Original paper

Synthetic microplastic fiber length influences accumulation in Daphnia magna

Simon, Conner J.; Cohen, Risa A.

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Fundamental and Applied Limnology Volume 197 Nr. 4 (2025), p. 329 - 337

54 references

published: Aug 27, 2025
published online: Jul 30, 2025
manuscript accepted: Jul 8, 2025
manuscript revision received: Jun 17, 2025
manuscript revision requested: Apr 24, 2025
manuscript received: Dec 27, 2024

DOI: 10.1127/fal/1574

BibTeX file

ArtNo. ESP141019704006, Price: 29.00 €

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Abstract

Surface waters receive megatons of plastic waste annually that degrade into microplastics in a variety of shapes including spheres, fragments, and fibers. Microplastic fibers (MFs) ranging in length from < 100 µm to 5 mm are most common, generated by synthetic textile laundering and aquatic equipment degradation. Zooplankton encountering MFs frequently mistake the foreign particles for food and/or become entangled. The current study investigated whether fiber length influences zooplankton MF ingestion and mortality. Daphnia magna were exposed to one of four polyethylene terephthalate (PET) MF treatments: 0 (control), 45, 70, or 100 µm lengths at a concentration of 50,000 MFs L–1 for 7 days in the laboratory. Mortality was assessed daily while the concentration of ingested MFs was measured only at the conclusion of the experiment. The proportion of zooplankton ingesting fibers was similar across treatments. However, length influenced the level of MF accumulation in zooplankton; accumulation of 70 µm MFs was 2 and 4× higher than for 45 or 100 µm lengths, respectively. There were no differences in mortality after 7 days across all treatments. This investigation demonstrated that zooplankton readily ingest MFs across a range of sizes and that fiber length influences the number of MFs consumed. However, no instances of entanglement were observed independent of fiber length, suggesting the primary mechanism through which zooplankton interact with MFs is via ingestion. Over longer time periods, it is possible that MF accumulation interferes with zooplankton feeding, which could elevate mortality and reduce food availability to higher trophic levels.

Keywords

Plastic pollution • Zooplankton • Ingestion • Entanglement • Mortality • Microcosm