Frédéric Bouchard (Stagiaire postdoctoral)

Abitibi-Price Building
Room 1206
Université Laval
2405 rue de la Terrasse
Québec, Canada
G1V 0A6

Phone: (418) 656-2131 ext. 8298

Research project
From climatic stress to hydrological response: recent dynamics of thermokarst lakes in western Hudson Bay Lowlands

What are the impacts of permafrost degradation on the integrity of northern lacustrine ecosystems? How these systems have reacted to environmental change in the past ? How will they evolve in the future ? These are the questions driving the present research project, in a context where prosperity and traditional use of the land by northern communities strongly depend on the quality and stability of water resources in circumpolar regions. Thermokarst lakes are formed by the local subsidence of the ground caused by the partial thawing of permafrost. These aquatic ecosystems are abundant in northern regions and their stability is greatly controlled by climate variations (e.g., temperatures, precipitations). Located on the southwest coast of Hudson Bay near Churchill (Manitoba), Wapusk National Park (WNP) houses several thousands of thermokarst lakes, which provide habitat for many floral and faunal species representative of the Hudson Bay Lowlands (HBL). However, hydrological properties and behavior of these basins are poorly known for the moment, and climate projections for the late 21st century report intense warming. Since thermokarst lakes of WNP are typically shallow (< 1 m), thus more sensible to hydroclimatic changes and potentially ephemeral, a better understanding of past and present hydrological conditions of these ecosystems is necessary to address future adaptation challenges. More specifically, this project aims to characterize the hydrological variablility of WNP lakes by analyzing several indicators (isotopic, geochemical and biological) in lacustrine sediments, across the boreal forest – arctic tundra landscape. To do this, surface sediments will be collected in ~ 30 lakes of WNP. Analyses will be conducted using a «multi-proxy» methodological approach combining physical (loss-on-ignition), biological (diatoms, pigments) and isotopic/geochemical (13C, 15N et 18O) analyses of the sediment organic fraction (carbon, nitrogen, cellulose, biogenic silica). Results anticipated from this research will bring an interdisciplinary and pancanadian knowledge of thermokarst landscapes of Hudson Bay Lowlands. This specific postdoctoral project builds on recent work (PhD) dealing with paleolimnology and geomorphology of thermokarst lakes located on the eastern coast of Hudson Bay (Kuujjuarapik-Whapmagoostui, Nunavik).

Scientific communications
Bouchard, F., Francus, P., Pienitz, R., Laurion, I., Feyte, S.
, 2014. Subarctic thermokarst ponds: investigating recent landscape evolution and sediment dynamics in thawed permafrost of northern Québec (Canada). Arctic, Antarctic, and Alpine Research, 40(1): 259-280. DOI: 10.1657/1938-4246-46.1.259.
Bouchard, F., Pienitz, R., Ortiz, J.D., Francus, P., Laurion, I.
, 2013. Palaeolimnological conditions inferred from fossil diatom assemblages and derivative spectral properties of sediments in thermokarst ponds of subarctic Quebec, Canada. Boreas, 42: 575-595. DOI: 10.1111/bor.12000.
Bouchard, F., Turner, K.W., MacDonald, L.A., Deakin, C., White, H., Farquharson, N., Medeiros, A.S., Wolfe, B.B., Hall, R., Pienitz, R., Edwards, T.W.D.
, 2013. Vulnerability of shallow subarctic lakes to evaporate and desiccate when snowmelt runoff is low. Geophysical Research Letters, 40(23): 6112-6117. DOI: 10.1002/2013GL058635.
Francus, P., von Suchodoletz, H., Dietze, M., Donner, R.V., Bouchard, F., Roy, A.-J., Fagot, M., Verschuren, D., Kröpelin, S.
, 2013. Varved sediments of lake Yoa (Ounianga Kebir, Chad) reveal progressive drying of the Sahara during the last 6100 years. Sedimentology, 60(4): 911-934. DOI: 10.1111/j.1365-3091.2012.01370.x.
Bouchard, F., Francus, P., Pienitz, R., Laurion, I.
, 2011. Sedimentology and geochemistry of thermokarst ponds in discontinuous permafrost, subarctic Quebec, Canada. Journal of Geophysical Research - Biogeosciences, 116: G00M04. DOI: 10.1029/2011JG001675.