Preliminary Assessment of Physical Oceanographic Forcing in Summer on Outlet Glaciers of Devon Ice Cap's Croker Bay and the Downstream Marine Ecological Response

Nicole Trenholm, University of Maryland Baltimore County, Annapolis, MD, United States and Donglai Gong, Virginia Institute of Marine Science, Gloucester Point, VA, United States
Summer's open water period within glacial fjords remains under characterized and satellite interpreted summer biomass concentration, as Chl a, across the Arctic is vastly unvalidated. As summer temperatures rise, physical processes induce the fertilization of surface waters as glacial melt water and ocean boundary currents converge. The West Greenland Boundary Current (WGBC) originates from the Atlantic Ocean and enhances Greenland glacial melt at ocean terminating outlet glaciers. Baffin Bay's anticyclonic water circulation draws the nutrient-rich WGBC into Lancaster Sound (LS), the eastern extent of the Northwest Passage (NWP). LS’s bathymetry is conducive for the WGBC’s entry but also limits westward progress. The northern reaches of LS are bordered by the Devon Island’s Ice Cap (DIC) and the Croker Bay (CB) outlet glacial fjord. DIC is the most prominent land ice feature of the NWP and a source of freshwater into LS. CB glaciers are known for their irregular melt behavior uncharacteristic of the rest of the DIC glaciers. Research suggests physical ocean forcing could be a driver of CB glacier mobility. A 2018 cruise observed WGBC water reaching the mouth of CB, flowing over a significant submerged sill into the fjord then diminishing within the fjord's deep meandering channel en route to Croker Bay Glacier South terminus. CB is an indigenous hunting site and tourist cruise location because it is a habitat for foraging native and migrant mammal, pelagic and avian species. An extensive plankton bloom encompassed the fjord waters during 2018 summer field observations while waters flowing out of CB yielded high biomass laden samples in 2019. The metazoan community members and the dominant planktonic taxonomic community members reliant on the CB out-flowing waters will be identified in association with the water mass characteristics observed at the time of water sample collection. Sample analysis will be accomplished through environmental DNA (eDNA) and High-Performance Liquid Chromatography pigments. Further analysis and more planned observations will improve the interpretation of coastal Arctic satellite ocean color data, the role which the WGBC has on CB outlet glaciers stability and the livelihood of the glaciated coastal marine ecosystem.