外加葡萄糖对洱海沉积物溶解性有机质光谱特征影响

利用三维荧光光谱(3DEEM)技术,研究了外加葡萄糖对洱海沉积物中DOM(溶解性有机质)释放和转化的影响以及DOM的光谱特征变化. 培养试验设4个处理(C₁、C₂、C₃、C₄),ρ(葡萄糖)分别为0、50、100和200mg/L. 结果表明:①洱海沉积物DOM出现了6种荧光峰,分别代表类蛋白荧光物质和类富里酸荧光物质,并且荧光峰位置在1~8d呈“蓝移”现象,8~17d呈“红移”现象. ②紫外区与可见区类富里酸(峰A和峰M)随培养时间延长逐渐升高,其中C₄处理的峰A荧光强度小于C₁处理；在培养初期C₄处理的峰M荧光强度小于C₁处理,培养后期则相反. ③随着培养时间延长,上覆水中类蛋白荧光强度呈“单峰”曲线变化,其峰值均出现在培养后第8天,在整个培养过程中,类蛋白荧光强度均表现为C₄处理>C₁处理. 外加葡萄糖可促进洱海沉积物DOM转化,使部分微生物难利用的DOM转化为易被微生物利用的类酪氨酸、类色氨酸等类蛋白物质. 

Effects of External Glucose on Spectral Characteristics of Dissolved Organic Matters in the Sediment of Erhai Lake

Variations of spectral characteristics for dissolved organic matter(DOM)were studied by analyzing the three dimensional fluorescence excitation-emission matrix(3DEEM)spectra, and then the effect of external glucose on the emission and transformation of DOM was investigated. Samples of the sediment from Erhai lake was cultured by adding four concentrations of glucose solution (0,0, 100and 200mg/L for C₁,C₂, C_3and C_4treatments respectively). The result of this study revealed:①there existed six forms of fluorophores, which represented protein-like fluorescence substance and class fulvic acid respectively. Phenomena of “blue shift” and “red shift” ocurred when fluorescence peak positions were on 1-8d and 8-17d, respectively. ②The luorescence intensities of fulvic acid in the ranges of ultraviolet and visible light increased with the progress of culturing. The peak A appeared as C₄1, while the peak M occurred as C₄>C₁during the initial cultivation, but opposite during the late cultivating period. ③With the extension of the cultural progress, protein-like fluorescence presented “the single-peak” curve changes in the overlying water. The “peak” appeared after eight days. During the entire cultivation period, protein-like fluorescence presented as C₄>C₁. The addition of glucose promoted biological transformation of DOM in the sediments of Erhai Lake, and a part of DOM those are difficult used by microorganisms transformed into protein-like substances.