BIOPHYLM: Biofilm on microplastics - a biophysical perspective

The ubiquitous presence of microplastics (MPs) in aquatic environments has become a major threat to ecosystems. In marine and freshwater environments, MPs interact with microorganisms, leading to the formation of biofilms on their surface and creating a complex community called the Plastisphere. This process can alter the particles’ physical and chemical properties and, in turn, affect their ecological risks, environmental transport, and fate. Our understanding of the influence of microbial colonisation on the transport of MPs in aquatic environments remains limited, warranting further research on microbe-MP interactions. The BIOPHYLM project aims to address these knowledge gaps by focusing on a less-investigated, yet significant, plastisphere aspect, which is the lower end of the MP size range, between 1-100 μm. For this purpose, MP particles will be exposed to river water (Donaukanal, Vienna) in a lab-based mesocosm setup and biophysical, colloidal, and high-throughput sequencing approaches will be applied for studying microbe-plastic interactions over time. Notably, the project aims to demonstrate real-time measurements of biofilm growth and MP particle mobility by monitoring the mesocosms with in-line digital holographic microscopy, a novel technology recently developed by BOKU researchers. By linking data from each technique, BIOPHYLM aspires to obtain a holistic view of MP-microbe interactions and fill important knowledge gaps that will improve our understanding of the role of biofilm on MP transport, and thus, reinforce a science-based risk assessment of plastic particles in the aquatic environment.

In this presentation, key elements of the project will be introduced and preliminary findings and results from its first year will be demonstrated.