The investiagtion of methane seeps and hydrothermal vents in the Middle Okinawa Trough

From October 3 to November 9, 2024, a manned deep-sea dive expedition in the Okinawa Trough was successfully conducted by the expedition team from the Chinese Academy of Sciences and Ministry of Natural Resources of China. Utilizing the exploration vessel "TAN-SUO-ER-HAO" and the manned submersible "SHEN-HAI-YONG-SHI," the expedition aimed to investigate the geological, environmental, and biological phenomena associated with the submarine fluid systems on the seafloor in the Middle Okinawa Trough. The expedition uncovered large-scale active cold seeps developing at the back-arc spreading center axis, covering an area of approximately several dozen square kilometers. Geological activities related to the release of high-temperature supercritical carbon dioxide fluids were also observed, with multiple venting sites identified that generate a carbon dioxide-rich hydrothermal plume. These discoveries provide an exceptional natural laboratory for observational research on critical issues such as deep-seated carbon release at back-arc spreading centers, localized deep-sea water acidification, and the life adaptation strategies in extreme environments.