Céleste MOUTH

Assessing the impact of nano- and microplastics (NMPs) is a major environmental challenge, as these particles (<5 mm) account for a large share of global plastic pollution. Originating from the fragmentation of plastics, they are found in all environments (water, air, soil) and act as vectors for toxic substances. In estuaries such as the Seine (France) and the St. Lawrence (Canada), abiotic processes transform plastics into NMPs, increasing their concentration while reducing their size. NMPs are categorized as primary (intentionally produced small particles) or secondary (resulting from degradation).
The copepod Eurytemora affinis, abundant in these estuaries, is particularly exposed to NMPs, which it can ingest and subsequently transfer to higher trophic levels. These interactions pose ecotoxicological risks, affecting vital traits such as growth and reproduction. The variability of responses across the cryptic clades (European and North American) of this species remains poorly understood, despite observed differences in sensitivity to pollutants.
This multidisciplinary PhD project aims to:
1) Quantify NMP contamination in water, sediments, and copepods across seasons and estuaries (Seine and St. Lawrence).
2) Assess the combined impacts of climate warming (+3.5°C) and plastic pollution on early life stages (nauplii).
3) Investigate NMP bioaccumulation under controlled conditions and its variation between populations.