Plastic litter in macrophyte system: environmental fate and ecological implications

Plastic is an emerging environmental contaminant that attracts social, political, and scientific attention. However, the effect mechanisms and ecological conditions that promote the consequences of plastic littering remain elusive because of the single-species approach in ecotoxicological testing. To make regulatory decisions mitigating the problem, the potential impacts and vulnerable habitats must be identified. In aquatic ecosystems, macrophyte beds are often a templet habitat providing foraging grounds for pelagic and benthic food webs. These systems are also at the forefront of plastic littering, with high fragmentation and accumulation of microplastic. I propose to conduct a systematic study to understand the multiple interactions between the key components in a coastal habitat exposed to plastic littering. Using the keystone macroalgae species in the Baltic, Fucus vesiculosus, this project aims to evaluate the microplastic effect mechanisms that are related to the species interactions in seaweed beds, with a microbiome being the key component mediating these interactions as well as microplastic retention in the system. I will also investigate the potential of the macrophyte habitat as an entrance point for microplastic in the food web, with particular focus on the primary consumers with different feeding modes. To evaluate the ecosystem health posed by microplastics, the project will also examine effects of microplastic and their leachates on plant physiology, including its growth and metabolite production. Finally, I will evaluate the effects of microplastic exposure on the macrophyte templet functions, including energy transfer efficiency and heat wave resilience. This framework will provide an understanding of the pathways, fate and effects of plastic debris in macrophyte system as well as an approach that applies to other anthropogenic contaminants released into the environment as particulates.