Dataset: Continuous rates of net community production and the O2/Ar data on the US Northeastern Shelf in the SPIROPA project during spring and summer 2018 and 2019.

Water from the underway was pumped into an equilibration cartridge (Liqui-Cel Extra-Flow 2.5x8 model G540). The gas stream was dried with the desiccants Nafion and Drierite and then transferred to a Hiden Quadrupole mass spectrometer via a deactivated fused silica capillary where ion currents of O2 and Ar, were measured. The system was calibrated by measuring the O2/Ar ratio in air for approximately 20 minutes every 6 hours and also by measurements of O2/Ar in samples collected into custom-made 300-mL glass bottles and analyzed post-cruise at a shore-based lab using an isotope ratio mass spectrometer. For details on the methods and analysis, see Castillo Cieza et al. (2024). The gas content in the underway water was confirmed to be statistically the same as that in the CTD surface Niskins by repeatedly comparing water from those sources during each cruise.