Microbes and Microplastics

This week is all about the next phase of my research, which involves the interactions between microbes/bacteria and microplastics. Shortly after our understanding of the ingestion risks that microplastics have on marine organisms, scientists discovered that microplastics may benefit microbes, which may be due to a few reasons. Microplastics have high surface area:volume ratios, which means that they act as nice solid structures for growth. Microbes will grow on nearly any surface, so microplastics provide a nice home for bacteria. Microplastics also may provide nutrients for bacterial growth, since some organic materials will adhere to microplastics in the water column and in the sediment. Furthermore, some microbes may stick to microplastics and breakdown the plastics to use their constituent parts as energy sources.

Since bacteria can grow on microplastics, researchers have discovered that microplastics act as transporters of new bacteria especially in marine environments. Bacteria in the Atlantic may adhere to a microplastic and end up in the Southern Ocean or in the Pacific because of ocean circulation. The introduction of new bacterial strains may be beneficial for some organisms and detrimental to others. Any bacteria that adheres to a microplastic also changes the microplastic's buoyancy. As more bacteria and organic materials adhere to the microplastic, its density will increase and it will eventually sink to the seafloor. Plastic polymers that usually would not reach the seafloor, therefore, may be introduced to new environments just by the association of microbes. 

Over the past month, I have been working to assess some of the interactions between microbes and microplastics by growing bacteria in the lab in the presence of microplastics. This early experiment is part of a larger study that I will start in the next few weeks to understand more about how interactions between microbes and microplastics alter the potential effects of microplastics to marine fauna. While I can't talk about the specifics of my work, I can share a picture I snapped today of bacterial growth in the presence of microplastics. 

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