著者

JUN-ICHIRO ISHIBASHI TAKUROH NOGUCHI TOMOHIRO TOKI SHUNSUKE MIYABE SHOSEI YAMAGAMI YUJI ONISHI TOSHIRO YAMANAKA YUKA YOKOYAMA ERIKO OMORI YOSHIO TAKAHASHI KENTA HATADA YUZURU NAKAGUCHI MOTOKO YOSHIZAKI UTA KONNO TAKAZO SHIBUYA KEN TAKAI FUMIO INAGAKI SHINSUKE KAWAGUCCI

出版者

GEOCHEMICAL SOCIETY OF JAPAN

雑誌

GEOCHEMICAL JOURNAL (ISSN:00167002)

巻号頁・発行日

vol.48, no.4, pp.357-369, 2014-07-20 (Released:2014-07-31)

参考文献数

48

被引用文献数

23 67

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Two active hydrothermal fields, Jade and Hakurei fields have been discovered within the Izena Hole, a rectangular 6 km × 3 km shape depression located in the middle Okinawa Trough back arc basin. In both fields, intense hydrothermal activity is represented by venting of high-temperature fluid (>300°C) and occurrence of sulfide/sulfate ore deposits. We collected hydrothermal fluids during dive expeditions of ROV Hyper Dolphin conducted in 2003, 2010 and 2011, in order to analyze both elemental and gas species. The geochemistry of high temperature hydrothermal fluids collected from the Jade and Hakurei fields is very similar to each other with exceptions in minor gas composition. Little temporal variation was observed in geochemistry of the high-temperature hydrothermal fluid of the Jade field over two decades, since a previous study carried out in 1989. These results suggest that these fluids are derived from a common fluid reservoir where fluid chemistry is basically controlled by fluid-mineral equilibria and gas species are dominantly contributed from the same magma. Venting of low temperature fluid (about 104°C) was discovered in the distal part of the Jade field, which was named as the Biwako vent. Chemical composition of the Biwako vent fluid was distinctive from that of the high temperature fluid in the proximal part of the Jade field, and could not be explained by simple dilution or cooling. This intra-field chemical diversity could be caused by phase separation and segregation during fluid upwelling, based on relationships in concentrations of Cl and major cations. On the other hand, the chemical diversity recognized in minor gas composition between the Jade and Hakurei fields is in accordance with results from previous plume survey. Difference in concentrations of minor gases such as H2 is attributed to contribution from thermal degradation of organic matter in the sediment, during fluid upwelling.

著者

Katsuhiro Asamatsu Kai Yoshitake Makoto Saito Wipoo Prasitwuttisak Jun-ichiro Ishibashi Akihi Tsutsumi Nurul Asyifah Mustapha Toshinari Maeda Katsunori Yanagawa

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.36, no.4, pp.ME21048, 2021 (Released:2021-11-25)

参考文献数

71

被引用文献数

1

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A novel deep-branching archaeal lineage was discovered at high-temperature hot springs around Oyasukyo Gorge in Akita Prefecture, Japan. Actively boiling hot spring water contained >1×104 microbes mL–1. The microbial community composition assessed by analyzing 16S rRNA gene amplicons revealed that the dominant bacterial phyla were Proteobacteria and Aquificae (>50% of the microbial composition) in samples collected in 2016 and 2019, respectively. Approximately 10% of the reads obtained in both years were not assigned to any taxonomy. The more detailed phylogenetic positions of the unassigned sequences identified using a clone library and phylogenetic tree showed that they formed a clade that was independent, distantly related to known phyla, and had low similarity (<82%) to all other sequences in available databases. The present results suggest that this novel archaeal phylum-level lineage thrives in boiling hot springs in Japan.

著者

WEN HSINYI Naoto Takahata Akizumi Ishida Kentaro Tanaka Yama Tomonaga Takanori Kagoshima Kotaro Shirai Jun-Ichiro Ishibashi Hisayoshi Yokose Urumu Tsunogai Yuji Sano

出版者

日本地球化学会

雑誌

日本地球化学会年会要旨集

巻号頁・発行日

vol.61, 2014

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The aim of this study is to get information of gas geochemical characteristics at hydrothermal vent sites in the adjacent region of Tokara Islands by using helium isotopes and methane concentration and its stable carbon isotope ratio to estimate the 3He flux and understand the mechanism of carbon cycling.