Paleolimnological studies into the recent (ca. last 200 years) history of northern lakes have revealed a striking discrepancy between climatic trends inferred for regions roughly located north and south of the Foxe Basin and Hudson Strait (Pienitz et al. 2004; Smol et al. 2005). While most freshwater ecosystems show signs of pronounced changes associated with global warming in the High Arctic, these changes are not yet detectable in lakes and ponds of northern Québec and Labrador. This remarkable stability at timescales of decades and hundreds of years suggests that northern Québec and Labrador lakes may experience less short-term or delayed climate change relative to other sectors within the Canadian Arctic. However, monitoring of permafrost temperatures now documents warming in the north-westernmost part of the Ungava Peninsula (Salluit area) since about 1995 (Allard et al., unpublished), and climate models imply that these regional differences in climate change may disappear during the coming decades (ACIA Report 2004) by which time the freshwater ecosystems of northern Québec and Labrador may be subjected to the climate impacts that are well advanced in other circumpolar regions. Thus, this sector could be the ultimate bellwether of large-scale circumpolar change because of its resistance to minor variations in the past. Its abundant freshwater ecosystems offer an unique opportunity for monitoring these changes at high temporal resolution and great detail, which is the primary focus of our ongoing research activities at Centre d’Études Nordiques.
Research objectives and methods
A major objective of this research initiative is to generate paleoclimate proxy data and monitor limnological change in a region that is of key importance to understanding the regionally very different dynamics and impacts of global climate change in Canada’s eastern Arctic, as it occupies a transitional position between areas undergoing detectable changes (High Arctic) and ar
eas that exhibit rather stable conditions (northern Québec and Labrador). Specialized equipments (e.g., thermistor chain (data loggers) monitoring water temperatures at 1 hour intervals) have been installed in the water column of selected lake and pond sites that will generate precious baseline data for regions with serious limnological data gaps, such as northern Québec and the Foxe Basin region. The annual visits of our study sites for data logger retrieval are accompanied by water column sampling and profiling (e.g., for observations of changes in thermal structure). Analyses of water samples (nutrients, cations, anions, trace metals) are performed by the National Laboratory for Environmental Testing (Dr. Derek Muir, Environment Canada, Burlington), while sediment trap samples will be analyzed for aquatic animal (crustaceans, insects) and plant remains (algae) by various researchers. This research provides a unique opportunity to follow and assess the impact of seasonal variability on northern lake ecosystems and their aquatic biota. Such comprehensive limnological surveys with field process studies permit developing robust, quantitative relationships between hydroclimatic and limnological variables and sedimentation processes. They are therefore of tremendous benefits for our paleoenvironmental interpretations in these remote northern regions.
Our long-term water monitoring program (Northern Lake Monitoring Network) was initiated in July 2004 with the installation of specialized equipments (e.g., data loggers, sediment traps) in the water column of selected lake and pond sites in northern Québec (Kuujjuarapik, Salluit, Kuujjuaq), the Foxe Basin region (Southampton Island, Nunavut) and on Bylot Island (Nunavut). Because this NSERC-funded (R. Pienitz- Northern Supplement) monitoring programme will, for the first time, generate precious baseline data for Canada’s eastern Subarctic region that lacks even the most basic information on aquatic ecosystem health and water quality, our research initiative was greeted with great interest, enthusiasm and support by the local native authorities. Since the beginnings of this initiative, residents from the native communities have been regularly involved in our field operations.
The long-term observations of limnological (e.g., thermal regime, water quality) changes generated through this initiative will enable us to closely track and predict the response of aquatic biota and the physical and chemical lake and pond characteristics to shifts in environmental conditions, such as climate warming and trophic loading (eutrophication). The data are complementary to those gathered for a few sites in the Canadian High Arctic by colleague W.F. Vincent (ULaval) and therefore offer the potential to be merged into larger databases that will be used for climate and environment calibrations and made available to others. Because the « health » of northern freshwaters is of fundamental importance to the native communities, the monitoring program will contribute to a better understanding of the potential social and economic impacts of global climate change. It also provides an « early warning system » for northern freshwater ecosystems that will help guide conservation measures.