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Using Environmental RNA to Evaluate the Impacts of Nanoplastic on Benthic Invertebrate Communities.
Citation:
Giroux, M., J. Reichman, T. Langknecht, B. Smith, R. Burgess, AND K. Ho. Using Environmental RNA to Evaluate the Impacts of Nanoplastic on Benthic Invertebrate Communities. Society of Environmental Toxicology and Chemistry North America, 42nd Annual Meeting, NA, Virtual, November 14 - 18, 2021.
Impact/Purpose:
This project will provide valuable information to the agency for potential regulation of nanoplastic materials, and provide the scientific community some of the first information on the effects of smaller sizes of nanoplastic particles on population and community-level endpoints. Additionally, this information is valuable to the public because it demonstrates that plastic particles in marine systems can have long term effects on a variety of marine organisms.
Description:
Plastic particles are ubiquitous in marine systems and the effects of nanoplastic particles on marine organisms are of growing concern. Nanoplastics enter marine systems primarily through the fragmentation of larger plastics present in the environment, often ultimately accumulating in sediments. Marine sediments act as a sink for many contaminants and are rich habitats for benthic micro- and meiofauna which form the base of the marine food web. However, little is known about the sensitivities of specific species to nanoplastics or the effects on community diversity. Utilizing molecular methods, such as metabarcoding of environmental DNA/RNA, allows for rapid and comprehensive detection of microscopic organisms via high-throughput sequencing and the ability to assess community diversity and structure. The objective of this study was to use an RNA metabarcoding approach to investigate the effects of nanoplastic particles on benthic micro- and meiofaunal community diversity. Sediment cores (mesocosms) were collected from the Narrow River estuary in Rhode Island (USA) and exposed to 200 nm polystyrene beads at concentrations of 0, 0.1, 1, 10, or 100 mg/kg dry weight in sediment for two weeks. Following exposure, RNA and DNA were co-extracted from the top 1 cm sediment layer, RNA was reverse-transcribed, 18S and CO1 markers were PCR-amplified, and amplicons were sequenced on an Illumina MiSeq. Key differences in the value of environmental DNA compared to environmental RNA for ecotoxicological applications were identified. Using the 18S marker, significant differences to α-diversity and β-diversity were observed in 200 nm nanoplastic exposures relative to the control. Observed community-level differences were driven by the differential abundance of several species of protozoa. This study highlights the utility of using community endpoints to assess nanomaterial impacts.
