Stephen Obrochta¹, Wataru Miwa¹, Kotaro Shirai², Kaoru Kubota³, Yusuke Yokoyama², Yosuke Miyairi², Takumi Asada⁴, Jody Webster⁵, Mahyar Mohtadi⁶ and Albert Case Hine⁷, (1)Akita University, Graduate School of International Resource Science, Akita, Japan, (2)The University of Tokyo, Atmosphere and Ocean Research Institute, Kashiwa, Chiba, Japan, (3)Isotope Geochemistry Group, Kochi Institute for Core Sample Research, JAMSTEC, Tokyo, Japan, (4)Akita University, Department of International Resource Science, Akita, Japan, (5)University of Sydney, Geocoastal Research Group, School of Geosciences, Sydney, NSW, Australia, (6)MARUM - University of Bremen, Bremen, Germany, (7)University of South Florida, College of Marine Science, St Petersburg, FL, United States