Wuet al/Water Research 165(21)114979 二Pg二Aeae二a二 Less than5%C 血d tetayc己 Do YIvxin MLS Rock Microplastic MDR 944 daunon 21% chloramphenicol 199%18%1%140%1A3 acriflavine厂 ARGs type sistance gene ()types and subtypes in es in B uoroquinol amcomyci MDR (A)Dist Fig. 5. Overview of the occurrence of different antibiotic resistance gene (ARG) types and subtypes in the three biofilm types and river water. The relative abundance of ARGs was determined by metagenomic analysis. (A) Percentage and total abundance of antibiotic resistance genes in three types of biofilms and river water. Circle size stands for the total abundance of antibiotic resistance genes; (B) Proportions of the ARG types in all samples; (C) Relative abundance of the ARG subtypes. MLS denotes macrolide-lincosamide￾streptogramin. Other types represent resistance genes that are not directly related to specific antibiotic classes. Fig. 6. Proportions of ARG type profiles and the distinctive ARG subtype profiles of microplastic, rock, and leaf biofilm. (A) Distributions of each ARG type in total annotated ARG sequences in the microplastic, rock, and leaf biofilm. The length of the bars of the biofilm samples on the outer ring represent the percentage of ARGs in each biofilm sample; (B) Unique ARG subtypes profiles of different biofilms (R stands for rock biofilm; MP stands for microplastic biofilm; L stands for leaf biofilm). 8 X. Wu et al. / Water Research 165 (2019) 114979