Methodology:Quantitative vacuum extraction and mass spectrometry.
Sampling and Analytical Procedures:
Water samples were transferred from Niskin bottles and stored in crimped copper tubing. Gases were extracted from the water samples in a shore-based vacuum system (see references for description) and stored in aluminosilicate glass ampoules. The extracted gases were chemically purified and cryogenically separated, then analyzed for argon, krypton, and xenon concentrations using ion counting in a triple filter quadrupole mass spectrometer. Argon was measured using ion current manometry corrected for small linearity effects. Krypton and xenon were determined using ratiometric isotope dilution. All measurements were standardized to air abundances. Details are given in Jenkins et al (2019) and Stanley et al (2007).
Samples were acquired at sea in replicate. During the generation of this dataset 53 pairs of replicates were analyzed to assess reproducibility. The results are summarized in the attached Supplemental File named "GP15_ArKrXe_Replicates.csv" (note the results listed in this Supplemental File are reported as molar quantities).
Dissolved helium, neon, and helium isotopes were also measured on the same samples and are available at BCO-DMO (see "Related Datasets").