In situ Prokaryotic and Eukaryotic Communities on Microplastic Particles in a Small Headwater Stream in Germany

Abstract

The ubiquitous use of plastic products in our daily life is often accompanied by improper disposal. The first interactions of plastics with organisms in the environment occur by overgrowth or biofilm formation on the particle surface, which can facilitate the ingestion by animals. In order to elucidate the colonization of plastic particles by prokaryotic and eukaryotic microorganisms in situ, we investigated microbial communities in biofilms on four different polymer types and on mineral particles in a small headwater stream 500 m downstream of a wastewater treatment plant in Germany. Microplastic and mineral particles were exposed to the free-flowing water for 4 weeks in spring and in summer. The microbial composition of the developing biofilm was analyzed by 16S and 18S amplicon sequencing. Despite the expected seasonal differences in the microbial composition of pro- and eukaryotic communities, we repeatedly observed polymer type-specific differentiation in both seasons. The order of polymer type-specific prokaryotic and eukaryotic community distances calculated by Robust Aitchison principal component analysis (PCA) was the same in spring and summer samples. However, the magnitude of the distance differed considerably between polymer types. Prokaryotic communities on polyethylene particles exhibited the most considerable difference to other particles in summer, while eukaryotic communities on polypropylene particles showed the most considerable difference to other spring samples. The most contributing bacterial taxa to the polyethylene-specific differentiation belong to the Planctomycetales, Saccharimonadales, Bryobacterales, uncultured Acidiomicrobia, and Gemmatimonadales. The most remarkable differences in eukaryotic microorganism abundances could be observed in several distinct groups of Ciliophora (ciliates) and Chlorophytes (green algae). Prediction of community functions from taxonomic abundances revealed differences between spring and summer, and – to a lesser extent – also between polymer types and mineral surfaces. Our results show that different microplastic particles were colonized by different biofilm communities. These findings may be used for advanced experimental designs to investigate the role of microorganisms on the fate of microplastic particles in freshwater ecosystems.

Microplastic polymer properties as deterministic factors driving terrestrial plastisphere microbiome assembly and succession in the field

“…Previous studies on plastisphere colonization have detected various taxa such as Alteromonadales, Caulobacterales, Chitinophagales, Cytophagales, Flavobacteriales, Frankiales, Saprospirales, Rhodospirillales, and Vibrionales that readily colonize plastic surfaces in freshwater, marine and soil environments (Dudek et al, 2020; Hansen et al, 2021; MacLean et al, 2021; Ogonowski et al, 2018; Vaksmaa et al, 2021; Weig et al, 2021; Xie et al, 2021; Zettler et al, 2013). Combined indicator analysis data of PS + PET showed that Bacillales are indicative of PS and PET treatments and might include plastic‐degrading taxa (Gambarini et al, 2021).…”

“…The sequences for all samples were processed and aligned using the 16S Pathogenic Identification Process (16SPIP) (Miao et al, 2017). Processing was done as previously reported (Li et al, 2021; Weig et al, 2021). In brief, database hits with a greater than 99% similarity to reference sequences were identified as taxa of potential concern to human health.…”

Microplastic ingestion affects hydrogen production and microbiomes in the gut of the terrestrial isopod Porcellio scaber

“…After demultiplexing of the sequencing reads, the QIIME2 software package (version 2021.2; http://www.qiime2.org) was used for further processing as described previously (Weig et al, 2021). Briefly, primer specific sequences were removed from sequencing reads that were subsequently subjected to the DADA2 pipeline for quality filtering, denoising and joining of paired reads.…”

Year-Long Microbial Succession on Microplastics in Wastewater: Chaotic Dynamics Outweigh Preferential Growth

“…It has been demonstrated across a variety of different studies that biofilm communities are far more linked to other factors, such as location or habitat, than by the composition of the substrate [25,34]. However, while geographical or temporal factors typically overshadow differences between MPs and natural particles, especially between MP polymer types, some slight differences have also been reported [35,36], often in relation to more nutrient-depleted environments such as the open ocean [37]. Nevertheless, evidence for a specific plastisphere community is still absent [25], especially concerning more nutrient-rich environments.…”