Geochemistry of hydrothermal fluids at the Lucky Strike Hydrothermal Field data from the EMSO-Azores observatory, 2021

High temperature hydrothermal fluids are collected collected during the MOMARSAT 2021 cruise by gas-tight fluid sampler manipulated and triggered by the hydraulic arm of the submarine vehicle (HOV Nautile). Several hydrothermal vents are sampled, namely : Aisics, Montsegur, Montserrat, Isabel, Sintra, Y3, White Castle, Crystal, South Crystal, Capelinhos. Several chemical analyses are performed aboard the research vessel: such as salinity and d20/20 by refractometer, Conductivity, salinity and total dissolved solid (TDS) by electrode (standard solution at 1413 µS/cm), pH and Eh by electrode (pH standard 4.01 and 7; Eh standard solution at -220mV), iron concentration by photometer (up to 5 ppm), H2S and total S concentrations measured by electrode (AquaMS, amperometric method) at measured pH value… Regional Node: EMSO-Azores Vent field : Lucky Strike Latitude : 37º17’N Longitude : 32º16’W 1600 – 1750 m depth