Infiltrating the food web: the role of zooplankton in providing an entry point for microplastics through trophic levels

This project aims to elucidate the pathway of microplastics through the food web via marine primary consumers. Microplastics (<0.5mm) interfere with organismal function by both inhibiting adequate ingestion of food and transferring harmful chemicals into their systems, as they carry with them environmental pollutants in addition to the chemical cocktail of additives already contained from manufacture. To address the issues surrounding the ultimate fate of microplastics, a series of incubation experiments are conducted with zooplankton, phytoplankton, and microplastics. These incubation experiments determine microbead (primary) and microfiber (secondary) ingestion or rejection by both laboratory-raised and naturally occurring Southern California zooplankton species. Less is known about the ingestion of plastic microfibers, which exist in higher concentrations in the environment but are more difficult to purchase for lab experiments. Because synthetic fibers are constantly released into the environment without regulation or restriction, this form of microplastic is of primary importance to understand and track through ecosystems and into organisms. Resolving any feeding patterns and preferences between microbeads and microfibers will help uncover which plastics are expected to accumulate in higher trophic organisms. In addition, these experiments further develop and refine methods in determining ingestion rates of microplastics by zooplankton.