Abstract
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.