Mechanical Weathering of Polystyrene Microplastics Intensifies Biological Stress but Enhances Ecosystem Multifunctionality in a Freshwater-Sediment Microcosm.

Authors

Di Wu, Laura Carter, Paul Kay, Joseph Holden, Ying Yin, Hongyan Guo

Published in

Environmental pollution (Barking, Essex : 1987). Pages 128969. Aug 15, 2026. Epub Aug 15, 2026.

Abstract

Microplastics are ubiquitous pollutants in freshwater ecosystems, yet their impacts on freshwater-sediment ecosystems remain poorly understood. Here, we investigated how pristine and mechanically weathered polystyrene (PS) microplastics influence organisms, sediment properties, and overall ecosystem multifunctionality (EMF) within an integrated freshwater-sediment microcosm containing the rooted macrophyte Vallisneria spiralis, the benthic snail Lymnaea stagnalis, and sediments. Results showed that mechanical weathering transformed the originally smooth spherical PS microplastics into particles with rougher and more irregular surfaces. Weathered PS microplastic induced stronger biological stress in both plants and snails, reflected in higher integrated biomarker response (IBR) scores. Weathered PS microplastics reduced chlorophyll a and carotenoid content and also altered plant nutrient content, indicating impaired photosynthesis and altered carbon metabolism. In snails, weathered PS microplastics triggered oxidative stress and significantly increased caspase-3 activity, suggesting elevated apoptotic responses and ionic regulation demands. Despite organism-level impairment, both pristine and weathered PS microplastics enhanced sediment EMF. This enhancement was primarily driven by increased dissolved organic carbon, elevated β-glucosidase activity, and intensified microbial respiration, reflecting stimulated carbon cycling. These results reveal ecological trade-off between organism health and ecosystem performance. Short-term functional stability was maintained through accelerated microbial metabolism, potentially masking underlying biological deterioration. Our findings demonstrate that microplastic weathering amplifies biological stress while simultaneously promoting ecosystem-level functional buffering, highlighting that apparent stability may entail long-term ecological risk. Integrating environmentally representative mechanically weathered microplastics with multi-species ecosystem assessments provides a more comprehensive framework for evaluating the ecological risks of microplastic contamination.

PMID:
42603584
Bibliographic data and abstract were imported from PubMed on 16 Aug 2026.

Read full publication at:
Please sign in to see all details.

Stats

1-terrible, 9-excellent. How would you rate this publication? Sign in in to submit your rating.

Post a comment

You need to be signed in to post comments. You can sign in here.

Comments

There are no comments yet.