Researchers at the University of Massachusetts Amherst have identified a surprising mechanism by which microscopic zooplankton can influence pollution in both marine and freshwater systems. The team reports that certain rotifers, tiny one-celled animals common in water bodies around the world, can accelerate the breakdown of microplastics into much smaller nanoplastic particles. The study appears in Nature Nanotechnology (Nnano).
According to the findings, rotifers take microplastics up to about 10 micrometers in size and convert them into nanoplastics. These minute particles can then be released back into the surrounding water, potentially facilitating broader environmental exposure. The researchers estimate that a single rotifer can produce hundreds of thousands of nanoplastic particles each day, underscoring how even small organisms may contribute to pervasive pollution under certain conditions.
As a concrete illustration, the team calculated that in Poyang Lake, China, which is the largest freshwater lake in the country, rotifers could generate an enormous daily output of nanoplastics. While this figure is specific to a defined ecosystem, the researchers point out that similar processes could occur in other water bodies where rotifers reside, suggesting a wide-reaching potential impact on nanoplastics distribution in aquatic environments.
The researchers emphasize that the release of nanoplastics during degradation raises questions about toxicity and transport in ecosystems. Nanoplastics are being studied for their potential to affect a range of organisms and for their role as carriers for various pollutants. The chemical additives that migrate from plastics may also be released during and after the breakdown process, adding another layer of complexity to environmental risk assessments.
Lead author Professor Jian Zhao notes that this work is among the first to document the widespread degradation of microplastics by rotifers and to highlight the potential ecological implications. The findings invite further investigation into how rotifers and similar microfauna influence plastic fate in diverse aquatic habitats and what this means for pollution management strategies in North America and beyond.
Overall, the study contributes a new piece to the growing puzzle of nanoplastic pollution, reminding scientists, policymakers, and the public that plastic waste can be altered by tiny creatures in ways that may affect exposure pathways and environmental health across water bodies.