Global Reanalysis Reveals Recurrent Cyanobacterial Enrichment in the Aquatic Plastisphere

The plastisphere is an emerging anthropogenic ecosystem hosting complex microbial assemblages. While heterotrophic colonizers are well studied, the role of primary producers such as cyanobacteria remains underexplored. Here, we reanalyzed 16S rRNA gene amplicon data from 3160 plastisphere samples across 62 aquatic studies to assess their role in community assembly at a global scale. Substrate type explained a significant but relatively small fraction of variation (R2 = 0.048), whereas β-diversity showed clear separation between marine and freshwater communities. Among all substrate types (plastic, microplastic, natural polymer, and nonplastic), plastic-associated communities exhibited the highest estimated contribution of deterministic assembly processes in both freshwater and marine ecosystems. Co-occurrence networks showed low modularity and high clustering, revealing recurrent community association patterns across plastisphere data sets, while several topologically central taxa exhibited frequent associations with cyanobacteria. Notably, Xenococcaceae and Phormidesmiaceae were consistently enriched on plastics relative to surrounding environments. Independent metagenomic analyses corroborate enrichment of Phormidesmiaceae. These results demonstrate recurrent cyanobacterial enrichment in plastisphere communities and identify co-occurrence patterns between cyanobacteria and heterotrophic taxa. These associations generate hypotheses regarding possible phototroph-heterotroph linkages on plastic surfaces that warrant experimental investigation.