As part of the BaySys project (https://umanitoba.ca/faculties/environment/departments/ceos/research/BaySys.html) to understand the role of freshwater in Hudson Bay, water samples were collected in 2017 and 2018, including oceanic vertical profiles collected by CTD-rosette from 4 depths (surface, subsurface chlorophyll maximum, 70 m and bottom water), surface river water collected by zodiac, and surface water from the ice edge and below ice collected with a pump. In total, 156 water samples were collected in 2017 and 162 samples in 2018, covering most of the western Hudson Bay and the entrance to Hudson Strait. To collect samples for DNA/RNA, water was filtered through 3-µm filters and 0.2 µm cartridges, which were conserved in a buffer at -80°C. These samples may be used for molecular techniques such as 16S/18S amplicons sequencing and shotgun metagenomic to identify the organisms present, gaining further insight into the structure of plankton communities and the potential genetic adaptations to salinity gradients. Other samples were collected at the same stations and depths for flow cytometry (to enumerate bacterial and/or pigmented cells), epifluorescence microscopy with DAPI stain, and fluorescent in-situ hybridization (another microscopy technique). All these samples were transported back to the lab for further analysis.
