In-situ, real-time methane sensor for vents and seeps

To meet the need for better analysis of ocean methane, we have developed an in-situ gas sensor, that combines a novel laser absorption spectrometer with a membrane-free approach to water sampling. The sensor was designed for real-time measurements of methane concentration and isotope ratio at depths down to 3000 m and is useful for scientific studies as well as energy exploration. We describe the design, development, and utilization of the sensor. Including presenting data from measurements at deep-sea hydrothermal vents on two recent scientific research cruises: July 2022 and March-April 2023.