Cassia Abbott-Leduc
MSc Student
The Arctic is warming at a rate four times faster than the rest of the globe. One significant consequence of this rapid warming is permafrost thaw. In aquatic ecosystems, permafrost thaw increases the input of terrestrial material (containing carbon, nutrients, and other particles) into the water. This can have serious consequences for primary production, as particulate and dissolved matter absorb light, and nutrients make certain molecules necessary for photosynthesis unavailable. Because primary production forms the base of all food webs, these changes may have devastating impacts on Arctic aquatic ecosystems.
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In my study, I focus on the effects of permafrost thaw on the nutritional quality of macroinvertebrates. Nutritional quality is assessed through the concentration of polyunsaturated fatty acids (PUFAs), particularly omega-3 fatty acids, as these are essential for growth, reproduction, immune function, and even survival at extremely low temperatures in many organisms. PUFAs are mainly synthesized by aquatic primary producers, such as periphyton and macrophytes, and are then transferred to higher trophic levels through primary consumers.
Like in most aquatic ecosystems, in the Arctic, primary consumers are benthic macroinvertebrates, which is why they are the focus of my study. These organisms play a key role in transferring PUFAs accumulated from their primary producer–rich diet to higher levels of the food web, notably to juvenal fish. A decrease in nutritional quality, abundance, or a shift in the taxonomic composition of macroinvertebrate communities could therefore have significant impacts on fish health and survival. This is particularly concerning in the Arctic, where country food, including fish such as Arctic char, is central to Inuit food security and cultural continuity.
My study site is the Kitigak River, located northwest of Cambridge Bay on Victoria Island. Community members have observed that the river has become increasingly turbid, and we have identified signs of permafrost thaw in the surrounding area. This river is of great cultural and nutritional importance to the Inuit of Cambridge Bay, as it is an Arctic char fishing site.
I began this project during my bachelor’s degree. Having fallen in love with the Arctic and with this research project, I decided to pursue a master’s degree with the goal of further developing this work and continuing to learn about permafrost thaw and its effects on the critters living in the Kitigak River. I aim to incorporate a multidisciplinary approach throughout my master’s project, from study design to data analysis and knowledge sharing, to ensure that my research is conducted respectfully and in collaboration with the people connected to the land I am studying.