Vertical particle flux data in the Beaufort Sea: 2002-2010
Ship: CCGS Amundsen CA
Principal Investigator: Louis Fortier
Start Date: 20-09-2002
End Date: 31-08-2010
Citation: Fortier, L., Makabe, R., Lalande, C., Sampei, M., & Forest, A. (2019). Vertical particle flux data in the Beaufort Sea: 2002-2010. Quebec, Canada: Canadian Cryospheric Information Netowork (CCIN). (Unpublished).
Abstract: Two to nine moorings carrying pre-programmed sequential sediment traps (at ~100 m and ~200 m depth) were deployed in the southeastern Beaufort Sea (Mackenzie Shelf and Amundsen Gulf) every year since 2002, except for 2013. Sediment traps were prepared following the JGOFS protocol (Knap et al., 1996). Sample cups were filled with filtered seawater (GFF 0.7µm) adjusted to 35 PSU with NaCl. Formalin was added as a preservative (5% v/v, sodium borate buffered). Mesozooplankton swimmers were removed from the samples with a 1-mm sieve and/or by hand-picking under a stereomicroscope. For most of the analyzed samples, Swimmers were identified to the lowest taxonomical level possible, as well as developmental stages in the case of copepods; and a known volume aliquot of the cup was also analyzed for phytoplankton abundance and diversity using inverted microscopy. Sediment trap sub-samples were filtered in triplicates through pre-weighted Whatman glass fibre filters (GFF 0.7µm, 25 mm, combusted 4h at 450°C) for the determination of total particulate matter (TPM), particulate organic carbon (POC) and particulate nitrogen (PN) fluxes. Filters were dried for 12 h at 60°C and weighted again for DW. After exposure for 12 hours to concentrated HCl fumes to remove the inorganic carbon fraction, samples were analyzed on a Perkin Elmer CHN 2400 Series II. Data have been partially published in peer-review journals. Downward fluxes of particles are produced in the oceans when particulate matter, either newly produced in the surface layer or transported from elsewhere, sinks passively to depth as a particle rain. These fluxes fulfill two roles in marine ecosystems: 1) to provide food to living organisms such as microbes, zooplankton, fish and benthic organisms; and 2) to withdraw carbon dioxide (CO2) from the atmosphere when particulate carbon reaching the seafloor is buried and sequestered within sediments for hundreds of years. In Arctic seas, decline of sea ice and increase of continental inputs (river runoff and coastal erosion) are likely to impose complex transformations to the marine food web and to the cycling of particulate matter. The characterization of the nature and magnitude of vertical particle fluxes over an annual cycle improves thus our knowledge of the: 1) spatial and seasonal variability of sediment transport; 2) timing and magnitude of biological production, predominantly from phytoplankton and zooplankton; 3) nature and quality of the material sinking in the pelagic system and available to the benthos. This knowledge is essential to our understanding of the biogeochemical cycling of organic and inorganic matter, especially under the present scenarios of climate change in the Arctic Ocean.