In 2017 and 2018, we sampled about 20 locations across Frobisher Bay, mostly in the deeper portions of outer Frobisher Bay that are only accessible for sampling from large ships. Sample stations were chosen to span the range of depth and slope values in the multibeam sonar dataset, and in 2018 sampling, also included gross bottom morphology, such as ridges and troughs. We also targeted some particular geomorphic features, such as suspected submarine extensions of moraines. In 2017, bottom samples were acquired using box-cores, and small scientific trawl (Agassiz trawl). In 2018, bottom samples were acquired using box-cores, combined with a drop-video camera. Agassiz trawls were collected at two stations in 2018. Sediment samples were described visually and subsamples frozen for grain size and organic content analysis. Where informative, subsamples of lithic fragments within the sediments were kept for mapping. Bottom faunal samples were enumerated and preserved in 2% formalin in seawater, except for larger faunal samples such as soft corals, which were frozen.

Ocean Mapping Group acoustic data generated from the 2011 multibeam sonar survey on the 2011 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.

Ocean Mapping Group acoustic data generated from the 2004 multibeam sonar survey on the 2004 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.

Environment Canada installed a meteorological system on the Voluntary Observing Ship (VOS) scheme part of the CCGS Amundsen. The system is composed of a Digital Barometer (Vaisala PTB-210), an R.M Anemometer (Young 05103) and a Humidity-Temperature Meteorological sensor (Rotronic MP101). The system continuously recorded Atmospheric pressure, Wind Speed and Direction, Air temperature and Humidity every 4 seconds for the CCGS Amundsen expeditions between 2004 and 2017. No data was collected in 2012 since the vessel was undergoing maintenance (dry docks). The true wind was directly calculated by the system using the ship's gyrocompass, the recorded apparent wind and Global Positioning System (GPS) data (speed and track of the ship from POS-MV and C-NAV Differential Global Navigation Satellite System (DGNSS) Precise Point positioning systems). Then the AVOS system averaged the data at 10 minute or hourly intervals. Outliers and suspicious measurements were removed from the dataset and the resulting controlled data are provided at 10 minute or hourly intervals for each day of the expeditions. Research programs participating in the Amundsen expeditions between 2004 and 2017 include CASES, ArcticNet, CFL, Geotraces, Malina, IOL and BP, BREA, Weston, Netcare, JAMSTEC, Statoil and iBO and GreenEdge.

The CTD data was obtained during the 2010 ArcticNet scientific cruise #1003c. The data were collected from October 24 to 27, 2010, aboard the CCGS Amundsen. There were 19 casts associated to 19 stations, located in the Labrador Fjords. The following parameters were measured: temperature, conductivity and pressure (with a Sea-Bird SBE-9plus), dissolved oxygen (Sea-Bird SBE-43), fluorescence (Seapoint chlorophyll fluorometer), CDOM (Wetlabs FL(RT)D), nitrate concentration (Satlantic MBARI-ISUS 5T), transmittance (Wetlabs C-Star transmissometer), light intensity (PAR; Biospherical Instruments QCP2300) and surface light intensity (sPAR; Biospherical Instruments QCP2200). Quality control procedures were applied to the data. Data are available on the Polar Data Catalogue and at the Marine Environmental Data Service (MEDS) of Fisheries and Oceans Canada.

Sample collection took place during both legs of the 2005 CCGS Amundsen cruise, during Leg 1 in 2006 and during Leg 3 in 2007. Water samples were collected using Teflon-lined Niskin bottles mounted on the ship¿s rosette system, at sites ranging from Hudson Bay, the North Open Water Polynya, the Northwest Passage and the Beaufort Sea. The water column was sampled at the surface, middle and bottom in 2005 and 2006 and at the surface and chlorophyll maximum in 2007. The resulting water chemistry dataset includes concentrations of total Hg, MMHg, DMHg and GEM in water. In addition, samples were also analyzed for sulfate and dissolved organic carbon in 2007 and for sulfate only in 2006. To quantify rates of biogeochemical Hg transformations in the water column, some water samples were amended with Hg stable-isotope tracers, namely 198Hg(II) and MM199Hg, and incubated on-board the ship for up to 25 hours before being preserved by acidification or freezing. Samples were then analyzed for MMHg, DMHg and GEM, using various mass-spectroscopy techniques at either the University of Alberta or Trent University. Thus, the rate of transformation of the 198Hg(II) tracer into MM198Hg, for example, could be quantified. This dataset includes rate constants for the following water column processes: the methylation of Hg(II) to MMHg, the methylation of MMHg to DMHg, the demethylation of MMHg, the reduction of MMHg to Hg(0) and the reduction of Hg(II) to Hg(0).

Ocean Mapping Group acoustic data generated from the 2009 multibeam sonar survey on the 2009 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.

The all-sky camera system consists of a Nikkon D-90 camera, with a wide-angle fisheye lens, a homemade enclosure with clear acrylic dome end-cap, and a small heater on a thermostat. The system is mounted on a small 'crows nest' above the wheelhouse on the CCGS Amundsen. Maintenance checks were performed daily.

During the ArcticNet annual cruises of the research icebreaker CCGS Amundsen, characteristics of the near-surface atmosphere (basic meteorological elements, incident radiation, CO2 concentration) are monitored in conjunction with surface sea water properties (temperature, salinity, dissolved CO2 and O2) to observe the relationship between the surface micro-climate and the air-sea exchange, with particular interest in CO2. As part of this integrated dataset, the following radiation variables were recorded at 1 minute intervals (instrument used to collect each variable is in parentheses): incoming shortwave radiation (Eppley pyranometer, model PSP); incoming longwave radiation (Eppley pyrgeometer, model PIR); incoming photosynthetically active radiation (Kipp & Zonen, PAR-Lite). All instruments were mounted on a meteorological tower on top of the wheelhouse of the research icebreaker CCGS Amundsen.

Ocean Mapping Group acoustic data generated from the 2007 multibeam sonar survey on the 2007 CCGS Amundsen ArcticNet Cruise. The data include high-resolution bathymetry and acoustic backscatter imagery collected 24 hours a day, whenever the ship was in transit or had dedicated survey time.