Inorganic carbon fluxes on the Mackenzie Shelf of the Beaufort Sea

Abstract

Abstract. The Mackenzie Shelf in the southeastern Beaufort Sea is a region that has experienced large changes in the past several decades as warming, sea-ice loss, and increased river discharge have altered carbon cycling. Upwelling and downwelling events are common on the shelf, caused by strong, fluctuating along-shore winds, resulting in cross-shelf Ekman transport, and an alternating estuarine and anti-estuarine circulation. Downwelling carries inorganic carbon and other 10 remineralization products off the shelf and into the deep basin for possible long-term storage in the world oceans. Upwelling River freshwater, and sea-ice melt on carbon dynamics and air-sea fluxes of carbon dioxide (CO 2 ) in the surface mixed layer. 20Understanding carbon transfer in this seasonally dynamic environment is key to quantify the importance of Arctic shelf regions to the global carbon cycle and provide a basis for understanding how it will respond to the aforementioned climateinduced changes.

Using Radiocarbon Measurements of Dissolved Inorganic Carbon to Determine a Revised Residence Time for Deep Baffin Bay

“…Surface water in Lancaster Sound (Station 323) contains Pacific Water entering Baffin Bay via the CAA. Enriched surface DIC d 13 C values in Lancaster Sound may be indicative of this Pacific influence, which has been observed to have DIC d 13 C values up to +2.20% in the Amundsen Gulf (Mol, 2017). Lancaster Sound is also a region of seasonal sea ice cover, high nutrient, primary production, and diatom species richness (Krawczyk et al, 2021).…”

“…For example, surface DIC d 13 C values in the Arctic Ocean range between -0.6 and +2.2‰, with deep DIC d 13 C ranging from -1.0 to +2.0‰, in both the Canadian and Eurasian Basins (Griffith et al, 2012;Bauch et al, 2015). DIC d 13 C values in the Beaufort Sea, which feeds Pacific water to the Canadian Arctic Archipelago (CAA), range between -0.5 to +2.2‰ (Mol, 2017). The North Atlantic Ocean, which receives Arctic water through Davis and Fram Strait, consists of DIC d 13 C between -0.1 to +1.9‰ (Humphreys et al, 2016).…”