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Recent projects

Arctic Lakes and Fjords Project

The ecosystems of the Canadian High Arctic, including freshwater systems, are recognized to be particularly vulnerable to the effects of global environmental change. Although freshwater systems of the High Arctic have undergone dramatic biotic shifts due to recent climatic change, very little information is available about the long-term responses of these systems to fluctuations in …

Circumpolar Diatom Database Project

The Circumpolar Data base Many data were collected into 18 years of paleolimnological studies supervised by Dr. Pienitz. For most of them, they were added into a data base program which was manage with File Maker© program. At these times, the aim of this system was especially to archive and unify the data into an …

Impacts of mining activities and human development on the evolution of the lakes from the Bécancour River basin (southern Québec, Canada)

Lakes of the Bécancour River basin (southern Quebec, Canada) are in a precarious state since many decades as they are suffering from high sediment loads and advanced eutrophication. This situation affects the socio-economic and touristic potential of the neighbouring municipalities and is inconvenient for their residents as it impacts water supply, resort activities and recreational …

Lake sediments as sentinels of the impacts of human activities in Tursujuq national Park and Lac-Mégantic, Québec

The general objective of this projec is to assess the impact of current and past human activities on aquatic ecosystems by studying geochemical indicators and diatoms fossils in lake sediments. My work takes place in two study areas: Tursujuq national parc, situated in Nunavik, and Lac-Mégantic, situated in the MRC des Granit in southern Québec. …

Millennial study climate change in the Eastern Canadian Arctic using diatom assemblages and oxygen stable isotopes

Diatoms are siliceous organisms composed of amorphous biogenic silica (SiO2 – nH2O). Siliceous organisms are resistant to dissolution and are ubiquitous in lake ecosystems. Diatoms have strong affinities with their habitat, they reproduce rapidly, and the assemblage of species reliably records changes in their environment. Diatoms preserve in the SiO2structure of their frustule (siliceous shell) …

New Technologies to Monitor Harmful Algal Blooms Project

Quebec’s territory is covered by millions of lakes and those located in densely populated areas in the south are subjected to the influence of human activities in their catchments. An increasing number of these lakes are affected by eutrophication, showing recurring blooms of cyanobacteria (blue-green algae). Since the summer of 1999, cyanobacterial blooms were reported …

Northern Lake Monitoring Program

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 …

Paleoenvironmental reconstruction of the Foxe Basin area (Nunavut)

The climate and landscapes of the Canadian Arctic are greatly influenced by anthropogenic activities. Drastic changes of ecosystems were observed for long time due to the rapid increase in average temperature, which result in the accelerated melting of glaciers and permafrost. To increase our understanding of these changes and their impacts, we will conduct paleolimnological …

Paleolimnological reconstruction of postglacial paleoclimate and landscape evolution of the Fury and Hecla Strait region, Nunavut

This project aims to analyze sediment cores of lakes located on both shores of the Fury and Hecla Strait, in the Canadian Arctic, in order to reconstruct past climates and landscapes since the end of the last glacial period. A multi-proxy approach, based on physical, chemical and biological parameters, will permit high-resolution paleoenvironmental reconstructions of …

Paleolimnological study of lac Papineau in the Ottawa River valley based on fossil diatom communities and sedimentological properties

This paleolimnological study, based on the analysis of fossilized diatoms and sedimentological properties, presents the stratigraphic profile of a sediment core taken from lac Papineau (Ottawa River valley) in spring 2018. The lake is located in a region with a rich anthropogenic history, and the discovery of a pirogue in autumn 2017 attracted high interest …

Project about the dynamic of peatlands in relation to climate change and human occupation in Iceland

This master’s project aims at understanding the settlement and spatiotemporal evolution of peatlands in the northeast of Iceland by examining the relationship between climate, land and human activities. The humid climate of northeastern Iceland led to the establishment of peatlands starting at approximately 6000 years BP (Hallsodttir and Caseldine 2005). The magnitude of expansion was …

Thermokarst Lake Project

Permafrost affects nearly 50% of the Canadian territory, and it is found almost everywhere in Northern Quebec. Recent climatic warming has triggered partial melting of the permafrost in subarctic regions. This process brings a local ground subsidence which creates water-filled depressions called «thermokarst lakes». Recently observed in many northern regions, these lakes seem to have …