From ice to ocean: Tracking the composition, fate, and impact of submarine glacial discharge in the nearshore coastal ocean in the Canadian Arctic Archipelago

Patrick Williams1, Megan Roberts2, Charvanaa Dhoonmoon1, David Burgess3, Erin Marie Bertrand2, Stephanie Waterman4 and Maya Bhatia1, (1)University of Alberta, Department of Earth and Atmospheric Sciences, Edmonton, AB, Canada, (2)Dalhousie University, Department of Biology, Halifax, NS, Canada, (3)Natural Resources Canada, Geological Survey of Canada, Ottawa, ON, Canada, (4)University of British Columbia, Department of Earth, Ocean and Atmospheric Sciences, Vancouver, BC, Canada
Abstract:
As glaciers melt, erosion, chemical weathering, biological reactions, and hydrologic fluxes transform and export entrained sediments and dissolved species to the ocean. This glacial runoff may influence biological productivity in nearshore coastal ecosystems by supplying essential nutrients and carbon. Previous studies of glacially-derived solute export to the ocean have either been conducted on rivers draining land-terminating glaciers or solely in fjords. These studies are limited in that they must speculate about either downstream effects (river studies) or upstream causes (fjord studies). We conduct a novel ice-to-ocean study at a large marine-terminating glacier in a previously uncharacterized Arctic region, the Canadian Arctic Archipelago. We present data from ice and meltwater collected on the glacier surface and margins in the spring and summer, in conjunction with marine measurements spanning the submarine discharge plume within 1 to 25-km of the glacier terminus. We track the biogeochemical properties of glacial runoff and its fate in the ocean by characterizing the downstream evolution of its sediment, carbon, nutrient, and biological community composition. Profiles of temperature, salinity, turbidity, and chlorophyll a provide broad-scale physical and biological oceanographic context and insight into meltwater plume extent and dynamics. Finally, an array of time-lapse cameras as well as historical satellite, meteorological, and global positioning station data are used to constrain the seasonal evolution of the glacier drainage system and its relationship to plume development at the terminus, placing our measurements in the broader seasonal context. Results from this ice-to-ocean study will help to clarify current uncertainties regarding the source, fate and biological impact of glacially-derived nutrients and carbon in the ocean, providing important insight into how Arctic coastal productivity will be impacted by future climate warming.
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