Investigating the potential uptake of microplastic-derived carbon into a boreal lake food web using carbon-13 labelled plastic

Investigating the potential uptake of microplastic-derived carbon into a boreal lake food web using carbon-13 labelled plastic

Microplastics degrade slowly over time, leaching carbon (C) that could be subsequently incorporated into aquatic food webs. Current estimates of microplastic degradation vary, and little is known about microplastic-derived C fate under natural environmental conditions. To investigate whether micropl...

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Bibliographic Details
Main Authors: Stephanie Graves, Shao-Min Chen, Rachel McNamee, Tazi H. Rodrigues, Brian Hayden, Chelsea M. Rochman, Jennifer F. Provencher, Michael D. Rennie, Daniel Layton-Matthews, Matthew Leybourne, Owen A. Sherwood, Diane M. Orihel
Format: Article
Language:English
Published: Canadian Science Publishing 2025-01-01
Series:FACETS
Subjects:
amino acids
biodegradation
aquatic food web
limnocorral
polystyrene
stable isotope analysis
Online Access:https://facetsjournal.com/doi/10.1139/facets-2024-0108
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Summary:Microplastics degrade slowly over time, leaching carbon (C) that could be subsequently incorporated into aquatic food webs. Current estimates of microplastic degradation vary, and little is known about microplastic-derived C fate under natural environmental conditions. To investigate whether microplastics leach C that is subsequently incorporated into aquatic food webs, we added isotopically enriched microplastics to Lake 378 at the Experimental Lakes Area in Ontario, Canada. In an ∼1100 L limnocorral (in situ open-bottom enclosure), we added 99% 13C-labelled polystyrene (8–216 µm in longest dimension) at a nominal concentration of 3268 particles/L. A second limnocorral without microplastics served as a negative control. Monthly measurements of δ13C-DIC and δ13C-DOC in filtered water revealed no detectable leaching of 13C from the plastic. Compound-specific isotope analysis of δ13C in amino acids of bulk plankton and periphyton revealed a slight (0.5‰) enrichment in 13C, within the range of natural variability for these organisms. Under the natural conditions of temperate oligotrophic lakes, degradation of microplastics is likely a very slow process that was not possible to detect in this 4-month experiment. Future studies should focus on assessing degradation of microplastics under realistic field scenarios to improve estimates of degradation pathways and associated time scales.
ISSN:2371-1671

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