覆盖金属氧化物对湖泊沉积物溶解性有机质特征的影响

为揭示不同金属氧化物对湖泊沉积物DOM（溶解性有机质）影响机制，通过室内模拟试验，在沉积物表层分别覆盖Fe、Al、Mn氧化物及湖沙后培养1 a，并利用三维荧光和紫外光谱方法进行表征.结果表明:① 覆盖Al、Fe、Mn氧化物和湖沙主要降低了0~3 cm沉积物的w（DOC），降幅分别为8.61%、6.27%、22.38%和0.44%. ② 沉积物中DOM的类络氨酸峰（peak B₁）和类色氨酸峰（peak T₂）均产生较大变化.其中三种氧化物均显著降低了上层沉积物中DOM的peak T₂，使底层DOM的peakT₂显著增加. Mn氧化物使DOM的peak B₁降低，Fe和Al氧化物使DOM的peak B₁增加，湖沙则使两类峰均降低. ③ 覆盖金属氧化物改变了沉积物DOM结构特征，其中覆盖Fe氧化物增强了其芳香性，而覆盖Mn氧化物和Al氧化却降低其芳香性，但三者均使DOM腐质化程度及官能团数量增加，并使FI（Fluorescence Index，荧光指数）增大，表明DOM向生物源转化.研究显示，沉积物表层覆盖金属氧化物影响了沉积物中DOM迁移和转化，并促进了其降解，导致其分子量和腐殖化程度增加. 

Dissolved Organic Matter Characteristics Affected by Covering Metal Oxides on Surface of Lake Sediment

Abstract: Indoor simulation experiments covering sediment surfaces with iron, aluminum, manganese oxide and lake sand for a year were conducted to investigate the impact mechanism of metal oxidex on sediment dissolved organic matter (DOM) by three dimensional fluorescence spectrum and ultraviolet-visible spectrum. The obtained results showed that:(1) the sediment DOC content of 0-3 cm depth decreased by 8.61%, 6.27%, 22.38% and 0.44% in the samples covered with Al, Fe, Mn oxide and lake sand, respectively. (2) The tyrosine peak (peak B₁) and tryptophan peak (peak T₂) in the sediment DOM varied greatly. Three oxides significantly reduced the peak T₂ of the surface sediments DOM, and significantly increased the peak T₂ of the underlying DOM; the Mn oxide reduced the peak B₁ of the DOM, and the Fe and Al oxides increased the peak B₁ of the DOM. The two peak types decreased by covering with lake sand. (3) The coverage by metal oxides changed the structure of sediment DOM, whereas the coverage of Fe oxides enhanced its aroma, while covering with manganese oxides and aluminum oxide reduced its fragrance. However, the three oxides increased the degree of DOM and the number of functional groups, increased FI value and promoted the DOM transformation to biological sources. The results showed that the sediment surface covered with metal oxides affected the sediment DOM migration and transformation, and promoted its degradation, resulting in increments of molecular weight and humification degree.