Microplastics do not significantly alter the physiology of Mediterranean gorgonians
The PLASTICOR project, led by Dr. Núria Viladrich and Dr. Odei Garcia-Garin, and funded by the Institut de Recerca de la Biodiversitat de la Universitat de Barcelona (IRBio), has evaluated for the first time, the long-term impact of microplastics on two emblematic species of Mediterranean gorgonians: the red gorgonian (Paramuricea clavata) and the white gorgonian (Eunicella singularis). The project responds to a growing concern about the effects of emerging pollutants on habitat-forming species.
The project, which ended in 2024, has evaluated the impact of microplastics on several key biological processes such as food capture, photosynthesis, respiration, reproductive capacity and ingestion of plastic particles over more than three months of experimentation under controlled conditions. One of the innovative aspects of the project has been the comparison between P. clavata, a heterotrophic and more vulnerable species, and E. singularis, a mixotrophic species that can generate additional energy thanks to the symbiotic algae it contains.
The experiments were carried out in the laboratories of the University of Barcelona, where marine conditions were simulated with microplastic concentrations similar to those predicted for the future of the Mediterranean. The results have been surprisingly positive: despite the confirmation of the ingestion of microplastics —mainly PET, PS and PP— no serious physiological effects or visible cellular damage were detected using electron microscopy. No significant alterations were observed in respiration rates or organic matter content.
In addition, all the colonies studied were reproductively active, although the researchers warn that additional studies will be needed to evaluate the quality and quantity of sexual products.
According to Dr. Viladrich and Dr. Garcia-Garin, “the results show that, despite the presence of microplastics, gorgonians maintain their capacity for food capture, photosynthesis and respiration within the usual values”. In other words, the two species of gorgonians show remarkable physiological resistance to a global threat such as microplastics. “However, we cannot let our guard down. In fact, these species are key to the proper functioning of benthic ecosystems and their loss could have important ecological consequences.”
This physiological resistance could be related to protective mechanisms such as mucous secretion or the ability of some species to discriminate between food and plastic particles. However, the team warns that it will be necessary to study sublethal, chronic or long-term reproductive effects, as well as scenarios with multiple environmental pressure factors (warming, acidification, etc.).
The project has been presented at international conferences such as MICRO 2024, and has had scientific dissemination actions through social networks and public events.
PLASTICOR marks an inflection point in the study of the effects of microplastics on Mediterranean marine species and highlights the importance of multidisciplinary research. It reinforces the importance of continuing to investigate the effects of emerging pollutants on marine ecosystems and highlights the resilience of Mediterranean gorgonians facing the growing threat of microplastics. In addition, PLASTICOR has been a first step in understanding how key species of our biodiversity can respond to this emerging pollutant and lays the foundations for more ambitious and interdisciplinary future projects.