Verification of intermittent methane emissions using radiocarbon age of shells from a large scale biological community off Tokai

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K13576
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Geology
• Research Institution: The University of Tokyo
• Principal Investigator: Ashi Juichiro 東京大学, 大学院新領域創成科学研究科, 准教授 (40251409)
• Co-Investigator(Renkei-kenkyūsha): YOKOYAMA Yusuke 東京大学, 大気海洋研究所, 教授 (10359648) ; MIYAIRI Yosuke 東京大学, 大気海洋研究所, 特任研究員 (30451800)
• Research Collaborator: YAGASAKI Kazuhiro 東京大学, 大学院新領域創成科学研究科, 大学院学生
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 深海環境 / 化学合成生物群集 / 海洋調査 / 冷湧水 / メタンハイドレート

Outline of Final Research Achievements

In order to clarify the formation of the giant colony composed of Calyptogena off Tokai, ocean floor observation, subbottom acoustic survey, radiocarbon dating and chemical analyses were carried out. The high-resolution sub-bottom survey using a remotely operated vehicle revealed multiple faults reaching to the seafloor around the colony. Furthermore, the largest colony corresponds to the site where the faults are densely distributed and forms a depression on the seafloor. Radiocarbon age of the shells spread across into more than three age groups, suggesting that the giant colony formation and the death of bivalves occurred due to the repeated intermittent methane emissions.

Free Research Field

海洋地質学