Abstract
Fossil-made polymers harbor unique bacterial assemblages, and concerns have been raised that ingested microplastic may affect the consumer gut microbiota and spread pathogens in animal populations. We hypothesized that in an ecotoxicity assay with a mixture of polystyrene (PS) and clay: (1) microbiome of the test animals inoculates the system with bacteria; (2) relative contribution of PS and the total amount of suspended solids (SS) select for specific bacterial communities; and (3) particle aggregation is affected by biofilm community composition, with concomitant effects on the animal survival. Mixtures of PS and clay at different concentrations of SS (10, 100, and 1000 mg/L) with a varying microplastics contribution (%PS; 0–80%) were incubated with Daphnia magna, whose microbiome served as an inoculum for the biofilms during the exposure. After 4-days of exposure, we examined the biofilm communities by 16S rRNA gene sequencing, particle size distribution, and animal survival. The biofilm communities were significantly different from the Daphnia microbiota used to inoculate the system, with an overrepresentation of predatory, rare, and potentially pathogenic taxa in the biofilms. The biofilm diversity was stimulated by %PS and decreased by predatory bacteria. Particle aggregate size and the biofilm composition were the primary drivers of animal survival, with small particles and predatory bacteria associated with a higher death rate. Thus, in effect studies with solid waste materials, ecological interactions in the biofilm can affect particle aggregation and support potentially harmful microorganisms with concomitant effects on the test animals.
Highlights
Fueled by recent interest in microplastic pollution research, the interactions of living matter with solid materials, with particular focus on anthropogenic materials, has become a subject of great interest
We found that suspended solids that were not exposed to the natural bacterioplankton had developed measurable bacterial biofilms, with the daphnids being the only possible source of the microorganisms
In ecotoxicity assay using no-food exposure to suspended particulates, we found that Daphnia microbiota served as an inoculum for biofilm formation in the study system
Summary
Fueled by recent interest in microplastic pollution research, the interactions of living matter with solid materials, with particular focus on anthropogenic materials, has become a subject of great interest. Despite frequent suggestions that particle behavior and physicochemical properties govern the interactions between biota and test particles (Anbumani and Kakkar, 2018; Rist and Hartmann, 2018), experimental data on these parameters, interactions and their contribution to the observed responses are limited. Plastics, like any other materials, are quickly colonized by diverse microbes forming biofilms (Rogers et al, 2020). These biofilm communities on plastics often differ from those in the surrounding water and other substrates (Ogonowski et al, 2018). The biofilms on the aggregates can improve animal nutrition, at low food availability (Kirk, 1992), and establish/strengthen pathways for channeling bacterial production to non-bacterivores in the food webs (Rogers et al, 2020)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
