Academic Staff

　Accretionary prisms are thick sediments. They are observed at convergent plate boundaries around the world; for example Alaska and Washington in the U.S., New Zealand, Chile, Peru, Indonesia, and Taiwan. In Southwest Japan, the accretionary prism situated along the Pacific side is traceable laterally for 1,800 km. The thick sediments are derived from marine sediment; therefore, they are rich in complex organic matter. The sediments contain layers of water-bearing permeable sandstone, and the anaerobic groundwater in the sandstone layers contains natural gas (mainly CH4) and microbial community.

　To reveal microbial metabolisms and material cycles present in the sedimentary layers, a series of geochemical and microbiological studies is performed. We identify the production pathway of CH4 that is reserved in the sedimentary layers. Additionally, we develop a novel bioenergy production system using anaerobic groundwater, CH4, and subterranean microbial communities associated with the accretionary prisms.