| Project/Area Number |
18405006
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 海外学術 |
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| Research Field |
Ecology/Environment
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KOJIMA Shigeaki The University of Tokyo, Ocean Research Institute, Professor (20242175)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Taketomo The University Museum, 総合研究博物館, Associate Professor (70313195)
SUZUKI Yohei The University of Tokyo, The National Institute of Advanced Industrial Science and Technology・Geological Survey of Japan, Researcher (00359168)
MIYAKE Hiroshi Kitasato University, Department of Fisheries, Lecturer (00373465)
YAMAGUCHI Toshiyuki Chiba University, Department of Science, Professor (10101106)
KANO Yasunori Miyazaki University, Department of Fisheries, Assistant Professor (20381056)
浦川 秀敏 東京大学, 海洋研究所, 助教授 (90370262)
土田 真二 独立行政法人海洋研究開発機構, 極限環境生物圏研究センター, 研究員 (30344295)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥12,550,000 (Direct Cost: ¥11,800,000、Indirect Cost: ¥750,000)
Fiscal Year 2007: ¥3,250,000 (Direct Cost: ¥2,500,000、Indirect Cost: ¥750,000)
Fiscal Year 2006: ¥9,300,000 (Direct Cost: ¥9,300,000)
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| Keywords | international exchange of researchers / hydrothermal vent fields / southwestern Pacific / chemosynthesis-based communities / provannid gastropods / endosymbiosis / chemosynthetic bacteria / carbon dioxide fixation system / アルビンガイ類 / 硫化水素 / パプアニューギニア:フィジー / 空間分布 / 分子系統学 |
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| Research Abstract |
Survey of chemosynthesis-based communities in the deep-sea hydrothermal vent fields in the Manus and North Fiji Basins in the southwestern Pacific was carried out using the submersible SHINKAI 6500 from Sept. 8 to Oct. 4, 2006. Changes of mode of hydrothermal venting and fauna containing Alviniconcha snails since 1990s were recognized. Population size of Alviniconcha snails in the southwestern Pacific was shown to have been maintained without rapid expansion in comparison with those in the Mariana Trough and the Indian Ocean. Chemical analyses of sea water samples collected around snails showed that Alviniconcha snails inhabit areas at 10-20°C where H_2S content is relatively high, while habitats of Ifremeria nautilei are areas at 4-8°C where H_2S content is at the undetectable level. At all habitats of Alviniconcha snails, epsilon-proteobacteria closely related to chemosynthetic bacteria with carbon dioxide fixation system using reverse TCA cycle, were dominated among planktonic free-living bacteria. Only at the Viena Woods site in the Manus Basin, where only Alviniconcha snails endosymbiosing with gamma-proteobacteria were distributed, bacteria related to the endosymbionts were detected in the water samples. Distribution of Alviniconcha snails endosynbiosing with gamma-proteobacteria is restricted by mode of hydrothermal venting rather than tectonic backgrounds of hydrothermal venting and physico-chemical characteristics of hot water. While they are thought to be sensitive to changes in biological, physical and chemical factors in the environments of their habitats, Alviniconcha snails endosynbiosing with epsilon-proteobacteria are probably able to adapt themselves to wider range of such factors.
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