Research Interests: mercury, organic contaminants, carbon cycling, greenhouse gases, climate change, stable-isotope applications, Arctic, alpine and boreal ecosystems, (paleo)limnology, environmental chemistry, nutrients, eutrophication, water-quality
Current Research Projects
Mercury and other contaminants in Arctic ecosystemsMercury is a contaminant of concern in the Canadian Arctic due to its potential negative health impacts on Arctic indigenous peoples. Our research seeks to determine how and where methylmercury (the toxic form of mercury that is bioaccumulated in foodwebs) is produced, what the environmental controls on net mercury methylation are, and how climate change will affect the exposure of wildlife and people to this toxin. We also use various environmental archives such as sediment cores, ice cores and tree rings to reconstruct past deposition of atmospheric mercury to various Arctic ecosystems and regions. In addition to mercury, we work with collaborators to quantify levels and identify transport pathways for various legacy and emerging organic contaminants.
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Ecosystem metabolism and carbon cycling in Arctic lakes and landscapesEcosystem metabolism is a key process in any ecosystem, controlling the productivity of these ecosystems and the amount of energy available to support higher trophic level organisms. In Arctic landscapes, lakes and ponds are biogeochemical hotspots processing carbon and exchanging greenhouse gases such as carbon dioxide and methane with the atmosphere. The objective of our research is to quantify ecosystem metabolism and air-water greenhouse gas exchange in Arctic lakes. We are particularly interested in the role of lake ice on these processes, contrasting spring, when lakes are still ice covered and supporting more extensive low redox processes such as methanogenesis, and summer when lakes are ice free, oxic and more productive.
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Climate change impacts on Arctic watershedsThe Arctic is warming at a faster rate than any other region around the globe. Some of the impacts of this changing climate have been well documented, such as the rapidly declining summer sea-ice cover. Our research aims to identify and quantify the impacts of a changing climate on Arctic lakes and watersheds to determine how sensitive (or resilient) these ecosystems might be to climate change. We are particularly interested at the processes coupling the terrestrial and aquatic compartments of watersheds, asking questions such as 'how do increased melting of glaciers impact lake biogeochemistry and ecology?'
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