School of Environment, Nanjing Normal University, Nanjing 210023, China.
Guangdong Provincial Key Laboratory of Chemical Measurement and Emergency Test Technology, Guangdong Provincial Engineering Research Center for Ambient Mass Spectrometry, Institute of Analysis, Guangdong Academy of Sciences (China National Analytical Center Guangzhou), 100 Xianlie Middle Road, Guangzhou 510070, China.
J Hazard Mater. 2024 Dec 5;480:135872. doi: 10.1016/j.jhazmat.2024.135872. Epub 2024 Sep 17.
Recent studies show that biodegradable microplastics (BMPs) could increase soil CO emission, but whether altered carbon emission results from modified soil organic matter (SOM) decomposition remains underexplored. In this study, the effect and mechanisms of BMPs on CO emission from soil were investigated, using poly(butylene adipate-co-terephthalate) (PBAT, the main component of agricultural film) as an example. Considering that straw returning is a common agronomic measure which may interact with microplastics through affecting microbial activity, both soils with and without wheat straw were included. After 120 d, 1 % (w/w) PBAT BMPs ificantly increased cumulative CO emission by 1605.6 and 1827.7 mg C kg in soils without and with straw, respectively. Cracks occurred on the surface of microplastics, indicating that CO was partly originated from plastic degradation. Soil dissolved organic matter (DOM) content, carbon degradation gene abundance (such as abfA, xylA and manB for hemicellulose, mnp, glx and lig for lignin, and chiA for chitin) and enzyme activities increased, which significantly positively correlated with CO emission rate (p < 0.05), suggesting that PBAT enhanced carbon emission by stimulating the decomposition of SOM (and possibly the newly added straw) via co-metabolism and nitrogen mining. This is supported by DOM molecular composition analysis which also demonstrated stimulated turnover of carbohydrates, amino sugars and lignin following PBAT addition. The findings highlight the potential of BMPs to affect SOM stability and carbon emission.
最近的研究表明，可生物降解微塑料（BMPs）可能会增加土壤 CO 排放，但改变的碳排放量是否源于土壤有机物质（SOM）分解的改变仍未得到充分探索。在这项研究中，以聚己二酸/对苯二甲酸丁二酯（PBAT，农业薄膜的主要成分）为例，研究了 BMPs 对土壤 CO 排放的影响和机制。考虑到秸秆还田是一种常见的农业措施，可能通过影响微生物活性与微塑料相互作用，因此同时包括了有和没有小麦秸秆的土壤。120 天后，添加 1%（w/w）PBAT 微塑料使无秸秆和有秸秆土壤的累积 CO 排放分别增加了 1605.6 和 1827.7 mg C kg。微塑料表面出现裂缝，表明 CO 部分来自塑料降解。土壤溶解性有机物质（DOM）含量、碳降解基因丰度（如半纤维素的 abfA、xylA 和 manB，木质素的 mnp、glx 和 lig，以及几丁质的 chiA）和酶活性增加，与 CO 排放速率呈显著正相关（p<0.05），这表明 PBAT 通过共代谢和氮矿化刺激 SOM（可能还有新添加的秸秆）的分解，从而增强了碳排放。DOM 分子组成分析也支持了这一观点，该分析还表明，添加 PBAT 后碳水化合物、氨基糖和木质素的周转得到了刺激。这些发现强调了 BMPs 影响 SOM 稳定性和碳排放的潜力。
