Microplastic distribution in large shallow lake sediments: Variations with offshore distance and implications for microbial communities

Microplastics (MPs) are ubiquitous in global ecosystems and pose potential threats to the environment and biodiversity. However, the impact of MPs on microorganisms in real environments remains unclear. Our study focuses on the composition and distribution of MPs in sediments at different offshore distances in Taihu Lake. Our results indicated that MP abundance ranged from 240 to 1120 items/kg and decreased linearly with increasing offshore distance. Fibres dominated, with an average proportion of 47.58 %, and MPs within a particle size range of 0.5-1 mm (53.88 %) had the highest content. PA and PVC were the most abundant polymer types, accounting for 55.85 % and 17.94 %, respectively. The abundance of MPs in sediments was significantly positively correlated (P < 0.01) with the abundance of Firmicutes and significantly negatively correlated with the abundance of Planctomycetota. MPs account for 0.49 % of the variation in microbial alpha diversity and 1.88 % of the variation in microbial community composition. Our study demonstrates that environmental factor and MPs significantly affect microbial diversity and species composition. In summary, our research reveals the distribution patterns of MPs in sediments at different offshore distances in Taihu Lake, confirming the potential impact of MPs on microbial communities.