Dynamic Behavior and Interaction Mechanism of Soil Organic Matter in Water Systems: A Coarse-Grained Molecular Dynamics Study.
Dynamic Behavior and Interaction Mechanism of Soil Organic Matter in Water Systems: A Coarse-Grained Molecular Dynamics Study.
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DOI：
10.1021/acs.est.3c05966
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发表时间：
2023-12
影响因子：
11.4
通讯作者：
Q. Xue;Zhiyue Jiao;Xian Liu;Wenxiao Pan;Jianjie Fu;Aiqian Zhang
中科院分区：
文献类型：
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作者：
Q. Xue;Zhiyue Jiao;Xian Liu;Wenxiao Pan;Jianjie Fu;Aiqian Zhang
研究土壤有机质（SOM）的微观组装和功能是具有挑战性的，因为它的复杂性。本研究构建了较为真实的SOM模型，包括Leonardite humic acid （LHA）、脂质、多肽、碳水化合物和木质素等多种成分，通过微秒级粗粒度分子动力学模拟揭示了它们在介观尺度上的自发自组装行为。我们发现有序的SOM聚集形成了从疏水核心到水相的层状相，导致O/C比增加和结构两亲性下降。值得注意的是，两亲性脂质形成了双层膜，与木质素合作构成了SOM的疏水核心。LHA尽管形成了一层，但却嵌入在这个结构中。这种复杂结构的形成是由组件之间的非键相互作用驱动的。我们的分析揭示了SOM系统中组分依赖的扩散效应。脂质、多肽和木质素对自扩散有抑制作用，而碳水化合物对自扩散有促进作用。本研究为研究水生环境中SOM组分的动态行为和组装提供了新的见解，为研究动态SOM机制提供了一种有效的方法。
Investigating soil organic matter's (SOM) microscale assembly and functionality is challenging due to its complexity. This study constructs comparatively realistic SOM models, including diverse components such as Leonardite humic acid (LHA), lipids, peptides, carbohydrates, and lignin, to unveil their spontaneous self-assembly behavior at the mesoscopic scale through microsecond coarse-grained molecular dynamics simulations. We discovered an ordered SOM aggregation creating a layered phase from its hydrophobic core to the aqueous phase, resulting in an increasing O/C ratio and declining structural amphiphilicity. Notably, the amphiphilic lipids formed a bilayer membrane, partnering with lignin to constitute SOM's hydrophobic core. LHA, despite forming a layer, was embedded within this structure. The formation of such complex architectures was driven by nonbonded interactions between components. Our analysis revealed component-dependent diffusion effects within the SOM system. Lipids, peptides, and lignin showed inhibitory effects on self-diffusion, while carbohydrates facilitated diffusion. This study offers novel insights into the dynamic behavior and assembly of SOM components, introducing an effective approach for studying dynamic SOM mechanisms in aquatic environments.