This dataset consists of vertical profiles of discrete depth sampled weekly at a fixed station under the ice in Franklin Bay (Southeastern Beaufort Sea) to determine bacteria abundance. Sampling took place from December 2003 to May 2004 through the moon-pool of the CCGS Amundsen for depth ranging from 10m to the bottom and through a hole in the ice cover for the surface depth (3-10m). Bacteria concentrations were counted by flow cytometry.

Microbial and environmental variables were collected from 8 depths at a 200-m deep site in Franklin Bay on 33 occasions, from 4 November 2003 to 6 August 2004, aboard the CCGS Amundsen. The following variables were measured: depth, temperature and salinity (Seabird 911+ CTD); CDOM (coloured dissolved organic matter) absorption coefficient at 320 nm (Varian Cary Bio 300 scanning spectrophotometer); chlorophyll a (ethanol pigment extraction); bacteria abundance (epifluorescence microscopy); tritiated leucine and thymidine incorporation rates (centrifugation method). Bacterial carbon production (BP) was estimated from leucine incorporation using the carbon conversion factor of 1.5 kgC/mol of leucine incorporation. BP was also estimated from thymidine incorporation using (1) the empirical carbon conversion factor of 2.0 x10^18 cells/mol of thymidine incorporated and (2) the bacterial cellular biomass of 10 fgC/cell.

Here, we sampled five specimens of Chondrocladia and Cladorhiza as part of the Hidden Biodiversity project, using the SuperMohawk ROV on board the CCGS Amundsen. In October 2015, samples were collected from Scott Inlet and off Qikiqtarjuaq, and retrieved using a custom-built sample elevator. Samples were immediately dissected and processed for DNA and histological analyses. The analysis of these samples is currently in progress.

DMSP and DMS water concentrations were determine at fixed depths and at selected stations (ArcticNet stations) along a transect beginning in the North Water Polynya, going through the Lancaster Sound and the Northwest Passage, and terminating in the Beaufort Sea. During transit time, near surface DMS measurements were conducted every 2 hours from the pumping system of the CCGS Amundsen. In all cases, DMSP and DMS measurements were done following the methods of Kiene and Slezak 2006 (Limnol. Oceanogr.: Methods 4: 80-95). At selected stations, DMSP and DMS microbial cycling was determined during onboard incubations following the 35S-DMSP protocol (Merzouk et al. 2006, Deep Sea Res. 53:2370-2383).

First-year sea ice was sampled on 36 occasions near the overwintering site of the CCGS Amundsen during the Canadian Arctic Shelf Exchange Study (CASES). Sea-ice and associated surface water samples were taken every 3 to 5 days between 24 February and 20 June 2004. Surface waters and the bottom 3-5 cm of ice cores were routinely analyzed for: salinity, pH, nutrients (NH4, NO2, NO3, Si(OH)4, and PO4), dissolved organic carbon and nitrogen (DOC, DON), exopolymeric substances (EPS), particulate inorganic carbon (PIC), particulate organic carbon and nitrogen (POC, PON), total and >5 µm chlorophyll a and phaeopigments, bacterial abundances/biomass, protist (excluding diatoms) abundances/biomass and ice algal/phytoplankton taxonomy. This data set also includes vertical and spatial profiles of ice algal distribution as well as measurements of sea-ice primary production, bacterivory and sea-ice algal and bacterial sinking velocities.

As part of the ArcticNet expeditions (http://www.arcticnet.ulaval.ca) on the CCGS Amundsen in 2008-2019, we collected water samples from stations throughout the Canadian Arctic. Cruise tracks varied from year to year, but always included a transect of northern Baffin Bay, and sometimes sampling in Lancaster Sound, the Beaufort Sea, and/or along the east coast of Baffin Island. The sampling period ranged from summer to autumn. Samples were collected by CTD-rosette from 2-8 depths corresponding to water column features such as surface water, the subsurface chlorophyll maximum, the nitracline, or Atlantic Water. 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 have been used for high-throughput sequencing for amplicon-based surveys, metagenomics, and other molecular techniques. Samples for flow cytometry (to enumerate bacterial and/or pigmented cells), microscopy (with a fluorescent DAPI stain, or using FNU preservative for identifying larger cells), fluorescent in-situ hybridization (another microscopy technique), chlorophyll a (to quantify photosynthetic organisms), and HPLC pigment analysis (to identify different algae taxa), were also collected. Samples from which nucleic acids have been extracted and sequenced in many projects. Samples from which nucleic acids have been extracted and sequenced can be found in the GenBank Short Read Archive under the project accession numbers PRJNA202104, PRJNA283142, PRJNA283296, PRJNA383398, and SRX037894-SRX037896

Samples were collected from nine sites distributed across the study region in 2008 and 2009. To avoid confounding influence of seasons, the same sites were sampled in the same season each year. Sampling was conducted onboard the CCGS Amundsen between July and October during the Circumpolar Flaw Lead Study, ArcticNet expeditions in collaboration with the Canadian Healthy Ocean Network and the Malina project. Locations were chosen to study both hotspots and coldspots in the Canadian Arctic. At each sampling station, an USNEL box corer was deployed for seafloor sediment collection. From each box core, three to five sub-cores of 10 cm diameter and approximately 20 cm sediment depth were taken for assessing benthic remineralisation function in shipboard microcosm incubations. After incubation, the same sediment cores were passed through a 0.5 mm mesh sieve under slow running seawater. The sieve residues were preserved in a 4% seawater-formaldehyde solution for later analyses of species diversity and abundance under a dissection microscope.

We are seeking answers to two key questions regarding the influence of marine processes on Arctic climate: 1) How will the increased flow of Pacific waters through the Canadian Archipelago affect the dynamics of climate-active gases in the ocean, and 2) How will these gases be affected by a reduction of sea-ice cover, and increased areas of open water? These questions have been addressed by our multidisciplinary team during two expeditions on the Canadian research ice-breaker Amundsen as part of the International Polar Year. The expeditions took place during the fall of 2007 and 2008. Eleven (2007) and ten (2008) Arctic SOLAS scientists from 7 Canadian institutions participated to these expeditions which allowed a unique and extensive longitudinal survey of these trace gases and aerosols in the High Canadian Arctic, from Baffin Bay to the Beaufort Sea. The missions enabled us to collect new oceanographic and atmospheric data on the distribution and cycling of DMS, N2O, and VOCs across the Canadian Archipelago and to relate these measurements to the distribution and chemical characteristics of aerosol particles. Activities of this program where coordinated with those of the IPY programs CFL, the Canadian program ArcticNet, and the international programs OASIS and SOLAS.

Free-drifting, short-term particle interceptor traps were deployed from the CCGS Amundsen on eight occasions between 23 September and 16 October 2005. The traps were deployed at two or three depths below the euphotic zone (from 25 to 150 m) for 8 to 20 h. The sinking material was analyzed for particulate inorganic carbon, particulate and dissolved organic carbon, biogenic and lithogenic silica and chlorophyll a concentrations. Phytoplankton abundance and composition, fecal pellet abundance and biovolume and bacterial abundances were also assessed for the sinking material. Water column samples, from depths between 10 and 150 m, were collected to quantify fecal pellets. Lastly, phytoplankton from the deep chlorophyll maximum depth was collected and their sinking velocity determined using settling columns.