Microplastics in Natural and Artificial Reefs

Microplastic pollution represents one of the most significant challenges for marine conservation. Reef ecosystems are particularly sensitive to environmental changes and are already experiencing the negative impacts of climate change and multiple human-induced stressors. To further aggravate the situation, natural and artificial reefs are now contaminated with microplastics. This chapter aims to summarize information on the contamination of natural and artificial reefs by microplastics, encompassing quali-quantitative patterns of various biotic and abiotic matrices. Reef fish and corals are the primary biological models, with fish predominating in situ collections and corals in manipulative experiments. Blue fiber is the dominant morphotype and color within organisms, water, and adjacent soft sediment. The main polymers are polyethylene, polypropylene, and polyvinyl chloride. Microplastic concentrations in water and sediment vary markedly due to the application of distinct collection methods. Corals have been exposed to significantly higher microplastic concentrations and different particle shapes compared to those found in field collections. Evidences suggest increased microplastic concentrations in unconsolidated sediment around reefs compared to non-reef areas. These findings highlight the role of natural and artificial reefs as critical microplastic retention zones in both biotic and abiotic compartments.