DEAFS – Deep-sea Autonomous and automated Fluid sampler data from the EMSO-Azores observatory, 2026

High temperature hydrothermal fluids are collected by the Deep-sea Autonomous and automated Fluid Sampler (DEAFS). The instrument is deployed at the footstep of the Montsegur edifice. The site, named Montserrat, expels hydrothermal fluid at 312°C which were collected beforehand by gas-tight fluid sampler manipulated and triggered by the hydraulic arm of the submarine vehicle (HOV Nautile). Several chemical analyses are performed aboard the research vessel: such as salinity and d20/20 by refractometer, pH and Eh by electrode (pH standard 4.01 and 7; Eh standard solution at -220mV). The DEAFS has performed three sample collection at the following dates: 3rd september 2025, 3rd November 2025 and 3rd June 2026. Regional Node: EMSO-Azores, Lucky Strike Hydrothermal Field Vent field : Montsegur Latitude : 37º17.2744’N Longitude : 32º16.5461’W 1699 m depth DEAFS set-up in 2025 after 3 days of deployment at the seabed

Fluid extraction from a DEAFS sampling bottle aboard the Pourquoi Pas? Research Vessel in 2026

DEAFS recovery in 2026