The TReX (Tracer ReleaseEXperiment) project is an interdisciplinary research project that aims to develop and demonstrate Canada's ability to predict the spread of contaminants and respond to their accidental discharges in coastal marine environments. The present CTD dataset comes from the first mission of the Trex-Deep phase, which aims to study transport and dispersal processes in the bottom waters of the Laurentian Channel, from the maritime estuary to Cabot Strait. This unique experiment, which combines the expertise of researchers from Quebec, Nova Scotia, and Germany, is used to predict the dispersal and advection of certain contaminants and understand the climate-related biogeochemical processes that control hypoxia and acidification conditions at the head of the Laurentian Channel.
This CTD dataset from the first mission in October 2021 presents vertical profiles of salinity, temperature, dissolved oxygen, density, and fluorescence from 4 to 360 m for about thirty stations between Rimouski and Cabot Strait. Although the probes were calibrated by the manufacturer during the year, discrete salinity samples were taken throughout the water column and analyzed on a Guildline Autosal 8400 salinometer calibrated with standard IAPSO (International Association for the Physical Sciences of the Oceans) seawater and CTD profiles reprocessed after the mission. Similarly, dissolved oxygen concentrations were determined by Winkler chemical titration (Grasshoff et al., 1999) on about forty discrete water samples collected directly from Niskin bottles. The relative standard deviation, based on repeated analyses of samples taken from the same Niskin bottle, was less than 1%. These measurements were also used to calibrate the SBE-43 oxygen probe mounted on the rosette.
It was acquired jointly by the teams of Douglas Wallace (U. Dalhousie), Gwénaëlle Chaillou (ISMER-UQAR) and Toste Tanhua (GEOMAR).