As glaciers melt, a range of glacier processes modify and export freshwater and sediments to the ocean. This glacial runoff may influence biological productivity in coastal ecosystems by supplying essential nutrients and labile carbon. Previous studies of glacial meltwater export to the ocean have primarily been conducted on rivers draining land-terminating glaciers, or in fjords with large tidewater glaciers. These studies speculate about downstream effects (river studies) or upstream causes (fjord studies) of differing carbon and nutrient availability and biological productivity, but do not measure them. Here, we conduct the first ice- to-ocean study at a marine-terminating glacier in the Canadian Arctic Archipelago (CAA). We characterize the nutrient and carbon content of ice and meltwater collected on the glacier surface, at its margins, and in the near-shore coastal ocean, all within 1 to 25-km of the glacier terminus. Results demonstrate that while meltwater from a shallow tidewater glacier did not directly increase downstream carbon and nutrient concentrations, it can induce upwelling of deeper nutrient-rich marine water. Also, although carbon concentrations in meltwater were low, results show that this carbon is potentially more bioavailable than marine carbon. Glacially-mediated delivery of labile carbon and upwelling of nutrient-rich water occurs in summer, when surface waters are nutrient-limited. Collectively, these processes could benefit surface marine plankton, potentially stimulating production at the base of the food web. Shallow tidewater glaciers are commonly retreating in Arctic regions like the CAA and Svalbard, and understanding how increased meltwater output from these systems impacts marine ecosystems is critical.

The Canadian Arctic Archipelago (CAA) is vulnerable to climate warming, and with over 300 tidewater glaciers, is a hotspot for enhanced glacial retreat and meltwater runoff to the ocean. In contrast to Greenlandic and Antarctic systems, CAA glaciers and their impact on the marine environment remain largely unexplored. Here we investigate how CAA glaciers impact nutrient delivery to surface waters. We compare water column properties in the nearshore coastal zone along a continuum of locations, spanning those with glaciers (glacierized) to those without (non-glacierized), in Jones Sound, eastern CAA. We find that surface waters of glacierized regions contain significantly more macronutrients (nitrogen, silica, phosphorus) and micronutrients (iron, manganese) than their non-glacierized counterparts. Water column structure and chemical composition suggest that macronutrient enrichments are a result of upwelling induced by rising submarine discharge plumes, while micronutrient enrichments are driven directly by glacial discharge. Generally, the strength of upwelling and associated macronutrient delivery scales with tidewater discharge volume. Glacier-driven delivery of the limiting macronutrient, nitrate, is of particular importance for local productivity, while metal delivery may have consequences for regional micronutrient cycling given Jones Sound’s important role in modifying water masses flowing into the North Atlantic. Finally, we use the natural variability in glacier characteristics observed in Jones Sound to consider how nutrient delivery may be affected as glaciers retreat. The impacts of melting glaciers on marine ecosystems through both these mechanisms will likely be amplified with increased meltwater fluxes in the short-term, but eventually muted as CAA ice masses diminish.