Floating microplastics in Frobisher Bay were assessed using a surface trawl. Four replicate tows of a Manta surface trawl with 200 micron mesh were carried out at each of two sites in Frobisher Bay from CCGS Amundsen. Four tows near the city of Iqaluit measured microplastics contamination close to that city, likely of local origin. Four tows in outer Frobisher Bay, spread over a wider distance, measured microplastics contamination from the northern Labrador Sea or from ships traversing Frobisher Bay. Samples were frozen following collection, for later processing.

Benthic grab samples and underwater towed video samples were collected at long-term ecology sites while onboard the Government of Nunavut vessel MV Nulialjuk and CCGS Amundsen in July and October 2016. On-board the MV Nulialjuk, benthic grab samples (triplicate samples) and underwater towed video samples were collected at 5 long-term ecology stations near Iqaluit. An additional 7 benthic grab samples (triplicate samples) and towed video samples were collected near Cairn Island. On-board the CCGS Amundsen, benthic grab samples were collected at two long-term ecology stations (triplicate samples) near Cairn Island. Sampling gear included a Van Veen grab sampler, box core, and HD GoPro video system. Initial observations suggest that these stations are predominantly muddy sand with some larger cobbles present. Towed video analysis and benthic grab samples indicate the presence of the algae Laminaria sp. and Agarum clathratum and bivalves Mya truncata, Yoldia hyperborea, Clinocardium ciliatum, and Serripes groenlandicus. Ophiuroid echinoderms and tubiculous polychaete worms and tubes are abundant. Once all benthic grab samples and towed video samples are processed, this data will be compared with the historic sample data to answer questions about the nature of long-term change of the benthos at this region in inner Frobisher Bay.

Multibeam sonar data and accompanying acoustic sub-bottom profile data were collected using the multibeam echosounder aboard the scientific icebreaker CCGS Amundsen. Particular focus in 2017 and 2018 mapping was on deep water troughs with apparent mega-scale glacial lineations (MSGL) in the northwest portion of outer Frobisher bay, and in the deep fault-bounded southwest margin of outer Frobisher bay.

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.

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.

This data is currently in relation to twelve piston cores collected aboard CCGS Amundsen, one on cruise 2014805, two on cruise 2015805, six on cruise 2016804, and three on cruise 2017805. Information about these cores (Location, length, grain size, radiocarbon dates, etc.) can be found by searching the NRCan Expedition Database.