Dataset: WBTS CTD casts

Sampling at the Wilkinson Basin Time Series (WBTS) station followed as a guideline the protocols established by the Atlantic Zone Monitoring Program (AZMP) established by Fisheries and Oceans Canada (Mitchell et al. 2002).

Sampling and analytical procedures:

Environmental data. The R/V Gulf Challenger system comprised a Sea-Bird Electronics (SBE) 25Plus CTD, an SBE-55 Sampling Rosette with six four-liter Niskin bottles, a dedicated Hawboldt Industries SPR 1424/S Science winch, and a SBE-33 real-time monitoring and sampling deck unit. The system provided high-resolution vertical profiling of hydrographic properties (e.g. conductivity, salinity, temperature), physiochemical properties (e.g. Photosynthetically Active Radiation (PAR)), and surrogates for biological and geological processes (e.g. dissolved oxygen, chlorophyll-a fluorescence, and beam transmittance). The raw CTD data and bottle trips were acquired by SBE Seasave on a Windows 7 workstation and were processed from hex files to .cnv files. Post cruise data processing was completed on a Windows 7 machine running SEABIRD SBE DATA Processing version 7.22.5 At most stations, Niskin bottles were used to capture water samples at depths of 2, 10, 20 and 40 meters. To measure chlorophyll a concentration at discrete depths, duplicate, 100 mL or 500-550 mL subsamples were collected from Niskin bottles at the surface, 10, 20 and 40 meters. Water was filtered immediately on the vessel using glass fiber filters (GF/F) and polycarbonate membrane filters with pore sizes of 0.7 µm and 0.1µm. Chlorophyll-a concentrations were calculated were using equations in Strickland and Parsons (1972). Prior to 2014, IOP profilers calibrated annually were used to measure water column stimulated fluorescence. After 2014, the nominal chlorophyll-a readings from stimulated fluorescence measured with a Wetlabs Wetstar Chlorophyll Fluorometer S/N WSS-164 were corrected with chlorophyll concentrations measured from bottle samples.