Collaborative Research: Assessing the Impact of Small, Canadian Arctic River Flows (SCARFs) to the Freshwater Budget of the Canadian Archipelago (Off Campus)

Assessing the Impact of Small, Canadian Arctic River Flows (SCARFs) to the Freshwater Budget of the Canadian Archipelago A. Proposal Summary Scientific Merit: The contribution of small Canadian Arctic rivers to the total freshwater flux through the Canadian Arctic Archipelago (CAA) is unknown and remains a significant gap in the growing data set addressing the freshwater budget of the Arctic and subarctic oceans. Limited geochemical data have been collected from the CAA, Nares Strait, and Baffin Bay, and the existing data sets are too sparse to differentiate among the various freshwater sources thought to contribute to the total freshwater pool (i.e., Pacific water, sea-ice meltwater, and meteoric water derived from the Mackenzie River, Eurasian rivers, and local runoff). New programs have begun to collect requisite geochemical data in Davis Strait and other regions. However, interpretation of these measurements may be biased by typical endmember assignments associated with Eurasian and North American river runoff. Characterizing the geochemical signature of local freshwater inputs is essential for distinguishing these contributions from those of Arctic Ocean origin, but virtually no studies have sampled small Arctic rivers discharging into the CAA. Available data collected from Baffin Bay and Hudson Strait suggest local rivers do not resemble the Mackenzie and Yukon Rivers typically assumed to represent North American runoff. While the annual discharge of any given river is relatively small, the combined discharge of all rivers is sufficient to support nearshore, narrow boundary currents, which provide an important, but often neglected, transport mechanism. Thus, local contributions of freshwater may impact the total volume flux and geochemistry of the Canadian Arctic throughflow that has historically been attributed entirely to export from the Arctic Ocean. We propose a three-year study to characterize the total alkalinity, barium, DOC, major ion and isotope (ä18O, 87Sr/86Sr) geochemistry of remote CAA rivers and estuaries with the ultimate aim of resolving the contribution of local freshwater inputs to CAA boundary currents. River sampling will occur during different flow regimes, but we will especially emphasize sample collection during the spring freshet, the time of year when terrestrial runoff from local CAA rivers maximally impacts coastal waters. Estuarine sampling will include both horizontal and vertical profiles.