The navigation data of the Amundsen scientific expeditions between 2003 and 2019 were recorded with the Position and Orientation Systems for Marine Vessels (POS-MV) and C-Nav Differential Global Navigation Satellite System (DGNSS) Precise Point Positioning systems. Two sets of controlled data are provided for each year of expedition. The first set is at time intervals of seconds for every day of the cruise and the second set is at 15 minute intervals. The data consist of Latitude, Longitude, Heading, Roll, Pitch, Heave, Track, Speed and Global Positioning System (GPS) sources at the second time intervals. The vessel's tracks in .kml (Google Earth format) were derived from the 15 minute time intervals dataset and are also provided. Research programs participating in the Amundsen expeditions between 2003 and 2017 were CASES, ArcticNet, IPY-CFL, Solas, Geotraces, Malina, IOL and BP, Jamstec, Netcare, Weston, BREA, iBO and GreenEdge.

The data set is composed of raw files recorded with the Kongsberg Maritime SX90 long-range, low frequency (20-30 kHz) fisheries sonar during the CCGS Amundsen 2013 summer expedition in the Eastern Canadian Arctic. The sonar transducer is lowered 2.5 feet below the hull through a gate-valve. The cylindrical 256-elements transducer allows both a horizontal and a vertical sound transmission, and the omni-directional (horizontal) sonar beam can be tilted from +10 to -60 degrees to scan a large portion of the water column. The raw acoustic data were saved onto an external drive and print screens of interesting targets (fish schools) were recorded.

The CTD data was obtained during the 2007-2008 ArcticNet scientific cruise #0806. The data were collected from September 5 to 25, 2008, aboard the CCGS Amundsen. There were 83 casts, associated to 44 oceanographic stations, in the Baffin Bay area. The following parameters were measured: temperature, conductivity and pressure (with a Sea-Bird SBE-9plus), dissolved oxygen (Sea-Bird SBE-43), pH (Sea-Bird SBE-18-I), fluorescence (Seapoint chlorophyll fluorometer), 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.

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. Central to this integrated dataset, the following meteorological variables were recorded at 1 minute intervals (instrument used to collect each variable is in parentheses, and approximate instrument height above surface is indicated): -Wind speed (RM Young Wind Monitor 05103) - 16m height -Wind direction (RM Young Wind Monitor 05103) -16m height -Air Temperature (Vaisala HMP45C212) - 15m height -Relative Humidity (Vaisala HMP45C212) -15m height -Surface temperature (Apogee SI-111 Precision Infrared radiometer) - 8m height All instruments were mounted on a meteorological tower on the bow of the research icebreaker CCGS Amundsen.

During the ArcticNet annual cruises of the research icebreaker CCGS Amundsen, characteristics of the near-surface atmosphere are monitored in conjunction with surface sea water properties to observe the relationship between the surface micro-climate and the air-sea exchange , with particular interest in CO2. Central to this integrated dataset is an eddy covariance system used to monitor fluxes of CO2, H2O, heat and momentum. The system continuously sampled the following variables at a rate of 10 Hz (instrument used to collect each variable is in parentheses, and approximate instrument height above surface is indicated): -3D wind velocity (Gill R3 and Gill Windmaster Pro ultra-sonic anemometer) - 15m -Sonic air temperature (Gill R3 and Gill Windmaster Pro ultra-sonic anemometer) - 15m -CO2 molar concentration (LI7500 open path gas analyzer) - 15m -H2O molar concentration (LI7500 open path gas analyzer) - 15m -CO2 mixing ratio (LI7000 integrated into a closed path system) - 15m -H2O mixing ratio (LI7000 integrated into a closed path system) - 15m -3D ship motion - angular rates and accelerations (MotionPak, Systron Donner) - 13m All instruments were mounted on a meteorological tower on the bow of the research icebreaker CCGS Amundsen.

During the ArcticNet annual cruises of the research icebreaker CCGS Amundsen, characteristics of the near-surface atmosphere are monitored in conjunction with surface sea water properties to observe the relationship between the surface micro-climate and the air-sea exchange , with particular interest in CO2. Central to this integrated dataset is an eddy covariance system used to monitor fluxes of CO2, H2O, heat and momentum. The system continuously sampled the following variables at a rate of 10 Hz (instrument used to collect each variable is in parentheses, and approximate instrument height above surface is indicated): 3D wind velocity (Gill WindMaster Pro ultra-sonic anemometer) - 15m; sonic air temperature (Gill WindMaster Pro ultra-sonic anemometer) - 15m; CO2 molar concentration (LI7500 open path gas analyzer) - 15m; H2O molar concentration (LI7500 open path gas analyzer) - 15m; CO2 mixing ratio (LI7000 integrated into a closed path system) - 15m; H2O mixing ratio (LI7000 integrated into a closed path system) - 15m; and, 3D ship motion - angular rates and accelerations (MotionPak, Systron Donner) - 13m. All instruments were mounted on a meteorological tower on the bow of the research icebreaker CCGS Amundsen.

Processed atmospheric ceiling heights were recorded from a CT25K ceilometer. The instrument was mounted on the CCGS Amundsen icebreaker on the port side directly behind the ship's wheelhouse. Data were collected during transit, set transects, 24-hour stations, and multi-day drift stations. The instrument was running continuously during the IPY-CFL project, with only minor interruptions for maintenance activities.

Samples were collected at two sites in the Eastern Canadian Arctic (Figure 1) aboard the scientific icebreaker CCGS Amundsen. The sampling positions at biogenic and non-biogenic habitats were defined during ROV video surveys at the two sites (Figure 2a-d). Positions were carefully selected to avoid overlap between the two types of habitats (i.e., when most of the camera’s field of view was dominated by a single habitat over the course of approximatively 5 meters). At each site, we deployed two box cores (0.5 × 0.5 m) per habitat (i.e., inside the biogenic structures and in the bare sediment; Figure 2e) approximately 200 m apart in FB site and 500 m apart in BB site. From each box core, we collected three sediment cores (i.d = 9.8 cm, H = 30 cm) for a total of six cores per habitat and 12 cores per site. Sediment cores sampled in biogenic structures habitats were visually exempted from biogenic structures. Bottom (10 m above the seafloor) temperature, salinity and oxygen saturation at each site were recorded with a conductivity-temperature-depth (CTD) probe. Sediment cores were incubated in the dark at a temperature-controlled room (2-4°C) until a maximum of 20% of available oxygen was consumed. Sediment samples for chlorophyll a, phaeopigments and sediment properties were also collected from each box core. sediment cores were sieved through a 500 µm mesh sieve to collect infauna. Organisms were fixed with 4% formaldehyde solution. They were sorted under a dissecting microscope in the laboratory and identified to the lowest possible taxonomic level.

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. Central to this integrated dataset, the following meteorological variables were recorded at 1 minute intervals (instrument used to collect each variable is in parentheses, and approximate instrument height above surface is indicated): wind speed (RM Young Wind Monitor 05103) - 16m height; wind direction (RM Young Wind Monitor 05103) -16m height; air temperature (Vaisala HMP45C212) - 15m height; relative humidity (Vaisala HMP45C212) -15m height; and, surface temperature (Everest IR Transducer, 4000.44ZL) - 8m height. All instruments were mounted on a meteorological tower on the bow of the research icebreaker CCGS Amundsen.

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. Central to this integrated dataset, the following meteorological variables were recorded at 1 minute intervals (instrument used to collect each variable is in parentheses, and approximate instrument height above surface is indicated): -Wind speed (RM Young Wind Monitor 05103) - 16m height -Wind direction (RM Young Wind Monitor 05103) -16m height -Air Temperature (Vaisala HMP45C212) - 15m height -Relative Humidity (Vaisala HMP45C212) -15m height -Surface temperature (Everest IR Transducer, 4000.44ZL) - 8m height All instruments were mounted on a meteorological tower on the bow of the research icebreaker CCGS Amundsen.