Oral Section MIS005-06 2010/05/24 (10:15 ~ 10:30 am) Influence of Gas Hydrate Dissociation and Methane Seeps in the Geochemistry of Seafloor Shallow Sediments of Joetsu Basin, Eastern Margin of Japan Sea Eastern Margin of Japan Sea Antonio Fernando Menezes FREIRE Antonio Fernando Menezes FREIRE Ryo MATSUMOTO Toshihiko SUGAI Fumio AKIBA Fumio AKIBA Maki SUZUKI