Jun-ichiro Ishibashi Kyoko Okino Michinari Sunamura Editors TAIGA Concept Subsea oor Biosphere Linked to Hydrothermal Systems Subseafloor Biosphere Linked to Hydrothermal Systems Jun-ichiro Ishibashi • Kyoko Okino Michinari Sunamura Editors Subseafloor Biosphere Linked to Hydrothermal Systems TAIGA Concept Editors Jun-ichiro Ishibashi Department of Earth and Planetary Science, Faculty of Sciences Kyushu University Fukuoka, Japan Kyoko Okino Atmosphere and Ocean Research Institute The University of Tokyo Kashiwa, Chiba, Japan Michinari Sunamura Department of Earth and Planetary Science Graduate School of Science The University of Tokyo Tokyo, Japan ISBN 978-4-431-54864-5 ISBN 978-4-431-54865-2 (eBook) DOI 10.1007/978-4-431-54865-2 Springer Tokyo Heidelberg New York Dordrecht London Library of Congress Control Number: 2014948334 # The Editor(s) (if applicable) and the Author(s) 2015. The book is published with open access at SpringerLink.com Open Access This book is distributed under the terms of the Creative Commons Attribution Noncommercial License, which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. All commercial rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcasting, reproduction on microfilms or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for commercial use must always be obtained from Springer. Permissions for commercial use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Cover illustration : # JAMSTEC 2014. Used with kind permission Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Preface This e-book is a collection of scientific results of studies obtained during the TAIGA project between 2008 and 2012. The TAIGA project was planned and organized to elucidate interactions between the lithosphere, hydrosphere, and biosphere through the fluid advection system beneath the seafloor through many cruises, modeling, and laboratory experiments. This interdisciplinary project was funded by MEXT (Ministry of Education, Culture, Sports, Science and Technology in Japan) from FY 2008 to FY 2012, as a project of a “ Grant-in- Aid for Scientific Research on Innovative Areas ” . The program name “ TAIGA ” represents a dynamic fluid advection system beneath the seafloor (In Japanese, taiga refers to “ a great river ” ), as introduced in Chap. 1. Multidisciplinary scientists from universities and institutes and many students worked together synergically for this program. Five research projects (A01–A05) were organized to attain major goals under the framework of the TAIGA program, as follows. A01: Diversity of TAIGA controlled by various geologic and geophysical structures; A02: Biogeochemical impact of TAIGA flux on the deep-sea environment; A03: Evolution of TAIGA—constraints from geochronology and molecular genetics; A04: Clarification of in situ physical, chemical, and biological interactive processes in TAIGAs; and A05: Laboratory experiments to eluci- date chemical and biological interactions in TAIGA. However, many individual specific studies were conducted by members across teams and disciplines, as will be obvious in the contents of this book. Several research cruises, dive expeditions, and drilling operations were conducted during the TAIGA project. To conduct these ocean field studies efficiently, three integrated study sites were selected, namely, the Central Indian Ridge, the Southern Mariana Trough, and the Okinawa Trough. Each of them represents different types of TAIGAs, as introduced in Chap. 1. Shallow seafloor drilling expeditions employing a Benthic Multicoring System (BMS) were conducted twice as hosted by the TAIGA project, once in August 2010 in the Southern Mariana Trough, and the other in July 2011 in the Okinawa Trough. Deep seafloor drilling during the Integrated Ocean Drilling Program (IODP) Expedition 331 was conducted in the Okinawa Trough in September 2010, in which several TAIGA project members participated. More than 30 submersible dive expeditions and surface ship research cruises were conducted under the framework of Japan Agency for Marine–Earth Science and Technology (JAMSTEC) deep-sea investigations and of the Atmosphere Ocean Research Institute, The University of Tokyo. These cruises were executed by research proposals submitted by TAIGA project members. This e-book consists of 51 chapters, which have been contributed by TAIGA project members as individual parts and critically reviewed by external reviewers or TAIGA project members. Part I compiles interdisciplinary studies, including summary articles for each research program. Parts II, III, and IV compile studies related to the three integrated study sites, the Central Indian Ridge, the Southern Mariana Trough, and the Okinawa Trough. Some of the chapters include review sections to overview the project results together with a summary of the background information and previous studies of the target site or the specialized field, for the benefit of readers. Appendices in three parts compile rather short reports which omit full discussion in order to give additional data or results. v This volume is being published as “ an open access e-book, ” which is a new style of publication for scientific articles. We hope that this e-book is well accepted among the scientific community as a whole, since it is the first publication covering wide ranges of research topics both on the arc–backarc systems such as the western Pacific and on the mid- ocean ridge system such as the Indian Ocean. We would like to urge readers to inform their colleagues of this publication by quoting it as follows: Subseafloor Biosphere Linked to Hydrothermal Systems: TAIGA Concept http://link.springer.com/978-4-431-54865-2 Tokyo, Japan Tetsuro Urabe Fukuoka, Japan Jun-ichiro Ishibashi March 2014 vi Preface Editorial Board The editorial board was organized from the principal members of the TAIGA project to handle editing work of the chapters. Members are listed below. Tatsuhiro Fukuba (Part I) Marine Technology and Engineering Center (MARITEC) Japan Agency for Marine–Earth Science and Technology (JAMSTEC) Jun-ichiro Ishibashi (Part III, chief executive editor) Faculty of Sciences Kyushu University Kyoko Okino (Part III, vice executive editor) Atmosphere and Ocean Research Institute (AORI) The University of Tokyo Michinari Sunamura (Part IV, vice executive editor) Department of Earth and Planetary Science The University of Tokyo Katsuhiko Suzuki (Part I) Research and Development (R&D) Center for Submarine Resources Japan Agency for Marine–Earth Science and Technology (JAMSTEC) Ken Takai (Part II) Department of Subsurface Geobiological Analysis and Research Japan Agency for Marine–Earth Science and Technology (JAMSTEC) Hiroyuki Yamamoto (Part IV) Research and Development (R&D) Center for Submarine Resources Japan Agency for Marine–Earth Science and Technology (JAMSTEC) Toshiro Yamanaka (Part I) Graduate School of Natural Science and Technology Okayama University vii Acknowledgments We would like to express our appreciation to the Ministry of Education, Culture, Sports, Science and Technology of Japan for funding this project from FY 2008 to FY 2012 (#20109001–20109006), as a project of a Grant-in-Aid for Scientific Research on Innovative Areas. Additional funding in FY 2013 supported editing work and publication of this e-book. We especially thank the crew, submersible teams, drilling operators, and onboard scientists of all of the research cruises related to the project. Ken Kimlicka and Taeko Sato at Springer Japan provided efficient assistance during all stages of the process of editing. Photographs on the cover were kindly provided by JAMSTEC. Harumi Fujita supported the handling, reviewing, and editing of the manuscripts. We sincerely appreciate the external reviewers (listed below) who substantially improved the accuracy of the contents and clarity of the presentations. List of External Reviewers Wolfgang Bach Department of Geosciences, University of Bremen Stace E. Beaulieu Woods Hole Oceanographic Institution Hitoshi Chiba Graduate School of Natural Science and Technology, Okayama University Jon Copley Ocean and Earth Science, University of Southampton Cornel E. J. de Ronde GNS Science Je ́ro ˆme Dyment Institut de Physique du Globe de Paris, CNRS Rob L. Evance Woods Hole Oceanographic Institution Toshiya Fujiwara Institute for Research on Earth Evolution, JAMSTEC Toshitaka Gamo Atmosphere and Ocean Research Institute, The University of Tokyo ix Yumiko Harigane Geological Survey of Japan, AIST Steven P. Hollis Earth Science and Resource Engineering, CSIRO Hironobu Hyodo Research Institute of Natural Sciences, Okayama University of Science Osamu Ishizuka Geological Survey of Japan, AIST Takashi Itoh College of Education, Ibaraki University Hiroyuki Kimura Graduate School of Science, Shizuoka University Tsuyoshi Komiya Graduate School of Arts and Sciences, The University of Tokyo Kaoru Kubokawa Misaki Marine Biological Station, The University of Tokyo Jun-ichi Miyazaki Graduate School of Education, Yamanashi University Takashi Naganuma Graduate School of Biosphere Science, Hiroshima University Masao Nakanishi Graduate School of Science, Chiba University Kenji Nanba Faculty of Symbiotic Systems Science, Fukushima University Kiyotaka Ninagawa Faculty of Science, Okayama University of Science Jun Nishikawa Atmosphere and Ocean Research Institute, The University of Tokyo Azusa Nishizawa Hydrographic and Oceanographic Department of Japan Yoshifumi Nogi National Institute of Polar Research Tatsuo Nozaki Institute for Research on Earth Evolution, JAMSTEC Yasuhiko Ohara Hydrographic and Oceanographic Department of Japan Soichi Omori The Open University of Japan Takenori Sasaki The University Museum, The University of Tokyo Takazo Shibuya Precambrian Ecosystem Laboratory, JAMSTEC x Acknowledgments Motohiro Shimanaga Center for Marine Environment Studies, Kumamoto University Robert Stern Department of Geosiences, The University of Texas at Dallas Saiko Sugisaki Graduate School of Science, the University of Tokyo Narumi Takahashi Institute for Research on Earth Evolution, JAMSTEC Yoshinori Takano Institute of Biogeoscience, JAMSTEC Fernando Tornos Centro de Astrobiologı ́a, CSIC-INTA Yuichiro Ueno Earth–Life Science Institute, Tokyo Institute of Technology Susumu Umino Faculty of Natural System, Kanazawa University Tomoo Watsuji Institute of Biogeoscience, JAMSTEC Toshitsugu Yamazaki Atmosphere and Ocean Research Institute, The University of Tokyo Fumitaka Yanagisawa Faculty of Science, Yamagata University Acknowledgments xi Contents Part I Interdisciplinary Studies 1 Introduction of TAIGA Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Tetsuro Urabe, Jun-ichiro Ishibashi, Michinari Sunamura, Kyoko Okino, Ken Takai, and Katsuhiko Suzuki 2 Geochemical Constraints on Potential Biomass Sustained by Subseafloor Water–Rock Interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Kentaro Nakamura and Ken Takai 3 Microbial Cell Densities, Community Structures, and Growth in the Hydrothermal Plumes of Subduction Hydrothermal Systems . . . . . 31 Michinari Sunamura and Katsunori Yanagawa 4 Systematics of Distributions of Various Elements Between Ferromanganese Oxides and Seawater from Natural Observation, Thermodynamics, and Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Yoshio Takahashi, Daisuke Ariga, Qiaohui Fan, and Teruhiko Kashiwabara 5 Evaluating Hydrothermal System Evolution Using Geochronological Dating and Biological Diversity Analyses . . . . . . . . . . . . . . . . . . . . . . . . . 49 Hidenori Kumagai, Hiromi Watanabe, Takuya Yahagi, Shigeaki Kojima, Shun ’ ichi Nakai, Shin Toyoda, and Jun-ichiro Ishibashi 6 Quantification of Microbial Communities in Hydrothermal Vent Habitats of the Southern Mariana Trough and the Mid-Okinawa Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Katsunori Yanagawa, Jun-ichiro Ishibashi, Takao Arai, Tetsuro Urabe, and Michinari Sunamura 7 Development of Hydrothermal and Frictional Experimental Systems to Simulate Sub-seafloor Water–Rock–Microbe Interactions . . . . 71 Katsuhiko Suzuki, Shingo Kato, Takazo Shibuya, Takehiro Hirose, Shigshi Fuchida, V.J Rejish Kumar, Motoko Yoshizaki, Yuka Masaki, Kentaro Nakamura, Kensei Kobayashi, Harue Masuda, Akihiko Yamagishi, and Tetsuro Urabe 8 Experimental Hydrogen Production in Hydrothermal and Fault Systems: Significance for Habitability of Subseafloor H 2 Chemoautotroph Microbial Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Katsuhiko Suzuki, Takazo Shibuya, Motoko Yoshizaki, and Takehiro Hirose xiii 9 Experimental Assessment of Microbial Effects on Chemical Interactions Between Seafloor Massive Sulfides and Seawater at 4 C . . . . 95 Shingo Kato, Katsuhiko Suzuki, Takazo Shibuya, Jun-ichiro Ishibashi, Moriya Ohkuma, and Akihiko Yamagishi 10 A Compilation of the Stable Isotopic Compositions of Carbon, Nitrogen, and Sulfur in Soft Body Parts of Animals Collected from Deep-Sea Hydrothermal Vent and Methane Seep Fields: Variations in Energy Source and Importance of Subsurface Microbial Processes in the Sediment-Hosted Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Toshiro Yamanaka, Sho Shimamura, Hiromi Nagashio, Shosei Yamagami, Yuji Onishi, Ayumi Hyodo, Mami Mampuku, and Chitoshi Mizota Part II Central Indian Ridge 11 Tectonic Background of Four Hydrothermal Fields Along the Central Indian Ridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Kyoko Okino, Kentaro Nakamura, and Hiroshi Sato 12 Indian Ocean Hydrothermal Systems: Seafloor Hydrothermal Activities, Physical and Chemical Characteristics of Hydrothermal Fluids, and Vent-Associated Biological Communities . . . . . . . . . . . . . . . . . . . . . . . 147 Kentaro Nakamura and Ken Takai 13 Petrology and Geochemistry of Mid-Ocean Ridge Basalts from the Southern Central Indian Ridge . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Hiroshi Sato, Kentaro Nakamura, Hidenori Kumagai, Ryoko Senda, Tomoaki Morishita, Akihiro Tamura, and Shoji Arai 14 Petrology of Peridotites and Related Gabbroic Rocks Around the Kairei Hydrothermal Field in the Central Indian Ridge . . . . . . . . . . . . 177 Tomoaki Morishita, Kentaro Nakamura, Takazo Shibuya, Hidenori Kumagai, Taichi Sato, Kyoko Okino, Hiroshi Sato, Rie Nauchi, Kaori Hara, and Ryo Takamaru 15 Distribution and Biogeochemical Properties of Hydrothermal Plumes in the Rodriguez Triple Junction . . . . . . . . . . . . . . . . . . . . . . . . . . 195 Takuroh Noguchi, Tatsuhiro Fukuba, Kei Okamura, Akira Ijiri, Katsunori Yanagawa, Yoshiyuki Ishitani, Teruo Fujii, and Michinari Sunamura 16 Vent Fauna on the Central Indian Ridge . . . . . . . . . . . . . . . . . . . . . . . . . . 205 Hiromi Watanabe and Girish Beedessee Part III Southern Mariana Trough 17 The Mantle Dynamics, the Crustal Formation, and the Hydrothermal Activity of the Southern Mariana Trough Back-Arc Basin . . . . . . . . . . . . . 215 Nobukazu Seama, Hiroshi Sato, Yoshifumi Nogi, and Kyoko Okino 18 Seismic Structure and Seismicity in the Southern Mariana Trough and Their Relation to Hydrothermal Activity . . . . . . . . . . . . . . . . . . . . . . . 229 Toshinori Sato, Mariko Mizuno, Hiroyoshi Takata, Tomoaki Yamada, Takehi Isse, Kimihiro Mochizuki, Masanao Shinohara, and Nobukazu Seama xiv Contents 19 Electrical Resistivity Structure of the Snail Site at the Southern Mariana Trough Spreading Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 Tetsuo Matsuno, Maho Kimura, and Nobukazu Seama 20 Asymmetric Seafloor Spreading of the Southern Mariana Trough Back-Arc Basin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253 Nobukazu Seama and Kyoko Okino 21 Geochemical Characteristics of Active Backarc Basin Volcanism at the Southern End of the Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . . 261 Harue Masuda and Patricia Fryer 22 Mineralogical and Geochemical Characteristics of Hydrothermal Minerals Collected from Hydrothermal Vent Fields in the Southern Mariana Spreading Center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275 Kei Ikehata, Ryohei Suzuki, Kazuhiko Shimada, Jun-ichiro Ishibashi, and Tetsuro Urabe 23 Dating of Hydrothermal Mineralization in Active Hydrothermal Fields in the Southern Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . 289 Jun-ichiro Ishibashi, Kazuhiko Shimada, Fumihiro Sato, Ai Uchida, Shin Toyoda, Asako Takamasa, Shun ’ ichi Nakai, Hironobu Hyodo, Keiko Sato, Hidenori Kumagai, and Kei Ikehata 24 Intra-Field Variation of Prokaryotic Communities On and Below the Seafloor in the Back-Arc Hydrothermal System of the Southern Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301 Shingo Kato, Moriya Ohkuma, and Akihiko Yamagishi 25 Vent Fauna in the Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313 Shigeaki Kojima and Hiromi Watanabe 26 Population History of a Hydrothermal Vent-Endemic Gastropod Alviniconcha hessleri in the Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . 325 Hiroka Hidaka, Tomomi Ogura, Hiromi Watanabe, Yasunori Kano, and Shigeaki Kojima Part IV Okinawa Trough 27 Hydrothermal Activity in the Okinawa Trough Back-Arc Basin: Geological Background and Hydrothermal Mineralization . . . . . . . . . . . . . 337 Jun-ichiro Ishibashi, Fumihiko Ikegami, Takeshi Tsuji, and Tetsuro Urabe 28 Active Rifting Structures in Iheya Graben and Adjacent Area of the Mid-Okinawa Trough Observed Through Seismic Reflection Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361 Fumihiko Ikegami, Takeshi Tsuji, Hidenori Kumagai, Jun-ichiro Ishibashi, and Ken Takai 29 ESR Dating of Barite in Sea-Floor Hydrothermal Sulfide Deposits in the Okinawa Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369 Taisei Fujiwara, Shin Toyoda, Ai Uchida, Jun-ichiro Ishibashi, Shun’ichi Nakai, and Asako Takamasa 30 Fluid Geochemistry of High-Temperature Hydrothermal Fields in the Okinawa Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387 Shinsuke Kawagucci Contents xv 31 Sediment–Pore Water System Associated with Native Sulfur Formation at Jade Hydrothermal Field in Okinawa Trough . . . . . . . . . . . 405 Yuka Yokoyama, Yoshio Takahashi, Youko Miyoshi, Jun-ichiro Ishibashi, and Shinsuke Kawagucci 32 Comparative Investigation of Microbial Communities Associated with Hydrothermal Activities in the Okinawa Trough . . . . . . . . . . . . . . . . 421 Ken Takai, Satoshi Nakagawa, and Takuro Nunoura 33 In Situ Determination of Bacterial Growth in Mixing Zone of Hydrothermal Vent Field on the Hatoma Knoll, Southern Okinawa Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437 Hiroyuki Yamamoto, Tomoko Maruyama, La ́szlo ́ G.-To ́th, Kenji Kato, Yasuo Furushima, Naoto Taira, Yoshiaki Maeda, and Kiminori Shitashima 34 Vent Fauna in the Okinawa Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449 Hiromi Watanabe and Shigeaki Kojima Part V Appendix I: Site Reports 35 Brief Report of Side-Scan Sonar Observations Around the Yokoniwa NTO Massif . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 463 Miho Asada, Kyoko Okino, Hisashi Koyama, Akira Asada, and Tamaki Ura 36 Examination of Volcanic Activity: AUV and Submersible Observations of Fine-Scale Lava Flow Distributions Along the Southern Mariana Trough Spreading Axis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469 Miho Asada, Shuro Yoshikawa, Nobutatsu Mochizuki, Yoshifumi Nogi, and Kyoko Okino 37 Brief Report of Side-Scan Sonar Imagery Observations of the Archaean, Pika, and Urashima Hydrothermal Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . 479 Miho Asada, Shuro Yoshikawa, Nobutatsu Mochizuki, Yoshifumi Nogi, and Kyoko Okino 38 The Yoron Hole: The Shallowest Hydrothermal System in the Okinawa Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 489 Tatsuhiro Fukuba, Takuroh Noguchi, and Teruo Fujii 39 The Irabu Knoll: Hydrothermal Site at the Eastern Edge of the Yaeyama Graben . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 493 Tatsuhiro Fukuba, Takuroh Noguchi, and Teruo Fujii 40 The Tarama Knoll: Geochemical and Biological Profiles of Hydrothermal Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 497 Toshiro Yamanaka, Hiromi Nagashio, Ryu Nishio, Kazuna Kondo, Takuroh Noguchi, Kei Okamura, Takuro Nunoura, Hiroko Makita, Kentaro Nakamura, Hiromi Watanabe, Kazuhiro Inoue, Tomohiro Toki, Kouichiro Iguchi, Urumu Tsunogai, Ryoichi Nakada, Shogo Ohshima, Shin Toyoda, Jun Kawai, Naohiro Yoshida, Akira Ijiri, and Michinari Sunamura xvi Contents Part VI Appendix II: Drilling Reports 41 Petrography and Geochemistry of Basement Rocks Drilled from Snail, Yamanaka, Archaean, and Pika Hydrothermal Vent Sites at the Southern Mariana Trough by Benthic Multi-Coring System (BMS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 507 Kentaro Nakamura, Hiroshi Sato, Patricia Fryer, and Tetsuro Urabe, TAIGA10M Shipboard Scientific Party 42 Pore Fluid Chemistry Beneath Active Hydrothermal Fields in the Mid-Okinawa Trough: Results of Shallow Drillings by BMS During TAIGA11 Cruise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535 Jun-ichiro Ishibashi, Youko Miyoshi, Kazuya Tanaka, Eriko Omori, Yoshio Takahashi, Yoshiko Furuzawa, Toshiro Yamanaka, Shinsuke Kawagucci, Junichi Miyazaki, Uta Konno, Shota Watanabe, Katsunori Yanagawa, Ryoto Yoshizumi, and Tetsuro Urabe 43 The Characteristics of the Seafloor Massive Sulfide Deposits at the Hakurei Site in the Izena Hole, the Middle Okinawa Trough . . . . . . 561 Ryoto Yoshizumi, Youko Miyoshi, and Jun-ichiro Ishibashi 44 Occurrence of Hydrothermal Alteration Minerals at the Jade Hydrothermal Field, in the Izena Hole, Mid-Okinawa Trough . . . . . . . . . . 567 Youko Miyoshi, Jun-Ichiro Ishibashi, Kazuhiko Shimada, Mitsuhiro Ooki, Seiichiro Uehara, Ryoto Yoshizumi, Shota Watanabe, and Tetsuro Urabe Part VII Appendix III: Data Reports 45 Chemical and Isotopic Compositions of Hydrothermal Fluids at Snail, Archaean, Pika, and Urashima Sites in the Southern Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587 Tomohiro Toki, Jun-ichiro Ishibashi, Takuroh Noguchi, Miki Tawata, Urumu Tsunogai, Toshiro Yamanaka, and Kentaro Nakamura 46 Gamma Ray Doses in Water Around Sea Floor Hydrothermal Area in the Southern Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . . . . . . 603 Shin Toyoda, Debabrata Banerjee, Hidenori Kumagai, Junichi Miyazaki, Jun-ichiro Ishibashi, Nobutatsu Mochizuki, and Shigeaki Kojima 47 226 Ra- 210 Pb and 228 Ra- 228 Th Dating of Barite in Submarine Hydrothermal Sulfide Deposits Collected at the Okinawa Trough and the Southern Mariana Trough . . . . . . . . . . . . . . . . . . . . . . . . . 607 Ai Uchida, Shin Toyoda, Jun-ichiro Ishibashi, and Shun’ichi Nakai 48 OSL Dating of Sea Floor Sediments at the Okinawa Trough . . . . . . . . . . . 617 Vaidehi Varma, Shin Toyoda, Yusuke Isono, Ai Uchida, Debabrata Banerjee, Ashok Kumar Singhvi, and Jun-ichiro Ishibashi 49 Immediate Change of Radiation Doses from Hydrothermal Deposits . . . . . 621 Shin Toyoda, Fumihiro Sato, Ai Uchida, and Jun-ichiro Ishibashi 50 Periodic Behavior of Deep Sea Current in the Hatoma Knoll Hydrothermal System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 625 Yasuo Furushima and Hiroyuki Yamamoto Contents xvii 51 The Gelatinous Macroplankton Community at the Hatoma Knoll Hydrothermal Vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 639 Dhugal Lindsay, Mitsuko Umetsu, Mary Grossmann, Hiroshi Miyake, and Hiroyuki Yamamoto xviii Contents Part I Interdisciplinary Studies