Gabrielle Boudreault- MSc candidate

Transgenerational responses of Daphnia mendotae to metal contamination in the Rouyn-Noranda region.

In Rouyn-Noranda, Quebec, the Horne smelter contaminates surrounding aquatic environments with trace metals (TMs) such as cadmium. Despite this pollution, Daphnia dubia persists in large numbers. To better understand the ecotoxicological impacts in a mining context, this study aims to evaluate the evolutionary responses of populations by comparing their tolerance. Its objectives are: 1) to conduct acute and chronic biological tests (based on mortality, growth, reproduction, and moulting) in different environments to compare the tolerance of three daphnia populations; 2) to identify certain tolerance mechanisms through proteomic analyses. To do this, daphnia will be collected from three lakes: Osisko (heavily contaminated), Dufault (moderately contaminated), and Duprat (reference site). They will be cultivated in the laboratory for five generations to minimize environmental effects (common garden method). Next, an initial exposure test will be conducted in the waters of the three lakes to assess mortality over time. A second test will measure cadmium tolerance at environmental concentrations by analyzing reproduction rates, growth, and molting time. The daphnia from this test will be used to examine their response through genomic analyses. It is expected that daphnia from contaminated lakes will be more tolerant to metals and possess specific detoxification mechanisms, but that they will exhibit trade-offs, including reduced reproduction and growth. This study will contribute to a better understanding of how organisms respond to mining contamination..
Co-supervised by Maikel Rosabal (UQAM)