The Lake Hazen watershed as a sentinel of Arctic environmental change

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Current climate change models predict that in the Canadian high Arctic, temperatures will rise 3-5°C over most land areas by 2100, but up to 9°C in the very northern Canadian Arctic Archipelago. At the same time, mean annual precipitation is predicted to increase ~12% for the Arctic, but up to 35% in regions with the highest warming. Such warming and wetting is anticipated to greatly alter the energy balance of Arctic landscapes, resulting in melting of glaciers, permafrost thaw, longer growing seasons and increased plant production on landscapes and in freshwaters. In fact, not only are these changes anticipated, but most are already occurring in Quttinirpaaq National Park (QNP; northern Ellesmere Island, Nunavut), Canada’s most northerly National Park. Situated in the middle of QNP is Lake Hazen, the world’s largest lake by volume north of the Arctic Circle. It supports one of the largest stocks of landlocked Arctic char, which has been historically harvested by Inuit, Thule and Paleo-Eskimo peoples. Lake Hazen is 540 km2 in surface area and 265 m deep, and has a 8400 km2 watershed that is half glaciated. Satellite observations of the watershed have revealed 2006-2012 summer glacier surface temperatures up to 1.3°C warmer than during 2000-2005, and a decline in ice cover duration on Lake Hazen. This has resulted in recent 10-fold increases in glacial meltwater and sediment inputs into Lake Hazen. Despite these recent and significant changes in the watershed, we know very little about how they are impacting water quality and metabolism in Lake Hazen itself, a freshwater jewel of Canada’s high Arctic. Will these landscape changes lead to a cascade of effects that will not only impact the normal metabolic functioning of Lake Hazen (e.g., algal production, sediment microbial respiration), but also degrade ecosystem services of socio-economic significance? I am proposing an integrated whole-ecosystem approach to quantifying impacts of climate change on high Arctic watersheds, using the Lake Hazen watershed as a sentinel system. There are three overarching objectives to my proposed research. My first objective is to quantify how the net energy balance of the Lake Hazen watershed is changing and how that is impacting both physical (e.g., the extent of permafrost thaw) and biological (e.g., plant production) processes occurring there. The second objective of my research program is to quantify inputs of organic carbon, nutrients and other chemical parameters including legacy contaminants (e.g., mercury, perfluorinated acids) to Lake Hazen from snowmelt, glacial melt and permafrost thaw. Finally, I am proposing to quantify how these inputs of organic carbon, nutrients and other chemical parameters are impacting metabolic processes like algal production and sediment microbial respiration, as well as basic water quality, in Lake Hazen. From a scientific basis, my team’s research will: 1) provide much-needed baseline data in Canada’s most understudied yet most changing ecoregion, from which all future data can be benchmarked; 2) assist modelers in predicting broader changes across the high Arctic; and 3) provide ground-truthing for remote sensors and satellite imagery. From the more applied and socio-economic perspective, increasing our ability to predict impacts of warming northern ecosystems on watershed productivity and water quality is vital for securing food, clean drinking water and traditional lifestyles for Northern peoples, as well as for sustainable resource development. All funding will go directly towards the training of highly qualified personnel, including northern training, consultation and outreach.