Cabled underwater observatory for long-term ecosystem monitoring at hydrothermal site

For the purpose of environmental impact assessment (EIA) at deep-sea hydrothermal environments towards development and utilization of seafloor massive sulfide (SMS) deposits, we have been developing a cost effective cabled underwater observatory. To realize a flexible and expandable system configuration, the observatory has a simple star-type network and power supply topology by employing an Ethernet interface. Pressure hulls and a framework of the observatory are composed of glass or plastic material to avoid corrosion of metals caused by hydrothermal fluid during long-term operation. The first observatory that has physicochemical sensors, water current profilers, and a video instrument will be deployed at the Oomuro Hole hydrothermal site, the northern Izu-Ogasawara arc for the purpose of system demonstration and practical data acquisition.