Global Responses of Soil Carbon Dynamics to Microplastic Exposure: A Data Synthesis of Laboratory Studies

Abstract

Microplastics (MPs) contamination presents a significant global environmental challenge, with its potential to influence soil carbon (C) dynamics being a crucial aspect for understanding soil C changes and global C cycling. This meta-analysis synthesizes data from 110 peer-reviewed publications to elucidate the directional, magnitude, and driving effects of MPs exposure on soil C dynamics globally. We evaluated the impacts of MPs characteristics (including type, biodegradability, size, and concentration), soil properties (initial pH and soil organic C [SOC]), and experimental conditions (such as duration and plant presence) on various soil C components. Key findings included the significant promotion of SOC, dissolved organic C, microbial biomass C, and root biomass following MPs addition to soils, while the net photosynthetic rate was reduced. No significant effects were observed on soil respiration and shoot biomass. The study highlights that the MPs concentration, along with other MPs properties and soil attributes, critically influences soil C responses. Our results demonstrate that both the nature of MPs and the soil environment interact to shape the effects on soil C cycling, providing comprehensive insights and guiding strategies for mitigating the environmental impact of MPs.

Do Added Microplastics, Native Soil Properties, and Prevailing Climatic Conditions Have Consequences for Carbon and Nitrogen Contents in Soil? A Global Data Synthesis of Pot and Greenhouse Studies

“…Long-term systematic studies, especially under realistic field conditions, are required. We found that PE had no significant effect on SOC, whereas Xiang et al observed an increase in SOC after PE MP pollution; this difference might be related to differing experimental conditions. Although polyester enhanced the C and N content, the increased C/N ratio outweighs any positive effects of this pollutant on the nutrient status.…”

“…However, this data synthesis did not include organic N or any other soil nutrients. Similarly, another data synthesis compared impacts of various important factors (such as exposure time and initial soil conditions) on SOC but did not incorporate other soil nutrients . Thus, our data synthesis takes the lead in investigating effects of multiple factors, to relate mechanistic knowledge of MP pollution impacts to key factors mediating MP impacts on the soil C and N status.…”