Differential colonization and succession dynamics of marine bacteria on different plastic polymers

During the past decades since plastic was introduced to the world, marine microorganisms have been adapted for life on marine plastic debris, forming unique plastic-attached microbial communities. To date, little is known about the colonization and succession processes that take place on plastic surfaces in marine environments and how the plastic polymer type affects the plastic-attached microbiome composition. To address this knowledge gap, we examined the colonization and succession dynamics of marine bacteria on four common plastic polymers - PE, PP, PS, and PET-compared to glass and wood in a controlled seawater system under different temperatures. Using a simple experimental design, coupled with a long-read 16S rRNA metabarcoding pipeline and a set of complementary data analyses, we characterized the temporal trends in the composition of the bacterial microbiome developed on different surfaces over 2 - 90 days. By applying weighted gene co-expression network (WGCNA) analysis, we established co-occurrence networks and identified genera with specific succession signatures, significant enrichment on specific plastic polymers and/or strong intra-genus connections. Among them, members of genus Alcanivorax were significantly enriched on either PE or PP plastic surfaces as early as 2 days post-inoculation. Alcanivorax colonization preference to polyolefins was confirmed in colonization assays with pure Alcanivorax strains. Our research approach presented here may contribute to understanding how plastisphere communities are being formed and help identify taxa with specific adaptations to plastic surfaces.