基于三维荧光光谱——平行因子分析技术的蠡湖CDOM分布特征

利用三维荧光光谱(EMMs),并结合平行因子分析法,研究了蠡湖水体中有色可溶性有机物(CDOM)的分布特征及其来源,并探讨了不同组分荧光强度与其他水质因子间的相关性.结果表明,蠡湖水体中CDOM主要由2个荧光组分组成,分别为类色氨酸荧光组分C1(225,280/335)和类腐殖质荧光组分C2(250,300/435),并且C1和C2对总荧光强度的贡献率分别75.70%和24.30%.空间上C1和C2荧光强度自东向西依次递减,呈现东蠡湖高于西蠡湖、沿岸区高于湖心区的趋势.荧光指数(FI)、生物源指数(BIX)和腐殖化指数(HIX)都显示蠡湖水体CDOM来源于自生微生物、藻类等新近自生源,整体呈现弱腐殖质特征.相关性分析表明,CDOM与N、P元素的迁移转化密切相关,并且对透明度有重要影响.

Distribution of chromophoric dissolved organic matter in Lihu Lake using excitation-emission matrix fluorescence and parallel factor analysis

Excitation-emission matrix spectroscopy (EEMS) combined with parallel factor analysis (PARAFAC) was applied to investigate the fluorescence characteristics and its source of chromophoric dissolved organic matter (CDOM) in the water of Lihu Lake, and the relationship between the fluorescence intensity of different components and other water quality parameter was also discussed. The results indicated that two fluorescence components were identified by PARAFAC, including one tryptophan-like component and one humic-like component, namely C1 (225,280/335) and C2 (250/435). The contribution rates to the total fluorescence intensity of C1 and C2 were 75.70% and 24.30%, respectively. Spatially, fluorescence intensity of C1and C2 decreased from the east district of Lihu Lake to the west, and lakeside areas was higher than lake center. Fluorescence index (FI), the index of recent autochthonous contribution (BIX) and humification index (HIX) show that CDOM in the water mainly derived from microbes, algae and other newly autochthonous sources, appeared weak humic characteristics overall. CDOM was closely related to the transformation and migration of nitrogen and phosophorus, and had important influence on transparency.