Biogeography rather than substrate type determines bacterial colonization dynamics of marine plastics

Abstract

Since the middle of the 20th century, plastics have been incorporated into our everyday lives at an exponential rate. In recent years, the negative impacts of plastics, especially as environmental pollutants, have become evident. Marine plastic debris represents a relatively new and increasingly abundant substrate for colonization by microbial organisms, although the full functional potential of these organisms is yet to be uncovered. In the present study, we investigated plastic type and incubation location as drivers of marine bacterial community structure development on plastics, i.e., the Plastisphere, via 16S rRNA amplicon analysis. Four distinct plastic types: high-density polyethylene (HDPE), linear low-density polyethylene (LDPE), polyamide (PA), polymethyl methacrylate (PMMA), and glass-slide controls were incubated for five weeks in the coastal waters of four different biogeographic locations (Cape Verde, Chile, Japan, South Africa) during July and August of 2019. The primary driver of the coastal Plastisphere composition was identified as incubation location, i.e., biogeography, while substrate type did not have a significant effect on bacterial community composition. The bacterial communities were consistently dominated by the classes Alphaproteobacteria, Gammaproteobacteria, and Bacteroidia, irrespective of sampling location or substrate type, however a core bacterial Plastisphere community was not observable at lower taxonomic levels. Overall, this study sheds light on the question of whether bacterial communities on plastic debris are shaped by the physicochemical properties of the substrate they grow on or by the marine environment in which the plastics are immersed. This study enhances the current understanding of biogeographic variability in the Plastisphere by including biofilms from plastics incubated in the previously uncharted Southern Hemisphere.

16s rRNA gene sequence analysis of the microbial community on microplastic samples from the North Atlantic and Great Pacific Garbage Patches

“…Biogeography is incontestably a driver of microbial diversity. Similar results were also obtained by Coons et al, 2021 who found that biogeography influences Plastisphere community structure more than substrate type. Differences in the biofilm community composition are related to different factors.…”

“…They found diverse microbial communities, including heterotrophs, autotrophs, predators, and symbionts, which they called a 'Plastisphere'. Coons et al (2021) investigated plastic-type and incubation locations in the Atlantic and Pacific oceans, focusing on shore locations as drivers of marine bacterial community structure development on plastic via 16S rRNA gene amplicon analysis. They found that incubation location was the primary driver of the coastal Plastisphere composition.…”

The geographical and seasonal effects on the composition of marine microplastic and its microbial communities: The case study of Israel and Portugal

“…At sea, microplastics are readily colonized by a variety of marine organisms, creating an ecosystem that is distinct from its surrounding water which is referred to as the plastisphere (Zettler et al, 2013). It was shown that the plastic microbiome composition is variable among different geographical locations (Oberbeckmann et al, 2014;Amaral-Zettler et al, 2015;Coons et al, 2021) and that it is affected by environmental factors such as salinity, water temperature, light, and nutrient availability (Amaral- Zettler et al, 2015;Oberbeckmann et al, 2018;Misic and Covazzi Harriague, 2019). Although the colonization characteristics of microbial communities on microplastics have been investigated in a variety of short-term (Oberbeckmann et al, 2014(Oberbeckmann et al, , 2016Coons et al, 2021;Zhang et al, 2022) and long-term (Pinnell and Turner, 2020) in-situ experiments, only few studies have investigated the effects of both geographical and seasonal factors in the natural environment (Dong et al, 2021;Yang et al, 2021).…”

Fluid dynamics and cell‐bound Psl polysaccharide allows microplastic capture, aggregation and subsequent sedimentation by Pseudomonas aeruginosa in water

“…Previous research has explored the taxonomic composition and spatiotemporal patterns of plastic‐colonizing microorganisms in aquatic environments using microscopy and molecular biology tools (Zettler et al ., 2013 ; Amaral‐Zettler et al ., 2015 ; Oberbeckmann et al ., 2018 ; Coons et al ., 2021 ). Results from these studies have indicated that microbes inhabiting the plastisphere reflect the local environments.…”

“…Results from these studies have indicated that microbes inhabiting the plastisphere reflect the local environments. These communities appear to be highly variable in taxa dominance compared with the populations in the surrounding water, with plastic‐type having a more minor influence on the community composition (Amaral‐Zettler et al ., 2015 ; Coons et al ., 2021 ). Importantly, plastic debris has been shown to serve as a substrate for colonization and spread of opportunistic human pathogens and bacteria related to antibiotic resistance, suggesting that these pollutants could constitute a vector for horizontal gene transfer (Zettler et al ., 2013 ; Oberbeckmann et al ., 2018 ).…”