Abstract：
Sediment-derived dissolved organic matter (SDOM) is instrumental in the cycling of nutrients and heavy metals within lakes, influencing ecological balance and contaminant distribution. Given the influence of photodegradation on the alteration and breakdown of SDOM, further understanding of this process is essential. In this research, the properties of the SDOM photodegradation process and its metal-binding reactions in Nansi Lake were analyzed using the EEM-PARAFAC and 2D-SF/FTIR-COS techniques. Our study identified three sorts of humic-like components and one protein-like component in SDOM, with the humic-like material accounting for 71.3 ± 5.19% of the fluorescence intensity (Fmax). Photodegradation altered the abundance and structure of SDOM, with a 41.6 ± 5.82% decrease in a280 and a 29.1 ± 9.31% reduction in Fmax after 7 days, notably reducing the protein-like component C4 by 54.0 ± 5.17% and the humic-like component C2 by 48.5 ± 2.54%, which led to SDOM being formed with lower molecular weight and aromaticity. After photodegradation, the LogKCu values for humic-like and protein-like substances decreased (humic-like C2: LogKCu: 1.35 ± 0.10-1.11 ± 0.15, protein-like C4: 1.49 ± 0.14-1.29 ± 0.34), yet the preferential binding sequence of protein-like materials and specific functional groups with Cu2+ such as aliphatic C-OH, amide (I) C=O and polysaccharide C-O groups remained unaltered. Our results enhance the knowledge of light-induced SDOM alterations and offer insights into SDOM-metal interactions in aquatic ecosystems.
摘要：
沉积物衍生的溶解有机物（SDOM）有助于湖泊中养分和重金属的循环，影响生态平衡和污染物分布。考虑到光降解对SDOM的改变和分解的影响，对这一过程的进一步理解至关重要。在这项研究中,使用EEM-PARAFAC和2D-SF/FTIR-COS技术分析了南四湖中SDOM光降解过程及其金属结合反应的性质。我们的研究确定了SDOM中的三种腐殖质样成分和一种蛋白质样成分，腐殖质类物质占荧光强度(Fmax)的71.3±5.19%。光降解改变了SDOM的丰度和结构，7天后，A280下降41.6±5.82%，Fmax下降29.1±9.31%，蛋白质样成分C4显著减少54.0±5.17%，腐殖质样成分C2显著减少48.5±2.54%，这导致形成具有较低分子量和芳香性的SDOM。光降解后，腐殖质样和蛋白质样物质的LogKCu值降低(腐殖质样C2:LogKCu:1.35±0.10-1.11±0.15,蛋白质样C4:1.49±0.14-1.29±0.34),然而，蛋白质样材料和特定官能团与Cu2+如脂肪族C-OH的优先结合序列，酰胺(I)C=O和多糖C-O基团保持不变。我们的结果增强了光诱导的SDOM变化的知识，并提供了对水生生态系统中SDOM-金属相互作用的见解。
