Impacts of warming and nutrient enrichment on the fate and effects of nanoplastics in a freshwater food web

Freshwater ecosystems face numerous pressures including climate-induced warming, eutrophication and contaminants such as nanoplastics (NPs), which have emerged as a major environmental concern. Despite evidence of harmful effects on freshwater biota, critical knowledge gaps persist regarding the fate and impacts of NP fate and impacts in natural aquatic systems. Here we conducted a 28-day mesocosm experiment in freshwater pond communities, investigating polystyrene NP fate and effects under ambient, warmed and nutrient-enriched conditions. Using palladium-doped polystyrene NPs for precise tracking, we observed NP presence in all ecological compartments, mainly accumulating in biofilms (~97%). NP accumulation was influenced by both nutrient enrichment and warming, with warming significantly increasing NP concentration in fish guts. NPs decreased macroinvertebrate abundance, attributed to the decline in benthic caddisfly larvae, which graze on the NP-rich biofilm. This research represents a important advancement in our understanding of plastic pollution impacts, revealing the complex interplay between NP pollution and global environmental change factors in freshwater ecosystems. Global warming and pollution both have a detrimental effect on the environment but little is known about their combined effects. A study based on metal-doped nanoplastics shows how temperature rise impacts the fate of nanoplastics, for example, by increasing accumulation in fish guts.