Time-Dependent Effect of Graphene on the Microbial Activity of the Soil Under Single and Repeated Exposures
Abstract Graphene (GR) has huge industrial and biomedical potential, and its adverse effect on soil microorganisms has been evaluated in some ecotoxicological studies. These studies focus on a single exposure to GR, but repeated exposures are more likely to occur in soil. In this study, we compared the impact of single and repeated exposures (one, two and three exposures that resulted in the same final concentration) of GR on structure, abundance and function of soil bacterial community based on soil enzyme activity and high-throughput sequencing. The activities of urease and fluorescein diacetate esterase and alpha diversity demonstrate that repeated exposure to GR increase the diversity of soil bacterial diversity after 4 days of incubation following the last application of GR to soil. And the PCoA and sample level clustering tree showed single exposure to GR after 4 days alter the soil bacterial community to some extent, but the difference has been narrowed with the extension of time. During the entire incubation process, no matter what kind of exposure scenarios to GR, the majority of bacterial phylotypes remained unchanged except for Proteobacteria and Actinobacteria according to the relative abundance of phylotypes.