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| Impact of microbial degradation on the molecular composition of soil dissolved organic matter |
| Received:March 23, 2025 |
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| KeyWord:soil organic matter;FT-ICR MS;biodegradability;bacterial community;correlation analysis |
| Author Name | Affiliation | E-mail | | LIU Tongxin | School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China | | | LIANG Yuzhen | School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China | yzliang@scut.edu.cn | | SHI Zhenqing | School of Environment and Energy, South China University of Technology, Guangzhou 510006, China
The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, South China University of Technology, Guangzhou 510006, China | |
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| Abstract: |
| To investigated the molecular composition changes of dissolved organic matter（DOM） extracted from surface soils of coastal forests in Taishan, Guangdong Province, during microbial degradation. Using native soil microorganisms as the inoculum, a shaking incubation system was established under simulated in-situ conditions at pH 4.7. Combined with UV-Vis spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry（FT-ICR MS）, 16S rRNA high-throughput sequencing, and Spearman correlation analysis, the study aimed to reveal the changes during microbial degradation in DOM molecular composition, microbial community structure, and their relationship. The results showed that DOM underwent three distinct phases during degradation：in the early stage（0-14 days）, microorganisms preferentially utilized proteins, lipids, and small molecules, leading to a rapid decline in DOM concentration; in the mid stage（14-21 days）, microbial cell lysis released intracellular compounds, resulting in a temporary increase in DOM concentration; in the late stage（21-35 days）, labile components became depleted, microbial degradation slowed, and recalcitrant, aromatic, and hydrophobic compounds such as lignin gradually accumulated. Spearman correlation analysis revealed that changes in the abundance of Gammaproteobacteria were significantly positively correlated with lipid components, while Bacteroidia, Alphaproteobacteria, and Acidobacteriae were closely associated with the enrichment of recalcitrant compounds such as lignin. These findings indicate that selective microbial degradation significantly alters the molecular composition of DOM, promoting its transformation toward more humified forms. |
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