Asian Journal of Environment & Ecology

Freshwater ecosystems face unprecedented threats from nanoplastic pollution, with particles smaller than 1000 nm emerging as a critical contaminant class capable of disrupting fundamental biological processes. This review examines how nanoplastics interfere with chemical communication systems in planktonic communities, including key groups such as copepods, Daphnia, rotifers, phytoplankton, and ciliates, which form the foundation of aquatic food webs. Plankton rely on infochemicals including pheromones, kairomones, and allelochemicals for essential processes such as mate recognition, predator detection, and resource competition. Nanoplastic disrupt these "invisible languages" through multiple mechanisms: physical adsorption of signalling molecules, alteration of chemical gradients, vectorial transport of co-contaminants, and direct biological effects, including oxidative stress and cellular damage. These disruptions impair mate location, misdirect defence strategies, create energetic trade-offs, and generate multigenerational impacts that persist across generations. The consequences cascade through entire ecosystems, triggering trophic disruptions, biodiversity loss, and the emergence of "silent chaos" environments where organisms can no longer effectively communicate or coordinate responses to environmental challenges. Current evidence indicates widespread and persistent nanoplastic contamination in freshwater systems, with particles bioaccumulating across food webs for decades. Major knowledge gaps remain regarding long-term multigenerational effects, species-specific sensitivities, and interactions with co-occurring stressors such as temperature shifts and chemical pollutants. Addressing these challenges will require targeted mechanistic research, improved monitoring frameworks, stricter regulation of primary nanoplastics, advances in wastewater treatment, and policy actions that explicitly consider the protection of chemical communication pathways essential for freshwater ecosystem stability.