*Shin-ichi Ito¹, Kotaro Shirai¹, Kazuki Yokouchi³, Toyoho Ishimura², Kagari Aoki¹ (1.Atmosphere and Ocean Research Institute, The University of Tokyo, 2.Graduate School of Human and Environmental Studies, Kyoto University, 3.Japan Fisheries Research and Education Agency)

*Hiroki Nishimura^1,2, Mariko Kouduka¹, Akari Fukuda¹, Toyoho Ishimura³, Yuki Amano^5,4, Hikari Beppu⁵, Kazuya Miyakawa⁴, Yohey Suzuki¹ (1.Graduate School of Science, Department of Earth and Planetary Science, The University of Tokyo, 2.Biogeochemistry Research Center (BGC), Research Institute for Marine Resources Utilization (MRU), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 3.Kyoto University, Graduate School of Human and Environmental Studies, 4.Horonobe Underground Research Center, Japan Atomic Energy Agency, 5.Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency)