Microplastics and their mechanisms in influencing methane oxidation: A physiological and ecological perspective

The presence of microplastics (MPs) is ubiquitous in the natural environment, inevitably impacting certain biochemical processes within ecosystems. As global warming becomes increasingly pressing, research on mitigating the greenhouse effect is crucial. Among the greenhouse gases, methane has a greenhouse effect that is 20-30 times more than that of carbon dioxide, contributing to a certain proportion of global warming. However, the physiological and ecological effects of MPs on methane oxidation process and their underlying mechanisms remain poorly understood. This article aims to summarize the possible effects of MPs on methane oxidation process through previous research, in order to gain a better understanding of the carbon cycling mechanisms present in the environment. The potential impacts of MPs are categorized as direct vs. indirect. We classify impacts caused directly by MPs-such as additive leaching, cell breakage, or biofilm formation-as direct impacts. In contrast, impacts caused by pollutants that MPs adsorb or by MP-induced changes to environmental chemistry are considered indirect impacts. We then analyze how both direct and indirect effects influence the mechanistic pathways of methane oxidation, as reflected in changes to microbial community composition, activity, or gene expression. This approach helps us gain a deeper understanding of the complex carbon cycling mechanisms in the environment and provides a basis for developing rational strategies to control MPs pollution in the future.