| Summary: | Climate change in permafrost regions is projected to alter water resource distribution and have detrimental effects on water quality. Pressured by both population increase and depleting water resources, the City of Iqaluit has designated the Apex River watershed as a Watershed Protection Area with the intent of using it as a supplementary water supply in the future. The aim of this study was to characterize seasonal hydrology and variations in the composition of dissolved organic matter (DOM) and the concentrations of dissolved organic carbon and total dissolved nitrogen (TDN) at four study sites in order to (1) identify water sources and pathways in the Apex River watershed and (2) explore possible relationships with standard microbiological indicators (E. coli, total coliforms). Parallel factor analysis of fluorescence excitation-emission matrices from 2015 samples suggest that Apex River water contains three main components of DOM: two humic-like (ex/em: 250/500nm and 300/450nm) and one tryptophan-like (275/350nm). Elevated DOC concentrations at the beginning of the ice-free season are consistent with snowmelt inputs to the river. Tryptophan-like peaks increasing in strength as the season progresses to baseflow conditions suggest that end-of-season DOM is primarily autochthonous, not derived from overland flow which could introduce microbiological contaminants from surface soils. The results of this study contribute to baseline data which policy-makers can use to understand how climate change affects seasonal hydrology and the repercussions these effects may have on water quality, allowing them to establish policies which ensure the sustainable use of Iqaluit’s water resources in the future.
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