Lecture: Making the Invisible Visible: When a Tiny Crustacean Reveals the Secrets of Plastic Pollution

Spanning the Seine Estuary, this exploration invites us to take a fresh look at this region situated between land and sea—a true crossroads of biodiversity, but also of pollution. It reveals how the invisible—from plastic particles to the biological responses of organisms—is already shaping the living world.

Straddling the worlds of science and the environment, this event will demonstrate that understanding the infinitely small has become essential to preserving the immensely living.

Summary of the ongoing research project: PLASTICOP

Plastic pollution is one of the most pressing environmental issues today. While the waste visible on beaches or floating on the surface of the oceans attracts attention, a large portion of this pollution is invisible: microplastics and nanoplastics. Resulting from the breakdown of plastic objects, these tiny particles are dispersed throughout all parts of the environment, particularly in estuaries—the transitional zones between rivers and the sea.

The PLASTICOP research project focuses specifically on the Seine estuary in France and the St. Lawrence estuary in Quebec, where nano- and microplastics are now present in the water, sediments, and living organisms. The goal is to better understand their fate and their effects on aquatic ecosystems. To this end, researchers are studying a small zooplankton crustacean, Eurytemora affinis, a species essential to the functioning of the food chain. As it feeds, this copepod may ingest nano- and microplastics, which can then be transferred to fish and other predators. The research will first aim to measure contamination levels in the two estuaries over the course of the seasons. Laboratory experiments will then be conducted to assess the combined effects of microplastics and global warming on the development, growth, behavior, and survival of juvenile copepods. The researchers will also seek to determine whether rising temperatures promote the accumulation of these particles within their bodies. Finally, a comparison between the French and Quebec populations will reveal whether they respond differently to these environmental pressures.

Beyond contributing new scientific knowledge, this dissertation will help improve our understanding of the impacts of plastic pollution on estuarine environments and aquatic biodiversity. It will also provide valuable information for improving the monitoring of these ecosystems and anticipating the combined effects of human activities and climate change.

Summary of the PLASTISENSE project currently under evaluation:

PLASTISENSE is an interdisciplinary project that explores the impacts of micro- and nanoplastics on estuarine ecosystems, viewing these particles not merely as contaminants, but as genuine ecological actors capable of altering interactions between organisms. Beyond its scientific advances in ecotoxicology, microbiology, and evolutionary ecology, the project places society at the heart of its approach through an integrated strategy combining participatory science and science communication. Citizens will be involved in collecting plastics along the Normandy coastline, directly contributing to the generation of knowledge about real-world environmental contamination. Students will also participate in the various stages of the project’s implementation, fostering exchanges between research, education, and society. Finally, art serves as a major tool for communication, translating scientific data from bioimaging and genomics into visual and sensory experiences. This Art & Science approach will make invisible pollution visible, evoke emotion as a driver of understanding, and encourage citizens to take ownership of the issues related to microplastics. By combining cutting-edge research, artistic creation, and public participation, PLASTISENSE offers a new way to disseminate scientific knowledge and strengthen the dialogue between researchers, citizens, and local communities.

Joëlle Forget-Leray

Joëlle Forget-Leray is a professor of ecotoxicology at the University of Le Havre Normandy in the laboratory titled “Environmental Stress and Biomonitoring of Aquatic Environments,” where her research focuses on understanding how aquatic ecosystems respond to environmental pressures. Through her study of copepods—tiny crustaceans that serve as sentinels of aquatic environments—she develops innovative biomonitoring tools designed to better assess water quality and support public policies for environmental protection. As a committed scientist, she combines academic excellence with the leadership of major national and European projects and institutional responsibilities in the service of research. Convinced that science must engage with society, she has been actively involved for many years in science communication—reaching out to citizens, students, and policymakers—on issues related to pollution, climate change, and ocean conservation. Her career path reflects a single ambition: to make research a catalyst for knowledge, action, and ecological transition.

Céleste Mouth

Céleste Mouth is a Ph.D. student in ecotoxicology at the SEBIO laboratory at the University of Le Havre Normandy. Originally from Greece, she grew up on the shores of the Aegean Sea, an environment that sparked her interest in aquatic ecosystems and their vulnerability to environmental changes at a very early age. Her research focuses on contamination by micro- and nanoplastics in two transatlantic estuaries: the Seine (France) and the St. Lawrence (Quebec). She is particularly interested in the consequences of early and multigenerational exposure to these pollutants on the copepod Eurytemora affinis, a small crustacean that plays an important role in estuarine ecosystems.