Seasonal and Late Holocene changes in export productivity as recorded in sediment traps and seafloor sediment collected in the Nares Strait

Historically, pack ice advected southward from the Arctic Ocean became congested in the narrow passages (e.g., Smith Sound) of the Nares Strait where it formed an ice arch. This ice arch sharply defines the northern boundary of the North Water polynya, which is the most biologically productive region of the Arctic. However, since the 1990s, the Nares Strait ice arch has become less stable and collapses earlier in the season compared to previous decades, resulting in increased variability in the seasonal duration, extent, and spatial configuration of the North Water polynya. This has significant implications for the future of this important ecosystem. This project aims to investigate biogenic matter export fluxes, including phytoplankton cells, pigments, microfossils, sedaDNA, particulate organic matter, and the geochemical signature of bulk organic matter, through the analysis of sediment trap samples and recent seafloor sediment collected in the Nares Strait and adjacent ecosystems. Sediment traps were deployed in 2023 for a one-year sampling cycle onboard the CCGS Amundsen on each side of Smith Sound and at the entrance to the Lincoln Sea and will be recovered in August 2024. Recent sediment was collected between 2019 and 2023 onboard the CCGS Amundsen, using a box corer, and the upper 5 cm of the cores will be studied.