【摘要】 通过对太湖北部不同湖区2005—2006年4个典型月份水体中有色可溶解性有机物(CDOM)的生物-光学特性进行研究,系统分析了太湖北部湖区水体中CDOM的生物-光学特性和时空分布变异规律,并对CDOM在自然光暴晒下的降解特性进行初步研究.结果表明,湖水中CDOM的分布,空间上竺山湾>梅梁湾>贡湖湾>大太湖,入湖河道附近要高于其他水面,时间上按冬季到次年秋季逐渐递减;表征CDOM谱形变化的指数函数S值没有显著性时空差异,冬、春季CDOM吸收系数与ρ(叶绿素a)完全没有相关性,夏、秋季CDOM的空间分布则与ρ(叶绿素a)分布较为一致,吸收系数与ρ(叶绿素a)存在正相关;CDOM定标后的荧光值与其吸收系数在4个月内均存在相对恒定的线性关系;在接受自然光特别是紫外辐射暴晒后,CDOM吸收明显降低,发生显著的光化学降解,其降解过程符合拟一阶动力学衰减反应.更多还原

【Abstract】 The biological and optical characteristics and spatial and temporal distribution of chromophoric dissolved organic matter (CDOM) in the northern part of Taihu Lake were investigated in four typical months from 2005 to 2006.Moreover,the degradation of CDOM in the natural condition was studied.The results indicated that the spatial pattern of CDOM absorption was Zhushan Bay > Meiliang Bay > Gonghu Bay > Taihu Lake center.Furthermore,CDOM absorption near the river inlet was generally higher than that in the open water in Meiliang Bay.Seasonally,CDOM absorption gradually decreased from the winter to the following autumn.The values of the exponential slope coefficient S had no significant temporal-spatial difference.In the winter and spring,no correlations were found between the CDOM absorption coefficient and chlorophyll a concentration;however,the CDOM absorption coefficient was consistent with the spatial distribution of chlorophyll a concentration in the summer and autumn,and both presented positive correlation.A significant linear relationship was established between CDOM absorption and fluorescence intensity in all four seasons.CDOM absorption markedly decreased and degraded when it was exposed to natural solar radiation,especially ultraviolet,and the degradation of CDOM fitted the pseudo-first-order dynamics reaction.更多还原