1045 avenue de la Médecine
Watersheds of arctic and subarctic rivers are undergoing profound transformations in response to climate change and the associated impacts such as shifting hydrological patterns, permafrost thawing and changes in vegetation. One of the consequences of these landscape changes is that a large pool of organic carbon is becoming more available; however, its ultimate fate is uncertain. Rivers are likely to play a substantial role in transportation and transformation of carbon, from terrestrial to marine ecosystems, and in the emission of greenhouse gases in the atmosphere. Microbial activities dominate these biogeochemical processes, but microbiome structure and function are still poorly understood in river ecosystems in general, and particularly at high latitudes.
This project aims to gain an improved understanding of carbon biogeochemistry of the Great Whale River (Nunavik), a large subarctic river discharging into southeastern Hudson Bay. The watershed of this river is characterized by heterogeneous landscapes, including sporadic permafrost areas in an advanced stage of thawing and erosion. We will apply flow cytometry to characterize the gradients in microbial cell concentrations along this river, including the application of a novel multimodal microfluidic system under development by Sentinel North. We will combine these measurements with molecular and pigment analysis of the microbiome, and measure the carbon dioxide concentrations and fluxes across physico-chemical gradients, including across the freshwater-saltwater transition zone.
The information gained during this project will yield valuable new insights into how higher latitude river ecosystems will respond to the ongoing transformation of their watersheds in the warming northern climate.