Co-supervising:

Jean-Simon Boulianne (Master student)

Supervised by:

Milla Rautio (Regular member)

Research project description

Arctic and under-ice freshwater ecology with focus on carbon transfer

IntroductionClimate change is inevitably shaping Arctic and northern aquatic ecosystems as well as their coupling with catchment dynamics through changes in temperature and precipitation. Mobilization of terrestrially originated carbon into aquatic systems is a major concern, and the ecological consequences for altered conduits of carbon remain poorly understood. Northern lakes are ice-covered for a good part of the year, highlighting the importance of under-ice processes for annual energy and carbon flow in the lakes. While the ice-covered period is traditionally considered quiescent, increasing amount of evidence shows biogeochemical complexity and community activity under ice. The interaction between ecological, biochemical and physical factors during the ice-covered season is understudied, even though it may have a cascading effect to the following open water season. ObjectivesThe objectives of my project are to improve the understanding of carbon transfer and biolability in a highly connected lake network in the low Arctic, and also during the winter season in the boreal environment. Climate change is altering conduits of carbon which further has ecological consequences, for instance, how carbon is incorporating into food webs and how it causes habitat change. Additionally, I will assess changes in quantity and quality of DOM and POM as well as other biogeochemical and ecological variables, across spatial and temporal gradients during the ice-covered season in the boreal environment. Study sitesMy study sites are located in the surroundings of Cambridge Bay (Victoria Island, Nunavut). I work with lakes and ponds mostly located within the vast watershed of Greiner Lake. Meanwhile the coronavirus pandemic is hindering the access to the Arctic, I am also studying under-ice winter limnology at Lac Simoncouche in Saguenay, Quebec. Material and methodsIn my work I combine paleo- and neolimnological methods to assess ecological changes linked to environmental change and climate change effects. I utilize various biogeochemical methods for sediment and water to, among other variables, characterize dissolved (DOM), particulate (POM) and sediment organic matter. My paleoecological target group is chironomids, and I use their subfossil remains and indicator potential to assess environmental change. In the boreal environment I will be assessing changes in the quantity and quality of DOM and POM as well as their biolability, by using e.g. parallel factor analysis and radiolabelled leucine uptake methods, to assess the fate of carbon during ice-covered season. The data is combined with multiple ecological and physico-chemical variables analysed from the lake to build and complement the limited understanding of what happens under the ice during early, middle and late winter. Expected resultsThe expected results of this project will provide further insight into carbon transfer in both fine (within season) and long (>100 years) temporal scales, as well as the ecological consequences associated with altered conduits of carbon in northern aquatic systems. Terrestrial carbon, amount of which in aquatic systems is on the rise due to the climate change, and its incorporation into the aquatic food web will be of special interest.

Research Site Coordinates