【摘要】 在三峡水库首次蓄水175 m最高水位及其消落至145 m最低水位期间,分别采集三峡水库8个段面的水样,应用三维荧光光谱(EEM)研究了三峡水库中溶解有机质(DOM),考察了DOM在整个三峡水库的组成、分布及其来源,着重探讨了30 m水位消落对DOM的影响,并拟合了DOM中各荧光峰强的比值变化及其与pH、溶解氧(DO)、溶解有机碳(DOC)、氧化还原电位(ORP)等环境因子的线性关系.结果显示,水库干流DOM的EEM均表现出4个荧光峰,归属为类蛋白质、类腐殖酸、类富里酸.最高水位时,从三峡水库上游至下游,荧光峰强逐渐增强,在大坝前最强;最低水位时,荧光峰强较其高水位均显著提高,受丰水期沿岸不同的陆源汇流影响,最强荧光峰出现在三峡水库中、上游.各荧光峰强与环境因子的线性关系在枯水期高水位时较好,在丰水期低水位时仅有DO与类蛋白有正相关性.揭示了三峡水库水质主要受丰水期的陆源汇流影响,而大坝运行模式的影响不显著.更多还原

【Abstract】 Fluorescence excitation emission matrix(EEM) are applied to characterize the dissolved organic matter(DOM) from waters in the Three Gorges Reservoir,sampled at near the highest water level 175 m for the first time and followed drawdown to the lowest water level 145 m respectively.The composition,distri-bution and source of the DOM in the Three Gorges Reservoir are investigated with impacted by 30 m water levels fluctuation,and the correlations between each fluorophore’s intensity and environmental factors such as pH,DO(dissolved oxygen),DOC(dissolved organic carbon),ORP(oxidation-reduction potential) etc.are fitted.From the results,all the DOM’s EEM from main streams in the Three Gorges Reservoir had four fluorescence peaks,attributed to protein-like,humic-like and fulvic-like respectively.During 175 m dry season,fluorescence intensities in EEMs increased from upstream to downstream,with the Dam section having the strongest intensity;comparatively,during 145 m wet season,the fluorescence intensities was ob-viously higher than those in dry season,impacted by terrestrial confluence along the bank of the Three Gorges Reservoir,and the strongest intensity occurred in the middle and upper reaches.A good correlation between environmental parameters and EEM Peaks was observed in dry season.On the contrary,only Peak A and DO has positive linear correlation during wet season.The present article revealed that the water qual-ity in the Three Gorges Reservoir is mainly affected by the terrestrial confluence,with less impact by the 30 m water level fluctuation in reverse way to the Yangtze River’s natural wet-dry law.更多还原