Can the bioturbation activity of the fiddler crab Minuca rapax modify the distribution of microplastics in sediments?

Fiddler crabs are known as eco-engineers who maintain habitat health through sediment bioturbation. They regularly interact with microplastics (MPs) due to their contact with the sediment. In this study we compared MPs concentration between burrows and pellets resulting from bioturbation, and MPs bioaccumulation in the soft tissues of Minuca rapax (Smith, 1870), along a gradient of urbanization in Isla del Carmen, southern Gulf of Mexico. Overall, MPs shape and color in the pellets and in the tissues reflected those of the burrow's sediments. MPs were more abundant and diverse in burrows (9 +/- 12 MPs.g(-1)) than in pellets (5 +/- 5 MPs.g(-1)) or in the soft tissues (1.3 +/- 1.2 MPs.g(-1)). Bioturbation can concentrate MPs in pellets and tissues, depending on the MPs contamination and urbanization level. M. rapax is an important structuring agent of sedimentary MPs, showing a strong top-down translocation of MPs in subtropical tidal flats.

Automated summary

Fiddler crabs, as eco-engineers, play an important role in maintaining habitat health through sediment bioturbation. This study found that they regularly interact with microplastics, with higher concentration and diversity observed in burrows compared to pellets and soft tissues. The results suggest that bioturbation can concentrate microplastics in different materials depending on contamination and urbanization levels.