Dataset: Carbon isotopes (13C and 14C) and concentrations of dissolved methane (CH4) in surface waters sampled in June 2019 at the Coal Oil Point seep field of the Santa Barbara Basin

Samples were collected from the small boat R/V Connell, operated by UCSB. Gases dissolved in seawater were extracted following the procedures outlined in Sparrow and Kessler (2017) and Joung et al (2019). As detailed in these prior publications, surface waters (~ 1 m below sea surface) were pumped through a suction hose with a discharge pump and were passed through multiple filters for removing particles. This water was then continuously passed through a gas-permeable membrane to vacuum extract the dissolved gases in the seawater.

Following these at-sea sample collection procedures, the extracted gas samples were purified and analyzed following vacuum line procedures previously detailed in Sparrow and Kessler (2017).

Please see the Sparrow and Kessler (2017) for detailed descriptions and validation tests for these procedures.

Dissolved methane concentration measurements were conducted using a headspace equilibration technique previously described in Weinstein et al. (2016) and Leonte et al (2017).