Supervised by:

Jérôme Comte (Regular Member (Co-researcher))

Research project description

Master’s degree in water sciences on the relation between the formation of taliks, the remobilisation of dissolved organic matter and the microbial community.

Introduction

For many municipalities in northern Quebec, access to drinking water can be a major challenge. The communities that live there rely mainly on surface water to meet their needs. However, these waters are more susceptible to contamination and their quantities can vary and become limited. An alternative would be to draw groundwater, but the presence of permafrost can make this water difficult to access. In Salluit, the water supply comes from the Kuuguluk River and groundwater, but the community regularly faces water quantity issues. Previous work has revealed the existence of a talik (area of permanently unfrozen ground in permafrost) under the river. Lately, an increase in the number and size of talik is observed in areas of continuous permafrost. These systems could therefore serve as a year-round source of water supply. Their potential must be evaluated.

Objectives

The goal of this master's project is to describe the relationship between taliks formation, the remobilization of organic matter, and the microbial community. Water samples, sediment samples and soil samples will be taken to evaluate the hydraulic connectivity between terrestrial and aquatic environments in regions of continuous permafrost. Samples will then allow to investigate the taxonomic and functional diversity of the microbial community of the talik and its environment and allow to assess the concentration of organic matter dissolved in water from different origin and the concentration present in soils. Samples will also be tested for contaminants, including polycyclic aromatic compounds (PACs) and metals, with the identification of PACs attempted where the concentrations allow it. Ultimately, this project aims to evaluate the vulnerability and sustainability of the subfluvial talik under the Kuuguluk River as a freshwater resource for the Inuit community of Salluit.

Study Sites

The study focuses on the talik beneath the Kuuguluk River in Salluit. This small village, located in Nunavik (Quebec, Canada), lies in a zone of continuous permafrost. Sampling will take place along four transects on the Kuuguluk River and its shore, where wells were drilled during the summer of 2024. Seven stations will be identified along the transects where both surface water and well water will be collected. Interstitial water and soil cores will also be sampled on the watershed of the river. The water samples will be filtered on-site and then transported to Quebec City. All samples will be analyzed at INRS (ETE center) as well as at Delta-Lab (Geological Survey of Canada – Quebec). Other field studies concerning the river, the wells and the soils will be conducted in collaboration with the CGC.

Material and methods

Several water and soil samples in the talik recharge area will be collected in partnership with members of the Salluit community. Some of the sampled water will first be filtered to concentrate microorganisms. The DNA from these filters and the soil will be extracted and then sequenced by a third-generation platform (Nanopore). Metagenomics and metabarcoding will be applied for sequencing to determine the taxonomy and functions of microorganisms present in sampled environments. In addition, microbiological tests will be performed to determine if there are pathogenic bacteria. The concentration of organic matter and polycyclic aromatic compounds (PACs) will be evaluated. If the concentrations of CAPs are high enough, they will be identified using isotypic analysis. The samples will also be analyzed to quantify the metals present.

References

Lemieux, J.-M., Fortier, R., Talbot-Poulin, M.-C., Molson, J., Therrien, R., Ouellet, M., Banville, D., Cochand, M. and Murray, R. (2016). Groundwater occurrence in cold environments: examples from Nunavik, Canada. Hydrogeology Journal 24, 1497-1513. Harris, S. A., French, H. M., Heginbottom, J. A., Johnston, G. H., Ladanyi, B., Sego, D. C. and van Everdingen, R. O. (1988). Glossary of permafrost and related ground-ice terms. In Technical Memorandum (National Research Council of Canada. Associate Committee on Geotechnical Research); no. ACGR-TM-142: National Research Council of Canada. Associate Committee on Geotechnical Research. Permafrost Subcommittee. Connon, R., Devoie, É., Hayashi, M., Veness, T. and Quinton, W. (2018). The Influence of Shallow Taliks on Permafrost Thaw and Active Layer Dynamics in Subarctic Canada. Journal of Geophysical Research: Earth Surface 123, 281-297.

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