Nutrient cycling
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Samples were collected at 5 sites ranging in water depth from 100 to 595 m at least once in each season (ice-covered and open-water condition) between March and August 2008 onboard the icebreaker CCGS Amundsen. At each sampling station, an USNEL box corer was deployed for collecting seafloor sediments. From each box core, 5 sub-cores of 11 cm diameter and 20 cm sediment depth were taken for assessing benthic carbon remineralisation in microcosm incubations and 3 additional subcores of 5 cm diameter and 10 cm length were taken for determining sediment properties. Incubations of sediment microcosms were run in a dark, temperature-controlled room (2-4 °C) for 24-48 h. Each sediment microcosm was sieved through a 0.5 mm mesh under running sea water at the end of incubations to determine biomass of macrofaunal communities. The sieve residue was preserved in a buffered 4% seawater-formaldehyde solution and analysed for species composition and abundance under a stereomicroscope in the lab.
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The CFL project consisted of ten sub-project teams: Physical oceanography; Sea ice; Light, nutrients, and primary production; Food webs; Marine mammals and birds; Gas fluxes; Carbon and nutrient fluxes; Contaminants; Modeling; and Traditional Knowledge. In the fall of 2007, 74 open water sites were sampled throughout the Amundsen Gulf and southern Beaufort Sea. During the winter months, 44 drift sites were sampled, ranging in duration from 1-22 days. Due to thin sea ice and high ice mobility, the fast ice bridge between Cape Parry and Banks Island did not form. For this reason, we were unable to establish a semi-permanent ice camp as originally planned. Instead, a series of ice camps were set up at the fast ice edge at the mouths of Franklin and Darnley Bays in May and June. Early results suggest that with decreasing ice cover we can expect powerful feedbacks into the climate system thereby exacerbating the reduction in multiyear sea ice, with commensurate changes in the ecosystem, biogeochemical cycling and human use of the flaw lead region. Nutrients may become more available to the food web through a higher occurrence of ice edge upwelling as well as eddies carrying Pacific water into the Amundsen Gulf. Frost flowers, which are produced on young first year ice, have been found to have an important role in atmospheric chemistry around flaw leads and may be important for contaminant transport. Marine mammal use of the flaw lead occurs much earlier and more extensively than previously known. Traditional Knowledge research efforts included the development, coordination and completion of community interviews in Sachs Harbour, Paulatuk and Ulukhaktok. This comprised of community-based field programs involving semi-directed interviews, a mapping component, and database development and input. The data gathered from 49 experts in 3 communities represents the first and most comprehensive documentation of Inuvialuit knowledge of the circumpolar flaw lead in the Beaufort Sea. The Traditional Knowledge study showed that Inuvialuit have extensive knowledge of changes taking place in seasonal patterns, marine and freshwater systems, fish and wildlife of the Beaufort Sea and their uses of these resources, as well as the implications of these changes for human travel and Inuvialuit subsistence and traditional activities.
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Our sampling program took place from August 27, 2009 through September 12, 2009. It was part of Leg 3a of the 2009 CCGS Amundsen Expedition in the Arctic Ocean (ArcticNet 0903). Sampling started in the Mackenzie River delta and continued into the Beaufort Sea (Shelf, slope and deep Canada Basin). Various measurements (temperature, salinity, nutrients, alkalinity, pH, primary production, bacterial production) and sampling (seawater, marine particles) were conducted at 10 stations. Underway measurements (temperature, salinity, trace gases) and sampling (marine particles) were also conducted along the cruise track. Sampling tools on stations were the ship's CTD/rosette (ArcticNet), a Trace-Metal CTD/rosette system (UVic / UBC) and large volume in-situ pumps (UBC). We conducted measurements and collected samples to document a suite of key physical (temperature, salinity, ice cover, light penetration), chemical (nutrients, trace metals, trace gases, radioisotopes, stable isotopes) and biological (phytoplankton and microbial assemblages, primary and microbial productivity, trace metal phytoplankton quotas) parameters in relation to proximity to the Mackenzie River delta, seafloor bathymetry and ice cover to elucidate the processes influencing phytoplankton growth and carbon cycling in the Arctic Ocean. In particular, we collected samples to study the processes which supply and remove trace metals, nutrients and carbon to and from the upper ocean, and conducted ship-board experiments to study how biological productivity is affected by various chemical and physical conditions. Through a combination of on-board measurements, experiments and subsequent laboratory analysis, our research program aims at: (i) documenting the pathways of addition, removal and cycling of key trace elements which act as biological micronutrients or tracers of carbon and nutrient cycles in the Arctic Ocean; (ii) elucidating the potential effects of changing ice cover and river discharge on productivity, carbon sequestration and trace gas emission in the Arctic Ocean; (iii) developing chemical tracers to establish a historical sedimentary record of Arctic Ocean productivity in relation to long term natural climate change.
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Samples were collected from nine sites distributed across the study region in 2008 and 2009. To avoid confounding influence of seasons, the same sites were sampled in the same season each year. Sampling was conducted onboard the CCGS Amundsen between July and October during the Circumpolar Flaw Lead Study, ArcticNet expeditions in collaboration with the Canadian Healthy Ocean Network and the Malina project. Locations were chosen to study both hotspots and coldspots in the Canadian Arctic. At each sampling station, an USNEL box corer was deployed for seafloor sediment collection. From each box core, three to five sub-cores of 10 cm diameter and approximately 20 cm sediment depth were taken for assessing benthic remineralisation function in shipboard microcosm incubations. After incubation, the same sediment cores were passed through a 0.5 mm mesh sieve under slow running seawater. The sieve residues were preserved in a 4% seawater-formaldehyde solution for later analyses of species diversity and abundance under a dissection microscope.
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