Effects of Nylon Microplastic on Feeding, Lipid Accumulation, and Moulting in a Coldwater Copepod

Abstract

In this exposure study we demonstrate that microplastics have the capacity to reduce feeding, stymie lipid accumulation, and trigger premature moulting in a boreal copepod. It should be noted that microplastic concentrations used in our exposure studies exceed those currently observed in the marine environment—although we would also highlight there is very little environmental data relating to concentrations of particles 10–30 μm in size owing to the technical challenges of sampling, extracting and identifying plastic particles of this size and where data are available, it suggests the smaller the microplastics the higher the concentration becomes.(65−68) While it is important the field of microplastics research shifts toward better understanding the risks environmentally relevant concentrations of microplastic pose to marine life, at this stage it remains essential to build a clearer picture of the modes of action by which microplastics can cause harm, identify relevant end points, and gauge the sensitivity of different life-stages and species.(69) Such knowledge is key in establishing probable and no-effect thresholds for risk assessment. In this study, the use of preadult copepods highlights that microplastics can affect moulting, which will inform future experimental work. As our results demonstrate, the shape and chemical profile of a microplastic can influence bioavailability and toxicity, and we would therefore promote the call for future studies to better incorporate a greater diversity of environmentally relevant microplastics.