The first quantitative marine measurements of trichlorotrifluoroethane (F-113) were made in the North Pacific subarctic gyre in July of 1986, using a modification of the analytical procedure developed for the transient tracers F-11 and F-12 (Gammon et al., 1982; Wisegarver and Cline, 1985). The measured mixed layer concentration was 0.29¿0.02 pM/L; the corresponding atmospheric mixing ratio was 35¿1 pptv (Rasmussen scale).

Below a subsurface maximum both F-11 and F-113 were found to fall off exponentially with increasing depth, F-113 reaching effective blank levels first. The significance of adding F-113 to the existing suite of measurable oceanic transient tracers rests in the possibility of age-dating water masses by their (F-113/F-11) ratio with near annual resolution for the period since 1977.