Carbonate Chemistry Along a Small River-Coastal Ocean Continuum (Kamouraska River, Qc, Canada)

This dataset contains all the chemical parameters measured during expeditions between May 2021 and October 2022 in the surface waters of Kamouraska's coastal waters. The data are divided into two databases.

The first contains all chemical parameters measured at fixed stations. Sampling was carried out along the Kamouraska River - Upper St. Lawrence Estuary coastal water continuum at 10 to 13 stations, depending on the expedition. The sampling strategy was to start collecting samples in the Kamouraska River at high-water slack water, then move towards the upper St. Lawrence estuary. Fixed stations upstream of the Kamouraska River, where the water is too low to go up with the boat, and at the mouth of the Kamouraska River, are also included in this database, along with the coordinates of all the stations. Surface water samples were collected using a Niskin bottle, and physico-chemical parameters were obtained using a CTD probe on board the boat, and using a YSI probe for the other stations. Parameters measured include :

• Temperature - T
• pH_NBS
• pH_T
• Practical salinity
• Dissolved inorganic carbon - DIC
• Measured Total alkalinity - TA_meas
• Calculated Total alkalinity - TA_calc
• 13C signature of the DIC - δC13-DIC
• Total nitrates - ƩNO₃
• Nitrites – NO₂^-
• Soluble reactive phosphorus – SRP
• Dissolved silicate - DSi

The second database contains in situ data collected in parallel. Continuous pCO₂ measurements were taken from the boat. A submersible pump was deployed from the side of the boat, pumping surface water into a degassing chamber connected to a CO₂ analyzer (LI-830). Data are obtained every second, 5 seconds or 30 seconds depending on the expedition, and each measurement is coupled to a GPS position.