Occurrence and Distribution of Plastispheres in Coastal Sediments and Waters along the Maharashtra Coast, India

Microplastics can promote microbial colonisation and biofilm growth, thus being referred to as "plastispheres". The global plastic pollution surge is likely to adversely impact ecology and human health by providing a novel habitat for microbial communities. Even though microplastics in marine environments have been the subject of in-depth research, plastispheres have recently received attention. Thus, the current study investigates the prevalence and distribution of plastispheres along the Maharashtra coast of India, considering their plausible implications for ecology and human health. Microplastics were isolated from sediment and water samples obtained from 10 sampling sites. Subsequently, these microplastic particles were subjected to ATR-FTIR and scanning electron microscopy (SEM) analyses to ascertain their chemical composition, surface topography, and presence of attached biofilms. The predominant polymers composing the microplastic particles were polypropylene (42.8%), polyethylene (28.6%), polystyrene (14.3%), and polyvinyl chloride (14.3%). SEM analysis revealed the presence of topographical structures and degradation effects, facilitating microbial attachment on the microplastic surface. About 50% of the microplastic particles tested positive for biofilms, with over 66% of those collected from Girgaon and Malvan beaches exhibiting biofilm presence. These positively screened particles also displayed comparatively rough surface structures, likely enhancing microbial colonisation. Microplastic ageing and polymer type could positively affect microbial colonisation. Diatoms and fungal hyphae exhibit varied interactions with microplastic polymers. Notably, microplastics host various reproductive stages of fungi, as evidenced by filamentous networks, mycelia, and conidiophores.