Fig 1.
Experimental setup and map of North Sea (UK) including currents and sampling stations.
(a) Map of SmartBuoy locations Dowsing (purple), Warp (green) and Gabbard (red), including dominant regional current systems (current flow information modified after [41]), (b) SmartBuoys from which PET bottles were deployed, including attachment setup, (c) samples and replicates included in this study.
Fig 2.
Principle Coordinate Ordinations relating variation in microbial community composition between plastic and seawater communities in summer.
PCOs representing similarity of biofilm communities based on counts of OTUs across samples (16S/18S rRNA gene data, see methods for OTU definition). Displayed are comparisons of (a) bacterial/archaeal and (b) eukaryotic communities of PET-attached, particle-associated (>3 μm) and free-living (0.22–3 μm) seawater communities sampled in summer.
Table 1.
PERMANOVA/PERMDISP results of substrate, season and station-specific variation in PET microbial communities.
Fig 3.
Abundant bacterial/archaeal families within PET communities.
Most abundant (top 25) bacterial and archaeal families present in PET-attached biofilm communities after deployment in the North Sea, grouped per deployment site/station and season (based on 16S rRNA gene analysis). * Gabbard represents data for winter and spring only; ** summer represents Warp and Dowsing data only; Gabbard summer was removed from analysis due to insufficient sequencing effort.
Fig 4.
Phylogenetic representation and relative abundances of OTUs comprising PET-attached and seawater communities.
Phylogenetic representation (based on 16S rRNA gene-based taxonomy assignment) of abundant OTUs (>0.5% of at least one community) and their relative abundances (pie charts based on log-scaled OTU counts) across treatments in summer.
Fig 5.
PET and glass biomarkers identified by linear discriminant analysis (LDA, LEfSe).
Representation of taxa significantly discriminant of either PET- or glass-attached communities across all stations after 5–6 weeks incubation in the North Sea. See S4 Table for complete list and statistical summaries.
Fig 6.
Abundant eukaryotic families within PET communities.
Most abundant (top 25) eukaryotic families present in PET-attached biofilm communities after deployment in the North Sea for 6 weeks, grouped per deployment site/station and season (based on 18S rRNA gene analysis).