Nanoplastics' complex interactions with the marine microbial plastisphere

Department

Themes

An illustration of a microbial community with nanoplastics

Plastic pollution has emerged as a major environmental concern, with much marine research focusing on the fate and impact of macro- and microplastics. Nanoplastics (plastic particles between 1–1000 nm), however, remain an understudied yet potentially more hazardous fraction of marine plastic debris. How do these particles interact with microbial communities living on ocean plastics, and could such interactions actively alter their fate and impact within the broader marine environment? On April 1st, Lia Corbett will defend her PhD thesis, “Nanoplastics & the Marine Microbial Plastisphere – Towards a Better Understanding of Fate and Impact,” at the University of Amsterdam.  

 

Investigating interactions

In her thesis, Lia Corbett investigated the fate and impact nanoplastics have on the marine microbial plastisphere. Particularly focusing on the influence of nanoplastics on microbial functional metabolism, plastic additive leaching with and without the presence of a plastisphere bacterium, and nanoplastic uptake by plastisphere–isolated protists. 

Central to her thesis were several hypotheses. Namely, that nanoplastics would interact dynamically with microbial biofilms in the plastisphere. That these biofilms modulate the environmental fate of nanoplastics and exposure to nanoplastics may alter microbial community composition and biofilm structure. And finally, that the plastisphere may function as a sink for nanoplastics while facilitating the accumulation of plastic–associated contaminants, thereby influencing their persistence and mobility in marine systems.

An improved understanding of environmental fate and impact of nanoplastics

An extensive literature review revealed that nanoplastics display distinct aggregation dynamics and frequently associate with organic matter, with the plastisphere serving as a dynamic hotspot for these interactions within marine environments.

Laboratory experiments provided new insights into how nanoplastics interact with the plastisphere. They showed that polystyrene nanoplastics (PS NPs) do not significantly inhibit the overall extent of PHBH biodegradation, although they can influence the composition and dynamics of biofilm microbial communities. The experiments also revealed that perfluoroalkyl carboxylic acids (PFCAs) leach from polytetrafluoroethylene (PTFE) and fluorinated ethylene propylene (FEP) micro- and nanoplastics (MNPs) in seawater to varying degrees depending on the presence of a plastisphere bacterium. 

Additionally, fluorescent nanoplastics of different shapes, created through nanoprecipitation with selective staining, could be tracked and distinguished once ingested by plastisphere-isolated protists.

A complex and active role

Altogether, these findings demonstrate the complex and active role of microbial communities in mediating nanoplastic fate. The methodologies employed in Corbett’s PhD - including the use of natural microbial consortia, tracking functional endpoints, and applying environmentally relevant nanoplastic concentrations - offer valuable tools for advancing nanoplastic research under realistic marine conditions.