Exposure to nanoplastics disturbs the gut microbiome in the soil oligochaete Enchytraeus crypticus

Microplastics are emerging pollutants that have recently aroused considerable concern but most toxicological studies have focused on marine biota, with little investigation of the influence of microplastics on terrestrial ecosystems. Here, we fed the soil oligochaete Enchytraeus crypticus with oatmeal containing 0, 0.025, 0.5, and 10% (dry weight basis) nano-polystyrene (0.05-0.1 μm particle size) to elucidate the impact of microplastics on the growth and gut microbiome of Enchytraeus crypticus. We observed a significant reduction of weight in the animals fed 10% polystyrene and an increase in the reproduction of those fed 0.025%. More importantly, using 16S rRNA amplification and high-throughput sequencing we found a significant shift in the microbiome of those fed 10% microplastics with significant decreases in the relative abundance of the families Rhizobiaceae, Xanthobacteraceae and Isosphaeraceae. These families contain key microbes that contribute to nitrogen cycling and organic matter decomposition.