SEAPLASTICS 25
Description
SeaPlastics Expedition 2025 (SP25) was born from the collaboration between the association FLOW – For Living Oceans and Water, the student crew SeaPlastics, and the scientific support of the CNRS. Its principal aim is to gain a clearer understanding of the distribution, nature, and biological dynamics of micro- and macroplastics from the Atlantic coastline to the Mediterranean, while raising public awareness of this environmental challenge.
Placed under the scientific responsibility of Pablo Bourcelet (FLOW) and overseen by Jean-François Ghiglione, CNRS research director, the mission brings together students, researchers, and citizens. FLOW designs the protocols, while the crew carries them out at sea and leads citizen-science workshops.
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Below is a summary of the scientific protocols :
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OSPAR – A protocol for collecting macro-debris (≥ 2.5 cm) and surface microplastics from the strandline. Conducted with the mobile app FLOW, it forms the basis of an educational workshop entitled “3…2…1… Hands On!” The data will feed into the international OSPAR database.
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NASSE – Eight cages (four in freshwater in the Garonne and four in seawater at La Rochelle) containing four types of polymers (PE, PHBV, PHBH, and PE biomedia) are submerged one month before departure. During the voyage, twenty successive samplings will track the evolution of microbial colonies on each plastic.
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MANTA – Each time a cage is opened, a Manta trawl is carried out (30–60 min at 2–3 knots) to capture surface microplastics. Comparing “environmental” plastics with the controlled plastics from the cages will reveal the influence of the transition from the Atlantic Ocean to the Mediterranean and highlight differences between freshwater and seawater microbial communities.
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The collected samples (microplastics) will be processed in the laboratory: DNA extraction, dPCR quantification, and metabarcoding (16S/18S) will characterize the microbial diversity of the plastisphere. These results will complement macroscopic observations and open new avenues for assessing the impact of plastics in the marine environment. SeaPlastics 2025 thus combines scientific rigour, citizen engagement, and educational action. The expedition also serves as a testbed for potential future missions under the FLOW banner.