| Microplastics is a new type of pollutant which has attracted intensive attention in recent decades.However,the understanding of the role and function of microorganisms in microplastics pollution is still limited.The main purpose of this paper is to provide useful information for assessing the natural diversity of microplastic-colonizing microbial communities.The formation of biofilm on the surface of microplastics and the microbial community structure of microplastic biofilm were investigated by laboratory and field studies.In the laboratory study,we investigated biofilm formation by microorganisms originating from lake water on low-density polyethylene?LDPE?MPs using a cultivation approach and the surface-related effects on the MP-associated microbial communities using 16S rRNA high-throughput sequencing.We found that microorganisms in lake water could form biofilm rapidly on the surface of LDPE microplastic.Both UV pretreatment and surfactants amendment that can change the surface roughness and hydrophilicity of microplastics improved the formation of biofilm and changed the community structure of biofilm.Microbial community analysis showed that,in lake water,some toxic and harmful microorganisms could grow and be enriched on the surface of LDPE microplastics.In the field study,we collected the surface water from the eight outlets of Pearl River Estuary in spring,summer and autumn.We isolated and identified microplastics from water sample,investigated the microplastic-colonizing microbial community structure,and analyzed the correlations between physical/chemical properties of water and microbial community structure.Results showed:1)the predominance of Proteobacteria and Firmicutes on all microplastic biofilm;2)distinct microbial assemblages between microplastics and surrounding waters,especially for Spring and Summer;3)alkalinity,TC,SO42-,salinity and IC,times were the main factors affecting microbial community structure of microplastic biofilms. |
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