A new mechanism for microplastics to enter the food chain

À gauche : image des microplastiques dans les agrégats de microalgues. À droite, l’étude du phénomène par AFM

Microplastics enter plankton aggregates, which are then ingested by fish and move up the food chain. Des scientifiques de trois laboratoires implantés à Toulouse, ont été les premiers à utiliser la microscopie à force atomique pour étudier le problème. In work published in the journal Science of the Total Environment, they confirmed the existence of a mechanism where the presence of microplastics favors the aggregation of microalgae, and discovered a second, previously unknown mechanism.

Plastic pollution affects all environments. In particular, microplastics enter the marine food chain and then make their way up to the largest animals and to humans. Interactions with plankton seem to be particularly important, but are still poorly understood. Microalgae, which make up most of the plankton and the first link in the aquatic food chain, can aggregate under certain conditions. Microplastics cause the formation of these aggregates, in which they mix and thus pass into the animals or spread in the depths of the oceans. The heavier aggregates sink instead of floating. Researchers from the Toulouse Biotechnology Institute, bio & chemical engineering (TBI, CNRS/INSA Toulouse/INRAE), du Laboratoire d’analyse et d’architecture des systèmes (LAAS-CNRS) and the laboratoire Interactions moléculaires et réactivité chimique et photochimique (IMRCPCNRS/Université Toulouse/Paul Sabatier) have shown that microplastics reinforce, in two different ways, the formation of plankton aggregates which they then mix with. Published in the journal Science of the Total EnvironmentThis work is based on a new methodology, centered around an atomic force microscope (AFM).

Références

The role of microplastics in microalgae cells aggregation: A study at the molecular scale using atomic force microscopy.
Irem Demir-Yilmaz, Nadiia Yakovenko, Clément Roux, Pascal Guiraud, Fabrice Collin, Christophe Coudret, Alexandra Ter Halle, Cécile Formosa-Dague. Science of the Total Environment, 2022

https://doi.org/10.1016/j.scitotenv.2022.155036

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