An observation network was initiated in 2021 in the framework of the CocoriCO2 project to monitore carbonate parameters along the French coastal systems. Six sites were selected along the French Atlantic and Mediterranean coastlines based on their importance in terms of shellfish production and the presence of high- and low-frequency monitoring activities. At each site, autonomous pH sensors were deployed both inside and outside shellfish production areas, next to high-frequency CTD (conductivity-temperature-depth) probes operated through two operating monitoring networks (SNO COAST-HF and Ifremer ECOSCOPA). pH sensors were set to an acquisition rate of 15 min and discrete seawater samples were collected biweekly in order to control the quality of pH data (laboratory spectrophotometric measurements) as well as to measure total alkalinity and dissolved inorganic carbon concentrations for full characterization of the carbonate system. While this network has been up and running for more than two years, the acquired dataset has already revealed important differences in terms of pH variations between monitored sites related to the influence of diverse processes (freshwater inputs, tides, temperature, biological processes).    

The COAST-HF/Arcachon-Ferret time series characterizes the hydrology of the interface between the Arcachon lagoon, located in the South-Western France, and the Atlantic Ocean. A buoy belonging to Phares et Balises is instrumented with a multi-parametric probe that records sub-surface temperature, conductivity, depth, turbidity and fluorescence every 10 minutes since February 2018. It is opérated by the OASU and EPOC teams (Univ. Bordeaux/CNRS). COAST-HF (Coastal OceAn observing SysTem - High Frequency; www.coast-hf.fr) is a national observation network accredited by the CNRS as a national Earth Science Observatory (Service National d’Observation: SNO). It aims to federate and coordinate a set of 14 fixed platforms instrumented with high-frequency in situ measurements for key parameters of coastal waters. The COAST-HF/Arcachon-Ferret buoy is one of them. COAST-HF is part of the French Research Infrastructure dedicated to coastal ocean observations (RI ILICO, https://www.ir-ilico.fr). Data are transmitted to the Coriolis Côtier database (https://data.coriolis-cotier.org/). Data are raw data.

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 (Osat, %) was estimated by Gac et al. (2020) following the method of Weiss (1970, DOI: 10.1016/0011-7471(70)90037-9). Atmospheric pressure (Patm, 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).

COAST-HF est un Service National d'Observation qui vise à fédérer et cordonner à l'échelle du littoral français un ensemble de plateformes fixes instrumentées de mesures in situ hautes fréquences pour des paramètres clés des eaux côtières. Ce réseau s'inscrit dans l'Infrastructure de Recherche ILICO. Il est constitué de 14 bouées ancrées instrumentées et autonomes permettant la mesure en continu de paramètres physiques et bio-géochimiques.