Methane and nitrous oxide are among the most potent greenhouse gases, with warming potentials far exceeding that of carbon dioxide. Natural wetlands are major contributors to global methane emissions but can also act as long-term carbon sinks. Meanwhile, nanoplastics are rapidly accumulating in aquatic and terrestrial environments as larger plastics degrade, yet their ecological consequences remain poorly understood. Previous studies have shown that microplastics can alter soil chemistry and microbial activity, but the effects of even smaller nanoplastics on greenhouse gas emissions remain largely unexplored. Based on these challenges, it is necessary to conduct in-depth research on how nanoplastics influence biogeochemical processes in wetland ecosystems.
Researchers from Tsinghua University and collaborating institutions report that nanoplastics significantly enhance methane and nitrous oxide emissions in wetland-like plant–soil systems. The study, published (DOI: 10.1007/s11783-025-2066-8) online on August 10, 2025, in Frontiers of Environmental Science & Engineering, used a controlled wetland simulation to examine how polystyrene nanoplastics affect greenhouse gas production. By combining gas flux measurements with microbial and plant analyses, the research provides mechanistic insight into how nanoplastics disrupt plant–soil interactions and alter carbon and nitrogen cycling.
Using simulated wetlands planted with reeds, the researchers introduced increasing concentrations of polystyrene nanoplastics to the soil and monitored greenhouse gas emissions over time. They found that nanoplastics increased methane emissions by 20% to nearly 100%, while nitrous oxide emissions approximately doubled under higher concentrations. These effects became more pronounced as plants matured and environmental temperatures rose.
Mechanistic analyses revealed that nanoplastics inhibited plant growth, reduced chlorophyll content, and weakened antioxidant defenses, impairing photosynthesis and stress resistance. Crucially, nanoplastics reduced oxygen release from plant roots, creating more anaerobic conditions in the rhizosphere. This shift favored methane-producing microorganisms and enhanced denitrification processes responsible for nitrous oxide formation.
Metagenomic analyses showed increased abundance of genes involved in acetoclastic methanogenesis and denitrification pathways, particularly in rhizosphere soils. At the same time, nanoplastics altered root exudate composition, sharply increasing the release of L-phenylalanine—a compound that can be converted into substrates fueling methane production. Although some methane-oxidizing and nitrous oxide–consuming microbes also increased, their activity was insufficient to offset the elevated greenhouse gas generation.
"This work demonstrates that nanoplastics are not just passive contaminants but active regulators of ecosystem processes," said the corresponding author. "By simultaneously impairing plant physiological functions and reshaping microbial communities in the rhizosphere, nanoplastics create conditions that strongly favor greenhouse gas production. These effects operate through multiple interconnected pathways, which helps explain why even small particles can have outsized impacts on climate-relevant processes in wetlands."
The findings suggest that plastic pollution may contribute to climate change in ways that are not currently accounted for in greenhouse gas models. Wetlands are widely recognized as nature-based solutions for carbon sequestration, yet nanoplastic contamination could undermine their climate-mitigation potential. Incorporating nanoplastics into environmental risk assessments and greenhouse gas inventories may therefore be essential. More broadly, the study underscores the urgency of controlling plastic pollution at its source, as continued accumulation of nanoplastics could amplify greenhouse gas emissions across sensitive ecosystems worldwide.
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References
DOI
10.1007/s11783-025-2066-8
Original Source URL
https://doi.org/10.1007/s11783-025-2066-8
Funding information
This work was supported by the National Key Research and Development Program of China (No. 2021YFC3200603) and the National Natural Science Foundation of China (No. 52221004).
About Frontiers of Environmental Science & Engineering
Frontiers of Environmental Science & Engineering (FESE) is the leading edge forum for peer-reviewed original submissions in English on all main branches of environmental disciplines. FESE welcomes original research papers, review articles, short communications, and views & comments. All the papers will be published within 6 months after they are submitted. The Editors-in-Chief are Academician Jiuhui Qu from Tsinghua University, and Prof. John C. Crittenden from Georgia Institute of Technology, USA. The journal has been indexed by almost all the authoritative databases such as SCI, EI, INSPEC, SCOPUS, CSCD, etc.