Marine plastic-associated bacterial community succession in response to exposure time and plastic type in Korean coastal waters

Abstract

Plastic pollution has provided a new surface for bacterial community and biofilm formation, it can facilitate bacterial dispersal and affect all aquatic ecosystems. Despite of the marine plastic-associated bacterial community has shown the different composition according to the plastic types, exposure time, location and environmental condition, information of colonization stages of bacterial communities remains limited. In this study, we investigated what microbial communities succeed after the initial attachment of the bacterial biofilm adhesion using 16S rDNA metabarcoding in four commercial plastic materials (EPS, PE, PET, PP) as well as ambient seawater in Jangmok Bay of Korean coastal waters. In the clustering analysis, the bacterial communities were firstly divided into two groups, the free-floating and plastic-associated bacteria with 75% dissimilarity. In four plastic materials, there was no substrate specificity of bacterial composition, which, however were classified according to the exposure time. Namely, the bacterial community was clearly classified for 3, 6, and 9 days. From 12 to 21 days, a similar bacterial community into one group was stably maintained, which can be considered a late stage in which a mature biofilm is formed. During the experiments, the dominant plastic-associated bacteria were Psedoalteronomas and Clostridium at the genus level. From early to late stages, Psedoalteromonas continuously occurred, which is known to biodegradation of plastics. Since 12 days, Clostridium species suddenly occurred, which is mainly found in sewage or marine sediments is an indicator of water contamination and is known as a potential pathogen. This is a first report of the colonization of plastic-associated bacteria in Korean coastal waters, the occurrence of specific bacteria indicate that the marine plastic provide the resources for biodegrading bacteria and transporters for potential pathogenic bacteria.