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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 …

Characterization of the diatom flora of Tursujuq Park, Nunavik, Canada

The development of tourism in the Tursujuq Park (Nunavik) could impact the balance of lake ecosystems. Before analyzing the biological indicators such as diatoms, it is first necessary to identify the species present in the different lakes. The main objective of this research project is to carry out a characterization of the diatom flora of …

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. …

Microbial communities as sedimentary indicators of anthropogenic impact in Fildes Peninsula, South Shetland Islands, Antarctica

Since the discovery of Antarctica in the early 19th Century, the number of humans arriving to the continent has progressively increased. This increased human footprint has generated concern about the threats posed to the region’s fragile ecosystems. The Fildes Peninsula (King George Island, South Shetland Islands) has been the site of year-round human presence since …

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 …

Paleolimnological assessment of the impacts of anthropogenic activities on Fildes Peninsula, South Shetland Islands, Antarctica

Since the discovery of Antarctica in the early 19th Century, the number of humans arriving to the continent has progressively increased. From the early explorers to hunters and whalers, scientists, and later tourists, all human visitors have left evidence on the Antarctic landscapes on their passage. The increasing human footprint has begun to strain sensitive …

Paleolimnological comparison of two postglacial regions: the eastern Canadian Arctic and the northern Mediterranean

Information about past climates is needed to interpret ongoing modern environmental changes. Knowledge about present and past microbiomes can be used to develop indicators of environmental change that, when applied to sediment cores, can help to develop records of past climate. During my PhD studies, I will examine the present and past diatom microbiomes of …

Paleolimnological reconstruction of postglacial coastal subarctic paleoenvironments and paleoclimates, Dog Island, Labrador

Climate fluctuations are driving increasingly disruptive changes in northern environments and the ecological services these ecosystems provide to Inuit communities in Labrador. Culture and human occupation evolve spatially and temporally in a complex relation with the dynamic natural landscape, for which the functioning and development are still poorly known in Labrador. Modern climate changes pose …

Stuckberry Valley lakes: Sentinels of environmental changes in the High Arctic

Among high latitude ecosystems, lakes are particularly sensitive to environmental variations. By studying their current and past conditions through their sediments, this project aims to provide a better understanding of the functioning of these high Arctic ecosystems and their roles in the global climate. The series of four lakes in Stuckberry Valley is one of …

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 …