient seawater and the shells of G. vivans during shell formation. The geographic distribution and stable isotopic features of G. vivans are shared among the multiserial planktic species that have appeared in geological history, and they should also share similar ecologies and habitats. The study of the ecology of G. vivans is important when considering the paleoecology of primitive forms of planktic foraminifera and their surrounding environments along continental margins.

    DOI: 10.1016/j.marmicro.2009.01.006

  97. Biogeochemical profiles in deep sedimentary rocks in an inland fore-arc basin, Central Japan 査読有り

    Suzuki, Yohey, Suko, Takeshi, Yoshioka, Hideyoshi, Takahashi, Masaaki, Nanba, Kenji, Tsunogai, Urumu, Takeno, Naoto, Ito, Kazumasa

    CHEMICAL GEOLOGY   259 巻 ( 40972 ) 頁: 107-119   2009年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Microorganisms thrive in the deep subsurface, but their extent and distribution, type and rate of metabolism are not well constrained, at least in part, owing to geochemical, lithological, hydrological and tectonic variations. We obtained deep sedimentary rocks from a tectonically stable inland basin in central Japan by drilling with minimized microbial and geochemical disturbance. Along with hydrogeological and microbial characterizations, geochemical properties of drilled cores from depths between similar to 200 and similar to 350 m were investigated. Except for a depth of 202 m, nitrate and/or nitrite were present in pore-water at all depths investigated in the present study. In most of the pore-water samples, the levels of dissolved Fe and H2S were low. Additionally, the presence of microbially reducible Fe(III) was not evident in most of the core samples. Based on the acetylene blockage method, it was revealed the denitrification potential was high at depths of 302 and 351 m where pore-water was depleted in nitrate and enriched in nitrite, while the denitrification potential was relatively low at depths of 300 and 340 m where nitrate and nitrite were both detected in pore-water. Potential rates of methane production via CO2 reduction were higher than those via acetate fermentation in the 302- and 350-m deep core samples. In the silty sandstone interval at depths of 340 and 351 m where permeability was relatively low, isotopically light methane of microbial origin was slightly enriched with sodium and chloride in pore-water. As a moderately mineralized fluid similarly enriched in sodium and chloride is entrained in the deeper subsurface with a depth over 1200 m around the drilling site, the increase in dissolved aqueous species is attributed to the remnant of the mineralized groundwater after the circulation of meteoric groundwater. The ubiquity of type of the sedimentary rocks suggests that the biogeochemical processes presented in this study might not be limited to the terrestrial sedimentary basin in central Japan.

    DOI: 10.1016/j.chemgeo.2008.10.028

  98. Geological background of the Kairei and Edmond hydrothermal fields along the Central Indian Ridge: Implications of their vent fluids' distinct chemistry 査読有り

    Kumagai, H., Nakamura, K., Toki, T., Morishita, T., Okino, K., Ishibashi, J. -I., Tsunogai, U., Kawagucci, S., Gamo, T. , Shibuya, T., Sawaguchi, T., Neo, N., Joshima, M., Sato, T., Takai, K.

    GEOFLUIDS   8 巻 ( 4 ) 頁: 239-251   2008年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Hydrogen-rich hydrothermal areas, such as those in the Indian Ocean, may have had an influence on early evolution of life on Earth and thus have attracted interest because they may be a proxy for ancient ecosystems. The Kairei and Edmond hydrothermal fields in the Indian Ocean are separated by 160 km, but exhibit distinct fluid chemistry: Kairei fluids are hydrogen-rich; Edmond fluids are hydrogen-poor. At this region, the Central Indian Ridge shows an intermediate spreading rate, 48 mm year(-1) as full rate, where the hydrothemal fields occur. Kairei field vent fluids show persistently high concentrations of H2. The Kairei field seems to be unique among hydrogen-enriched hydrothermal regions: most similar hydrogen-rich hydrothermal activity occurs along slowly spreading ridge, < 40 mm year(-1). The geological and tectonic aspects of the Kairei and Edmond hydrothermal fields were studied to try to elucidate geological constraints on hydrogen production. Visual observations of the seafloor near Kairei from a submersible revealed olivine-rich plutonic rocks with olivine gabbro-troctolite-dunite assemblages exposed within 15 km of the vent field, with serpentinized ultramafic mantle rocks on the Oceanic Core Complex (OCC). The OCC area might be a recharge zone of Kairei hydrothermal activity producing H2-rich vent fluids. The chaotic seafloor within 30 km of the Kairei field reflects a magma-starved condition persisting there for 1 Myr. Asymmetric geomagnetic and gravity anomalies near the Kairei field can be used to infer that patchy olivine-rich intrusions are scattered within mantle ultramafics, where infiltrated seawater reacts with magma and ultramafic rocks or olivine-rich rocks. The heterogeneous uppermost lithosphere containing shallow olivine-rich rock facies surrounding the Kairei field provides abundant H2 into the vent fluid through serpentinization. The hydrogen-rich Kairei field is hosted by basalt, with mafic-ultramafic olivine-rich lithology; the ordinary, hydrogen-poor Edmond field is hosted by a normal basaltic lithology. The contrasting geochemical signatures of the two fields reported here can also be found in ancient rocks from a juvenile Earth. This suggests that lithology-controlled generation of hydrogen may have operated for a long time and be relevant to the origin of life on Earth.

    DOI: 10.1111/j.1468-8123.2008.00223.x

  99. Methane, manganese, and helium-3 in newly discovered hydrothermal plumes over the Central Indian Ridge, 18°-20° S 査読有り

    Kawagucci, Shinsuke, Okamura, Kei, Kiyota, Kaoru, Tsunogai, Urumu, Sano, Yuji, Tamaki, Kensaku, Gamo, Toshitaka

    GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS   9 巻   2008年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We have investigated newly discovered submarine hydrothermal plumes over the Central Indian Ridge, 18° - 20° S. Onshore chemical analyses of methane, its carbon isotope, manganese, and helium-3 in seawater samples obtained from the plumes revealed their detailed geochemical characteristics. One of the newly discovered hydrothermal plumes located over the western wall of the axial valley at Segment 15B (19°33' S), called the Roger Plateau, showed constant CH4/Mn and CH4/3He ratios throughout the plume. The CH4/3He ratio (4*106) and delta13C (-17.5 per mil) are consistent with those of basalt-hosted sediment-free hydrothermal systems, although the CH4/Mn ratio (~1) is moderately higher. These features are thought to indicate a metal-depleted fluid chemistry. The other hydrothermal field is located within the axial valley at the northern part of the smooth lava plain at Segment 16 (18°20' S), called the Dodo Great Lava Plain, where several plumes were detected.The CH4/Mn and CH4/3He ratios showed large variation through the plumes while delta13C values were almost constant. Geochemical characteristics of venting fluid estimated from those of the plumes were apparently high CH4/Mn (>6) and CH4/3He (>60*106) ratios and low delta13C values (<-27.5 per mil), suggesting possible influences of several methane input processes to the fluid chemistry.

    DOI: 10.1029/2008GC002082

  100. A multi-isotope study of deep-sea mussels at three different hydrothermal vent sites in the northwestern Pacific 査読有り

    Naraoka, Hiroshi, Naito, Taku, Yamanaka, Toshiro, Tsunogai, Urumu, Fujikura, Katsunori

    CHEMICAL GEOLOGY   255 巻 ( 40910 ) 頁: 25-32   2008年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    To investigate symbiotic bacterial ecosystems at different deep-sea hydrothermal systems in the northwestern Pacific, compound-specific carbon and hydrogen isotope analyses of lipid biomarkers have been performed in addition to bulk C, H, N, S and O isotope analyses on Bathymodiolus mussels from the Hatoma seamount (B. platifrons), the Daiyon-Yonaguni (Yonaguni) knoll (B. platifrons), and the Suiyo seamount (B. septemdierum). The two B. platifrons contain large amounts of diploptene, while no hopanoid is detected in B. septemdierum, suggesting that B. platifrons and B. septemdierum harbors methanotrophic and thiotrophic bacteria, respectively. In spite of the same symbiont, the large bulk delta C-13 difference between the Hatoma (-44.8 parts per thousand) and Yonaguni (-24.5 parts per thousand) mussels reflects isotopically distinct hydrothermal CH4 (Hatoma: similar to-48 parts per thousand, Yonaguni: similar to-26 parts per thousand) as a carbon source. Fatty acids of the Hatoma and Yonaguni mussels are more enriched in D (-144 to -101 parts per thousand) than the Suiyo mussel (-265 to -162 parts per thousand), suggesting that D-depleted magmatic water or D-enriched hydrogen derived from CH4 could be a partial hydrogen source for methanotrophy or thiotrophy, respectively. Apparent positive correlations are observed between delta C-13 and delta D of the bulk and biomarkers for each mussel due to similar biochemical processes during de novo synthesis. The compound-specific delta C-13 and delta D variations have provided much information on not only distinct carbon and hydrogen sources but also the lipid synthesis with respect to different symbiotic bacterial ecosystems.

    DOI: 10.1016/j.chemgeo.2008.05.015

  101. Methane enrichment in low-temperature hydrothermal fluids from the Suiyo Seamount in the Izu-Bonin Arc of the western Pacific Ocean 査読有り

    Toki, Tomohiro, Tsunogai, Urumu, Ishibashi, Jun-ichiro, Utsumi, Motoo, Gamo, Toshitaka

    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH   113 巻 ( B8 )   2008年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The gas geochemistries of high-temperature and low-temperature hydrothermal fluids (HTHFs and LTHFs, respectively) were studied for the Suiyo Seamount hydrothermal system (140 degrees 39'E, 28 degrees 33'N) in the southern Izu-Bonin (Ogasawara) Arc of the western Pacific Ocean. HTHFs (290 +/- 20 degrees C) were collected from four active vents using a gastight fluid sampler, which prevented the loss of volatile components through degassing during sample processing. The end-member CH4 concentrations were homogeneous across the vent fields. LTHFs were collected from four diffuse flow zones using a funnel, which was deployed on the seafloor with replacement of the seawater inside the funnel by the LTHF. Strong linear relationships were found among the concentrations of CH4, Sigma CO2, and Si of the obtained samples, which ensured that the end-member chemical composition of the LTHFs could be accurately estimated. While the Sigma CO2 concentrations of the HTHFs and LTHFs were similar, all four LTHFs showed enrichment of CH4 as compared to the HTHFs. The carbon isotopic composition of CH4 also revealed a significant difference: the LTHFs (delta13C(CH4) = -4.8 +/- 0.3 parts per thousand PDB) showed 13C enrichment, as compared to the HTHFs (delta13C(CH4) = -5.8 +/- 0.4 parts per thousand PDB). The 13C enrichment can be explained by a combination of microbial CH4 production and oxidation after formation of the LTHFs. On the basis of the observed differences in CH4 concentrations and carbon isotopic compositions of the HTHFs and LTHFs, microbial methane oxidation and production are estimated to have comparable impacts. These results support the notion of a subseafloor microbial consortium of methanogens and methanotrophs.

    DOI: 10.1029/2007JB005476

  102. Cell proliferation at 122 degrees C and isotopically heavy CH4 production by a hyperthermophilic methanogen under high-pressure cultivation 査読有り

    Takai, Ken, Nakamura, Kentaro, Toki, Tomohiro, Tsunogai, Urumu , Miyazaki, Masayuki, Miyazaki, Junichi, Hirayama, Hisako, Nakagawa, Satoshi, Nunoura, Takuro, Horikoshi, Koki

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   105 巻 ( 31 ) 頁: 10949-10954   2008年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We have developed a technique for cultivation of chemolithoautotrophs under high hydrostatic pressures that is successfully applicable to various types of deep-sea chemolithoautotrophs, including methanogens. It is based on a glass-syringe-sealing liquid medium and gas mixture used in conjunction with a butyl rubber piston and a metallic needle stuck into butyl rubber. By using this technique, growth, survival, and methane production of a newly isolated, hyperthermophilic methanogen Methanopyrus kandleri strain 116 are characterized under high temperatures and hydrostatic pressures. Elevated hydrostatic pressures extend the temperature maximum for possible cell proliferation from 116 degrees C at 0.4 MPa to 122 degrees C at 20 MPa, providing the potential for growth even at 122 C under an in situ high pressure. In addition, piezophilic growth significantly affected stable carbon isotope fractionation of methanogenesis from CO2. Under conventional growth conditions, the isotope fractionation of methanogenesis by M. kandleri strain 116 was similar to values (-34 parts per thousand to-27 parts per thousand) previously reported for other hydrogenotrophic methanogens. However, under high hydrostatic pressures, the isotope fractionation effect became much smaller (<-12 parts per thousand), and the kinetic isotope effect at 122 degrees C and 40 MPa was -9.4 parts per thousand, which is one of the smallest effects ever reported. This observation will shed light on the sources and production mechanisms of deep-sea methane.

    DOI: 10.1073/pnas.0712334105

  103. Grain-scale heterogeneities in the stable carbon and oxygen isotopic compositions of the international standard calcite materials (NBS 19, NBS 18, IAEA-CO-1, and IAEA-CO-8) 査読有り

    Ishimura, Toyoho, Tsunogai, Urumu, Nakagawa, Fumiko

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   22 巻 ( 12 ) 頁: 1925-1932   2008年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We determined grain-scale heterogeneities (from 6 to 88 mu g) in the stable carbon and oxygen isotopic compositions (delta13C and delta(18)O) of the international standard calcite materials (NBS 19, NBS 18, IAEA-CO-1, and IAEA-CO-8) using a continuous-flow isotope ratio mass spectrometry (CF-IRMS) system that realizes a simultaneous determination of the delta13C and the delta(18)O values with standard deviations (S.D.) of less than 0.05 parts per thousand for CO2 gas. Based on the S.D. of the delta13C and delta(18)O values determined for CO2 gases evolved from the different grains of the same calcite material, we found that NBS 19, IAEA-CO-1, and IEAE-CO-8 were homogeneous for delta13C (less than 0.10 parts per thousand S.D.), and that only NBS 19 was homogeneous for delta(18)O (less than 0.14 parts per thousand S.D.). On the level of single grains, we found that both IAEA-CO-1 and IAEA-CO-8 were heterogeneous for delta(18)O (1.46 parts per thousand and 0.76 parts per thousand S.D., respectively), and that NBS 18 was heterogeneous for both delta13C and delta(18)O (0.34 parts per thousand and 0.54 parts per thousand S.D., respectively). Closer inspection of NBS 18 grains revealed that the highly deviated isotopic compositions were limited to the colored grains. By excluding such colored grains, we could also obtain the homogeneous delta13C and delta(18)O values (less than 0.18 parts per thousand and less than 0.16 parts per thousand S.D., respectively) for NBS 18. We conclude that NBS 19, IAEA-CO-1, or pure grains in NBS 18 are suitable to be used as the standard reference material for delta13C, and that either NBS 19 or pure grains in NBS 18 are suitable to be used as the reference material for delta(18)O during the grain-scale isotopic analyses of calcite.

    DOI: 10.1002/rcm.3571

  104. Determination of the 15N/14N, 17O/16O, and 18O/16O ratios of nitrous oxide by using continuous-flow isotope-ratio mass spectrometry 査読有り

    omatsu, D.D., T. Ishimura, F. Nakagawa, U. Tsunogai

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   22 巻 ( 10 ) 頁: 1587-1596   2008年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We developed a rapid, sensitive, and automated analytical system to determine the delta15N, delta18O, and Δ17O values of nitrous oxide (N2O) simultaneously in nanomolar quantities for a single batch of samples by continuous-flow isotope-ratio mass spectrometry (CF-IRMS) without any cumbersome and time-consuming pretreatments. The analytical system consisted of a vacuum line to extract and purify N2O, a gas chromatograph for further purification of N2O, an optional thermal furnace to decompose N2O to O2, and a CF-IRMS system. We also used pneumatic valves and pneumatic actuators in the system so that we could operate it automatically with timing software on a personal computer. The analytical precision was better than 0.12 parts per thousand for delta15N with >4 nmol N2O injections, 0.25 parts per thousand for delta18O with >4 nmol N2O injections, and 0.20 parts per thousand for Δ17O with >20 nmol N2O injections for a single measurement. We were also easily able to improve the precision (standard errors) to better than 0.05 parts per thousand for delta15N, 0.10 parts per thousand for delta18O, and 0.10 parts per thousand for Δ17O through multiple analyses with more than four repetitions with 190 nmol samples using the automated analytical system. Using the system, the delta15N, delta18O, and Δ17O values of N2O can be quantified not only for atmospheric samples, but also for other gas or liquid samples with low N2O content, such as soil gas or natural water. Here, we showed the first ever Δ17O measurements of soil N2O.

    DOI: 10.1002/rcm.3493

  105. Radiocarbon-based carbon source quantification of anomalous isotopic foraminifera in last glacial sediments in the western North Pacific 査読有り

    Uchida, Masao, Ohkushi, Ken'ichi, Kimoto, Katsunori, Inagaki, Fumio, Ishimura, Toyoho, Tsunogai, Urumu, TuZino, Taqumi, Shibata, Yasuyuki

    GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS   9 巻   2008年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A previous study interpreted extremely 13C-depleted excursions of planktonic and benthic foraminifera in last glacial sediments (17,500 to 25,400 cal years B. P.) of the core retrieved from off Shimokita Peninsula and off Hokkaido, Japan, as evidence for periodic releases of methane, arising from the dissociation of methane hydrate. To better understand the formation process of the 13C-depleted excursions, we conducted high-resolution natural radiocarbon measurements and biogeochemical analyses. We found highly depleted 13 C excursions ranging from -10.2 % to -1.6 % and -6.8 % to -1.6 % in planktonic and benthic foraminifera, respectively. Most of the foraminiferal tests in these horizons were brown, most likely as a result of postdepositional alteration, reflecting the formation of authigenic carbonate on the surface of tests. These alterations were also supported by high levels of Mg-calcite and the acid-leaching test for anomalous foraminifera. To evaluate the carbon sources in the altered foraminifera tests, we quantified the relative contributions of (14)C-free methane-derived carbon sources to the formation of authigenic carbonates in foraminifera with depleted 13 C excursions using a coupled mass balance isotopic model ((14)C/C and 13C/(12)C). The radiocarbon ages of both planktonic and benthic 13C-depleted foraminifera were approximately 600 to 2000 years older than those of normal tests from nearby horizons. The relative contributions of authigenic carbonates derived from the methane oxidizing process reached to -22 wt % for planktonic foraminifera and -15 wt % for benthic foraminifera. The delta13C values of methane calculated from the mass balance model were between -29 % and -68 % for planktonic foraminifera and between -40 % and -108 % for benthic foraminifera, consistent with delta13C values reported for thermogenic and abiogenic methane in global methane hydrate reservoirs. These data consistently suggest that methane-related drastic environmental change occurred in the horizons that included delta13C anomalies. This study provides important information for interpreting geological records of the methane hydrate instability associated with climate.

    DOI: 10.1029/2006GC001558

  106. Carbon isotopic characterization for the origin of excess methane in subsurface seawater 査読有り

    Sasakawa, Motoki, Tsunogai, Urumu, Kameyama, Sohiko, Nakagawa, Fumiko, Nojiri, Yukihiro, Tsuda, Atsushi

    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS   113 巻 ( C3 )   2008年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We collected samples of seawater, zooplankton, and sinking particles in the northwestern North Pacific to determine the source of excess CH4 over the saturation value in equilibrium with the atmospheric CH4 in the oxygenated open ocean, using stable carbon isotope as a tracer. We found that subsurface (similar to 100 m depth) seawater is supersaturated (up to 12 %) with 13C-enriched CH4 (up to -33.1 %) relative to surface seawater in equilibrium with the atmosphere (-47 %), suggesting that in situ addition of 13C-enriched CH4 must be responsible for CH4 enrichment at depth. The delta13C of CH4 emitted from sinking particles (from -36.7 +/- 1.2 % to +5.9 +/- 7.5 %) is within the range of that of excess CH4 in seawater, suggesting that the major source of subsurface excess CH4 is sinking particles. The unusually 13C-enriched delta13C composition of CH4 emitted from sinking particles suggests that active microbial CH4 oxidation occurs within the oxic/anoxic boundary of these particles. On the basis of the Rayleigh equation, we estimated that at least 62 % of CH4 produced within the anoxic center of sinking particles is oxidized within 100 m of the surface.

    DOI: 10.1029/2007JC004217

  107. Sensitive determinations of stable nitrogen isotopic composition of organic nitrogen through chemical conversion into N2O 査読有り

    Tsunogai, U., T. Kido, A. Hirota, S.B. Ohkubo, D.D. Komatsu, F. Nakagawa

    Rapid Communications in Mass Spectrometry   22 巻 ( 3 ) 頁: 345-354   2008年1月

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    担当区分:筆頭著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We present a method for high-sensitivity nitrogen isotopic analysis of particulate organic nitrogen (PON) in seawater and freshwater, for the purpose of determining the aquatic nitrogen fixation rate through the 15N(2) tracer technique for samples that contain a low abundance of organisms. The method is composed of the traditional oxidation/reduction methods, such as the oxidation of PON to nitrate (NO(3)) using persulfate, the reduction of NO(3) to nitrite (NO(2)) using spongy cadmium, and further reduction of NO(2) to nitrous oxide (N(2)O) using sodium azide. Then, N(2)O is purged from the water and trapped cryogenically with subsequent release into a gas chromatography column to analyze the stable nitrogen isotopic composition using continuous-flow isotope ratio mass spectrometry (CF-IRMS) by simultaneously monitoring the NO(+) ion currents at masses 30,31, and 32. The nitrogen isotopic fractionation was consistent within each batch of analysis. The standard deviation of sample measurements was less than 0.3 %. for samples containing PON of more than 50 nmolN, and 0.5 parts per thousand for those of more than 20 nmolN, by subtracting the contribution of blank nitrogen, 8 +/- 2 nmol at final N(2)O. By using this method, we can determine delta15N for lower quantities of PON better than by other methods, so we can reduce the quantities of water samples needed for incubation to determine the nitrogen fixation rate. In addition, we can expand the method to determine the nitrogen isotopic composition of organic nitrogen in general, such as that of total dissolved nitrogen (TDN; sum of NO(3), NO(2), ammonium, and DON), by applying the method to filtrates.

    DOI: 10.1002/rcm.3368

  108. Long-term observation of mass-independent oxygen isotope anomaly in stratospheric CO2 査読有り

    Kawagucci, S., Tsunogai, U., Kudo, S., Nakagawa, F., Honda, H., Aoki, S., Nakazawa, T., Tsutsumi, M., Gamo, T.

    ATMOSPHERIC CHEMISTRY AND PHYSICS   8 巻 ( 20 ) 頁: 6189-6197   2008年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Stratospheric and upper tropospheric air samples were collected during 1994-2004 over Sanriku, Japan and in 1997 over Kiruna, Sweden. Using these archived air samples, we determined the triple oxygen-isotope composition of stratospheric CO2 and the N(2)O mixing ratio. The maximum Delta17O(CO2) value of +12.2 parts per thousand, resembling that observed previously in the mesosphere at 60 km height, was found in the middle stratosphere over Kiruna at 25.6 km height, suggesting that upper stratospheric and mesospheric air descended to the middle stratosphere through strong downward advection. A least-squares regression analysis of our observations on a delta(18)O(CO2)-delta17O(CO2) plot (r(2)> 0.95) shows a slope of 1.63 +/- 0.10, which is similar to the reported value of 1.71 +/- 0.06, thereby confirming the linearity of three isotope correlation with the slope of 1.6-1.7 in the mid-latitude lower and middle stratosphere. The slope decrease with increasing altitude and a curvy trend in three-isotope correlation reported from previous studies were not statistically significant. Using negative linear correlations of Delta17O(CO2) and delta(18)O(CO2) with the N(2)O mixing ratio, we quantified triple oxygen-isotope fluxes of CO2 to the troposphere as +48 parts per thousand GtC/yr (Delta17O(CO2))and +38 parts per thousand GtC/yr (delta(18)O(CO2)) with similar to 30 % uncertainty. Comparing recent model results and observations, underestimation of the three isotope slope and the maximum Delta17O(CO2) value in the model were clarified, suggesting a smaller O(2) photolysis contribution than that of the model. Simultaneous observations of delta(18)O(CO2), delta17O(CO2), and N(2)O mixing ratios can elucidate triple oxygen isotopes in CO2 and clarify complex interactions among physical, chemical, and photochemical processes occurring in the middle atmosphere.

  109. Diverse range of mineralization induced by phase separation of hydrothermal fluid: Case study of the Yonaguni Knoll IV hydrothermal field in the Okinawa Trough back-arc basin 査読有り

    Suzuki, Ryohei, Ishibashi, Jun-Ichiro, Nakaseama, Miwako, Konno, Uta, Tsunogai, Urumu, Gena, Kaul, Chiba, Hitoshi

    RESOURCE GEOLOGY   58 巻 ( 3 ) 頁: 267-288   2008年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The Yonaguni Knoll IV hydrothermal vent field (24 degrees 51'N, 122 degrees 42'E) is located at water depths of 1370-1385 m near the western edge of the southern Okinawa Trough. During the YK03-05 and YK04-05 expeditions using the submersible Shinkai 6500, both hydrothermal precipitates (sulfide/sulfate/carbonate) and high temperature fluids (Tmax = 328 degrees C) presently venting from chimney-mound structures were extensively sampled. The collected venting fluids had a wide range of chemistry (Cl concentration 376-635 mmol kg(-1)), which is considered as evidence for sub-seafloor phase separation. While the Cl-enriched smoky black fluids were venting from two adjacent chimney-mound structures in the hydrothermal center, the clear transparent fluids sometimes containing CO2 droplet were found in the peripheral area of the field. This distribution pattern could be explained by migration of the vapor-rich hydrothermal fluid within a porous sediment layer after the sub-seafloor phase separation. The collected hydrothermal precipitates demonstrated a diverse range of mineralization, which can be classified into five groups: (i) anhydrite-rich chimneys, immature precipitates including sulfide disseminations in anhydrite; (ii) massive Zn-Pb-Cu sulfides, consisting of sphalerite, wurtzite, galena, chalcopyrite, pyrite, and marcasite; (iii) Ba-As chimneys, composed of barite with sulfide disseminations, sometimes associated with realgar and orpiment overgrowth; (iv) Mn-rich chimneys, consisting of carbonates (calcite and magnesite) and sulfides (sphalerite, galena, chalcopyrite, alabandite, and minor amount of tennantite and enargite); and (v) pavement, silicified sediment including abundant native sulfur or barite. Sulfide/sulfate mineralization (groups i-iii) was found in the chimney-mound structure associated with vapor-loss (Cl-enriched) fluid venting. In contrast, the sulfide/carbonate mineralization (group iv) was specifically found in the chimneys where vapor-rich (Cl-depleted) fluid venting is expected, and the pavement (group v) was associated with diffusive venting from the seafloor sediment. This correspondence strongly suggests that the subseafloor phase separation plays an important role in the diverse range of mineralization in the Yonaguni IV field. The observed sulfide mineral assemblage was consistent with the sulfur fugacity calculated from the FeS content in sphalerite/wurtzite and the fluid temperature for each site, which suggests that the shift of the sulfur fugacity due to participation of volatile species during phase separation is an important factor to induce diverse mineralization. In contrast, carbonate mineralization is attributed to the significant mixing of vapor-rich hydrothermal fluid and seawater. A submarine hydrothermal system within a back-arc basin in the continental margin may be considered as developed in a geologic setting favorable to a diverse range of mineralization, where relatively shallow water depth induces sub-seafloor phase separation of hydrothermal fluid, and sediment accumulation could enhance migration of the vapor-rich hydrothermal fluid.

    DOI: 10.1111/j.1751-3928.2008.00061.x

  110. Determination of formaldehyde mixing ratios in air with PTR-MS: laboratory experiments and field measurements 査読有り

    Inomata, S., Tanimoto, H., Kameyama, S., Tsunogai, U., Irie, H., Kanaya, Y., Wang, Z.

    ATMOSPHERIC CHEMISTRY AND PHYSICS   8 巻 ( 2 ) 頁: 273-284   2008年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Formaldehyde (HCHO), the most abundant carbonyl compound in the atmosphere, is generated as an intermediate product in the oxidation of nonmethane hydrocarbons. Proton transfer reaction mass spectrometry (PTR-MS) has the capability to detect HCHO from ion signals at m/z 31 with high time-resolution. However, the detection sensitivity is low compared to other detectable species, and is considerably affected by humidity, due to back reactions between protonated HCHO and water vapor prior to analysis. We performed a laboratory calibration of PTR-MS for HCHO and examined the detection sensitivity and humidity dependence at various field strengths. Subsequently, we deployed the PTR-MS instrument in a field campaign at Mount Tai in China in June 2006 to measure HCHO in various meteorological and photochemical conditions; we also conducted intercomparison measurements by Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS). Correction of interference in the m/z 31 signals by fragments from proton transfer reactions with methyl hydroperoxide, methanol, and ethanol greatly improves agreement between the two methods, giving the correlation [HCHO]MAX-DOAS=(0.99±0.16) [HCHO]PTR-MS+(0.02±0.38), where error limits represent 95% confidence levels.

  111. Geochemical studies of pore fluid in surface sediment on the Daini Atsumi Knoll 査読有り

    Toki, T., Tsunogai, U., Gamo, T., Tanahashi, M.

    JOURNAL OF GEOCHEMICAL EXPLORATION   95 巻 ( 40911 ) 頁: 29-39   2007年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We collected sediment samples and pore water samples from the surface sediment on the Daini Atsumi Knoll, and analyzed the sediments for CH4, C2H6, and delta C-13(CH4), and the pore fluids for CH4, C2H6, delta C-13(CH4), Cl-, SO42- delta O-18(H2O), and delta D-H2O, respectively. A comparison of the measured concentration and isotopic composition of methane in pore water samples with those in sediment samples revealed that methane was present in the sediment samples at a higher concentration and was isotopically heavier than those in the pore water samples. It suggests that the effect of the release of a sorbed gas bound to organic particles when heated prior to analysis of hydrocarbons was larger than that of the degassing process. A large amount of a sorbed gas would be a significant source of natural gas. Two striking features are the chemical and isotopic composition of the pore water samples taken from the different sites around the Daini Atsumi Knoll. In the KL09, KL10, and KP07 samples, Cl- concentrations in the pore water samples showed depletion to a minimum of 460 mmol/kg, correspond to similar to 17 % dilution of seawater, however the latter was not enriched in CH4. The isotopic compositions of pore water samples suggested the low-Cl- fluids in the pore water were not derived from dissociation of methane hydrate, but were derived from input of meteoric water. In contrast, in the KP05 samples from the north flank of the Daini Atsumi Knoll, pore water were characterized by CH4 enrichment more than 370 mu mol/kg, but not depleted in Cl- concentrations. The observed methane concentration in the KP05 samples is not sufficient for methane hydrate to form in situ, indicating that the existence of methane hydrate in the surface sediment is negligible, as supported by Cl- concentration. Based on the stable carbon isotope ratio of methane in the pore fluid from the KP05 site (delta C-13(CH4) <-50 parts per thousand PDB), methane is thought to be of microbial origin. The pore waters in the surface sediments in the north flank of the Daini Atsumi Knoll were not directly influenced by upward fluid bearing methane of thermogenic origin from a deeper part of the sedimentary layer. However, extremely high methane concentration in the north flank site as compared with the concentration of pore water taken from the normal seafloor suggests that the north flank site is not the normal seafloor. We hypothesize that upward migration of chemically-reduced fluids from a deeper zone of the sedimentary layer reduces chemically-oxidized solutes in the surface sediment. As a consequence methane production replaced sulfate reduction as the microbial metabolism in the reduced environment of the surface sediment.

    DOI: 10.1016/j.gexplo.2007.05.009

  112. Assessment of winter fluxes of CO2 and CH4 in boreal forest soils of central Alaska estimated by the profile method and the chamber method: a diagnosis of methane emission and implications for the regional carbon budget 査読有り

    Kim, Yongwon, Ueyama, Masahito, Nakagawa, Fumiko, Tsunogai, Urumu, Harazono, Yoshinobu, Tanaka, Noriyuki

    TELLUS SERIES B-CHEMICAL AND PHYSICAL METEOROLOGY   59 巻 ( 2 ) 頁: 223-233   2007年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This research was carried out to estimate the winter fluxes of CO2 and CH4 using the concentration profile method and the chamber method in black spruce forest soils in central Alaska during the winter of 2004/5. The average winter fluxes of CO2 and CH4 by chamber and profile methods were 0.24 +/- 0.06 (SE; standard error) and 0.21 +/- 0.06 gCO2-C/m(2)/d, and 21.4 +/- 5.6 and 21.4 +/- 14 mu gCH4-C/m(2)/hr. This suggests that the fluxes estimated by the two methods are not significantly different based on a one-way ANOVA with a 95 % confidence level. The hypothesis on the processes of CH4 transport/production/emission in underlying snow-covered boreal forest soils is proven by the pressure differences between air and in soil at 30 cm depth. The winter CO2 emission corresponds to 23 % of the annual CO2 emitted from Alaska black spruce forest soils, which resulted in the sum of mainly root respiration and microbial respiration during the winter based on the delta(CO2)-C-13 of -22.5 parts per thousand. The average wintertime emissions of CO2 and CH4 were 49 +/- 13 gCO2-C/m(2)/season and 0.11 +/- 0.07 gCH4-C/m(2)/season, respectively. This implies that winter emissions of CO2 and CH4 are an important part of the annual carbon budget in seasonally snow-covered terrain of typical boreal forest soils.

    DOI: 10.1111/j.1600-0889.2006.00233.x

  113. Geochemical characterization of the organic matter, pore water constituents and shallow methane gas in the eastern part of the Ulleung Basin, East Sea (Japan Sea) 査読有り

    Kim, Ji-Hoon, Park, Myong-Ho, Tsunogai, Urumu, Cheong, Tae-Jin , Ryu, Byong-Jae, Lee, Young-Joo, Han, Hyun-Chul, Oh, Jae-Ho , Chang, Ho-Wan

    ISLAND ARC   16 巻 ( 1 ) 頁: 93-104   2007年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Geochemical analyses of sediments, pore water and headspace gas of the piston cores taken from the eastern part of Ulleung Basin of the East Sea (Japan Sea) were carried out to assess the origin of the sedimentary organic matter and interstitial fluid. Several tephra layers within the core are identified as the Ulleung-Oki (10.1 ka), the Aira-Tanzawa (23 ka) and the Ulleung-Yamato (30.9 ka) tephras. With the exception of these volcanic layers, the cores consist predominantly of muddy sediments that contain > 0.5 % total organic carbon. Atomic C/N ratios and delta C-13(org) values suggest that the organic matter originated from marine algae rather than from land vascular plants, whereas Rock-Eval pyrolysis suggests that the organic matter is thermally immature and comes from a land vascular plant (Type III). These conflicting results seem to be caused by the heavy oxidization of the marine organic matter. Sulphate concentration profiles of pore waters show strongly linear depletion (r(2) > 0.97) with sediment depth. The estimated sulphate-methane interface (SMI) depth using the sulphate concentration gradient was nearly 3.5 m below seafloor (mbsf) in the southern part of the study area, and deeper than 6 mbsf in the northern part of the area. The difference in SMI depths is likely associated with the amount of the methane flux. The methane concentration below the SMI in the two southern cores increases rapidly, implying the occurrence of methanogenesis and anaerobic methane oxidation (AMO). In contrast, the two northern cores have a low methane concentration below the SMI. delta C-13(CH4) values measured from all cores were in the range of -83.5 to -69.5 parts per thousand, which suggests that the methane derives from a methanogenic microbe. delta C-13(CH4) values become decreased toward SMI, but increased below SMI; therefore, delta C-13(CH4) has eventually the minimum value near the SMI. The delta C-13(CH4) values are also decreased when the methane concentration is increased. These phenomena support the typical occurrence of AMO in the study area.

    DOI: 10.1111/j.1440-1738.2007.00560.x

  114. Chemical and isotopic characteristics of interstitial fluids within the Taiwan Chelungpu fault 査読有り

    Hirono, Tetsuro, Tsunogai, Urumu, Maegawa, Kenji, Toki, Tomohiro, Tanimizu, Masaharu, Soh, Wonn, Lin, Weiren, Yeh, En-Chao, Song, Sheng-Rong, Wang, Chien-Ying

    GEOCHEMICAL JOURNAL   41 巻 ( 2 ) 頁: 97-102   2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We determined chloride and sulfate concentrations and (delta D-H2O and delta O-18(H2O) isotope ratios of interstitial fluids extracted from cores from two fault zones within the Taiwan Chelungpu fault. The fluids had higher concentrations of chloride and sulfate and higher delta D-H2O and delta O-18(H2O) values than the local meteoric water. We concluded that the higher (delta D-H2O) and delta O-18(H2O) values were the result of either entry of surface meteoric water at low altitude via fault zones, or isotopic fractionation by depletion at 50 degrees C in a shallower fault zone, and at 125 degrees C in the deeper fault zone. The high temperature in the deeper fault zone might have been earthquake-related frictional heating, which led to isotopic fractionation. However, neither of the above hypotheses explains the high concentrations of Cl- and SO42-. We concluded that the high concentrations of Cl- and SO42- might have resulted from mixing with seawater and dissolution of pyrite, respectively.

  115. Rare earth elements in the hydrothermal system at Okinawa Trough back-arc basin 査読有り

    Hongo, Yayoi, Obata, Hajime, Gamo, Toshitaka, Nakaseama, Miwako , Ishibashi, Junichiro, Konno, Uta, Saegusa, Shunsuke, Ohkubo, Satoru, Tsunogai, Urumu

    GEOCHEMICAL JOURNAL   41 巻 ( 1 ) 頁: 40923   2007年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We present novel data sets of rare earth element (REE) distributions in a hydrothermal vent field at Yonaguni Knoll IV in the Okinawa Trough. Vertical REE profiles in three water columns showed horizontal variation of REE concentrations within 1000-1200 m. Hydrothermal plumes were discovered by anomalous values of methane, manganese and transmissometry at that site. Europium anomalies in the North Pacific deep water (NPDW) (Nozaki et al., 1999) normalized pattern decreased with distance from the hydrothermal vent site, indicating that the dilution of hydrothermal fluid in the plume can be traced using REE. The horizontal variation of negative Ce-anomalies represents the continuous scavenging of REE by suspended matter in the plume. In addition, we measured nine hydrothermal fluid samples. The REE geochemistry of hydrothermal vent systems had been investigated intensively at sediment-starved mid-oceanic ridges, but few studies had examined sediment-hosted hydrothermal systems like those of the Okinawa Trough. The chondrite-normalized REE patterns of the fluids collected at Yonaguni Knoll IV show typical lighter rare earth elements (LREE) and Eu enrichment similar to at the Mid-ocean Ridge sites. A remarkable characteristic of the Yonaguni Knoll IV fluid pattern is its higher concentrations of heavier rare earth elements (HREE) and La composition than the hydrothermal fluids of the sediment-starved East Pacific Rise and Trans-Atlantic Geotraverse. Such a feature is explainable by influences of covering sediments in the back-arc basin Okinawa Trough. At the hydrothermal vent, lighter REE (LREE) in the fluid was reduced systematically during fluid mixing with seawater within the chimney. Light REE elimination resembles fractionation caused by particle scavenging within the water column. However, the lack of Ce depletion, which is a typical REE feature in the water column, along with distinctive Eu reduction, were unique in the Yonaguni Knoll IV fluid, suggesting that fluid REE fractionation at the vent site was induced predominantly by coprecipitation with hydrothermally originated minerals (e.g. sulfate and carbonate), not by adhesive removal by Fe and/or Mn oxide particles. Previous studies had shown that REE removal and fractionation of the hydrothermal system were observed only in deposit samples. Results of this study elucidated REE fractionation in fluid samples using previous analytical data. We were also able to distinguish REE removal mechanisms occurring at the vent site and water column using REE pattern characteristics.

  116. Microbial community in a sediment-hosted CO2 lake of the southern Okinawa Trough hydrothermal system 査読有り

    Inagaki, Fumio, Kuypers, Marcel M. M., Tsunogai, Urumu, Ishibashi, Jun-ichiro, Nakamura, Ko-ichi, Treude, Tina, Ohkubo, Satoru, Nakaseama, Miwako, Gena, Kaul, Chiba, Hitoshi, Hirayama, Hisako, Nunoura, Takuro, Takai, Ken, Jorgensen, Bo B. , Horikoshi, Koki, Boetius, Antje

    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA   103 巻 ( 38 ) 頁: 14164-14169   2006年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Increasing levels Of CO2 in the atmosphere are expected to cause climatic change with negative effects on the earth's ecosystems and human society. Consequently, a variety of CO2 disposal options are discussed, including injection into the deep ocean. Because the dissolution Of CO2 in seawater will decrease ambient pH considerably, negative consequences for deep-water ecosystems have been predicted. Hence, ecosystems associated with natural CO2 reservoirs in the deep sea, and the dynamics of gaseous, liquid, and solid CO2 in such environments, are of great interest to science and society. We report here a biogeochemical and microbiological characterization of a microbial community inhabiting deep-sea sediments overlying a natural CO2 lake at the Yonaguni Knoll IV hydrothermal field, southern Okinawa Trough. We found high abundances (> 10(9) CM(-3)) of microbial cells in sediment pavements above the CO2 lake, decreasing to strikingly low cell numbers (107 CM-3) at the liquid CO2/CO2-hydrate interface. The key groups in these sediments were as follows: (i) the anaerobic methanotrophic archaea ANME-2c and the Eel-2 group of Deltaproteobacteria and (ii) sulfur-metabolizing chemolithotrophs within the Gamma- and Epsilonproteobacteria. The detection of functional genes related to one-carbon assimilation and the presence of highly 13C-depleted archaeal and bacterial lipid biomarkers suggest that microorganisms assimilating CO2 and/or CH4 dominate the liquid CO2 and CO2-hydrate-bearing sediments. Clearly, the Yonaguni Knoll is an exceptional natural laboratory for the study of consequences of CO2 disposal as well as of natural CO2 reservoirs as potential microbial habitats on early Earth and other celestial bodies.

    DOI: 10.1073/pnas.0606083103

  117. Origins of hydrocarbons in the Sagara oil field, central Japan 査読有り

    Toki, Tomohiro, Gamo, Toshitaka, Tsunogai, Urumu

    ISLAND ARC   15 巻 ( 3 ) 頁: 285-291   2006年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We collected free-gas and in situ fluid samples up to a depth of 200.6 m from the Sagara oil field, central Japan (34 degrees 44'N, 138 degrees 15'E), during the Sagara Drilling Program (SDP) and measured the concentrations and stable carbon isotopic compositions of CH4 and C2H6 in the samples. A combination of the CH4/C2H6 ratios with the carbon isotope ratios of methane indicates that the hydrocarbon gases are predominantly of thermogenic origin at all depths. The isotope signature of hydrocarbon gases of delta C-13(CH4)< delta C-13(C2H4) suggests that these gases in the Sagara oil field are not generated by polymerization, but by the decomposition of organic materials.

    DOI: 10.1111/j.1440-1738.2006.00528.x

  118. Liquid CO2 venting on the seafloor: Yonaguni knoll IV hydrothermal system, Okinawa Trough 査読有り

    Konno, Uta, Tsunogai, Urumu, Nakagawa, Fumiko, Nakaseama, Miwako, Ishibashi, Jun-ichiro, Nunoura, Takuro, Nakamura, Ko-ichi

    GEOPHYSICAL RESEARCH LETTERS   33 巻 ( 16 )   2006年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We determined the chemical and isotopic compositions of the liquid CO2 found on Yonaguni IV knoll hydrothermal site, as well as those in hydrothermal fluid venting from the surrounding chimneys. The delta13C of both CO2 and CH4 in the liquid CO2 almost coincide with those in the hydrothermal fluid, suggesting that the liquid CO2 must be derived from the hydrothermal fluid. While showing homogeneous delta13C, the hydrothermal fluids exhibit wide variation in gas contents. Active phase separation must be taking place within the conduits. Besides, H2-depletion in the liquid CO2 suggests formation of solid CO2-hydrate must also precede the venting of liquid CO2. In conclusion, liquid CO2 must be produced through following subseafloor processes: phase separation of hydrothermal fluid due to boiling, formation of solid CO2-hydrate due to cooling of vapor phase, and melting of the solid CO2-hydrate to liquid CO2 due to a temperature increase within the sedimentary layer.

    DOI: 10.1029/2006GL026115

  119. Molecular phylogenetic and chemical analyses of the microbial mats in deep-sea cold seep sediments at the northeastern Japan Sea 査読有り

    Arakawa, Shizuka, Sato, Takako, Sato, Rumi, Zhang, Jing, Gamo, Toshitaka, Tsunogai, Urumu, Hirota, Akinari, Yoshida, Yasuhiko, Usami, Ron, Inagaki, Fumio, Kato, Chiaki

    EXTREMOPHILES   10 巻 ( 4 ) 頁: 311-319   2006年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Microbial communities inhabiting deep-sea cold seep sediments at the northeastern Japan Sea were characterized by molecular phylogenetic and chemical analyses. White patchy microbial mats were observed along the fault offshore the Hokkaido Island and sediment samples were collected from two stations at the southern foot of the Shiribeshi seamount (M1 site at a depth of 2,961 m on the active fault) and off the Motta Cape site (M2 site at a depth of 3,064 m off the active fault). The phylogenetic and terminal-restriction fragment polymorphism analyses of PCR-amplified 16S rRNA genes revealed that microbial community structures were different between two sampling stations. The members of ANME-2 archaea and diverse bacterial components including sulfate reducers within Deltaproteobacteria were detected from M1 site, indicating the occurrence of biologically mediated anaerobic oxidation of methane, while microbial community at M2 site was predominantly composed of members of Marine Crenarchaeota group I, sulfate reducers of Deltaproteobacteria, and sulfur oxidizers of Epsilonproteobacteria. Chemical analyses of seawater above microbial mats suggested that concentrations of sulfate and methane at M1 site were largely decreased relative to those at M2 site and carbon isotopic composition of methane at M1 site shifted heavier (C-13-enriched), the results of which are consistent with molecular analyses. These results suggest that the mat microbial communities in deep-sea cold seep sediments at the northeastern Japan Sea are significantly responsible for sulfur and carbon circulations and the geological activity associated with plate movements serves unique microbial habitats in deep-sea environments.

    DOI: 10.1007/s00792-005-0501-0

  120. Development of a multibottle gas-tight fluid sampler WHATS II for Japanese submersibles/ROVs 査読有り

    Saegusa, S., Tsunogai, U., Nakagawa, F., Kaneko, S.

    GEOFLUIDS   6 巻 ( 3 ) 頁: 234-240   2006年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This paper summarizes the design and performance of our recently developed gas-tight fluid sampler WHATS II, especially designed to collect seafloor venting gas-rich fluid from submersibles/remotely operated vehicles (ROVs). It consists of four 150-cm(3) stainless steel sample cylinders, eight ball valves, a motor-driven arm, a rail, a peristaltic pump, a control unit, and a flexible Teflon tube connected to a titanium inlet tube. All the parts have been designed to be used at undersea as deep as 4000 m. The motor-driven arm on the rail can open and close each of the four cylinders. By pumping out distilled water that has filled an open cylinder and the dead spaces of the sampler, we can fill the cylinder with sample fluid. WHATS II can take a maximum of four different gas-tight samples in a series. The whole operation can be arranged from the cabin, etc., of a submersible/ROV. Use of only one motor to operate eight valves makes the sampler small, light (21 kg in sea water), and easy to handle. In addition, the sampler is able to collect an almost uncontaminated gas-tight sample from the seafloor. To date, the sampler has been used in more than 90 dive surveys by Japanese submersibles/ROVs, including Shinkai 2000, Shinkai 6500, and Hyper Dolphin, with a success rate of > 90 %.

    DOI: 10.1111/j.1468-8123.2006.00143.x

  121. Geomicrobiological exploration and characterization of a novel deep-sea hydrothermal system at the TOTO caldera in the Mariana Volcanic Arc 査読有り

    Nakagawa, T, Takai, K, Suzuki, Y, Hirayama, H, Konno, U, Tsunogai, U, Horikoshi, K

    ENVIRONMENTAL MICROBIOLOGY   8 巻 ( 1 ) 頁: 37-49   2006年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Novel hydrothermal activities accompanying effluent white smokers and elemental sulfur chimney structures at the north-east lava dome of the TOTO caldera depression in the Mariana Volcanic Arc have been explored and characterized by geochemical and microbiological surveys. White smoker hydrothermal fluids were observed in the potential hydrothermal activity centre of the field and represented the maximal temperature of 170 degrees C and the lowest pH of 1.6. The chimney structures, all consisting of elemental sulfur (sulfur chimney), were also unique to the TOTO caldera hydrothermal field. Microbial community structures in a sulfur chimney and its formation hydrothermal fluid with a high concentration of hydrogen sulfide (15 mM) have been investigated by culture-dependent and -independent analyses. 16S rRNA gene clone analysis and fluorescence in situ hybridization (FISH) analysis revealed that epsilon-Proteobacteria dominated the microbial communities in the sulfur chimney structure and formed a dense microbial mat covering the sulfur chimney surface. Archaeal phylotypes were consistently minor components in the communities and related to the genera Thermococcus, Pyrodictium, Aeropyrum, and the uncultivated archaeal group of `deep-sea hydrothermal vent euryarchaeotal group'. Cultivation analysis suggested that the chemolithoautotrophs might play a significant ecological role as primary producers utilizing gas and sulfur compounds provided from hydrothermal fluids.

    DOI: 10.1111/j.1462-2920.2005.00884.x

  122. Polar and neutral isopranyl glycerol ether lipids as biomarkers of archaea in near-surface sediments from the Nankai Trough 査読有り

    Oba, Masahiro, Sakata, Susumu, Tsunogai, Urumu

    ORGANIC GEOCHEMISTRY   37 巻 ( 12 ) 頁: 1643-1654   2006年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The molecular and carbon isotopic compositions of polar isopranyl glycerol ether lipids, which are direct indicators of viable archaea, and neutral isopranyl glycerol ether lipids, which are derived from polar lipids via hydrolysis, in near-surface sediments from a methane seep in the Nankai Trough (off central Japan) were investigated. Procedures for extracting, separatine and derivatizing polar and neutral ether lipids for detection using gas chromatography were first examined with one sediment sample and a cultivated methanogen. For all sediment samples, archaeol and hydroxyarchaeol were detected in both the polar and neutral ether lipid fractions. Acyclic and cyclic biphytanes were also detected in both types of lipid fractions after treatment with HI/LiAlH4 for ether cleavage and alkylation. The delta C-13 values of archaeol, sn-2-hydroxyarchaeol, and sn-3-hydroxyarchaeol in the sample from 0.82 in below the seafloor were lower than -100 parts per thousand relative to PDB, indicating that diverse living methanotrophic archaea are present in the seep sediments. Biphytanes released from polar ether lipids in the same sample were less depleted in delta C-13 (-71 parts per thousand to -36 parts per thousand). The wide range of delta C-13 values suggests that the biphytanes were derived not only from methanotrophic but also from non-methanotrophic archaea, and that the relative contributions of the methanotrophic and non-methanotrophic archaea differed, depending on the biphytane compound. The vertical profiles and delta C-13 values of the neutral ether lipids were similar to those of the intact polar ether lipids, suggesting that neutral ether lipids derived from fossil archaea in the samples had mainly been lost by the time of sampling.

    DOI: 10.1016/j.orggeochem.2006.09.002

  123. Stable isotopic compositions of methane and carbon monoxide in the Suiyo hydrothermal plume, Izu-Bonin arc: Tracers for microbial consumption/production 査読有り

    Tsunogai, U, Nakagawa, F, Gamo, T, Ishibashi, J

    EARTH AND PLANETARY SCIENCE LETTERS   237 巻 ( 40972 ) 頁: 326-340   2005年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Effluent hydrothermal water samples in and around the water column of the Suiyo seamount caldera (ca. 2 km diameter), Izu-Bonin arc, were taken to determine concentrations and stable carbon isotopic compositions (delta13C) of methane (CH4) and carbon monoxide (CO) in the plume. Venting fluids on the caldera floor (ca. 1370 m depth) were also examined, using the manned submersible Shinkai 2000, to compare the chemical composition and isotopic composition of CH4 and CO with those in the hydrothermal plume. Strong CH4 enrichment was detected not only in the water column within the caldera, but also on those outside the caldera at the depth of ca. I 100 m, the sill depth of the caldera wall. Within the plume, we also detected significant CO enrichment. The delta13C of CO in the plume, however, exhibited highly C-13-depleted values (-110 parts per thousand(VPDB) to -60 parts per thousand(VPDB)) compared with those in seafloor venting hydrothermal fluids (around - 31 parts per thousand(VPDB)). Besides, the plume samples exhibited higher CO/CH4 ratios depending on the distance from the seafloor venting site. We conclude that in situ microbial activity in the plume causes the CO enrichment in the hydrothermal plume. The present results suggest that CO enrichment in deep sea water could act as a new tracer for unidentified seafloor hydrothermal activities, especially for detecting plumes distant from venting sites, as well as for quantifying in situ microbial activity related to CO production in hydrothermal plumes.

    DOI: 10.1016/j.epsl.2005.05.042

  124. 溶存メタンを指標に用いた富山湾海底湧出地下水の地球化学的研究 査読有り

    亀山宗彦, 角皆 潤, 蒲生俊敬, 張 勁, 鈴木麻衣, 小山裕樹

    地球化学   39 巻   頁: 131-140   2005年8月

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  125. An analytical system for determining delta O-17 in CO2 using continuous flow-isotope ratio MS 査読有り

    Kawagucci, S, Tsunogai, U, Kudo, S, Nakagawa, F, Honda, H , Aoki, S, Nakazawa, T, Gamo, T

    ANALYTICAL CHEMISTRY   77 巻 ( 14 ) 頁: 4509-4514   2005年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We developed a simple measurement system for delta17O in nanomole quantities of CO2 using continuous flow isotope ratio mass spectrometry (CF-IRMS). The analytical system consisted of a sample injection system, a helium-purged CO2 purification line, a capillary GC, a combustion unit, and CF-IRMS. A unique feature of the system is that we use molecular CO2 to determine the isotopic compositions including delta17O. The delta17O Of CO2 in a sample is calculated from the mass ratios of both 45/44 and 46/44 of two different kinds Of CO2, which have been purified quantitatively from different aliquots of a sample. While one aliquot (rCO2) flows into IRMS directly, the other (eCO2) flows through a CuO unit (900 degrees C) prior to injection into IRMS, to exchange oxygen atoms in the sample CO2 molecules with those in CuO for which we can assume Delta17O = 0. In our system, we introduce both rCO2 and eCO2 alternately to IRMS repeatedly by using an automatic multianalytical system to improve analytical precision statistically. The standard deviation of 0.35 parts per thousand for Delta17O can be realized using as little as 8.7 nmol CO2 in a similar to 3-h analysis. Based on this system, we have quantified delta17O in the stratospheric CO2 over Japan.

    DOI: 10.1021/ac050266u

  126. 海底熱水活動地帯の化学環境を明らかにする試み 招待有り 査読有り

    石橋純一郎, 中村光一, 岡村慶, 下島公紀, 土岐知弘, 角皆 潤

    海の研究   14 巻 ( 2 ) 頁: 251-266   2005年3月

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    記述言語:日本語  

    海底熱水活動地帯は高温で還元的な熱水と低温で酸化的な海水が混合する場である。熱水活動地帯の生態系機能を研究するうえで, 場所ごとに化学環境を明らかにしていくことは, 最も基本的な解析手法となる。近年, このような目的を目指した試料採取法の工夫がさかんに行なわれている。また, 試料採取と分析に頼る従来の研究を打破する手法として, 現場化学分析や化学センサーなどの技術を深海底で実用化して, さらに連続観測を行なうことも試みられている。アーキアン・パーク計画では, 化学環境の時空間変動を明らかにすることを目的として, 新しい発想に基づく様々な機器が開発されてきた。その結果, 水曜海山で行なわれた一連の研究から, この熱水地帯の化学環境がこの海域特有の強い底層流の時間変動と相関を持って変動していたことが示された。

  127. 化学トレーサーを用いた水曜海山熱水プルーム中における微生物活動の定量化 招待有り 査読有り

    角皆 潤, 中川書子, 岡村 慶

    海の研究   14 巻 ( 2 ) 頁: 279-295   2005年3月

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    担当区分:筆頭著者   記述言語:日本語  

    本論文はアーキアン・パーク計画において行われた熱水プルーム中における微生物活動の解明に関する化学的調査の成果をまとめたもので, この調査によって水曜海山カルデラ内外の海水において微生物活動に関連する化学成分の濃度と一部の同位体組成の分布が定量された。また, カルデラ底に湧出する熱水の採取と分析も行なわれた。その結果, 熱水に由来する濁度異常やCH4, Mn, Feの高濃度異常が, カルデラ内はもちろん, カルデラ外でも検出され, 熱水プルームがカルデラ壁上の鞍部を経由して外に漏出していることが判明した。また, 熱水由来のMnの約半分がカルデラ内で分解されているのに対して, CH4は大部分が分解されずにそのまま外に漏出していることも明らかになった。さらに, 水曜海山の熱水プルームではCOも高濃度異常を示すことが明らかになったが, このCOは熱水に由来するのではなく, プルーム内部の微生物活動によって二次的に生成した可能性が高いと結論された。

  128. A selective unsaturated hydrocarbon subtraction technique for stable carbon isotopic analysis of atmospheric methyl chloride, methyl bromide, and C(2)-C(5) saturated hydrocarbons using continuous-flow isotope ratio mass spectrometry 査読有り

    Komatsu, DD, Tsunogai, U, Yamaguchi, J, Nakagawa, F

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   19 巻 ( 4 ) 頁: 477-483   2005年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Using continuous-flow isotope ratio mass spectrometry, we have developed a new analytical system which enables us to determine the stable carbon isotopic composition of CH(3)Cl, CH(3)Br, and C(2)-C(5) saturated hydrocarbons in gas samples even if they contain substantial amounts of unsaturated hydrocarbons, using an I(2)O(5) reagent for their selective subtraction. The analytical precision of the delta13C determinations is better than 0.5parts per thousand for >300 pmolC injections and better than 5parts per thousand for 20 pmolC injections. Using the system, delta13C values for CH(3)Cl and CH(3)Br were found in burning exhaust that contain a substantial quantity of unsaturated hydrocarbons. CH(3)Cl and CH(3)Br measured in exhaust from burning rice plants exhibit highly 13C-depleted values of -56.6 +/- 1.3parts per thousand and -48.6 +/- 3.9parts per thousand, respectively, while saturated hydrocarbons exhibit delta13C values (-26.4 to -28.9parts per thousand) that are comparable with the total delta13C value of the parent material (rice plant; -28.0parts per thousand). Using the system, we can determine the delta13C values of methyl halides and hydrocarbons in many kinds of gas samples.

    DOI: 10.1002/rcm.1795

  129. Automobile exhaust as a source of C-13- and D-enriched atmospheric methane in urban areas 査読有り

    Nakagawa, F, Tsunogai, U, Komatsu, DD, Yamada, K, Yoshida, N , Moriizumi, J, Nagamine, K, Iida, T, Ikebe, Y

    ORGANIC GEOCHEMISTRY   36 巻 ( 5 ) 頁: 727-738   2005年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The stable carbon and hydrogen isotopic compositions (delta13C and delta D, respectively) of methane (CH4) in automobile exhaust were determined in order to quantify by mass balance the contribution from this source to atmospheric CH4 in an urban area of Nagoya, Japan. Both delta13C and delta D values of CH4 in automobile exhaust increased in accordance with the model year of the engine, probably as a result of isotope fractionation effects associated with oxidation over metal catalysts in the catalytic converter of modern vehicles. Thus, CH4 emissions from recent automobiles exhibit conspicuous C-13 and D enrichment compared to the flux from other major anthropogenic sources, such as natural gas leakage, landfills and rice paddies. Using average delta13C and delta D CH4 values estimated for local sources, automobile exhaust in Nagoya, Japan, was determined to contribute significant amounts (up to 30 %) of CH4 to the troposphere in the study area.

    DOI: 10.1016/j.orggeochem.2005.01.003

  130. Characterization of C-1-metabolizing prokaryotic communities in methane seep habitats at the Kuroshima Knoll, southern Ryukyu arc, by analyzing pmoA, mmoX, mxaF, mcrA, and 16S rRNA genes 査読有り

    Inagaki, F, Tsunogai, U, Suzuki, M, Kosaka, A, Machiyama, H , Takai, K, Nunoura, T, Nealson, KH, Horikoshi, K

    APPLIED AND ENVIRONMENTAL MICROBIOLOGY   70 巻 ( 12 ) 頁: 7445-7455   2004年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Increasing levels Of CO2 in the atmosphere are expected to cause climatic change with negative effects on the earth's ecosystems and human society. Consequently, a variety of CO2 disposal options are discussed, including injection into the deep ocean. Because the dissolution Of CO2 in seawater will decrease ambient pH considerably, negative consequences for deep-water ecosystems have been predicted. Hence, ecosystems associated with natural CO2 reservoirs in the deep sea, and the dynamics of gaseous, liquid, and solid CO2 in such environments, are of great interest to science and society. We report here a biogeochemical and microbiological characterization of a microbial community inhabiting deep-sea sediments overlying a natural CO2 lake at the Yonaguni Knoll IV hydrothermal field, southern Okinawa Trough. We found high abundances (> 10(9) CM(-3)) of microbial cells in sediment pavements above the CO2 lake, decreasing to strikingly low cell numbers (107 CM-3) at the liquid CO2/CO2-hydrate interface. The key groups in these sediments were as follows: (i) the anaerobic methanotrophic archaea ANME-2c and the Eel-2 group of Deltaproteobacteria and (ii) sulfur-metabolizing chemolithotrophs within the Gamma- and Epsilonproteobacteria. The detection of functional genes related to one-carbon assimilation and the presence of highly 13C-depleted archaeal and bacterial lipid biomarkers suggest that microorganisms assimilating CO2 and/or CH4 dominate the liquid CO2 and CO2-hydrate-bearing sediments. Clearly, the Yonaguni Knoll is an exceptional natural laboratory for the study of consequences of CO2 disposal as well as of natural CO2 reservoirs as potential microbial habitats on early Earth and other celestial bodies.

    DOI: 10.1128/AEM.70.12.7445-7455.2004

  131. Detection of low-chloride fluids beneath a cold seep field on the Nankai accretionary wedge off Kumano, south of Japan 査読有り

    Toki, T, Tsunogai, U, Gamo, T, Kuramoto, S, Ashi, J

    EARTH AND PLANETARY SCIENCE LETTERS   228 巻 ( 40910 ) 頁: 37-47   2004年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Chemical and isotopic characteristics were determined for interstitial waters extracted from surface sediments in and around dense biological communities on the seafloor of the Nankai accretionary prism off Kumano, south of Japan. We found the following unique features when compared with usual interstitial water samples of normal seafloor in those of samples from bacterial mats on the Oomine Ridge, one of the outer ridge in the Nankai accretionary prism: (1) significant depletion of chloride concentration (maximum 10% depletion from bottom seawater), (2) high concentrations of CH4 and SigmaCO2 (more than 660 mumol/kg and 60 mmol/kg, respectively), (3) sulfate depletion (more than 90% depletion compared to bottom seawater), and (4) deltaDH2O and delta(18)O(H2O) depletion [more than 4parts per thousand and 0.7parts per thousand depletion, respectively, compared to standard mean ocean water (SMOW)]. The highest CH4 value among these samples was comparable to the highest value so far reported at one of the most active seep areas in the Nankai Trough, suggesting that these sites should also be regarded as one of the most active seep sites in the Nankai Trough. The chemical compositions of the samples taken from the Oomine Ridge strongly suggest that the fluid originates not from normal sediment-seawater interaction at the sediment surface of hemipelagic environments, but from active seepage of fluids that are rich in CH4 and SigmaCO2, depleted in Cl- and SO42-, and low in deltaD(H2O) and delta(18)O(H2O) compared to normal seawater. Values for the carbon isotopic composition (delta13C(CH4)) of the dissolved methane in the interstitial fluid [less than -70parts per thousand PeeDee Belemnite (PDB)] and for the C2H6/CH4 ratio (less than 10(-3)) suggest that the methane originates from microbial production in a relatively shallow layer of sediment, not from the deep sedimentary layer of higher temperature than 60 degreesC at the depthof more than 300 m below the seafloor. The Cl-=0 mmol/kg extrapolated end-member deltaD(H2O) and delta(18)O(H2O) values of low-chloride fluids were -46+7parts per thousand and -6.3+0.7parts per thousand SMOW, respectively, suggesting that land-derived groundwater could be one of the possible sources for the low-Cl- fluids. Depth profiles of chloride concentrations of interstitial fluids show the heterogeneity of end members ad upward sluid velocities suggest active fluid seepage on the Oomine Ridge seems to be a localized phenomenon. Assuming steady-state emission of fluid from the cold seep vent, upward fluid flow velocities from the seeping vent are estimated to be 40-200 cm year(-1), comparable to the previously reported values within the bacterial mats in Nankai Trough accretionary wedge. Development of bacterial mat might favor slower advection, which might allow longer time for diagenetic reactions in the vent conduits, and consequently, carry more reductive compounds in the fluids.

    DOI: 10.1016/j.epsl.2004.09.007

  132. Geochemical and microbiological evidence for a hydrogen-based, hyperthermophilic subsurface lithoautotrophic microbial ecosystem (HyperSLiME) beneath an active deep-sea hydrothermal field 査読有り

    Takai, K, Gamo, T, Tsunogai, U, Nakayama, N, Hirayama, H, Nealson, KH, Horikoshi, K

    EXTREMOPHILES   8 巻 ( 4 ) 頁: 269-282   2004年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Subsurface microbial communities supported by geologically and abiologically derived hydrogen and carbon dioxide from the Earth's interior are of great interest, not only with regard to the nature of primitive life on Earth, but as potential analogs for extraterrestrial life. Here, for the first time, we present geochemical and microbiological evidence pointing to the existence of hyperthermophilic subsurface lithoautotrophic microbial ecosystem (HyperSLiME) dominated by hyperthermophilic methanogens beneath an active deep-sea hydrothermal field in the Central Indian Ridge. Geochemical and isotopic analyses of gaseous components in the hydrothermal fluids revealed heterogeneity of both concentration and carbon isotopic compositions of methane between the main hydrothermal vent (0.08 mM and -13.8parts per thousand PDB, respectively) and the adjacent divergent vent site (0.2 mM and -18.5parts per thousand PDB, respectively), representing potential subsurface microbial methanogenesis, at least in the divergent vent emitting more C-13-depleted methane. Extremely high abundance of magmatic energy sources such as hydrogen (2.5 mM) in the fluids also encourages a hydrogen-based, lithoautotrophic microbial activity. Both cultivation and cultivation-independent molecular analyses suggested the predominance of Methanococcales members in the superheated hydrothermal emissions and chimney interiors along with the other major microbial components of Thermococcales members. These results imply that a HyperSLiME, consisting of methanogens and fermenters, occurs in this tectonically active subsurface zone, strongly supporting the existence of hydrogen-driven subsurface microbial communities.

    DOI: 10.1007/s00792-004-0386-3

  133. Stable isotopic compositions and fractionations of carbon monoxide at coastal and open ocean stations in the Pacific 査読有り

    Nakagawa, F, Tsunogai, U, Gamo, T, Yoshida, N

    JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS   109 巻 ( C6 )   2004年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Included in this report are the results of the first isotopic studies of seawater-dissolved carbon monoxide ( CO). Large variations in both carbon and oxygen isotopic compositions (delta13C: -44.7 similar to -21.1parts per thousand PDB, and delta(18)O: + 8.7 similar to + 32.9parts per thousandSMOW) were observed in seawater-dissolved CO due to the combination of isotopically light CO production in seawater and the enrichment of heavy isotopes during the microbial consumption of CO. Compared with the total delta13C value of dissolved organic matter (DOM), the isotopic compositions of the photochemically produced CO in seawater are depleted in C-13 by more than 20parts per thousand, probably due to large fractionation processes during the photochemical production of CO from DOM. In addition, the isotopic fractionation factors resulting from the microbial oxidation of CO in seawater were estimated to be 1.005 +/- 0.002 and 1.006 +/- 0.002 for carbon (alpha(c)) and oxygen (alpha(o)) based on the incubation experiments. By calculating the weighted mean of the isotopic composition of CO according to the CO concentration observed in surface seawater, the mean delta13C and delta(18)O for CO emitted from the oceans were estimated to be -40parts per thousand PDB and + 15parts per thousand SMOW, respectively. Oceanic CO is a unique source of C-13 and O-18-depleted CO relative to that of fossil fuel combustion and biomass burning, which will help us create a better isotopic mass balance for both global and local CO budget.

    DOI: 10.1029/2001JC001108

  134. Geophysical and geochemical observations on actively seeping hydrocarbon gases on the south-eastern Yellow Sea continental shelf 査読有り

    Jeong, KS, Cho, JH, Kim, SR, Hyun, S, Tsunogai, U

    GEO-MARINE LETTERS   24 巻 ( 1 ) 頁: 53-62   2004年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In the southeastern Yellow Sea, active seepage of hydrocarbon gases has been observed by high-resolution (3.5 kHz) seismic profiling both in 1987 and 2001, occurring through a large number of plumes from the topmost pre-Holocene sedimentary layer. It is strong enough to compensate for current speed, extending vertically up to the sea surface. The gas seepage often appears to be explosive to form craters and diapirs, although pockmarks are rare due to the redistribution of mobile palimpsest sands. In core-top seawater and sediments, the gases are characterized by high amounts of C-2, homogenous delta13C(1) values and a large difference (19.7parts per thousand on average) between delta13C(1) (-55.2 to -53.6parts per thousand PDB) and delta13C(2) (-36.8 to -32.5parts per thousand PDB) values. The gases are considered to be generated with a smaller amount of C-1 at the early thermal cracking stage of labile source materials, after which the C-2 gas is enriched in C-13 by diffusion or biological alternation at the generation or accumulation site. The homogenous delta13C(1) values may be one of the geochemical characteristics of gases acquired at depth which are less altered in the case of rapid diffusive gas migration to the seafloor.

    DOI: 10.1007/s00367-003-0164-8

  135. Stable carbon and oxygen isotopic determination of sub-microgram quantities of CaCO3 to analyze individual foraminiferal shells 査読有り

    Ishimura, T, Tsunogai, U, Gamo, T

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   18 巻 ( 23 ) 頁: 2883-2888   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We have developed an analytical system to determine stable isotopic compositions (delta13C and delta18O) of sub-microgram quantities of CaCO3 for the purpose of analyzing individual foraminiferal shells, using continuous-flow isotope ratio mass spectrometry (CF-IRMS). The system consists of a microvolume CaCO3 decomposition tube, stainless steel CO2 purification vacuum line with a quantity-regulating unit, helium-purged CO2 purification line, gas chromatograph, and a CF-IRMS system. By using this system, we can determine stable carbon and oxygen isotopic compositions as low as 0.2 µg of CaCO3, with standard deviations of +/-0.10 parts per thousand for delta13C and +/-0.18parts per thousand for delta18O within a 4-h reaction time and 30-min analysis period.

    DOI: 10.1002/rcm.1701

  136. Discovery of a new hydrothermal venting site in the southernmost Mariana Arc: Al-rich hydrothermal plumes and white smoker activity associated with biogenic methane 査読有り

    Gamo, T, Masuda, H, Yamanaka, T, Okamura, K, Ishibashi, J , Nakayama, E, Obata, H, Shitashima, K, Nishio, Y, Hasumoto, H, Watanabe, M, Mitsuzawa, K, Seama, N, Tsunogai, U, Kouzuma, F, Sano, Y

    GEOCHEMICAL JOURNAL   38 巻 ( 6 ) 頁: 527-534   2004年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This paper reports a series of studies leading to the discovery of a submarine hydrothermal field (called Nakayama Field) at an arc seamount (12degrees43' N, 143degrees32' E) in the southernmost part of the Mariana Trough, western Pacific Ocean. We first detected hydrothermal plumes characterized by water column anomalies of temperature, light transmission, Mn, Fe, Al, O-2, CH4, and delta13C of CH4 above the summit caldera of the seamount. Then deep-tow camera surveys confirmed the existence of hydrothermal activity inside the caldera, and an ROV dive finally discovered white smoker-type fluid venting associated with vent fauna. A high concentration of aluminum in the plume and white smoker-type emissions imply acidic hydrothermal activity similar to that observed at the DESMOS Caldera in the eastern Manus Basin, Papua New Guinea. Anomalously low delta13C (CH4) of -38parts per thousand of a vent fluid sample compared to other arc hydrothermal systems along the Izu-Bonin and Mariana Arcs suggests an incorporation of biogenic methane based on a subsurface microbial ecosystem.

  137. An updated estimation of the stable carbon and oxygen isotopic compositions of automobile CO emissions 査読有り

    Tsunogai, U, Hachisu, Y, Komatsu, DD, Nakagawa, F, Gamo, T , Akiyama, K

    ATMOSPHERIC ENVIRONMENT   37 巻 ( 35 ) 頁: 4901-4910   2003年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We estimate up-to-date values of the average isotopic compositions of CO emitted from automobiles. In the estimation, we determined the isotopic compositions of CO in tail pipe exhaust for four gasoline automobiles and two diesel automobiles under varying conditions of both idling and running. While the dependence on the automobile manufacturer is little, each automobile equipped with functional catalytic converter exhibits a large temporal delta13C and delta(18)O variation. They tend to show C-13 and O-18 enrichment in accordance with the reduction of CO in exhaust, suggesting that the functional catalytic converter in engines enhances the delta13C and delta(18)O values of CO from tail pipes through a kinetic isotope effect during CO destruction. Assuming that automobiles run a modeled driving cycle, we estimated the average delta13C and delta(18)O of CO to be -23.8 +/- 0.8parts per thousand(PDB) and +25.3 +/- 1.0parts per thousand(SMOW), respectively, for recent gasoline automobiles, and -19.5 +/- 0.7parts per thousand(PDB) and +15.1 +/- 1.0parts per thousand(SMOW), respectively, for recent diesel automobiles. While the delta13C and delta(18)O values of recent gasoline automobiles coincide well with the isotopic compositions of source CO in present trunk road atmosphere estimated in this study, those are +4-+6parts per thousand (delta13C) and +1-+3parts per thousand (delta(18)O) higher than those reported previously and also those emitted from old, non-catalyst automobiles determined in this study. Recent improvements in functional catalytic converters have enhanced and will enhance the delta13C and delta(18)O values of CO from automobiles.

    DOI: 10.1016/j.atmosenv.2003.08.008

  138. 潜水調査船用多連式ガスタイト海底湧水採取装置の開発 査読有り

    角皆 潤, 土岐知弘, 中山典子, 蒲生俊敬, 加藤博之, 金子 将

    地球化学   37 巻 ( 3 ) 頁: 101-109   2003年8月

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    担当区分:筆頭著者   記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  139. Stable isotope evidence for a putative endosymbiont-based lithotrophic Bathymodiolus sp mussel community atop a serpentine seamount 査読有り

    Yamanaka, T, Mizota, C, Satake, H, Kouzuma, F, Gamo, T, Tsunogai, U, Miwa, T, Fujioka, K

    GEOMICROBIOLOGY JOURNAL   20 巻 ( 3 ) 頁: 185-197   2003年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A putative endosymbiont-based benthic animal community composed of at least two kinds of bivalves has been found atop the South Chamorro serpentine seamount in the Mariana fore-arc, western Pacific. Multiple stable isotopic analyses ( hydrogen, carbon, nitrogen, and sulfur) were carried out on the soft tissues of an undescribed mussel species belonging to the genus Bathymodiolus. Markedly higher stable carbon (delta13C: -21.4 to -18.9 % vs. PDB) and lower sulfur (delta(34)S: +10.2 to +10.6 % vs. CDT) isotopic compositions of the mussel tissues suggested that they utilized both methane and sulfide as nutrient sources of carbon and sulfur. Analyses of in situ shimmering water and clayey sediment under the mussel bed supported these findings. These results strongly suggest that the mussels harbored both methanotrophic and thioautotrophic bacterial symbionts in their gills. This is the first stable isotopic evidence of a dual symbiotic Bathymodiolus sp. in the western Pacific. It is proposed that the major substrates for energy acquisition-methane and hydrogen sulfide-may be responsible for results from serpentinization in the lower crust. This abiotic process would be followed by abiotic or archaeal methane production and bacterial sulfate-reduction as evidenced by high delta13C value (-14.6 %) of methane in the shimmering water and low delta(34)S value (-32.3 %) of sulfides in the immediate sediments, respectively. Due to the very low organic matter content (0.5 mg C/g dry sediment) of the immediate sediment, it is further proposed that sulfate-reduction occurred using hydrogen (or possibly methane) as an electron donor. Thus, the mussel community living independently of magmatism and sedimentary organic matter is a lithotrophic animal community.

    DOI: 10.1080/01490450390206674

  140. 海水中のメタンを指標に用いた三宅島周辺における火山活動調査の結果について 査読有り

    土岐知弘, 角皆 潤, 蒲生俊敬, 皆川昌幸

    火山   48 巻 ( 1 ) 頁: 63-67   2003年

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    記述言語:日本語   掲載種別:研究論文(学術雑誌)  

  141. A simple method for oxygen-18 determination of milligram quantities of water using NaHCO3 reagent 査読有り

    Ijiri, A, Tsunogai, U, Gamo, T

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   17 巻 ( 13 ) 頁: 1472-1478   2003年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This paper presents a modified H2O-CO2 equilibration method for stable oxygen isotopic composition (delta18O) analysis of water. This method enables rapid and simple delta18O analysis of milligram quantities of water, by employing solid reagent NaHCO3 as the CO2 Source, a small (0.6 mL) glass vial for the equilibration chamber, and an isotope-monitoring gas chromatography/mass spectrometry (irm-GC/MS) system for delta18O(CO2) analysis. This method has several advantages, including simple handling for the H2O-CO2 equilibration (without purging and/or evacuation treatments), rapid and easy delta18O analysis of equilibrated CO2, and highly sensitive and highly precise delta18O analysis of H2O, using samples as small as 10 mg and with a precision of less than +/-0.12parts per thousand. The time needed to attain oxygen isotopic equilibration between CO2 and water is also comparable (17 h for 10 mg H2O and 10 h for 100 mg H2O) to other previous methods using CO2 gas for the CO2 source. The extent of delta18O variation of sample water from its initial delta18O value due to isotope exchange with added NaHCO3 is also discussed. It is concluded that the correction needed is negligible (less than 0.1parts per thousand) as long as the oxygen atom ratio (O-NaHCO3/O-H2O) is less than 3.3 +/- 10-3 and provided the delta18O(H2O) determination is made by comparing delta18O of CO2 equilibrated with sample water and that equilibrated with standard water of a moderately close delta18O value, less than 30parts per thousand difference.

    DOI: 10.1002/rcm.1081

  142. Stable carbon and oxygen isotopic analysis of atmospheric carbon monoxide using continuous-flow isotope ratio MS by isotope ratio monitoring of CO 査読有り

    Tsunogai, U, Nakagawa, F, Komatsu, DD, Gamo, T

    ANALYTICAL CHEMISTRY   74 巻 ( 22 ) 頁: 5695-5700   2002年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We have developed a rapid and simple measurement system for both content and stable isotopic compositions (C-13 and O-18) of atmospheric CO, using continuous-flow isotope ratio mass spectrometry by simultaneously monitoring the CO+ ion currents at masses 28, 29, and 30. The analytical system consisted sequentially of a sample trapping port (liquid nitrogen temperature silica gel and molecular sieve 5A), a gas dryer, a CO purification column (molecular sieve 5A), a cryofocusing unit, and a final purification column using a GC capillary. Analytical precision of 0.2parts per thousand for C-13 and 0.4parts per thousand for O-18 can be realized for samples that contain as little as 300 pmol of CO within 40 min for one sample analysis. Analytical blanks associated with the method are less than 1 pmol. The extent of analytical error in delta13C due to mass-independent fractionation of oxygen in natural CO is estimated to be less than 0.3parts per thousand. Based on this system, we report herein a kinetic isotopic effect during CO consumption in soil.

    DOI: 10.1021/ac020290x

  143. Carbon isotopic evidence of methane oxidation through sulfate reduction in sediment beneath cold seep vents on the seafloor at Nankai Trough 査読有り

    Tsunogai, U, Yoshida, N, Gamo, T

    MARINE GEOLOGY   187 巻 ( 40910 ) 頁: 145-160   2002年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    During the Kaiko-Tokai project, we took a total of 15 near-surface sediment push cores from inside and outside seafloor clam colonies and bacterial mats in the Nankai Trough. In this study, we present the chemical and isotopic composition of pore fluids extracted from the sampled cores, with special emphasis on those taken at the Ryuyo Canyon, and discuss (a) the chemical relation between the seeping fluid and biological communities, and (b) the origin of cold seep fluids. Compared with bottom seawater, up to 5 % depletion of chloride concentration, extremely high CH4 concentration of more than 300 mumol/kg, and slight deltaD(H2O) depletion are observed in pore fluids at the Ryuyo Canyon, which suggests that the Ryuyo Canyon is an active seep zone of low chloride, CH4-rich, low deltaD(H2O) fluid from the sea bottom. Remarkable depletion of sulfate and significant enrichment of dissolved inorganic carbon and of hydrogen sulfide are also observed in the pore fluids, particularly those taken within bacterial mats, while the carbon isotopic composition of pore fluid dissolved methane (delta13C(CH4)) shows large heterogeneity (up to 30parts per thousand) in and around the vents. These chemical and isotopic characteristics might be due to active anaerobic methane oxidation and hydrogen sulfide production (methane oxidation through sulfate reduction) in the sedimentary layer just below (within 30 cm) the vents on the seafloor. The carbon isotopic composition of methane can be considered direct evidence of the mediation process between methane-enriched cold seep fluid and the H2S-dependent biological community on the cold seep vent. After correcting for the effect of methane oxidation at the sediment surface, we estimate the end-member carbon isotopic composition of methane as less than -90parts per thousand PDB, and the end-member CH4/C2H6 ratio as more than 10(3), which suggests a microbial, shallow layer is the origin of methane in the fluid.

    DOI: 10.1016/S0025-3227(02)00263-3

  144. Surface expression of fluid venting at the toe of the Nankai wedge and implications for flow paths 査読有り

    Henry, P, Lallemant, S, Nakamura, K, Tsunogai, U, Mazzotti, S, Kobayashi, K

    MARINE GEOLOGY   187 巻 ( 40910 ) 頁: 119-143   2002年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Cold seeps have been observed with manned submersibles at many sites on the Tokai margin. Most sites are found on the hanging wall of major thrust faults, within 1-2 km of their outcrop. Few sites relate to purely erosional features. This relationship between thrusting and venting may be explained either by fluid flow along fault zones, by fluid flow along permeable layers outcropping at the fault scarp, or by diffuse upward flow of fluids released during footwall compaction. We use deep-towed side-scan sonar and sediment sounder profiles acquired at the toe of the Nankai accretionary wedge to identify the context of seepage at a smaller scale. Modes of fluid expulsion inferred from observations in this zone include flow channelling along strata, along thrusts, along gravity faults, and along joint fractures as well as diffuse flow. We then combine visual observation and monitoring of electrochemical potential (Eh) to assess the relative importance of seepage sites. We show that bacterial mats are better visual indicators of active seepage than bivalve beds and that the most active seepage sites correlate with outcrops of coarse turbidites, cemented by authigenic carbonates. These were sampled and have permeability high enough to channel fluid flow (1-4 x 10(-14) m(2)). We suggest they are the main conduits near the seafloor. However, seepage sites are also observed directly on the outcrop of major thrusts, indicating that they do play a role as fluid conduits. We observe negative polarity seismic reflections on these faults below 1 km depth and wonder about their significance.

    DOI: 10.1016/S0025-3227(02)00262-1

  145. Stable carbon isotopic compositions of light hydrocarbons over the western North Pacific and implication for their photochemical ages 査読有り

    Saito, T, Tsunogai, U, Kawamura, K, Nakatsuka, T, Yoshida, N

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   107 巻 ( D4 )   2002年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Light hydrocarbons collected over the western North Pacific in canisters during an oceanographic cruise in May 1999 were analyzed for the mixing ratios and the stable carbon isotopic compositions (delta13C). Their mixing ratios decreased during the passage of a warm front. By contrast, they increased after the passage of a cold front. The delta13C values of ethane were found to be in a range of -26 to -19parts per thousand and to be systematically heavier when the mixing ratios (range of 1.7-0.6 ppbv) became lower. The delta13C values of ethane over the open ocean generally showed heavier values than those previously reported in the source regions, suggesting an isotopic fractionation during a long-range atmospheric transport. In contrast, delta13C values of i- and n-butanes varied in a wide range (-37 to -16parts per thousand and -37 to -21parts per thousand, respectively); however, their averaged values are comparative to the isotopic source compositions. Likewise, no systematic relationships were found between the mixing ratios and the delta13C values of the butane isomers. For n-butane the observed relationship was substantially different from that predicted by kinetic isotope effect by the reaction with OH radicals probably due to the contribution of effective mixing process. From the changes in the delta13C values for ethane and n-butane the averaged photochemical ages were calculated to be 49 +/- 26 days and 2 +/- 6 days, respectively. The difference in the estimated ages is attributed to the different reactivity of hydrocarbons. The average ages for n-butane were found to be consistent with numbers of days, which the air mass took for the transport from the continent to the sampling site over the ocean, on the basis of backward trajectory analysis. This study suggests that the photochemical ages are useful for assessing the importance of recent emission in the marine atmosphere.

    DOI: 10.1029/2000JD000127

  146. Production mechanism and global budget of N2O inferred from its isotopomers in the western North Pacific 査読有り

    Toyoda, S, Yoshida, N, Miwa, T, Matsui, Y, Yamagishi, H, Tsunogai, U, Nojiri, Y, Tsurushima, N

    GEOPHYSICAL RESEARCH LETTERS   29 巻 ( 3 )   2002年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We measured the intramolecular distribution of N-15 as well as conventional nitrogen and oxygen isotope ratios in oceanic nitrous oxide (N2O) in the western North Pacific for the first time. In contrast to a nearly homogeneous vertical distribution of a bulk nitrogen isotope ratio, a wide variation in site preference for intramolecular N-15 distribution was found, suggesting the subsurface and deep source mixing and the production mechanism in the ocean. The oceanic composition of N2O isotopomers quantitatively outlines the ocean as the most significant source after the terrestrial one.

    DOI: 10.1029/2001GL014311

  147. 超微量炭素同位体比測定による熱水・冷湧水溶存気体に関する研究(日本地球化学会奨励賞受賞記念論文) 招待有り 査読有り

    角皆 潤

    地球化学   36 巻 ( 1 ) 頁: 51-63   2002年

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    担当区分:筆頭著者   記述言語:日本語  

  148. Chemical characteristics of newly discovered black smoker fluids and associated hydrothermal plumes at the Rodriguez Triple Junction, Central Indian Ridge 査読有り

    Gamo, T, Chiba, H, Yamanaka, T, Okudaira, T, Hashimoto, J , Tsuchida, S, Ishibashi, J, Kataoka, S, Tsunogai, U, Okamura, K, Sano, Y, Shinjo, R

    EARTH AND PLANETARY SCIENCE LETTERS   193 巻 ( 40972 ) 頁: 371-379   2001年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The chemical characteristics of hydrothermal fluids in the Indian Ocean have been revealed for the first time. A hydrothermal field (called the Kairei field), including active black smoker chimneys, was discovered by ROV Kaiko dives at 25 degrees 19.17'S, 70 degrees 02.40'E ( similar to 2450 to depth) on the southwestern flank of an off-axis knoll located similar to 15 miles north of the Rodriguez Triple Junction, Central Indian Ridge, after detailed tow-yo surveys of the hydrothermal plume distribution. The temperature of the fluid expelled from the most active chimney was almost stable (359-360 degreesC) throughout three successive days of fluid sampling. The endmember fluid has a chemical composition similar to the hydrothermal fluids sampled from sediment-starved mid-ocean ridges in the Pacific and the Atlantic oceans, suggesting typical interactions between hot fluid and mid-ocean ridge basalts in the subseafloor reaction zone.

    DOI: 10.1016/S0012-821X(01)00511-8

  149. Carbon isotopic distribution of methane in deep-sea hydrothermal plume, Myojin Knoll Caldera, Izu-Bonin arc: Implications for microbial methane oxidation in the oceans and applications to heat flux estimation 査読有り

    Tsunogai, U, Yoshida, N, Ishibashi, J, Gamo, T

    GEOCHIMICA ET COSMOCHIMICA ACTA   64 巻 ( 14 ) 頁: 2439-2452   2000年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The concentration and stable carbon isotopic composition; (delta13C) Of methane have been measured for both seafloor hydrothermal venting fluids and effluent plume waters supplied from the vents at the Myojin Knell Caldera, Izu-Bonin are, in the western North Pacific. The hydrothermal end-member concentrations and delta13C of methane show near-homogeneity among vents. 41.2 (mu mol/kg) and -16.3 +/- 0.8 (parts per thousand PDB), respectively, while those in the effluent plume are stratified m the caldera and vertically exhibit a large variation (2.1-11 (nmol/kg) and -29.0 to -11.3 ( %BDB), respectively). Comparison of concentration and delta13C data between vent fluids and plume waters suggest that the methane is not conserved but microbially oxidized along with the plume. Gradual decrease of diffusive methane flux in proportion to distance from the vent fields supports the occurrence of significant microbial oxidation within the plume. Assuming steady state emission of methane from the vents, (1) kinetic isotope effect due to the microbial oxidation (k(12)/k(13)); (2) methane flux from the vents (F-vents); (3) heat flux from the vents (Q); and (4) average turnover time of hydrothermal methane (T-all) are estimated to be k(12)/k(13) = 1.005 +/- 0.001, F-vents = 90-340 (mol/d), Q = 30-110 (MW), and T-all = 60 -240 (d), respectively. The estimated turnover times, however, are not uniform within the water column. Around the vents, a turnover time of less than 50 d for methane is one of the shortest values in the pelagic ocean, while those at the distant points correspond to values more typical for deep ocean water.

    DOI: 10.1016/S0016-7037(00)00374-4

  150. Stable carbon and oxygen isotopic analysis of carbon monoxide in natural waters 査読有り

    Tsunogai, U, Nakagawa, F, Hachisu, Y, Yoshida, N

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY   14 巻 ( 16 ) 頁: 1507-1512   2000年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Techniques have been developed to allow on-line simultaneous analysis of concentration and stable isotopic compositions (C-13 and O-18) of dissolved carbon monoxide (CO) in natural water, using continuous-flow isotope ratio mass spectrometry (CF-IRMS), The analytical system consisted sequentially of a He-sparging bottle of water, a gas dryer, CO2-trapping stage using both Ascarite trap and silica-gel packed gas chromatography (GC), on-line oxidation to CO2 using the Schutze reagent, cryofocusing, GC purification using a capillary column and measurement by CF-IRMS, Each sample analysis takes about 40 minutes. The detection limit with delta13C standard deviation of 0.5 parts per thousand is 300 pmol and that with delta(18)O deviation of 1.0 parts per thousand is 750 pmol. Analytical blanks associated with these methods are 21 +/- 9 pmol, The procedures are evaluated through analyses of temporally varying concentration and isotopic compositions of CO in an artificial lake on the university campus. The delta13C and delta(18)O values of CO showed wide variation in accordance with diurnal variation of CO concentration, probably due to significant isotopic effects during photochemical production and microbial oxidation of CO in the aquatic environment. The delta13C and delta(18)O values of CO should be a useful tool in studies of the mechanism and pathways of CO production and consumption in natural waters.

    DOI: 10.1002/1097-0231(20000830)14:16<1507::AID-RCM56>3.3.CO;2-5

  151. Carbon isotopic compositions of C2-C5 hydrocarbons and methyl chloride in urban, coastal, and maritime atmospheres over the western North Pacific 査読有り

    Tsunogai, U, Yoshida, N, Gamo, T

    JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES   104 巻 ( D13 ) 頁: 16033-16039   1999年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    C-2, - C-5, non-methane hydrocarbons (NMHCs) and methyl chloride in the remote maritime atmosphere over the western North Pacific are analyzed in regard to their variation of mixing ratio and C-13/C-12 ratio (delta13C), together with those in polluted urban (Nagoya and Yokohama) and coastal (Tokyo Bay) atmosphere in Japan. NMHCs show large atmospheric mixing ratio and reacts between urban (coastal) and maritime atmospheres probably due to emission from urban areas and degradation within the maritime atmosphere. Reflecting isotopic fractionation during the degradation within the maritime atmosphere, ethane shows large and systematic delta13C variation between urban (around -27 parts per thousand ethane Peedee belemnite (PDB)) and maritime atmosphere s (up to -22 parts per thousand PDB). Except for ethane, however, alkanes show small isotopic variation around delta13C = -27 +/- 2 parts per thousand PDB (lo) without systematic isotopic differences between urban and maritime atmospheres, suggesting br,th small delta13C: variation a ithin major emission sources and also little isotopic fractionation during atmospheric degradation for alkanes other than ethane. Alkenes show large delta13C variation from -37 to -12 parts per thousand PDB for ethylene and from -27 to -14 parts per thousand PDB for propylene. Combination of both large delta13C differences between major sources (especially between land and maritime sources) and large isotopic fractionation effect during atmospheric degradation call be suggested for alkenes. Methyl chloride also shows large isotopic variation from -44 to -30 parts per thousand PDB in spite of their similar atmospheric mixing ratios from 580 to 710 parts per trillion by volume (pptv), probably due to the contribution of highly C-13-depleted, anthropogenic methyl chloride especially to urban atmospheres, Thr general delta13C pattern of NMHCs and methyl chloride in polluted urban city air agrees s strongly with those of biomass (C-3 plant) burning plumes, suggesting that thermal breakdown of C-3 plant (or related organic matter) is one of the representative sources of these hydrocarbons in urban atmospheres. Further investigations of the isotopic signature of source materials as well as laboratory studies of isotopic fractionation processes resulting from atmospheric degradation will improve our understanding of the sources, sinks, and atmospheric distributious of NMHCs and methyl chloride.

    DOI: 10.1029/1999JD900217

  152. Carbon isotope measurement of extremely low amounts of CH4: Application to volcanic gases from Satsuma-Iwojima, Japan 査読有り

    Sato, M, Tsunogai, U, Ishibashi, J, Notsu, K, Wakita, H

    ANALYTICAL SCIENCES   15 巻 ( 6 ) 頁: 513-516   1999年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A preconcentration system attached to a GC/C/MS (gas chromatography/combustion/mass spectrometer) was developed to determine the carbon-isotope composition of methane in volcanic gases with extremely low concentration. With this system, we can analyze the carbon isotope ratio (C-13/C-12) of 0.7 - 6 nmol methane with a precision of +/-1.6 parts per thousand, unlike other conventional methods without preconcentration (150 - 1000 nmol CH4 with a precision of +/-0.2 parts per thousand). This system was tested with volcanic gas samples from Satsuma-Iwojima volcano, suggesting a mixture of magmatic and thermogenic origins for methane.

    DOI: 10.2116/analsci.15.513

  153. Origin of 13C-enriched methane in the crater lake Towada, Japan 査読有り

    Nishimura, R, Tsunogai, U, Ishibashi, J, Wakita, H, Nojiri, Y

    GEOCHEMICAL JOURNAL   33 巻 ( 4 ) 頁: 277-283   1999年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Concentration and stable carbon isotopic composition (delta13C) of CH4 are determined in a water column of an 327 m deep oxic oligotrophic crater lake, Lake Towada in Japan. The results of CTD measurements show relatively high temperature and high conductivity in the Lower part of the column, possibly derived from hot springs at the crater wall approximately 150 m deep. The vertical profile of CH4 concentration shows two sharp maxima of 68 and 69 nmol/kg at depths of 20 and 150 m, respectively, The delta13C value of CH4 at 20 m is -55 parts per thousand PDB, suggesting microbial production in and around the lake. In contrast, the delta13C value of CH4 at 150 m is +11 parts per thousand PDB, which suggests some secondary isotopic alternation processes peculiar to hot spring-derived CH4 in the oxic water column, such as rapid aerobic microbial oxidation.

  154. Methane-rich plumes in the Suruga Trough (Japan) and their carbon isotopic characterization 査読有り

    Tsunogai, U, Ishibashi, J, Wakita, H, Gamo, T

    EARTH AND PLANETARY SCIENCE LETTERS   160 巻 ( 40910 ) 頁: 97-105   1998年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The carbon isotopic compositions (delta13C(CH4)) Of the methane-rich buoyant plumes, observed in the oxygenated hemipelagic sea waters of the Suruga Trough, Japan, are discussed in relation to their sources. During a survey made in May 1996, two layers of anomalous methane-rich plumes, both of which centred at the same station about a few tens of kilometres off the coast, were found in the Suruga Trough. The deeper plume (ca. 2100 m depth, with a maximum methane concentration of 13 nmol/kg) had already been detected by a previous survey in 1986 at the same station, whereas the shallower plume (ca, 1000 m depth, with a maximum methane concentration of 10 nmol/kg) was newly discovered. The estimated end-member delta13C(CH4) value (-59 +/- 3 parts per thousand PDB) for the deeper plume suggests a microbial origin of the methane, probably derived from some shallow (surface) layer of sediment. The plume could be supplied from a continuous cold fluid seepage on the sea floor of the Suruga Trough. On the other hand, the shallower plume is characterized by more C-13-enriched end member methane (delta13C(CH4) = -38 +/- 2 parts per thousand PDB), presumably produced by the thermogenic degradation of organic matter. Since thermogenic methane should originate from a deeper part (more than 1000 m) of the sedimentary layer, it is unlikely that the thermogenic methane reaches the sea water by normal transport processes. The shallower plume may be a result of some sudden, catastrophic event on the sea floor, such as earthquakes.

    DOI: 10.1016/S0012-821X(98)00075-2

  155. Neutron activation analysis of deep sea sediments from the regions near Japan 査読有り

    Minai, Y, Tsunogai, U, Takahashi, H, Ishibashi, J, Matsumoto, R, Tominaga, T

    JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY   216 巻 ( 2 ) 頁: 265-277   1997年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Eighteen trace elements, including seven rare earth elements (REEs), and major and minor elements in the sediment samples from the Japan Sea and the northwestern Pacific near Japan were determined with instrumental neutron activation analysis (INAA). Most REE patterns (chondrite-normalized) of the sediments were nearly identical to the patterns of terrigenous materials without cerium anomaly whereas the La/Yb ratio varied with the site locations. The variation of the La/Yb ratio of the sediments may indicate the regional variation of the mixing proportion of the terrigenous materials from the continent to the materials from the volcanic island area including the Japanese islands. The Th/Sc ratio of the sediments tended to increase with distance from the island-arc volcanism. Regional variation of the Th/Sc ratio may indicate variation of amount of the continental terrigenous materials supplied to the sediments.

    DOI: 10.1007/BF02033789

  156. Discrete scaling in earthquake precursory phenomena: Evidence in the Kobe earthquake, Japan 査読有り

    Johansen, A, Sornette, D, Wakita, H, Tsunogai, U, Newman, WI , Saleur, H

    JOURNAL DE PHYSIQUE I   6 巻 ( 10 ) 頁: 1391-1402   1996年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We analyze the ion concentrations of groundwater issuing from deep wells located near the epicenter of the recent earthquake of magnitude 6.9 near Kobe, Japan, on January 17, 1995. These concentrations are well fitted by log-periodic modulations around a leading power law. The exponent (real and imaginary parts) is very close to those already found for the fits of precursory seismic activity for Loma Prieta and the Aleutian Islands. This brings further support for the general hypothesis that complex critical exponents are a general phenomenon in irreversible self-organizing systems and particularly in rupture and earthquake phenomena.

    DOI: 10.1051/jp1:1996143

  157. Fresh water seepage and pore water recycling on the seafloor: Sagami Trough subduction zone, Japan 査読有り

    Tsunogai, U, Ishibashi, J, Wakita, H, Gamo, T, Masuzawa, T , Nakatsuka, T, Nojiri, Y, Nakamura, T

    EARTH AND PLANETARY SCIENCE LETTERS   138 巻 ( 40912 ) 頁: 157-168   1996年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We collected 19 samples of bottom sea water (including 8 samples of shimmering fluid), using the Japanese submersible Shinkni 2000, in the bathyal Calyptogena community area (the Hatsushima area) along Sagami Trough, at the northern end of the Philippine Sea plate, in order to clarify the source of fluid seepage, Shimmering fluid samples showed a maximum temperature of 11.6 degrees C, which is about 9 degrees C higher than the ambient sea water. The fluid chemistry of these samples is summarized as follows: (1) alkalinity, H2S, SiO2, NH4, Sigma CO2 and CH4 show enrichment and Cl, SO4, K, Na, Mg and Ca show depletion compared with ambient sea water; (2) Cl depletion is about 20 %; and (3) the content and He-3/He-4 ratio of dissolved helium show little anomaly compared with ambient sea water. The observed chemical composition and temperature of the fluid is well explained by mixing of sea water, pore water and land-derived groundwater with a temperature of about 40 degrees C and a seeping flux of about 400 m(3) per day. A preliminary estimation of the global chemical flux implies that groundwater discharge to the ocean (including pore water recycling) is an important factor in controlling ocean chemistry.

    DOI: 10.1016/0012-821X(95)00228-5

  158. Anomalous changes in groundwater chemistry - Possible precursors of the 1995 Hyogo-ken Nanbu earthquake, Japan 査読有り

    Tsunogai, U and Wakita, H

    JOURNAL OF PHYSICS OF THE EARTH   44 巻 ( 4 ) 頁: 381-390   1996年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A post-earthquake investigation revealed statistically significant changes in the chemical composition of groundwater pumped from wells located about 20 km east of the epicenter within the aftershock region, preceding the disastrous M7.2 Hyogo-ken Nanbu earthquake in southwestern Japan on January 17, 1995. The chloride ion concentration had increased steadily after August 1994, compared to the constant level since July 1990, and reached an excess of about 10 % just before the earthquake. Groundwater sampled after the earthquake showed much higher Cl- concentrations. Together with the increase in Cl-, sulfate and alkaline earth metal ions (Mg2+, Ca2+, Sr2+, Ba2+) showed similar increases in their concentrations, while sodium ion and silica contents showed decreases. These changes may be the result of shallow groundwater inflow, enriched in chloride, sulfate and alkaline earth metal ions, to the artesian layer of the wells, due to permeability enhancement in the shallow stratum. The observed changes in groundwater chemistry before and after the earthquake are useful clues to understanding the mechanism of the present earthquake.

  159. Precursory chemical changes in ground water - Kobe Earthquake, Japan 査読有り

    Tsunogai, U. and Wakita, H.

    SCIENCE   269 巻 ( 5220 ) 頁: 61-63   1995年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Chloride (Cl-) and sulfate (SO42-) ion concentrations of ground water issuing from two wells located near the epicenter of the Kobe earthquake in Japan fluctuated before the disastrous magnitude 7.2 event on 17 January 1995. The samples measured were pumped ground water packed in bottles and distributed in the domestic market as drinking water from 1993 to April 1995. Analytical results demonstrate that Cl- and SO42- concentrations increased steadily from August 1994 to just before the earthquake. Water sampled after the earthquake showed much higher Cl- and SO42- concentrations. The precursory changes in chemical composition may reflect the preparation stage of a large earthquake.

    DOI: 10.1126/science.269.5220.61

  160. Peculiar features of Suiyo seamount hydrothermal fluids, Izu-Bonin arc: Differences from subaerial volcanism 査読有り

    Tsunogai, U, Ishibashi, J, Wakita, H, Gamo, T, Watanabe, K, Kajimura, T, Kanayama, S, Sakai, H

    EARTH AND PLANETARY SCIENCE LETTERS   126 巻 ( 4 ) 頁: 289-301   1994年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    This is the first report of the dissolved gas composition of a deep-sea venting hydrothermal system originating from are volcanism; the origin of dissolved gases in hydrothermal fluids from the Suiyo seamount in the southern Izu-Bonin (Ogasawara) Are is discussed on the basis of chemical and isotopic compositions. Twelve high-temperature (up to 310 degrees C) fluid samples were collected from three vents of the hydrothermal system using the submersible Shinkai 2000. The average He-3/He-4 ratio of the dissolved He is 8.1 (R/R(atm)), which is within the range of values reported for N-MORB. The CO2/He-3 ratio is 12 x 10(9), which is within the range of are volcanic gas values. The delta13C values of CO2 and CH4 are -1 and -8.5 parts per thousand respectively, which is quite high compared with other subaerial are volcanic gases and those from mid-ocean ridges. These results, which do not accord with those from subaerial volcanism, are unlikely to result from fractionation or addition of carbon sources during the fluid circulation, but are regarded as characteristic of the magma source of Suiyo Seamount. A simple mixing of 97 % MORB mantle with 3 % subducting slab explains well the composition of the helium and carbon in the parent magma.

    DOI: 10.1016/0012-821X(94)90113-9

▼全件表示

書籍等出版物 8

  1. 海洋底科学の基礎

    日本地質学会「海洋底科学の基礎」編集委員会( 担当: 分担執筆 ,  範囲: 10.4 間隙水の採取と分析)

    共立出版  2016年9月  ( ISBN:978-4-320-04729-7

     詳細を見る

    総ページ数:408   記述言語:日本語 著書種別:学術書

  2. 地球と宇宙の化学事典

    日本地球化学会 編( 担当: 共著)

    朝倉書店  2012年9月  ( ISBN:978-4-254-16057-4

     詳細を見る

    記述言語:日本語

  3. 生物学辞典

    石川 統ほか( 担当: 共著)

    東京化学同人  2010年12月  ( ISBN:9784807907359

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    記述言語:日本語

  4. 地球惑星科学入門

    在田一則ほか( 担当: 共著)

    北海道大学出版  2010年11月  ( ISBN:978-4-8329-8195-9

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    記述言語:日本語

  5. 地球の変動と生物進化

    沢田 健ほか( 担当: 共著)

    北海道大学出版  2008年3月  ( ISBN:978-4-8329-8184-3

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    記述言語:日本語

  6. 環境の地球化学

    蒲生俊敬ほか( 担当: 共著)

    倍風館  2007年1月 

     詳細を見る

    記述言語:日本語

  7. 実験化学講座第20-2巻「環境化学」

    日本化学会 編( 担当: 単著)

    丸善出版  2007年1月  ( ISBN:978-4-621-07806-8

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    記述言語:日本語

  8. 海と環境-海が変わると地球が変わる-

    日本海洋学会 編( 担当: 単著)

    講談社サイエンティフィック  2001年9月  ( ISBN:978-4-06-155212-8

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    記述言語:日本語

▼全件表示

講演・口頭発表等 44

  1. UAV搭載用火山プルーム採取装置の開発

    角皆 潤, 新宮原 諒, 伊藤昌稚, 中川書子, 吉川 慎, 宇津木 充, 横尾亮彦

    2020年度日本地球化学会第67回オンライン年会  日本地球化学会

     詳細を見る

    開催年月日: 2020年11月19日 - 2020年11月21日

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  2. 多段フィルターパック法を用いたガス状亜硝酸および二酸化窒素の三酸素同位体異常定量

    頼 鵬, 中川書子, 角皆 潤, 丁 とう, 野口 泉, 山口高志

    2020年度日本地球化学会第67回オンライン年会  日本地球化学会

     詳細を見る

    開催年月日: 2020年11月19日 - 2020年11月21日

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  3. 対流圏一酸化窒素の窒素及び三酸素同位体組成の定量

    平野一哉, 角皆 潤, 中川書子, 伊藤昌稚

    第25回大気化学討論会  2020年11月11日  日本大気化学会

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    開催年月日: 2020年11月11日 - 2020年11月13日

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:オンライン   国名:日本国  

  4. 火山噴煙中の水蒸気の同位体組成定量

    角皆 潤 , 伊藤 昌稚 , 新宮原 諒 , 中川 書子 , 高橋 幸士 , 横尾 亮彦

    日本火山学会  2020年10月8日  日本火山学会

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    開催年月日: 2020年10月8日 - 2020年10月10日

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  5. えびの高原硫黄山火山ガス組成と2018年水蒸気噴火の関係

    大場 武, 谷口 無我, 角皆 潤, 伊藤 昌稚, 新宮原 諒

    日本火山学会  2020年10月8日  日本火山学会

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    開催年月日: 2020年10月8日 - 2020年10月10日

    記述言語:日本語   会議種別:口頭発表(一般)  

    国名:日本国  

  6. Variation in the chemical and isotopic composition of fumarolic gas at Taal volcano, Philippine prior to the 2020 eruption 国際会議

    JpGU-AGU Joint Meeting 2020, Virtual 

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    開催年月日: 2020年7月12日 - 2020年7月15日

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:日本国  

  7. 現場環境下における都市河川中の脱窒・同化・硝化速度定量法開発 国際会議

    中川 書子, 鈴木 謙介, 伊藤 昌稚, 角皆 潤

    日本地球惑星科学連合

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    開催年月日: 2020年7月12日 - 2020年7月15日

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:日本国  

  8. 安定同位体組成を指標に用いた伊勢湾における過飽和メタンの起源および挙動解明 国際会議

    蘭 慧, 角皆 潤, 中川 書子, 伊藤 昌稚, 三好 友子, 原 修一

    日本地球惑星科学連合

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    開催年月日: 2020年7月12日 - 2020年7月15日

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:日本国  

  9. UAV搭載用火山プルーム自動採取装置の開発と阿蘇中岳の噴気温度遠隔測定への応用 国際会議

    角皆 潤, 新宮原 諒, 伊藤 昌稚, 中川 書子, 吉川 慎, 宇津木 充, 横尾 亮彦

    日本地球惑星科学連合

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    開催年月日: 2020年7月12日 - 2020年7月15日

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:日本国  

  10. 南部沖縄トラフ多良間海丘で発見された高温熱水活動域の熱水チムニーの鉱物組成と熱水の地球化学的研究 国際会議

    山中 寿朗, 横田 瑛里, 岡村 慶, 野口 拓郎, 土岐 知弘, 角皆 潤, 大西 雄二, 牧田 寛子

    日本地球惑星科学連合

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    開催年月日: 2020年7月12日 - 2020年7月15日

    記述言語:英語   会議種別:口頭発表(一般)  

    国名:日本国  

  11. 現場環境下における河川硝酸除去速度の時間変化定量法開発

    鈴木 謙介, 角皆 潤, 中川 書子, 伊藤 昌稚

    日本地球化学会年会要旨集 

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    開催年月日: 2019年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>生態系に対する人間活動の影響を正しく評価し、対策を講じていく上で、河川環境下における硝酸除去速度や硝化速度を正確に定量化する必要がある。従来の河川硝酸除去速度の定量は培養実験による推定が主であったが、現場環境を再現するのは難しいという問題があった。また、河川水中の硝酸のΔ<sup>17</sup>O (=δ<sup>17</sup>O-0.52×δ<sup>18</sup>O) から算出した大気硝酸濃度の空間変化観測による現場環境下における定量法もあるが、同化・脱窒速度を区別して評価することができず、またそれらの時間変化も定量できなかった。そこで本研究では、対象となる河川区間の前後における大気硝酸濃度変化だけに着目し、これを夜間も含めた24時間連続で観測することで、同化・脱窒速度の時間変化の定量ができると考え、これに挑戦した。その結果、硝酸除去速度は夏に活発化し、冬に不活発にとなることが明らかになった。</p>

    CiNii Article

  12. 水環境中の溶存無機態リン酸の三酸素同位体組成定量

    三歩一 孝, 角皆 潤, 中川 書子, 伊藤 昌稚

    日本地球化学会年会要旨集 

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    開催年月日: 2019年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>水環境中の溶存無機態リン酸(以下リン酸)は、一次生産(光合成)を律速する重要な物質である。また、人為的なリン酸の局在化は、生態系の破壊につながる危険性がある。そのため、環境変化の現状把握や予測、修復を実現する上で水環境中のリン酸濃度の規定要因や循環機構を理解することが重要である。従来の研究では、水環境中の主要リン酸負荷源を推定するため、リン酸の酸素安定同位体比(d18O(PO4))が指標として活用されてきた。しかし、実際の水環境中では、様々なリン酸負荷源が存在するため、d18O(PO4)のみを指標に用いて各負荷源の混合割合まで推定することは困難となることが多い。そこで本研究では、三酸素同位体異常(D17O≒d17O – 0.528•d18O)を負荷源推定の新指標として追加で活用することで上述の課題を克服できないか検討した。これまでに溶存無機態リン酸のD17O値の報告例はなく、本研究が初の試みである。</p>

    CiNii Article

  13. 炭素および水素の安定同位体比を複合的に指標に用いた酸化的水柱に溶存するメタンの起源および挙動解明

    角皆 潤, 三好 友子, 松下 俊之, 伊藤 昌稚, 小松 大祐, 鋤柄 千穂, 中川 書子

    日本地球化学会年会要旨集 

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    開催年月日: 2019年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>大気中のメタンは代表的な温室効果気体であるが、その発生源・供給源や挙動には未解明の点も多い。本研究では、琵琶湖水中に過飽和となっているメタンの起源を特定し、さらに酸化分解を中心とした水柱内でのメタンの挙動を把握することを目的に、2013年以降水柱中の溶存メタンの安定同位体比(炭素および水素安定同位体比)を継続的に観測した。水柱の溶存メタンの炭素および水素安定同位体比から、水柱で進行した酸化分解を補正し、その起源のみを反映していると考えられる新指標の値を算出し、水柱の溶存メタンの主要供給源となっている可能性のある複数のメタンと、その値を比較した。その結果、琵琶湖表層で過飽和となっているメタンは琵琶湖の沿岸域 (littoral zone) からの流入によって供給されている可能性が高いと結論した。これは炭素安定同位体比のみを指標に用いて得られた先行研究の知見とも一致した。</p>

    CiNii Article

  14. 大気硝酸添加培養法に基づく都市河川における河床窒素循環速度の季節変化定量

    中川 書子, 山本 雄大, 池上 文香, 角皆 潤

    日本地球化学会年会要旨集 

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    開催年月日: 2019年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>河川における硝酸は, その下流域や流出先の水圏生態系の一次生産や生物量を律速する重要物質であり、その濃度変化を正しく評価するためには各硝酸生成および除去過程における速度をそれぞれ定量する必要がある。本研究では, 人工的に大気硝酸を添加した河川水とともに, 河床堆積物を閉鎖系において培養し, その間の河川水中の大気硝酸と再生硝酸の時間変化を定量化することで系内における硝化および同化,・脱窒速度の定量を試みた。観測は愛知県内の都市河川である天白川で行い, そこにおける各窒素循環速度とその季節変化の定量に挑戦した。</p>

    CiNii Article

  15. <sup>15</sup>Nアンモニア添加培養に基づく水柱の硝化速度定量

    水野 宏香, 角皆 潤, 中川 書子, 伊藤 昌稚

    日本地球化学会年会要旨集 

     詳細を見る

    開催年月日: 2019年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>水環境中の窒素は一次生産に必須の栄養塩であり、その多くは硝酸の形で存在している。この硝酸の大部分は水環境下でアンモニアから硝化反応によって形成される。各水環境中の硝化速度の絶対値やその制御因子解明は、一次生産量の理解にとって不可欠である。本研究では、窒素の微量安定同位体である<sup>15</sup>Nを人工的に濃縮したアンモニアを水試料に添加し、培養期間中の硝化反応に伴う硝酸の濃度と<sup>15</sup>N/<sup>14</sup>N比の時間変化から、硝化速度を定量する手法を確立した。本手法の検証を琵琶湖で行った結果、水柱の硝化速度は0.6~146 nmolN/L/dayと見積もられ、浅い層で遅く、深度と共に速くなることが分かった。この結果は、各深度を沈降する新鮮な有機体粒子の量を反映したものと考えられる。</p>

    CiNii Article

  16. フィリピン・タール山の火山ガス

    大場 武, 角皆 潤, 伊藤 昌稚, 新宮原 諒, 谷口 無我, 沼波 望, 笹井 洋一, C.L. Barairo, P. Alanis, M.A. Bornas, 楠本 成寿, 長尾 年恭

    日本火山学会講演予稿集 

     詳細を見る

    開催年月日: 2019年

    記述言語:日本語   会議種別:口頭発表(一般)  

    CiNii Article

  17. 南部沖縄トラフ多良間海丘で発見された高温熱水活動域で採取された熱水チムニーの鉱物組成と熱水の地球化学

    横田 瑛里, 山中 寿朗, 岡村 慶, 野口 拓郎, 土岐 知弘, 角皆 潤, 大西 雄二, 牧田 寛子

    日本地球化学会年会要旨集 

     詳細を見る

    開催年月日: 2019年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>沖縄トラフ南部、多良間島の北約60kmの海底に位置する多良間海丘で、2017年8月、調査船「よこすか」によるYK17-17研究航海において有人潜水艇「しんかい6500」の潜航調査により、300℃を超える高温の熱水噴出孔が水深1,840m付近の海底についに発見され、YZサイトと名付けられた。この海丘では2009年に実施された潜航調査により山頂付近から周囲の海水温度に比べ約20℃高い熱水の湧出が確認され、その湧水と関連すると考えられる鉄酸化物を主体とした堆積物が認められていたが(Foxサイト)、高温熱水の噴出は確認されていなかった。この海丘は南部沖縄トラフの主たるrifting zoneである八重山海底地溝のやや南に位置し、西表島北北東海底火山にあたる石垣海丘群に東側延長にあたる島弧火山列の一つと推定される。2017年の潜航調査では、両サイトから、熱水、チムニーなどの採取が行われた。本発表では得られたチムニー試料の鉱物組成や元素組成と、熱水の地球化学的特徴について報告する。</p>

    CiNii Article

  18. 貧栄養海域における溶存硝酸の三酸素同位体組成定量への挑戦

    Peng Weiqing, 松本 佳海, 鋤柄 千穂, 伊藤 昌稚, 中川 書子, 角皆 潤

    日本地球化学会年会要旨集 

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    開催年月日: 2018年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>本研究では、貧栄養海域の表層海水中に低濃度で溶存する硝酸の三酸素同位体組成を定量することに挑戦した。2種類の異なるD17O値をもつ内標準物質を用意し、添加後の海水試料中の硝酸濃度が500-800 nmol/Lおよび1000-2500 nmol/Lの範囲に入るようにし、それぞれのD17O値を測定した。硝酸のD17O値と濃度の逆数との関係式を使って海水試料中の硝酸濃度とそのD17O値を算出した。本手法で、溶存硝酸濃度が0.05-0.5 µmol/Lの海水試料については、D17O値を定量することができることを検証した。本研究で用いた日本海及び西部北太平洋おける表層海水中の硝酸のD17O値はそれぞれ+7‰程度、+5‰程度であった。これは、それぞれ19-33%、15-20%が大気由来の硝酸であることを意味する。</p>

    CiNii Article

  19. 河床堆積物に対する硝酸の添加培養に基づく河川環境下における硝化速度定量

    山本 雄大, 角皆 潤, 池上 文香, 中川 書子

    日本地球化学会年会要旨集 

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    開催年月日: 2018年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>河川水中の硝酸濃度は, 流域や下流域(湖沼・沿岸域)の一次生産を左右する。河川環境に対する人為的な硝酸流入の影響の評価・対策を行う上で, 河川内の供給である硝化速度を把握する必要があるが, 河床は不均一系であり, さらに供給(硝化)と除去(脱窒・同化)が共存するため, 硝化速度の個別定量は難しいとされてきた。大気沈着由来の硝酸(大気硝酸)のみにみられる三酸素同位体異常は, 硝酸除去過程で値が変化しない。これを指標とすると, 大気硝酸と硝化由来の硝酸の混合比が定量でき, 全硝酸濃度とあわせて, 河川水中の硝化速度が定量化できる。本研究では, 愛知県東部の天白川において河床堆積物を採取し, 人為的に大気硝酸を添加した河川水を加えて疑似現場環境下で培養実験を行い, 全硝酸と大気硝酸の各濃度の時間変化を定量することで, 河床における硝化速度の日変化・季節変化を定量化した。</p>

    CiNii Article

  20. 火山性流体中の水同位体組成に発見された負の三酸素同位体異常とその起源

    角皆 潤, 倉 和臣, 中川 書子, 大場 武, 篠原 宏志

    日本地球化学会年会要旨集 

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    開催年月日: 2018年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>水(H<sub>2</sub>O)の安定同位体比は、D/<sup>1</sup>H比と<sup>18</sup>O/<sup>16</sup>O比以外に<sup>17</sup>O/<sup>16</sup>O比が存在する。火山ガス中の水蒸気や火山性温泉水などの火山性流体について、その起源や、地殻内部における挙動を明らかにすることを目的に、世界で初めて<sup>17</sup>O-excess値の高精度測定を行った。測定の結果、温泉水試料では、天水より有意に低い<sup>17</sup>O-excess値を示す試料が多数見つかった。</p>

    CiNii Article

  21. 硝酸の三酸素同位体異常を指標に用いた水-堆積物インターフェースにおける脱窒速度定量

    佐野 陽子, 角皆 潤, 池上 文香, 中川 書子

    日本地球化学会年会要旨集 

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    開催年月日: 2018年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>脱窒は一次生産や富栄養化、温室効果気体の生成に関連しており、極めて重要な物質循環プロセスである。このため、脱窒速度は堆積物コア直上の水の硝酸濃度の減少速度をもとに推定されてきた。しかし、脱窒は硝化と同時に進行する可能性があり、従来法では脱窒速度が過小評価される危険性があった。最近になって、脱窒過程で値が変化しない三酸素同位体異常 (D17O値) を指標として用いることで大気沈着由来の大気硝酸と硝化由来の再生硝酸との混合比が定量できるようになった。そこで本研究では諏訪湖をフィールドとして、大気硝酸を堆積物直上水に人為的に添加し、この直上水中の大気硝酸と再生硝酸の濃度変化を観測することで、脱窒速度を求めた。</p>

    CiNii Article

  22. 自然同位体組成を指標に用いた植物中の硝酸同化過程解析

    中川 書子, 小幡 祐介, 伊藤 昌稚, 角皆 潤

    日本地球化学会年会要旨集 

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    開催年月日: 2018年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>本研究では、自然環境下で生育した植物試料(メタセコイアなどの針葉樹、アラカシなどの広葉樹を含む木本類、ササを含む草本類の葉)から抽出した硝酸の自然同位体組成を指標として用いることで、植物体内における窒素酸化物の代謝および硝酸同化過程を明らかにすることに挑戦した。硝酸還元酵素をほとんど含まないツツジ科の植物は三酸素同位体組成とd<sup>18</sup>O値間に明瞭な正相関が見られた。ツツジ科以外の植物は、ツツジ科が示す直線関係よりも高いd<sup>18</sup>O値を示した。これは硝酸の同化に伴う同位体分別効果によってd<sup>18</sup>O値が高くなったと考えられ、硝酸が窒素源として利用されたことを意味している。</p>

    CiNii Article

  23. 水圏環境下における高感度酸素消費速度定量法開発

    柏木 章吾, 角皆 潤, 伊藤 昌稚, 中川 書子, 鋤柄 千穂

    日本地球化学会年会要旨集 

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    開催年月日: 2018年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>水中の溶存酸素濃度は水質を規定する主要因子であり、溶存酸素の不足は水質の劣化や生物の大量死、青潮等の環境問題に直結する。従って、様々な水圏環境下における溶存酸素の消費速度やその制御因子を明らかにすることは重要である。水試料中の溶存酸素消費速度は、従来は、閉鎖環境下における一定時間の培養に伴う各水試料の酸素濃度の変化を定量することで測定されてきた。しかし、有光環境の試料では、酸素の生成反応である光合成が同時進行する可能性があり、このため光を遮断するなど現場とは環境を変えて培養する必要があった。また、感度が低く、応用範囲が限られていた。本研究では酸素の微量安定同位体である<sup>17</sup>Oを人工トレーサーとして利用することで、高感度かつ有光条件下でも応用可能な新手法を開発した。この方法を用いて、海洋 湖沼、地下水において酸素消費速度を実測し、各フィールド間でその大きさを比較し、制御因子を考察した。</p>

    CiNii Article

  24. 自然界の三酸素同位体異常を指標に用いた河川・湖沼の窒素循環定量化 招待有り

    角皆 潤, 中川 書子

    第31回東海陸水談話会 

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    開催年月日: 2017年10月30日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地: 愛知工業大学本山キャンパス2階多目的室   国名:日本国  

  25. 自然界の三酸素同位体異常を指標に用いた河川・湖沼の窒素循環定量化 招待有り

    角皆 潤, 中川 書子

    第31回東海陸水談話会 

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    開催年月日: 2017年10月30日

    記述言語:日本語   会議種別:口頭発表(一般)  

    開催地:愛知工業大学本山キャンパス2階多目的室  

  26. 軽元素安定同位体比の高感度分析に基づく地球環境科学研究の新展開

    角皆 潤

    日本地球化学会第64回年会 

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    開催年月日: 2017年9月13日 - 2017年9月15日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:東京工業大学大岡山キャンパス   国名:日本国  

    学会賞受賞記念講演

  27. 海洋学における軽元素安定同位体地球化学の新展開

    角皆 潤, 伊藤 昌稚, 鋤柄 千穂, 小松 大祐, 中川 書子

    日本地球化学会第64回年会 

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    開催年月日: 2017年9月13日 - 2017年9月15日

    記述言語:日本語   会議種別:口頭発表(基調)  

    開催地:東京工業大学大岡山キャンパス   国名:日本国  

  28. 海洋学における軽元素安定同位体地球化学の新展開 国際会議

    角皆 潤, 伊藤 昌稚, 鋤柄 千穂, 小松 大祐, 中川 書子

    日本地球化学会第64回年会  2017年9月13日  日本地球化学会

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    開催年月日: 2017年9月13日

    記述言語:日本語   会議種別:口頭発表(基調)  

    開催地:東京工業大学大岡山キャンパス  

  29. あいち森と緑づくり税は地球温暖化防止に役に立っているのか? 招待有り

    角皆 潤

    サロン・ド・Arimoto 講演会 

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    開催年月日: 2017年6月27日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:うなぎ有本   国名:日本国  

  30. 酸素の微量同位体トレーサーを用いた水柱中の酸素消費速度定量法開発

    柏木 章吾, 角皆 潤, 伊藤 昌稚, 鋤柄 千穂, 中川 書子

    日本地球化学会年会要旨集 

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    開催年月日: 2017年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>近年多くの沿岸海域の底層で、貧酸素水塊の発生が報告されている。海洋底層においては、水柱中を沈降する有機物粒子の酸化に伴う消費と、海底堆積物表面における消費の二種類の酸素消費が進行する。このどちらがより貧酸素水塊の形成に寄与しているのかを明らかにすることは、貧酸素水塊の形成過程や対策等を考える上で重要である。水柱中の酸素消費反応は、有機物が酸素により酸化分解され、二酸化炭素と水が生成する反応であるため、酸素原子の一部を<sup>17</sup>Oに置換したO<sub>2</sub>を水試料に添加し、生成する水の同位体比の時間変化を測定することで、酸素消費速度を見積もることが出来ると考えられる。そこで本研究では、底層における著しい貧酸素化が報告されている伊勢湾をフィールドに、この新手法を用いて水柱中の酸素消費速度を実測し、伊勢湾における貧酸素水塊の形成過程を考察した。</p>

    CiNii Article

  31. 溶存酸素の三酸素同位体組成を指標に用いた琵琶湖水中の鉛直輸送解析

    伊藤 昌稚, 角皆 潤, 中川 書子, 鋤柄 千穂

    日本地球化学会年会要旨集 

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    開催年月日: 2017年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>本研究では、近年深水層で低酸素化の傾向が見られる琵琶湖北湖観測点において、年間を通じてどのように湖内水中へ溶存酸素が供給されているかの季節変化を定量的に明らかにすることを主目的に、酸素とアルゴンの比の変化が大きい水環境においても十分な精度を得ることが可能な自動分析システム(水試料から抽出した溶存ガスから酸素のみを自動的に分離・精製する)を構築し、琵琶湖北湖について、その濃度と三酸素同位体組成を含めた酸素安定同位体組成を、季節変化を含めて一年間に渡って調べた。</p>

    CiNii Article

  32. 火山性流体中の水同位体組成に発見された負の三酸素同位体異常とその原因

    倉 和臣, 角皆 潤, 中川 書子, 大場 武, 篠原 宏志

    日本火山学会講演予稿集 

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    開催年月日: 2017年

    記述言語:日本語   会議種別:口頭発表(一般)  

    CiNii Article

  33. 炭素および水素の安定同位体比を指標に用いた酸化的水圏環境下における過飽和メタンの起源および挙動解明

    三好 友子, 角皆 潤, 中川 書子, 鋤柄 千穂, 伊藤 昌稚, 松下 俊之, 小松 大祐

    日本地球化学会年会要旨集 

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    開催年月日: 2017年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>先行研究により、本来メタン分解が促進される酸化的な海洋や湖沼水中において、メタンが大気平衡に対して過飽和に溶存するmethane paradoxと呼ばれる現象が多数報告されているが、その原因は未だ解明されていない。本研究では酸化的な水圏環境下で過飽和化しているメタンの起源を特定するため、琵琶湖と伊勢湾・三河湾をフィールドとして、水柱中の溶存メタンの安定同位体比(δ<sup>13</sup>CとδD)を同時に指標に用いることでメタンの起源と水圏環境における挙動を解明することに挑戦した。具体的には、過飽和をもたらすメタンの起源として、河川からの流入、湖底堆積物からの供給、沈降粒子から供給、の3つの可能性を考え、それぞれについて同位体比を定量化し、水柱のメタンと比較した。またメタンの酸化の進行を補正したΔ(2,13)(=δD-11×δ<sup>13</sup>C)を新しく定義し、起源推定において活用した。</p>

    CiNii Article

  34. 硝酸の三酸素同位体組成を利用した河川水中の窒素循環速度測定

    池上 文香, 角皆 潤, 小幡 祐介, 安藤 健太, 中川 書子

    日本地球化学会年会要旨集 

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    開催年月日: 2017年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>河川水中の硝酸の濃度は、下流の湖沼や沿岸海域の一次生産や生態系構造に直接的に影響を与えるため、流域内のどのような過程に支配され、変化するのかについて知見を深める必要がある。近年では水環境中の硝酸の窒素・酸素安定同位体組成の高感度分析法が確立し、指標として利用できるようになった。特に、同化や脱窒過程で値が変化しない三酸素同位体異常は有用で、これを定量化することで、大気沈着由来の硝酸(大気硝酸)と硝化によって生成する硝酸(再生硝酸)の混合比を正確に定量出来るようになった。さらに、大気硝酸の混合比と全硝酸の濃度から、大気硝酸の絶対濃度を求められるようになった。本研究では、流下に伴う大気硝酸の絶対濃度の変化が、河川水中の硝化速度などの窒素循環速度の指標として利用できる可能性があると考えた。そこで、野洲川を対象に、流下に伴う全硝酸と大気硝酸の濃度変化を求め、河川水中の窒素循環の定量化に挑戦した。</p>

    CiNii Article

  35. 対流圏HONOの三酸素同位体組成の日変化とその起源

    丁 懂, 中川 書子, 角皆 潤, 野口 泉, 山口 高志

    日本地球化学会年会要旨集 

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    開催年月日: 2017年

    記述言語:日本語   会議種別:口頭発表(一般)  

    <p>亜硝酸ガス(HONO)は光分解反応によりOHラジカルを放出するため、大気中の重要な微量成分である。しかし、都市大気中のHONO起源は未だに明らかにはなっておらず、その濃度の日週変化のメカニズムについても、未だに議論がある。本研究は、北海道立総合研究機構環境科学センター(札幌市)の屋上で、2017年4月3日の16:00から4月10日16:00まで、時間帯を6つに区分してHONOを捕集し、その三酸素同位体組成(Δ<sup>17</sup>O) を定量した。「直接排出」のHONOは光化学反応過程を経由しないため、Δ<sup>17</sup>O値は0‰と考えられるが、「二次生成」由来のHONOは大きなΔ<sup>17</sup>O値を持つNO<sub>2</sub>を経由するため、大きなΔ<sup>17</sup>O値を示すはずである。そこで、Δ<sup>17</sup>O値を指標に用いて、都市大気中のHONO濃度の日週変化の原因を考察した。</p>

    CiNii Article

  36. 北極海カナダ海盆における溶存メタン分布に対する暖水渦の影響

    BUI THI NGOC OANH, 亀山 宗彦, 川口 悠介, 笹野 大輔, 石井 雅男, 西野 茂人, 小杉 如央, 角皆 潤, 吉川 久幸

    日本地球化学会年会要旨集 

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    開催年月日: 2017年

    記述言語:英語   会議種別:口頭発表(一般)  

    <p>北極海は地球温暖化に対して最も鋭敏に応答する海域であるといわれている。メタンは温室効果をはじめとした大気環境に影響を及ぼす気体成分であり、北極域はメタンの大きなソースであることが指摘されていながら北極海での観測は十分になされていない。本研究では2015年に海洋研究開発機構の「みらい」MR15-03航海でカナダ海盆における詳細な溶存メタン分布を明らかにした。この溶存メタンの分布と海洋の暖水渦や生物学的パラメーターとの関係性について検討を行った。</p>

    CiNii Article

  37. 同位体分別を利用した地球環境科学の基礎と応用

    角皆 潤

    第9回日本地球化学会ショートコース 

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    開催年月日: 2014年9月15日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:富山大学, 2014年9月15日.   国名:日本国  

  38. 栄養塩の生成量や消費量を測る:その意義と新手法への挑戦

    角皆 潤

    大津臨湖実験所開所100 周年記念事業「京都大学の琵琶湖研究100年と今後の多様な共同研究のために」 

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    開催年月日: 2014年7月26日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:コラボしが21   国名:日本国  

  39. 試料前処理

    角皆潤, 中川書子, 小松大祐

    2012年質量分析学会同位体比部会プレゼミ「Nuts and Bolt of Inorganic Mass Spectrometry」 

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    開催年月日: 2012年11月21日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:仙台秋保温泉佐勘   国名:日本国  

  40. Quantifying nitrate dynamics in hydrosphere using the triple oxygen isotopes as tracers 国際会議

    Tsunogai, U., Komatsu, D. D., Nakagawa, F.

    Utilizing Rare isotopE for biogeochemistrY (UREY) Workshop 

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    開催年月日: 2012年10月2日 - 2012年10月3日

    記述言語:英語   会議種別:口頭発表(招待・特別)  

    国名:台湾  

  41. Breakthrough in Isotope-Ratio Mass Spectrometry 国際会議

    Tsunogai, U., D.D. Komatsu, and F. Nakagawa

    Pre-seminar 2011 in Busan, Meeting on Isotope-ratio mass spectrometry, The Mass Spectrometry Society of Japan 

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    開催年月日: 2011年11月23日 - 2011年11月25日

    記述言語:英語   会議種別:口頭発表(招待・特別)  

    国名:大韓民国  

  42. 硝酸の三酸素同位体組成を指標に用いた水環境中の窒素循環の定量化:非培養・現場型の窒素同化速度定量法開発

    角皆潤, 小松大祐, 中川書子

    日本地球惑星科学連合2011年大会 

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    開催年月日: 2011年5月22日 - 2011年5月27日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:幕張メッセ国際会議場   国名:日本国  

  43. Tracing the fate of atmospheric nitrate deposited onto a forest ecosystem in eastern Asia using triple oxygen isotopes 国際会議

    Tsunogai, U., D.D. Komatsu, S. Daita, G.A. Kazemi, F. Nakagawa, I. Noguchi, and J. Zhang

    European Geosciences Union General Assembly 2010 

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    開催年月日: 2010年5月2日 - 2010年5月7日

    記述言語:英語   会議種別:口頭発表(招待・特別)  

    国名:日本国  

  44. 溶存硝酸の三酸素同位体組成をトレーサーに用いた地下水中の窒素循環解析

    角皆 潤・小松 大祐・代田 里子・中川 書子・張 勁

    日本地球惑星科学連合2009年大会 

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    開催年月日: 2009年5月16日 - 2009年5月21日

    記述言語:日本語   会議種別:口頭発表(招待・特別)  

    開催地:幕張メッセ国際会議場   国名:日本国  

▼全件表示

共同研究・競争的資金等の研究課題 2

  1. 同位体組成を指標に用いた硝酸の高精度起源推定法開発

    2006年04月 - 2008年03月

    地球環境研究総合推進費(地球環境研究革新型研究課題) 

      詳細を見る

    資金種別:競争的資金

  2. 海底熱水系における生物・地質相互作用の解明に関する国際共同研究

    2000年04月 - 2005年03月

    特色ある大学教育支援プログラム 

      詳細を見る

    資金種別:競争的資金

科研費 13

  1. 極微量酸素同位体をトレーサーに用いた水試料中の呼吸速度定量法開発

    研究課題/研究課題番号:19K22908  2019年06月 - 2021年03月

    独立行政法人日本学術振興会  科学研究費補助金  挑戦的研究(萌芽)

    角皆 潤

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:6240000円 ( 直接経費:4800000円 、 間接経費:1440000円 )

    本研究は、極微量安定同位体である質量数17の酸素原子を標識トレーサーに用いた、高感度かつ高確度、そして簡便な水試料中の呼吸速度定量法を開発することを目的とする。具体的には、質量数17の酸素原子を濃縮した酸素ガスを水試料に添加して培養し、その間に進行した呼吸反応が引き起こす、水の酸素同位体比変化を超高精度で定量化することで、呼吸速度を求める。また伊勢湾で観測を行い、同湾における貧酸素水発生の主要因を明らかにするとともに、その大きさを規定する主要環境因子を考察する。また、光環境の影響を無視して定量化する従来法の問題点について考察する。
    本研究は、酸素の極微量安定同位体である質量数17の酸素原子(17-O)を標識 (トレーサー) に用いた、高感度かつ高確度、そして簡便な水試料中の呼吸速度定量法を開発する。具体的には、17-Oを濃縮した酸素分子(17-O2)を密閉容器中の水試料に添加し、一定の培養期間中に進行する呼吸で増大するH水分子中の17-O量を高精度に定量化することで、呼吸速度を求める。
    本年度は、以下の5項目について研究を行った。①17-O2準備: 17-O純度50%の水を購入するとともに、内容積1 mL程度の小型の電解分解セルを自作し、この中で水電気分解することで17-O2を作成し、容器中に保存した。②添加法開発:市販のガスタイトシリンジと分注器を組み合わせ、高い再現性を示すガス分注器を製作した。また17-O2添加量の絶対値を、以下の方法で正確に見積もった。(1) 自然同位体組成の純酸素ガスを内容積既知の容器中に用意する、(2) ここに各試料に対して添加する場合と同様に17-O2を添加した、(3) 添加前後の純酸素ガスの17-O/16-O 比の微小変化を自然同位体比専用の気体質量分析計を用いて高精度定量し、これを元に17-O2添加量を算出した。③培養容器の選定とブランク量等の評価:超純水を試料として、多種の容器やゴム栓の組み合わせの中から、ブランクH217O量を最も低く抑えることの出来る容器を選定した。また、ブランクH217O量の絶対値や、その再現性から、本手法の定量下限や測定精度を見積もった。④大学構内のため池の水を使って、従来法との比較実験を行い、新手法の精度や確度を検証した。⑤伊勢湾 (最大水深38 m) で、2019年9月に試験観測を実施し、良好な結果を得た。また成果を2019年度に国内の学会で報告した。
    分析法開発に目処が立った。国内学会における発表を完了し、論文投稿段階に移行した。また当初計画の無かった日本海でも、観測を実行した(現在分析中)。
    夏季に大規模な貧酸素水が湾内の海底面上に発生することが知られている伊勢湾 (最大水深38 m) で、2020年9月に観測を実施する。具体的には、呼吸速度を水柱各深度と海底面上のそれぞれで実測し、貧酸素水発生の主要因がどちらにあるか明らかにするとともに、それぞれの大きさを規定する環境因子を考察する。また、有光環境下で採取した試料について、現場と同じ有光環境下の培養以外に、無光環境下でも同時に培養して得られた呼吸速度を比較し、光環境の影響を無視する暗瓶法に問題が無いか検証する。観測は三重大学の練習船「勢水丸」を用いる。

  2. 硝酸の三酸素同位体異常を利用した非培養型の窒素循環速度定量法確立

    研究課題/研究課題番号:17H00780  2017年04月 - 2021年03月

    独立行政法人日本学術振興会  科学研究費補助金  基盤研究(A)

    角皆 潤

      詳細を見る

    担当区分:研究代表者  資金種別:競争的資金

    配分額:42380000円 ( 直接経費:32600000円 、 間接経費:9780000円 )

    湖沼に溶存する硝酸の三酸素同位体異常(地球表層圏の平均的な酸素原子存在度と、一般的な酸素同位体分別を仮定した時に期待される質量数17の酸素原子存在度に対する、実際の質量数17の酸素原子存在度の過剰量)は、その湖沼に対して大気からの沈着を経て供給される硝酸と、湖沼内部で進行する硝化反応を経て供給される硝酸の、供給速度比を反映する。本研究では、この硝酸の三酸素同位体異常の特徴を利用して、対象とする湖沼系内で進行する窒素循環の速度(硝化速度や硝酸同化速度)を、簡便かつ高確度に定量する新手法を確立する。また従来法である培養法に基づく窒素循環速度も同時に観測して比較し、新手法の信頼性(確度)を評価する。本提案の新手法が確立されることで、窒素循環速度の観測が広く一般化・普遍化することが期待できる。
    本年度は、琵琶湖における観測を継続的に実施して、湖水中の硝酸の平均的な三酸素同位体異常と湖内で進行する年平均の窒素循環速度(総硝化速度や総硝酸同化速度)を、その時間変化を含めて定量化した。さらに本年度は海洋域に本手法を世界で初めて応用することに挑戦した。具体的には、新青丸(全国共同利用)を用いて、2019年6月と10月の二回に渡って日本海の計5点において、硝酸の三酸素同位体異常の鉛直分布を定量化し、有意な三酸素同位体異常が水深300m付近まで広がっていることを明らかにして、成果を国内学会および国際学会で報告した。今後は大気からの硝酸の沈着速度を求め、これを元に日本海で進行する年平均の窒素循環速度(総硝化速度や総硝酸同化速度)を算出する。
    湖沼での観測に成功するとともに、第一報は欧文誌への論文掲載が完了した。さらに2019年度は当初予定に無かった海洋環境への応用にも挑戦し、これを成功させた。
    最終年度である2020年度は、前半に琵琶湖で追加観測を実施する。追加観測とこれまでの観測で得られた結果の解析を行い、培養法で得られる個々の水塊中の同化速度と、三酸素同位体異常から求められる湖沼全体の同化速度を、それぞれの年平均値と、各観測インターバルのそれぞれで比較し、本研究の主要課題である三酸素同位体異常法の確度に関して、最終的な結論を得る。また両者が有意に異なる場合には、その原因を解釈する。加えて琵琶湖の窒素循環の経年変化の有無や一次生産の特徴を、過去3年間の観測の蓄積から定量的に把握する。また前年度に海洋域で採取した試料に対して本研究で開発した手法を応用し、海洋域における窒素循環速度定量に本手法が応用出来るかどうか、検証する。成果をまとめて欧文誌に投稿する。

  3. 火山噴火タイプの新指標:噴煙中の水蒸気の同位体組成

    研究課題/研究課題番号:16K13914  2016年04月 - 2018年03月

    独立行政法人日本学術振興会  科学研究費補助金  挑戦的研究(萌芽)

    角皆 潤

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    担当区分:研究代表者  資金種別:競争的資金

    配分額:3510000円 ( 直接経費:2700000円 、 間接経費:810000円 )

    火山ガス中の水蒸気の起源には、マグマ水の場合と、山体内部の地下水の場合(天水)があり、両者間で水素および酸素の安定同位体比が大きく異なることが知られている。噴火に伴って大気中に放出され、風下に流下してくる噴煙中の水蒸気の同位体比を定量化することができれば、そこから水蒸気の起源(マグマ水か、天水か)が判別できるし、山体内の流体挙動の理解も進展する。そこで本研究では、容器中に採取して持ち帰った噴煙試料中の水蒸気の同位体比を定量化する新システムを開発した。また実際の火山の噴気孔で、噴煙中の水蒸気の同位体比分析から噴気孔における水蒸気の同位体比が推定出来ることを確認した。

  4. 対流圏オゾンの三酸素同位体組成測定

    2014年04月 - 2017年03月

    科学研究費補助金  基盤研究(A)

      詳細を見る

    担当区分:研究代表者 

  5. 無人航空機で拓く新しい火山観測:噴煙の水素同位体比を利用した遠隔噴気温度測定

    2014年04月 - 2016年03月

    科学研究費補助金 

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    担当区分:研究代表者 

  6. 最新の安定同位体分析技術を応用した海洋物質循環速度定量法の革新

    2013年04月 - 2015年03月

    科学研究費補助金  新学術領域研究(研究領域提案型)

    角皆 潤

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    担当区分:研究代表者 

  7. 三酸素同位体組成を指標に用いた陸水環境中の硝酸の総同化速度定量法開発

    2012年04月 - 2014年03月

    科学研究費補助金 

      詳細を見る

    担当区分:研究代表者 

  8. 硝酸の三酸素同位体組成を指標に解析する東アジア域の大気光化学過程の現状と変化

    2011年04月 - 2014年03月

    科学研究費補助金  基盤研究(A)

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    担当区分:研究代表者 

  9. 海水中硫化ジメチルおよび関連有機化合物の高時間分解能計測手法の確立

    2011年04月 - 2014年03月

    科学研究費補助金  基盤研究(B)

    谷本浩志

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    担当区分:研究分担者 

  10. 硝酸の同位体組成を指標に用いた植物の窒素同化過程解析

    2010年04月 - 2012年03月

    科学研究費補助金 

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    担当区分:研究代表者 

  11. 硝酸の三酸素同位体組成を指標に用いた大気から沈着した窒素の環境動態解析

    2008年04月 - 2011年03月

    科学研究費補助金  基盤研究(B)

      詳細を見る

    担当区分:研究代表者 

    本研究では、東アジア域では初となる一般水環境試料中に含まれるNO3-のΔ17O組成定量を実現し、そのNO3-中に含まれる大気由来のNO3-(NO3-atm)の混合比のトレーサーとしてのΔ17O組成の信頼性を検証するとともに、その有用性を実証することを目的としている。特に、全NO3-中に占めるNO3-atm 混合比は、定常状態下では、総NO3-供給速度に対する大気からのNO3-atm沈着速度の相対比に等しいので、これを活用する。まず北海道の利尻島において、長期に渡って湿性沈着試料を集めてNO3-atmのΔ17O組成の連続観測を成功させ、その年平均値(Δ17Oatm)を見積もった。次に同島の森林域から流出する地下水試料中のNO3-について、Δ17O値定量を実現し、Δ17Oatm との比較から、大気から沈着した窒素が森林生態系によって浄化される過程を定量的に評価した。さらに摩周湖の湖水中に溶存するNO3-のΔ17O組成の分布を定量し、大気から貧栄養の水環境下に沈着したNO3-atmの挙動を定量化した。

  12. 海洋表層における生物起源微量気体の生成・分解過程とその気候変化への応答

    2006年04月 - 2011年03月

    科学研究費補助金  特定領域研究

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    担当区分:研究代表者 

    本研究では海水中の複数の揮発性有機化合物(VOC)を連続的に測定するために平衡器インレット-陽子移動反応質量分析計(EI-PTR-MS)を開発した。対象とした6種のVOC(硫化ジメチル(DMS)、イソプレン、プロピレン、アセトン、アセトアルデヒド、メタノール)について、室内実験で平衡到達度や応答時間の評価を行った。海水試料とキャリアガスの間の平衡はVOCの溶解度に依存し、プロピレンとイソプレンは平衡に達しなかったが、他のVOCは平衡器内で十分に平衡に達していた。我々は、西部北太平洋における研究航海においてEI-PTR-MSを初めて運用し、サンプリング手法による汚染の影響が無い事を確認した。EI-PTR-MSで得られたDMSとイソプレンの結果をGC法で得られた結果と比較し、概して良く一致することが分かった。EI-PTR-MSは小さい時空間スケールにおける海水中のVOCの変動を捉えることができており、複数のVOC種を同時かつ連続的に測定する能力を有していることが実証された。

  13. サハリンおよび南プリモーリエ州周辺に湧出するメタンおよび軽炭化水素類の起源

    2005年04月 - 2007年03月

    科学研究費補助金  二国間交流事業

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    担当区分:研究代表者 

▼全件表示

産業財産権 3

  1. ベンゼンの炭素源特定方法

    角皆 潤, 山口 潤子, 米山 泰之

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    出願人:国立大学法人北海道大学, JFEスチール株式会社

    出願番号:2005-213094  出願日:2005年7月22日

    公開番号:2007-33076 

    特許番号/登録番号:4708110  登録日:2011年3月25日 

    出願国:国内  

  2. 液中の地球温暖化気体成分測定装置

    角皆 潤, 紀本 岳志, 紀本 英志, 高 翔

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    出願人:角皆 潤, 紀本電子工業株式会社

    出願番号:2003-283090  出願日:2003年7月30日

    公開番号:2005-49279 

    特許番号/登録番号:3696223  登録日:2005年7月8日 

    出願国:国内  

  3. 海底湧水採取装置

    角皆 潤, 金子 将

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    出願人:日油技研工業株式会社, 角皆 潤

    出願番号:2002-20041  出願日:2002年1月29日

    公開番号:2003-214994 

    特許番号/登録番号:3766634  登録日:2006年2月3日 

    出願国:国内  

 

担当経験のある科目 (本学) 44

  1. 大気水圏環境の科学

    2020

     詳細を見る

    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  2. 地球惑星科学特別研究

    2020

  3. 大気水圏フィールドセミナーⅡ

    2020

  4. 海洋科学

    2020

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  5. 物質循環科学セミナー1B

    2020

  6. 物質循環科学セミナー1A

    2020

  7. 物質循環科学セミナー1C

    2020

  8. 物質循環科学セミナー2D

    2020

  9. 物質循環科学セミナー2C

    2020

  10. 物質循環科学セミナー2B

    2020

  11. 物質循環科学セミナー2A

    2020

  12. 物質循環科学セミナー1D

    2020

  13. 物質循環科学セミナー2F

    2020

  14. 物質循環科学セミナー2E

    2020

  15. 物質循環科学セミナー1F

    2020

  16. 物質循環科学セミナー1E

    2020

  17. 大気水圏環境の科学

    2019

     詳細を見る

    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  18. 海洋科学

    2019

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  19. 大気水圏環境の科学

    2018

     詳細を見る

    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  20. 海洋科学

    2018

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  21. 大気水圏フィールドセミナーⅡ

    2017

     詳細を見る

    二酸化炭素による温暖化など、今日の地球環境に関する諸問題は、フィールドにおける難易度の高い観測を実現したことで、その存在が明らかになったものが多い。しかしながら、特に海洋域には実現が難しい観測が多く、未解明の課題も数多く残されていると考えられる。本演習では、三重大学生物資源学部のご協力のもと、同大の練習船「勢水丸」をお借りして、海洋観測の乗船実習を実施する。具体的には、伊勢湾を中心とした海域で、自らの手で観測やサンプリングを行い、さらに自らの手で化学分析やデータ解析を行うことで、伊勢湾を取り巻く海洋環境の現状を、実体験によって理解することを目標とする。

  22. 海洋科学

    2017

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  23. 大気水圏環境の科学

    2017

     詳細を見る

    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  24. 大気水圏環境の科学

    2016

     詳細を見る

    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  25. 大気水圏フィールドセミナーⅡ

    2016

     詳細を見る

    二酸化炭素による温暖化など、今日の地球環境に関する諸問題は、フィールドにおける難易度の高い観測を実現したことで、その存在が明らかになったものが多い。しかしながら、特に海洋域には実現が難しい観測が多く、未解明の課題も数多く残されていると考えられる。本演習では、三重大学生物資源学部のご協力のもと、同大の練習船「勢水丸」をお借りして、海洋観測の乗船実習を実施する。具体的には、伊勢湾を中心とした海域で、自らの手で観測やサンプリングを行い、さらに自らの手で化学分析やデータ解析を行うことで、伊勢湾を取り巻く海洋環境の現状を、実体験によって理解することを目標とする。

  26. 海洋科学

    2016

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  27. 物質循環科学

    2015

  28. 海洋科学

    2015

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  29. 大気水圏フィールドセミナーⅡ

    2015

     詳細を見る

    二酸化炭素による温暖化など、今日の地球環境に関する諸問題は、フィールドにおける難易度の高い観測を実現したことで、その存在が明らかになったものが多い。しかしながら、特に海洋域には実現が難しい観測が多く、未解明の課題も数多く残されていると考えられる。本演習では、三重大学生物資源学部のご協力のもと、同大の練習船「勢水丸」をお借りして、海洋観測の乗船実習を実施する。具体的には、伊勢湾を中心とした海域で、自らの手で観測やサンプリングを行い、さらに自らの手で化学分析やデータ解析を行うことで、伊勢湾を取り巻く海洋環境の現状を、実体験によって理解することを目標とする。

  30. 環境化学

    2015

  31. 大気水圏環境の科学

    2015

     詳細を見る

    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  32. 環境化学

    2014

  33. 物質循環科学

    2014

  34. 大気水圏環境の科学

    2014

     詳細を見る

    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  35. 海洋科学

    2014

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  36. 大気水圏フィールドセミナーⅡ

    2014

     詳細を見る

    二酸化炭素による温暖化など、今日の地球環境に関する諸問題は、フィールドにおける難易度の高い観測を実現したことで、その存在が明らかになったものが多い。しかしながら、特に海洋域には実現が難しい観測が多く、未解明の課題も数多く残されていると考えられる。本演習では、三重大学生物資源学部のご協力のもと、同大の練習船「勢水丸」をお借りして、海洋観測の乗船実習を実施する。具体的には、伊勢湾を中心とした海域で、自らの手で観測やサンプリングを行い、さらに自らの手で化学分析やデータ解析を行うことで、伊勢湾を取り巻く海洋環境の現状を、実体験によって理解することを目標とする。

  37. 物質循環科学

    2013

  38. 大気水圏フィールドセミナーⅡ

    2013

     詳細を見る

    二酸化炭素による温暖化など、今日の地球環境に関する諸問題は、フィールドにおける難易度の高い観測を実現したことで、その存在が明らかになったものが多い。しかしながら、特に海洋域には実現が難しい観測が多く、未解明の課題も数多く残されていると考えられる。本演習では、三重大学生物資源学部のご協力のもと、同大の練習船「勢水丸」をお借りして、海洋観測の乗船実習を実施する。具体的には、伊勢湾を中心とした海域で、自らの手で観測やサンプリングを行い、さらに自らの手で化学分析やデータ解析を行うことで、伊勢湾を取り巻く海洋環境の現状を、実体験によって理解することを目標とする。

  39. 海洋科学

    2013

     詳細を見る

    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  40. 大気水圏環境の科学

    2013

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    大気環境・海洋環境の科学を理解する上で必須となる、基礎的な物理学・化学・生物学・地学を包括的に理解し、科学的・合理的な知識に基づく正しい地球環境像を確立する。各回の講義では、提示されたテーマに関して、基本事項(大気や海水の物理的・化学的特徴や、物質・熱の移動・拡散・反応を支配する法則など)を習得して、回答を導出する作業を繰り返す。最終的に地球環境の成り立ちや、それらの制御因子など、複雑系である地球環境に関する総合的な理解力を身につける。

  41. 環境化学

    2013

  42. 大気水圏フィールドセミナーⅡ

    2012

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    二酸化炭素による温暖化など、今日の地球環境に関する諸問題は、フィールドにおける難易度の高い観測を実現したことで、その存在が明らかになったものが多い。しかしながら、特に海洋域には実現が難しい観測が多く、未解明の課題も数多く残されていると考えられる。本演習では、三重大学生物資源学部のご協力のもと、同大の練習船「勢水丸」をお借りして、海洋観測の乗船実習を実施する。具体的には、伊勢湾を中心とした海域で、自らの手で観測やサンプリングを行い、さらに自らの手で化学分析やデータ解析を行うことで、伊勢湾を取り巻く海洋環境の現状を、実体験によって理解することを目標とする。

  43. 海洋科学

    2012

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    地球表層環境に果たす海洋の役割を理解する。まず海洋を理解する上での基本事項(海水の物理的・化学的性質や、海洋における水や物質、熱の移動・拡散過程等)を概説した上で、地球上の炭素循環に果たす海洋の役割や、海域毎の一次生産量の分布、さらにそれを理解する上で鍵となる海水中の栄養塩元素の分布や、その制御因子など、海洋における物質の分布や循環を解説する。さらに、結果として明らかになった海洋像だけでなく、それを明らかにした手法や歴史的背景についても、適宜解説を加える。

  44. 物質循環科学

    2012

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担当経験のある科目 (本学以外) 2

  1. 生物圏環境科学特別講義Ⅰ

    2016年4月 - 2017年3月 富山大学)

  2. 安定同位体地球化学

    2012年4月 - 2013年3月 広島大学)

 

社会貢献活動 6

  1. サロン・ド・Arimoto 講演会

    講師

    うなぎ有本  2017年6月

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    対象: 社会人・一般

    種別:講演会

    サロン・ド・Arimoto 講演会にて、「あいち森と緑づくり税は地球温暖化防止に役に立っているのか?」というタイトルで講演を実施。

  2. 第9回日本地球化学会ショートコース(日本地球化学会主催)における講師

    2014年9月

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    日本地球化学会主催のショートコース(2014年9月15日(月)、富山大学)の講師。

  3. 公開講演会「京都大学の琵琶湖研究100年と今後の多様な共同研究のために」(京都大学生態学研究センター主催)における講演

    2014年7月

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    大津臨湖実験所開所100 周年記念事業第1回公開講演会 「京都大学の琵琶湖研究100年と今後の多様な共同研究のために」
    日時:平成26 年7 月26 日(土)
    場所:コラボしが21(滋賀県大津市)
    講演タイトル:「栄養塩の生成量や消費量を測る:その意義と新手法への挑戦」

  4. 北海道大学サスティナビリティ・ウィークの市民向けセミナー(自然界における多様性の起源と進化)講演

    2008年6月

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    北海道大学主催の市民向けセミナーで講演「炭素循環から見た地球環境問題」

  5. 市民セミナー(北大総合博物館主催)講演

    2004年6月

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    北大総合博物館主催の市民向けセミナーで講演

  6. UHB大学講師

    2004年4月 - 2005年3月

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    北海道のテレビ局UHBが主催する生涯学習講座「UHB大学」で講師

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メディア報道 3

  1. 火山ガス、ドローンで採取 新聞・雑誌

    日本経済新聞社  日本経済新聞  2021年3月9日

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    執筆者:本人以外 

  2. ドローンで火山ガス採取 安全、正確に噴火規模予測 新聞・雑誌

    産経新聞社  産経新聞  2021年3月6日

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    執筆者:本人以外 

  3. ドローンで火山ガス採取 安全、正確に噴火規模予測 新聞・雑誌

    東奥日報社  東奥日報  2021年3月6日

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    執筆者:本人以外