A deep-sea in-situ chemical laboratory for cabled seafloor observatories

A deep-sea in-situ chemical laboratory (DICL) is proposed for new insight into ocean chemical evolution. The DICL integrates a deep-sea in-situ anion analyzer (DIAA) and several chemical sensors connected to cabled seafloor observatories via a science instrument interface module (SIIM). It can measure the concentrations of seawater anions (e.g., Fˉ, Clˉ, Brˉ, NO3ˉ, SO42ˉ, PO43ˉ), chlorophyll-a, dissolved oxygen, and methane, as well as pH value. The system operation status can be monitored remotely on the shore, and the science data can be acquired in real-time. After water pressure tests and shallow sea trials, the DICL was tested in the Monterey Accelerated Research System (MARS) deep-sea observatory and collected high-resolution time-series chemical parameters. The experimental results demonstrated that the DICL's mechatronics integration design is reasonable and feasible.