Selective bacterial attachment and emergence of potentially pathogenic bacteria on four plastic surfaces: Adhesion study in natural marine environment

Abstract

The surface of marine plastic debris (MPD) provides new habitats for adherent bacterial communities, and can facilitate bacterial dispersal throughout aquatic ecosystems. Although the composition of marine plastic-attached bacterial communities has been shown to differ based on plastic type, exposure time, location, and environmental conditions, information regarding the colonization stages of bacterial communities remains limited. Hence, the current study employed 16S rRNA metabarcoding to establish which bacteria initially attach to four plastic materials (i.e., expanded polystyrene, polyethylene, polypropylene, and polyethylene terephthalate). Furthermore, the study determined which bacteria selectively adhere after initial biofilm formation, and which potential pathogenic bacteria emerge in comparison to the bacterial species observed in ambient seawater within Jangmok Bay, South Korea. Cluster analysis revealed a clear distinction between the bacterial communities within ambient seawater and those on all MPD surfaces. Additionally, among the four plastic materials, specific characteristics of the attached bacterial communities were noted based on exposure time. Specifically, distinct changes in the bacterial community were observed on Day 3, 6, 9, and 12–21. More specifically, on Day 3, Psedoalteromonas had a relative abundance > 80%; whereas, the prevalence of Vibrio spp.—potential pathogenic bacteria—increased rapidly on Day 6 and 9. However, after 12 days, the prevalence of another potential pathogen, i.e., Clostridium spp., steadily increased. Hence, regardless of polymer type, bacteria attached to plastic exhibit substrate-adhesion specificity and unique community characteristics compared to those in the surrounding seawater. In particular, pathogenic bacteria that are rare in seawater, exhibit high adhesion specificity on plastics. As such, MPD provides the necessary resources to serve as an effective transporter and habitat of potential pathogenic bacteria in aquatic ecosystems.