Baseline measurements of bottom water, sediment and nutrients for the benthic environments of Saguenay fjord, Quebec, Canada

Fjords are distinctive geomorphological features that hold global significance for carbon burial and biogeochemical cycling, yet comprehensive datasets describing benthic environmental conditions are scarce. Here we provide a comprehensive georeferenced database of measured values of bottom-water (depth, fluorescence, dissolved oxygen, pH, salinity, temperature, turbidity), sediment (organic matter content, sediment particle-size descriptors [D₅₀, sorting, skewness, kurtosis]) and dissolved nutrient concentrations ( \({{NO}}_{{2}}⁻⁻\) , \({{NO}}_{{3}}⁻⁻\) , \({{PO}}_{{4}}^{--{3}}\) , \({{SiO}}_{{4}}^{--{4}}\) ) compiled from the peer-reviewed literature (1931–2025) for the Saguenay Fjord, a glacially carved tributary of the St. Lawrence Estuary, Quebec, Canada. We include metadata relating to the study region and season. The dataset represents the most comprehensive synthesis to date for the Saguenay fjord, and is designed to support ecological, geochemical, and modelling applications, while providing a transferable framework for establishing fjordic information globally in support of management and conservation.