Zhou Xu, Xiao Cunde, Zhang Bingwei, Yang Xiaofan
Guangdong Provincial Observation and Research Station for Coupled Human and Natural Systems in Land-ocean Interaction Zone, Beijing Normal University at Zhuhai, Zhuhai 519087, China; State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
Guangdong Provincial Observation and Research Station for Coupled Human and Natural Systems in Land-ocean Interaction Zone, Beijing Normal University at Zhuhai, Zhuhai 519087, China; Zhuhai Branch of State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University at Zhuhai, Zhuhai 519087, China.
J Hazard Mater. 2025 Jun 5;489:137664. doi: 10.1016/j.jhazmat.2025.137664. Epub 2025 Feb 21.
The impacts of microplastics (MPs) on greenhouse gas emissions from mangrove soil remain poorly understood. Previous studies mostly focused on the topsoil in stable inundation state, ignoring the effects of natural tidal cycle and deep soil under different soil oxygen conditions. In this study, we analyzed soil microbial communities and greenhouse gas emissions from mangrove soils across various depths and tidal conditions (by adding seawater to create different inundation durations) in response to polylactic acid (PLA) MP exposure. Results indicated that PLA MPs addition enhances CO and CH release from the continuously anaerobic subsoil (100-120 cm). With increasing submersion duration, PLA MPs facilitate the emission of CH from the topsoil (0-5 cm). An elevated C:N ratio may promote microbial nitrogen mining and organic carbon mineralization, indicating the threat of PLA MPs to soil carbon and nitrogen pools. PLA MPs addition significantly altered the bacterial community structure and reduced bacterial diversity in the subsoil. Increases in the abundance and functioning of communities associated with methanogenesis and sulfate reduction contributed to the release of CO and CH. The duration of inundation had no significant impact on the microbial community structure in the topsoil. These findings demonstrate the accelerating effect of PLA MPs on organic carbon mineralization and carbon release, which was critically regulated by the soil depth and tidal inundation.
微塑料（MPs）对红树林土壤温室气体排放的影响仍知之甚少。以往的研究大多集中在处于稳定淹没状态的表层土壤，而忽略了自然潮汐周期和不同土壤氧气条件下深层土壤的影响。在本研究中，我们分析了在不同深度和潮汐条件（通过添加海水以创造不同淹没持续时间）下，红树林土壤中土壤微生物群落和温室气体排放对聚乳酸（PLA）微塑料暴露的响应。结果表明，添加PLA微塑料会增加连续厌氧的深层土壤（100 - 120厘米）中一氧化碳和甲烷的释放。随着淹没持续时间的增加，PLA微塑料会促进表层土壤（0 - 5厘米）中甲烷的排放。升高的碳氮比可能会促进微生物的氮素开采和有机碳矿化，这表明PLA微塑料对土壤碳氮库构成威胁。添加PLA微塑料显著改变了深层土壤中的细菌群落结构并降低了细菌多样性。与甲烷生成和硫酸盐还原相关的群落丰度和功能增加导致了一氧化碳和甲烷的释放。淹没持续时间对表层土壤中的微生物群落结构没有显著影响。这些发现证明了PLA微塑料对有机碳矿化和碳释放的加速作用，这受到土壤深度和潮汐淹没的关键调节。
