This database consists of several time series recorded at 30-minute intervals on the ASTAN cardinal buoy, located 3.1 km offshore from Roscoff in the western English Channel (France). It was originally developed by Gac et al. (2020, DOI:10.3389/fmars.2020.00712). The present version corresponds to the dataset used in Robache and Schmitt (2025, DOI:10.5194/egusphere-2025-972).

Sea surface temperature (SST, °C) and salinity (SSS, psu) were recorded using a SeaBird Inc. SBE16+ sensor. Dissolved Oxygen (DO) and chlorophyll a (chl a, µg L^-1) concentrations were respectively recorded with a SeaBird Inc. SBE43 sensor and a Cyclops7 sensor. Oxygen saturation (O_sat, %) was estimated by Gac et al. (2020) following the method of Weiss (1970, DOI: 10.1016/0011-7471(70)90037-9). Atmospheric pressure (P_atm, hPa) data were obtained from the weather station at the Roscoff Marine Station. The seawater surface partial pressure of CO₂ (pCO₂, µatm) data was collected on the buoy using a SAMI-CO₂ sensor (SunBurst Sensors).