Exploration for New Lost Cities

We have brought some additional sensors to use on the exploratory platforms (ABE, CTD) to perhaps aid in sensing the presence hydrothermal fluids in the water column that are similar to those at Lost City. Finding similar temperature and chemical anomalies provides strong hints that a hydrothermal field like Lost City is near, or perhaps a new black smoker field. However, because Lost City fluids are quite low in temperature and do not contain high concentrations of particles, traditional signals of temperature and particles (light scattering) may be very weak above system we are “prospecting” for. Because of this, we will add a specialized instrument on to both ABE and the CTD that measures “eH”. These electrochemical sensors look for the presence of “reduced” chemical species in the waters above the areas of interest. Provided by Dr. Ko-ichi Nakamura of the Geological Survey of Japan, these sensors provide electrode surfaces on which many vent-derived chemical species react. We have also provided a commercially made CH₄ sensing unit, which we hope will indicate the increased levels of methane found in the fluids vented from Lost City-like structures. This will be primarily used on the CTD, but both sensors will likely be put aboard Alvin early in the program to evaluate their responses when placed very near the venting fluids.