Towards an ecology of soil microplastics

Microplastic pollution is a topic of increasing concern for the world's oceans, freshwaters and, most recently, soils. Microplastics have been found in soils across the globe. Like other anthropogenic pollutants, they can negatively affect a range of soil organisms through several mechanisms, though often dependent on particle size, shape and polymer type. However, microplastics are unique among pollutants due to the diversity of ways in which soil organisms may themselves be able to affect their occurrence and distribution and mediate their effects on the rest of the soil food web. In this review, we argue for a more explicitly ecological framing of this novel issue for the soil environment and discuss their potential interactions with soil communities, including microplastic formation via microbial and faunal fragmentation of large plastic debris and organisms such as earthworms placing microplastic particles in unique pedological contexts they could not otherwise reach. Ecological interactions may be crucial for dictating microplastics' ultimate fate and effect on terrestrial ecosystems. A free Plain Language Summary can be found within the Supporting Information of this article.