Multiyear variations in High Arctic river temperatures in response to climate variability

Abstract

Water temperature measurements (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016) from two small rivers in the High Arctic were analyzed to determine the effects of climate variability on thermal regime and the sensitivity to climate change. The East and West rivers (unofficial names) drain similar watersheds (11.6 and 8.0 km 2 , respectively) and are located at the Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, Canada (74°55′N, 109°35′W). Differences in seasonal timing of river temperatures were evident when comparing the coldest and warmest years of the study period, and across different discharge conditions. Snowmelt runoff is characterized by uniformly cold water (∼0-1°C) over a wide range of discharge conditions, followed by warming water temperatures during flow recession. The rivers showed varying sensitivity to mid-summer air temperature conditions in a given year, with warmer years indicating high correlation (r 2 = 0.794-0.929), whereas colder years showed reduced correlation (r 2 = 0.368-0.778). River temperatures reached levels which are reported to negatively affect fish and other cold-water aquatic species (>18°C) with greater frequency and duration during the warmest years. These results provide a basis to further enhance prediction of river thermal conditions to assess ecosystem health in a river system and to refine insights into the effects of climate change on High Arctic aquatic ecosystems. Arctic ScienceDownloaded from www.nrcresearchpress.com by 44.224.250.200 on 07/04/20 For personal use only. Ces résultats établissent une base pour davantage améliorer la prédiction des conditions thermiques fluviales, et ce, afin d'évaluer la santé de l'écosystème d'un système fluvial, ainsi que d'affiner les observations concernant les effets du changement climatique sur les écosystèmes aquatiques du Haut-Arctique. [Traduit par la Rédaction]Mots-clés : température de l'eau, Arctique, neige, pergélisol, changement climatique. 606

Characterization of contrasting flow and thermal regimes in two adjacent subarctic alpine headwaters in Northwest Canada

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An ecothermal paradox: bull trout populations diverge in response to thermal landscapes across a broad latitudinal gradient

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