Development of submarine methane-hydrate assessment using high precision chlorine isotope ratio

2014 Fiscal Year Final Research Report

• Project/Area Number: 25550011
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental dynamic analysis
• Research Institution: University of Toyama
• Principal Investigator: ZHANG Jing 富山大学, 大学院理工学研究部(理学), 教授 (20301822)
• Co-Investigator(Kenkyū-buntansha): TAKEUCHI Akira 富山大学, 大学院理工学研究部(理学), 教授 (20126494)
• Project Period (FY): 2013-04-01 – 2015-03-31
• Keywords: メタンハイドレート / メタンプルーム / 塩素同位体比 / 日本海東縁 / アスファルトシープ / ブラジル沖

Outline of Final Research Achievements

Multiple biogeochemical tracers (e.g. stable isotopes, major and trace elements) were utilized for sea water and pore water in sediment as approaches to establishing methane hydrate (MH) monitoring in this study. Comparative studies off Joetsu coast, western central Japan, with MH and non-MH areas off eastern Brazil were conducted. A new MH area off the Joetsu coast with multiple methane plumes in the water column and bacteria mats on the sea floor was discovered and investigated. Significant sulfate reduction occurring in the pore water indicates high microbial activity in the sediment and also that nutrient/methane is supplied from the MH. There was no sulfate reduction and also moderately low phosphate observed in the pore water off Brazil coast indicating little microbial activity in the surface sediment. Moreover, a higher silicate gradient in pore water at an asphalt area, three times greater than at other dive sites observed, suggests higher seep activity under the seafloor.

Free Research Field

複合新領域