Gulf of St. Lawrence and Estuary Dataset (GOSLED): a 20-year compilation of quality-controlled biogeochemical observations (2003–2023)

Abstract. This paper presents the Gulf of St. Lawrence and Estuary Dataset (GOSLED), a quality-controlled compilation of biogeochemical observations collected during 21 research cruises in the St. Lawrence Estuary, Gulf of St. Lawrence, and Saguenay Fjord between 2003 and 2023. This dataset integrates hydrographic measurements and a broad suite of discrete biogeochemical variables into a single, standardized compilation suitable for reuse, synthesis, and long-term analysis. GOSLED includes discrete measurements of dissolved oxygen, carbonate-system parameters, macronutrients, dissolved organic carbon, selected biogeochemical gases, stable isotope ratios of carbon and water, and transient and deliberate tracers. Data were compiled from multiple independent research cruises and laboratory archives (2003–2020), including contributions from the Marine Environmental Observation, Prediction and Response Network (MEOPAR) – Réseau Québec maritime (RQM) Gulf of St. Lawrence Tracer Release Experiment (TReX; 2021–2023), RQM Odyssée Saint Laurent program (2018–2023), and the Fisheries and Oceans Canada (DFO) Atlantic Zone Monitoring Program (AZMP; fall 2022). Sampling was conducted predominantly during the ice-free season, resulting in limited winter coverage across much of the system. All data were harmonized and processed following primary quality-control procedures adapted from GLODAP and CODAP-NA standards. Secondary crossover analysis was not possible due to a lack of deep-water (>1500 m) sampling. This paper documents the data provenance, quality-control procedures, known limitations, and recommended considerations for dataset usage. GOSLED is archived at the Canadian Integrated Ocean Observing System – St. Lawrence Global Observatory (CIOOS-SLGO) and is publicly accessible at https://doi.org/10.26071/d6f3fdfc-788d-48ff (Nesbitt et al., 2026).