Evaluation of laser-induced breakdown spectroscopy (LIBS) as a new in situ chemical sensing technique for the deep ocean

Present day expeditionary oceanography based on short term ship and submersible deployments is beginning to shift to an ocean observatory mode where long term temporally focused studies become feasible. As a result, a greater need for in situ chemical and biological sensors is evolving. Laser-induced breakdown spectroscopy (LIBS) possesses many of the characteristics required for such in situ chemical sensing, and is a promising technique for field measurements in extreme environments. LIBS has many possible applications in the ocean, including the analysis of rocks, sediments, and hydrothermal vent fluids. Although many LIBS researchers have focused their work on solids, very little attention has been paid to bulk liquid analysis, and especially on the effect of oceanic pressures on LIBS signals. In this work, preliminary laboratory experiments are presented to validate the technique in a simulated deep ocean environment; more specifically, the focus is on using LIBS to study hydrothermal vent fluids.