Consequences of Microplastics on Global Ecosystem Structure and Function

Microplastics (MPs) are a class of pollutants that can persist for centuries, entering global ecosystems in large amounts. Previous studies have focused on the toxicological effects of MPs on single species or population scales from a narrow ecotoxicological perspective, while the systemic effects of MPs on the structure and function of global terrestrial and aquatic ecosystems are still unknown. In this review, we describe the fate and trophic transfer of MPs in ecosystems, which determines the possible scenarios of their interaction with ecosystems, highlighting the alteration of ecosystem structure and function by MPs. The presence of MPs in ecosystems changes the physicochemical properties of the abiotic environment and the habitat of organisms; these particles then directly or indirectly interact with organisms, leading to toxicological and ecological effects. Importantly, MPs, as a new global pressure, likely affect essential biogeochemical processes such as carbon and nitrogen processes. In addition, MPs affect energy flow by interfering with processes such as energy fixation and transfer in primary producers, energy acquisition, consumption and distribution in consumers, and energy metabolism in decomposers. The effects of MPs on information exchange alter the growth, development, and reproduction of organisms, as well as intraspecific and interspecific relationships. At the same time, as vectors for other global pollutants and pathogens, MPs influence their global transport patterns and pose a significant ecological risk. Early understanding of the toxic costs of MPs from the perspective of ecosystem structure and function is essential to maintain the homeostasis and stability of global ecosystems.