Anthropogenic particles accumulation in sea cucumbers: insights from a transitional environment

Detritivorous organisms, such as sea cucumbers, are key components of marine benthic ecosystems, contributing to sediment bioturbation and nutrient recycling, and thereby playing a pivotal role in ecosystem functioning. However, due to rising plastic production and inadequate waste management, their sediment-ingesting feeding strategy makes them particularly susceptible to anthropogenic particle (AP) contamination, potentially influencing trophic transfer and benthic-pelagic coupling. This study represents the first investigation on AP occurrence in holothuroids, Holothuria sanctori and H. tubulosa, inhabiting the transitional coastal waters of the Capo Peloro Natural Reserve (Mediterranean Sea). Raman and FT-IR analyses identified 12 synthetic polymers, three elastomers, one rubber, one petroleum derivative, and one semisynthetic particle. Additionally, cotton and dyed cellulose were also identified. Overall, our findings reveal a broader spectrum and higher level of complexity of APs than previously reported in sea cucumbers from marine environments, with 18 types identified in H. sanctori and 17 in H. tubulosa. Neoprene and cotton were the most frequently detected APs. The results underscore the suitability of the studied invertebrates as sentinel species for assessing plastic contamination in transitional environments.