The distribution of dissolved organic carbon (DOC) in the water column of the Canadian Arctic was investigated in 2007, as part of the ArcticNet program. Summer-fall DOC concentrations were measured at 30 stations between 29 September and 3 November 2007. Samples were collected using the rosette onboard the CCGS Amundsen. Euphotic zone sampling depths corresponded to surface irradiances between 0.2 and 100% as well as the chlorophyll a maximum depth. Aphotic sampling depths ranged from 75 m to the bottom waters.

The distribution of dissolved organic carbon (DOC) in the water column of the Canadian High Arctic was investigated in 2006, as part of the ArcticNet program. Summer-fall DOC concentrations were measured at 27 stations between 4 September and 17 October 2006. Samples were collected using the rosette onboard the CCGS Amundsen. Euphotic zone sampling depths corresponded to surface irradiances between 0.2 and 100% as well as the chlorophyll a maximum depth. Aphotic sampling depths ranged from 75 m to the bottom waters.

Replicate cores spanning the entire thickness of the floe were taken from a single sampling site on a multi-year sea ice floe in the southwestern Beaufort Sea in August 2011 as part of the ArcticNet 2011 cruise of the CCGS Amundsen. Quantification of total mercury (THg), methylmercury (MeHg), Chlorophyll a, dissolved organic carbon (DOC) and delta 18O was performed on separate cores, and temperature and salinity profiles were recorded. THg was analyzed via CVAFS on board the Amundsen in the Portable In-situ Lab for Mercury Speciation (PILMS), while MeHg was analyzed via GC-CVAFS in the Ultra-Clean Trace Elements Lab (UCTEL) at the University of Manitoba. Chlorophyll a concentrations were analyzed onboard the Amundsen via fluorimetry, and salinity was recorded using a Hach Sension probe. DOC was analyzed by Dr. Michel Gosselin's lab at the Université du Québec à Rimouski via a high-temperature combustion Shimadzu TOC-5000A autoanalyzer. Delta 18O analysis was performed by G.G. Hatch Isotope Laboratories, University of Ottawa, Canada. Samples and standards (calibrated against several samples of Vienna - SMOW) were flushed with a gas mixture of 2 % CO2 in helium off-line, equilibrated at 21°C for 5 d, then analyzed using the Gasbench + DeltaPlus XP isotope ratio mass spectrometer (ThermoFinnigan, Germany).

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.

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.

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.