Samples were collected during the Malina programme at 8 sites ranging in water depth from 47 m to 577 m in July and August 2009 onboard the icebreaker CCGS Amundsen. At each sampling station, an USNEL box corer (50 cm×50 cm×30 cm) was deployed for seafloor sediment collection. From each box core, 3 sub-cores of 10 cm diameter and approximately 20 cm sediment depth were taken for assessing benthic oxygen demand and nutrient remineralisation in microcosm incubations. Six additional sub-cores of 2.4 cm diameter were taken, three of 8 cm and 1 cm length, respectively, for determining sediment pigment concentration, water content and sediment solid phase composition.

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.

Sampling took place on legs 6, 7, 8b, and 9 of the CFL project on the CCGS Amundsen (2008). Zooplankton were sampled with a 1x1m2 (200 µm mesh) net through the moon-pool and with a 1m diameter (200 µm mesh) ring net on the ice at ice covered stations. In open water, samples were collected with 2x1 sq.m (500 µm mesh), 4x1 sq.m (500 and 200 µm mesh), and rectangular mid-water trawl (1600 µm mesh). Samples were live sorted to species and frozen at -25C. Algae were collected from the bottom ice via ice cores and the dive program, from the ice interface/surface water with a Hg clean Niskin and a hose and pump on a 1m arm, and from the chlorophyll a maximum depth via the rosette. Samples in ice were frozen in the dark, while samples in water were filtered via dual filtration following Morrison and Watras (1999) and filters were frozen at -25C. Zooplankton species Calanus glacialis and Calanus hyperboreus were analyzed for total mercury using CVAAS; C. hyperboreus was also analyzed for methyl mercury via Gas Chromatography Atomic Fluorescence Spectrophotometry (GC AFS). The algae samples were analyzed for THg using cold vapour atomic absorption spectrometry (CVAAS) and MeHg using cold vapour atomic fluorescence spectroscopy (CVAFS).

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 project, with only minor interruptions for maintenance activities.

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 -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.

Ocean Mapping Group acoustic data generated from the 2005 multibeam sonar survey on the 2005 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.

During the ArcticNet annual cruises of the research icebreaker CCGS Amundsen, characteristics of the surface sea water (temperature, salinity, dissolved CO2 and O2) are monitored in conjunction with properties of the near-surface atmosphere (basic meteorological elements, incident radiation, CO2 concentration) to observe the relationship between the surface microclimate and the air-sea exchange, with particular interest in CO2. Central to this integrated dataset is an under-way sea water pCO2 system (General Oceanics 8050) attached to the ship's clean water intake. The following variables were measured continuously and logged at 1 minute intervals: -pCO2sw (LI7000 gas analyzer) -Equilibrator water temperature -conductivity -pH -dissolved O2

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.

The dataset is composed of raw files recorded with a SIMRAD EK60 three-frequency split-beam echosounder that was operated continuously during the annual ArcticNet (2005-2014) sampling expeditions in the Canadian Arctic aboard the CCGS Amundsen. Three 7° transducers were hull-mounted, two in oil-filled arctic wells protected by a 2.5 cm thick acoustically transparent polycarbonate plate (38 and 120 kHz) and one in a Traveocean piston well in direct contact with water (200 kHz). The acoustic signal was recorded continuously on a PC using ER60 software version 2.0.0. Ping interval was set at 2 or 3 s and the pulse length was set at 1.024 ms.

Samples collected by rosette or hand-deployed niskin, directly transferred into acid-washed and backed glass vials with teflon-lined silicone septa caps, and frozen at -20 or -80 C. Analyses conducted by high-temperature catalytic combustion and calibrated again standards provided by the University of Miami. In 2002, all samples were total organic carbon (TOC), and in 2003-04, all samples were dissolved organc carbon (DOC, filtered through combusted GFF), and TOC was also collected at full stations at in surface waters at the overwintering site.