Plastics are a large and increasing component of marine litter that harms marine life. The degradation of plastics leads to minute plastic particles (microplastics – MPs) being accumulated in the sea, which can be ingested or passively adsorbed by heterotrophs leading to blockage of the gastrointestinal tract and inflammatory responses. In autotrophs, exposure to MPs may hamper photosynthesis and change nutritional quality for grazers. Moreover, the chemical composition and small size make MPs effective sorbents of persistent organic pollutants (POPs) which may be transferred to biota and alter bioaccumulation. Despite these concerns, the impact of MPs and their role in mediating POP transport and bioaccumulation in aquatic food webs is largely unknown. In particular, the net effects of MPs in food webs have not been addressed in a coherent manner to examine relative contributions of ecological (i.e. particles exerting mostly mechanical disturbance for photosynthesis, food uptake and trophic interactions) vs. ecotoxicological (i.e. particles acting as vectors of POPs, increasing exposure) factors. Our aim is to develop and apply an integrated approach for delineating direct effects of MPs on basic physiological functions in model aquatic organisms, and the effects of MP-associated transfer of POPs. These effects will be examined across trophic levels spanning from primary producers to top consumers and integrated in a modeling framework; which can be applied in risk assessment.
Photo: Stephanie Wright, University of Exeter