Microplastics Abundance in Aquatic Environment and its Impact on Macrobenthos

Microplastic (MP) pollution is an escalating environmental concern with comprehensive implications for aquatic ecosystems and their inhabitants. Understanding the intricate relationship between MPs and macrobenthos is paramount for grasping the full extent of environmental degradation within aquatic ecosystems. As MP pollution proliferates, its repercussions for macrobenthic communities including poriferans, corals, aquatic arthropods (Daphnia, crabs, and shrimps), mollusks (unio and mussels), and echinoderms (starfish and sea cucumbers), has become increasingly evident. This review delves into the multifaceted impacts of MPs on macrobenthos, shedding light on the ecological disruption, behavioral alterations, and potential cascading effects throughout marine and freshwater environments. From tropical reefs to freshwater rivers, sponge tissues exhibit escalating levels of MP contamination over time, reflecting the extensive bio-accumulative potential of these organisms. By studying and exploring the effects of MPs on poriferans with a comprehensive examination of existing literature, it becomes evident that MP exposure induces adverse effects including impaired feeding, increased mucus production, altered gene expression, and coral bleaching. Nanosized polystyrene (PS)-MPs delayed the developmental time and downregulated Usp gene expression in Tigripous japonicus. In mollusks, studies revealed diminished filtration rates and altered energy reserves in bivalves exposed to MPs, accompanied by oxidative damage and compromised activity of digestive enzymes. MP exposure leads to various developmental defects such as larval morphological alteration and a size-dependent impact on the larval growth and development of echinoderms. The mechanisms underlying MP-induced toxicity across various phylum are discussed, highlighting the urgent need for further research to elucidate their cumulative impacts on organismal health and fitness.