Pelastic: a whole-ecosystem experiment to understand the fate and effects of microplastics

Microplastics (MPs) are globally ubiquitous, yet our understanding of their environmental fate and effects is mostly limited to theoretical models and laboratory experiments. Our proposed project, which to the best of our knowledge would be the first of its kind, is to experimentally manipulate an entire lake, testing the impacts of microplastics at the ecosystem scale. This experiment can only be carried out at the world-renowned International Institute for Sustainable Development's Experimental Lakes Area (IISD-ELA), which has provincial and federal legislation permitting whole-lake experimentation. IISD-ELA enables real-world projects that provide a critical missing step from theoretical, lab, and tank studies to natural ecosystems. Guided by smaller-scale experiments already funded and planned by our team, the research objectives for this environmentally relevant project are to determine 1) the physical, chemical, and biological fate of MPs in lakes and their watersheds; 2) how MPs impact aquatic ecosystems across all levels of biological organization; 3) how ecosystem processes and functions, such as nutrient cycling and photosynthesis, are affected by MPs; and 4) the recovery of an ecosystem exposed to MPs, including how MPs break-down and/or transform over time. Rooted in the program objectives, the expected outcomes of our proposed research are to increase research capacity on MPs through the training of diverse HQP, close knowledge gaps in our scientific understanding of the fate and effects of MPs in aquatic ecosystems, develop new tools and protocols for the sampling and characterization of MPs and their impacts (aimed at addressing the global need for standardization/harmonization of methods to inform monitoring), and generate knowledge to inform risk assessments and policies in Canada and beyond.