RQM - CTD Data From the Lampsilis Concerted Mission (MAL2020): State of Health of the St. Lawrence 2020

The Lampsilis concerted mission of August 2020, funded by the Odyssée Saint-Laurent program of the Réseau Québec maritime (RQM), aimed to gather strategic scientific knowledge for the understanding and management of the St. Lawrence River and Gulf. The mission resulted in the acquisition of a wide range of multidisciplinary data for 6 projects focusing on two main areas of research: water quality, and the monitoring of biological communities in the St. Lawrence, as part of the St. Lawrence System continuum.

Vertical profiles of CTD data (conductivity, temperature, depth) were made in the water column at 26 stations in the St. Lawrence River (from Quebec City) and its Upper Estuary (at Cacouna). These profiles were taken from the surface to an average distance of around 1 m from the seabed. They include measurements of temperature, salinity, density, dissolved oxygen, light transmission, vertical stratification and sound velocity in seawater. Discrete water samples were taken at various stations and depths to compare CTD's direct measurements with laboratory analyses of chlorophyll a concentration (63 samples, 37 stations). These comparisons were used to adjust the calibration of fluorescence data from the CTD probe.