Euphotic Zone Metabolism in the North Pacific Subtropical Gyre Based on Oxygen Dynamics

We report in situ rates of gross oxygen production (GOP), community respiration (R), and net (NCP) the North Pacific Subtropical Gyre derived from mixed layer O2/Ar measurements. The measurements were conducted between November 2013 January 2019 at site Hawaii Ocean Time-series program. Biological O2 concentration anomalies showed a consistent diel variation, with values increasing during daytime due to decreasing nighttime respiration. In GOP R, determined these variations, covaried but no clear seasonal pattern, averaging 0.9 0.8 mmol m−3 d−1, respectively. NCP ranged −1.2 16.6 m−2 d−1. Our analyses indicate that certain times year diapycnal flux across base may be non-negligible and, therefore, fraction O2/Ar-derived form below layer. climatology (down 150 m) was also estimated using near-monthly changes dissolved concentrations. These calculations allowed us estimate for entire euphotic zone (0–150 m), which shows pronounced seasonality, maximum April-May minimum December, when ecosystem becomes temporarily heterotrophic. Annual 2.1 ± 0.6 mol yr−1, approximately 1.7 export C through sinking particles captured sediment traps m.