According to a study, degraded ecosystems have more microplastics than well-conserved ones

A scientific study has highlighted the crucial role of vegetated coastal ecosystems, such as seagrass beds, mangroves, and salt marshes, in the accumulation and filtration of microplastics. The work was carried out by Drs. Gema Hernán and Fiona Tomas, along with Esther Rodríguez, a master's student at IMEDEA (UIB-CSIC).

Since 2011, several studies have addressed the issue of microplastics in these ecosystems, investigating their origin, distribution, characterization, and fate. One of the most notable findings of the study is the uneven geographic distribution of the research, with a higher concentration of studies in the Northern Hemisphere and in mangrove areas where the highest concentrations of microplastics are observed, especially near urban and fishing areas. The review highlights that nearly 40% of the studies report a greater accumulation of microplastics in vegetated areas compared to non-vegetated areas, underscoring the important role of these zones as natural filters. Moreover, it was found that highly degraded ecosystems have higher concentrations of microplastics than those in better conservation status, emphasizing the vulnerability of deteriorated environments to plastic pollution.

"Seagrass beds and salt marshes on our coasts can become hotspots for the accumulation of microplastics," states Dr. Hernán.

The study also reveals that secondary microplastics—fibers and fragments resulting from the degradation of larger plastics—are the most common in these ecosystems. Among the types of polymers identified, the most abundant are those of lower density, such as polyethylene, polystyrene, and polypropylene.

One of the main challenges pointed out by the authors is the lack of standardization in the methods used to measure and report microplastic pollution. Differences in units of measurement, sampling depths, and extraction methods limit comparability between studies, complicating a broader understanding of the issue.

Finally, the study emphasizes the need to investigate how factors such as vegetation density, species diversity, and hydrological dynamics influence the distribution of microplastics in these environments.

This work represents a significant advance in the knowledge of microplastic pollution in vegetated coastal ecosystems and underscores the importance of continuing research to understand the long-term effects of this issue.