How do ecosystems work? This is the big question that Cassandre Lazar, a professor in UQAM’s Department of Biological Sciences and a specialist in microbial ecology, wants to answer, on the smallest possible scale.
Even several hundred metres beneath our feet, rocks contain microorganisms of all kinds. What are they, and how do they manage to survive? Thanks to a collaboration with a geologist at Ressources Utica, Cassandre Lazar has gained access to some underground samples that are normally very difficult to obtain.
The researcher had the opportunity to work with water samples from underground wells with a uniquely high salt content, as well as with rock cores collected from the same site in Bécancour. She was also provided with samples of Gaspesian rocks from another geological era.
The samples were reduced to a powder from which the researcher then extracted the DNA of the microorganisms present. The very low biomass available at such depths made it difficult to establish a complete genetic portrait, but the researcher was nonetheless able to identify the microorganisms and examine the community structures they formed. The results showed a correlation between the species found in the rocks and the geological epochs from which the samples came.
As well as advancing fundamental research into microorganisms, these results also have practical implications. It is important to know which microorganisms are present underground if, for example, hydrogen is to be stored in groundwater or nuclear waste is to be buried, so as to prevent potential interactions of these substances with microorganisms that could pose a threat to ecosystems and humans. The researcher will use the results of her project as a springboard for another research project in collaboration with the mining industry. She will continue her exploration of microorganisms in deep rocks and the influence of minerals on these species, as well as the effect of microbial activity on rock and mineral alteration throughout Québec.
Référence
Gagnon, Jean-Christophe, Beauregard-Tousignant, Samuel, Marcil, Jean-Sébastien et Cassandre Sara Lazar (2023). « Deep Isolated Aquifer Brines Harbor Atypical Halophilic Microbial Communities in Quebec, Canada ». Genes, 14(8), 1529. https://www.mdpi.com/2073-4425/14/8/1529