This study aims to quantify groundwater discharges and associated DIC and CO2 fluxes at a high- and low- resolution scales on the Matane River (Qc, Canada). The flux calculations were based on a dataset including radon-222 activities (i.e., 222Rn), and measurements of dissolved inorganic carbon (i.e., DIC), total alkalinity, CO2 partial pressure (i.e., PCO2), and pH. The low-resolution study was undertaken at the corridor scale (07/2017), while the high-resolution study focused on a ~800 m long meander reach (08/2017). At the corridor scale, for the 12 sampling points, river water was analyzed in a riffle and in a pool to better represent river sections. Groundwater was also sampled from 4 private wells and in 2 piezometers for the corridor scale study, and from 12 piezometers inserted into the 18 ha meander floodplain for the meander scale study.

PCO2 method: "TA-pH" and "DIC-pH" refer to calculated values with the fresh water compatible R package "Aquaenv" for experimental aquatic chemistry using the couples pH and total alkalinity or DIC respectively"