Nunataryuk field campaigns: Understanding the origin and fate of terrestrial organic matter in the coastal waters of the Mackenzie Delta region

• Main Authors: Lizotte, Martine, Juhls, Bennet, Matsuoka, Atsushi, Massicotte, Philippe, Mével, Gaëlle, Anikina, David Obie James, Antonova, Sofia, Bécu, Guislain, Béguin, Marine, Bélanger, Simon, Bossé-Demers, Thomas, Bröder, Lisa, Bruyant, Flavienne, Chaillou, Gwénaëlle, Comte, Jérôme, Couture, Raoul-Marie, Devred, Emmanuel, Deslongchamps, Gabrièle, Dezutter, Thibaud, Dillon, Miles, Doxaran, David, Flamand, Aude, Fell, Frank, Ferland, Joannie, Forget, Marie-Hélène, Fritz, Michael, Gordon, Thomas J., Guilmette, Caroline, Hilborn, Andrea, Hussherr, Rachel, Irish, Charlotte, Joux, Fabien, Kipp, Lauren, Laberge-Carignan, Audrey, Lantuit, Hugues, Leymarie, Edouard, Mannino, Antonio, Maury, Juliette, Overduin, Paul, Oziel, Laurent, Stedmon, Colin, Thomas, Crystal, Tisserand, Lucas, Tremblay, Jean-Éric, Vonk, Jorien, Whalen, Dustin, Babin, Marcel
• Format: Text
• Language: English
• Published: 2022
• Subjects: Aklavik; Arctic; Arctic Ocean; Canada; Inuvik; Mackenzie Delta; Tuktoyaktuk; Beaufort Sea; Ice; permafrost
• Online Access: https://doi.org/10.5194/essd-2022-163; https://essd.copernicus.org/preprints/essd-2022-163/

Climate warming and related drivers of soil thermal change in the Arctic are expected to modify the distribution and dynamics of carbon contained in perennially frozen grounds. Thawing of permafrost in the Mackenzie Delta region of northwestern Canada, coupled with increases in river discharge and coastal erosion, trigger the release of terrestrial organic matter (OMt) from the largest Arctic drainage basin in North America into the Arctic Ocean. While this process is ongoing, well-established, and its rate is accelerating, the fate of the newly-mobilized organic matter, as it transits from the watershed through the delta and into the marine system, remains poorly understood. In the framework of the European Horizon 2020 Nunataryuk programme, and as part of the Work Package 4 (WP4) Coastal Waters theme, four field expeditions were conducted in the Mackenzie Delta region and southern Beaufort Sea from April to September 2019. The temporal sampling design allowed the survey of ambient conditions in the coastal waters under full ice cover prior to the spring freshet, during ice break-up in summer, as well as anterior to the freeze-up period in fall. To capture the fluvial-marine transition zone, and with distinct challenges related to shallow waters and changing seasonal and meteorological conditions, the field sampling was conducted in close partnership with members of the communities of Aklavik, Inuvik and Tuktoyaktuk, using several platforms: helicopters, snowmobiles and small boats. Water column profiles of physical and optical variables were measured in situ, while surface water, groundwater and sediment samples were collected and preserved for the determination of the composition and sources of OMt, including particulate and dissolved organic carbon (POC, DOC), and chromophoric dissolved organic matter (CDOM), as well as a suite of physical, chemical and biological variables. Here we present an overview of the standardized datasets, including hydrographic profiles, remote sensing reflectance, temperature and ...