Mercury dynamics under combined effects of run-of-river dams and watershed disturbances [Haute-Mauricie, Quebec, Canada, 2018-2023]

This dataset contains water biogeochemical parameters (pH, DO, TN, TP, DOC, CH₄, CO₂, δ¹³C-CH₄, δ¹³C-CO₂) and various biological matrices (macrophytes, periphyton, macroinvertebrates and fish) analyzed for mercury and methylmercury concentrations, as well as stable isotopes of carbon, hydrogen and nitrogen. These measurements were used to assess the effects of various watershed and hydropower-related disturbances within six sectors characterized by distinct disturbance regimes along the upstream-to-downstream gradient in the upper Saint-Maurice River, Quebec, Canada. Sampling took place in August 2023, during the peak summer period. To allow for historical comparisons with fish, data from the 2018 sampling campaign (Ponton et al. 2021) were also used.