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Effects of Nanoplastic Particles on Benthic Microbial Communities
Citation:
Giroux, M., J. Reichman, T. Langknecht, B. Smith, R. Burgess, AND K. Ho. Effects of Nanoplastic Particles on Benthic Microbial Communities. PRIMO22, Nantes, FRANCE, May 26 - 29, 2024.
Impact/Purpose:
This project will provide valuable information to the agency for potential regulation of micro and nanoplastic particles. This work also provides the scientific community with information on the adverse effects of nanoplastic particles on microbial communities that contribute to ecosystem maintenance and biogeochemical cycles. Additionally, this information is valuable to the public because it demonstrates that plastic particles may directly interact with microbes in the environment.
Description:
Marine sediments are rich habitats for microbial communities and act as a sink for many environmental contaminants including plastic particles, which may fragment into nanoplastic (NP) particles (<1 µm). Plastics can be substrates for microbial growth, but less is known about the interaction of NPs and microbes. The objective of this study was to use a 16S barcoding approach to investigate the effects of polystyrene NPs on microbial community diversity and structure. Sediment cores were collected from the Narrow River estuary in Rhode Island (USA) and used as mesocosms for exposures to seawater-weathered 900 nm NP spheres at concentrations of 0, 0.1, 1, 10, or 100 mg/kg dry weight amended to a reference sediment for two weeks. DNA was extracted from the top 1 cm sediment layer, 16S rRNA gene marker was PCR-amplified, and amplicons sequenced on an Illumina MiSeq. A dose-dependent decreasing trend in α-diversity was observed. Additionally, the abundance of anaerobic, sulfur-reducing bacteria increased in higher NP treatments compared to lower treatments. Sulfur-reducing bacteria are known Hg-methylators, so total mercury and methylmercury (MeHg) concentrations were measured in the exposed sediment. A minor trend towards an increase in MeHg and the MeHg/total mercury ratio with increasing NP concentrations was observed. These results, and the findings of previous studies evaluating NP impacts to eukaryotic communities, contribute to the understanding of plastic particles directly and indirectly affecting environmental conditions leading to community-level impacts.
