Etienne Boucher's lecture

Des arbres virtuels pour prédire et reconstituer les interactions entre les cycles de l’eau et du carbone en forêt boréale.

The dynamic interactions between boreal vegetation and the atmosphere are of considerable importance for many ecosystem services provided to Canadians: atmospheric CO2 uptake, H2O transpiration and climate regulation, etc. Paradoxically, little is known about these interactions, the processes that govern them on all scales of time and space, and their sensitivity to environmental changes affecting the North. This considerably reduces our ability to anticipate the future response of one of the world's largest natural ecosystems. In this presentation, we focus on the possibilities offered by the analysis of stable and radiogenic isotopes of wood cellulose in growth rings, in order to document gas exchanges between vegetation and the atmosphere. We use these measurements to constrain ecophysiological models (also called "virtual trees") which, once calibrated, allow us to free ourselves from simplistic statistical relationships between climate and ecosystem response, and to make realistic, deterministic predictions that are informed by our knowledge of ecophysiological processes. In inverse mode, these virtual trees also pave the way to reconstitutions of the hydro-climate on very long time scales (e.g., centuries to millennia scales). These reconstructions have the advantage of being consistent with our knowledge of ecophysiological processes. Based on various examples from recent research conducted by our group in the boreal forest (eastern Canada), I draw a portrait of the achievements, opportunities and challenges posed by this paradigm shift in dendroclimatology.

Pascale Roy-Léveillée's lecture

Research program for the new Research Chair on Permafrost Geomorphology in Nunavik

Thawing permafrost affects ecosystems and threatens the stability of northern infrastructure. Exceptional work has been accomplished by CEN researchers on permafrost conditions in Nunavik communities. The new research chair in permafrost geomorphology continues to study the vulnerability of permafrost to thawing in the context of infrastructure planning and maintenance, and will extend this work to areas used for hunting, fishing, and harvesting outside municipalities. The investigation of spatio-temporal dynamics of geomorphological and ecological disturbances related to permafrost thaw, and of the impacts of thaw on biological transformation and mobilization of contaminants to aquatic environments, will extend the assessment of hazards and vulnerabilities affecting Nunavik communities beyond built environments. To facilitate the direct application of research results in other fields the chair collaborates with experts in, for instance, infrastructure design and maintenance, carbon cycling, contaminant mobilization, and with local knowledge holders who can facilitate proactive adaptation to environmental change in their own communities. A component of the Chair program is dedicated to the bi-directional (North-South and South-North) transfer of permafrost information, including strategies to promote the appropriation and application of permafrost science by people living in northern communities and those developing infrastructure there, as well as the integration of local perspectives into large-scale studies.

Alexandre Roy's lecture

Northern remote sensing, from cryosphere to vegetation, to the carbon cycle: perspectives, challenges and opportunities

Remote sensing is a particularly interesting and promising tool for monitoring and understanding the transformations of northern regions in relation to climate change. Recent technological developments suggest that this field is entering a new era with a multiplication of new sensors (new constellation of satellites, drones and ground-based), but also unprecedented data access. The presentation will attempt to take a critical look at the challenges related to northern remote sensing research based on recent advances in the Laboratoire en Télédétection Nordique's projects on multi-scale microwave remote sensing of snow, freeze/thaw cycles and vegetation. In light of these results, some new projects on remote sensing applied to the carbon cycle in high latitudes and on other approaches under development (drones, ground validation, radar, etc.) are starting.

Elise Imbeau's lecture

Sampling north of the 60th parallel

At the end of June, at the 69th parallel north, the weather is mild, a very comfortable 7 degrees celcius. The sun no longer sets in the evening. The majestic Greiner Lake is still covered with 165 cm of ice, allowing everyone to walk around, drill holes and cross their fingers to catch delicious Arctic chars. There are several groups of friends and family on the horizon, all of whom are busy holding the line, drinking tea and enjoying the moment.

The only strangeness is a small convoy of 2 cyclists and a delighted dog, pulling boxes of equipment on improvised sleds, built from snowmobile skis collected at the local free Canadian Tire (or the dump). These two people are dedicated scientists who don't want to miss this window of opportunity to collect samples just because the ice near the shoreline is no longer strong enough to support the vehicle normally used.

The Arctic is breathtakingly beautiful! It is a world where time is different, the land of polar bears and the northern lights. When it comes to scientific sampling, the Arctic is an adventure and, above all, the need for constant adaptation. In this presentation, Elise Imbeau invites us to take a tour of her world, on the magnificent tundra of Cambridge Bay, Nunavut. She shares with us her vision of the challenges and particularities of sampling in the Arctic as well as the reality she experienced in times of pandemic.