太湖流域昆承湖春季颗粒物和有色可溶性有机物吸收特性

Absorption characteristics of particulates and the CDOM in spring in Lake Kuncheng,Taihu Basin

利用2010年4月23日在昆承湖采集的水体吸收系数数据,对总悬浮物颗粒物、浮游植物色素颗粒物、非色素颗粒物和有色可溶性有机物的吸收特征进行研究.结果表明,春季昆承湖水体除675 nm附近具有叶绿素吸收峰的红光波段外,非色素颗粒物吸收系数大于浮游植物色素颗粒物吸收系数,总颗粒物吸收系数光谱分布与非色素颗粒物的吸收光谱类似,即吸收系数随波长的增大而减小;非色素颗粒物和有色可溶性有机物的吸收系数随波长的增大接近指数衰减规律,且不同波段存在一定关系,非色素颗粒物在400和440 nm的吸收系数与总颗粒物浓度存在显著多项式关系;多项式关系能较好地表达浮游植物色素颗粒物单位吸收系数与叶绿素a浓度之间的关系;不同采样点的组分吸收系数对总吸收系数的贡献不同,大致有四种表现类型.

Field work was carried out in Lake Kuncheng,Taihu Basin on April 23, 2010 to analyse the absorption characteristics of total particulates, phytoplankton pigment, tripton and chromophoric dissolved organic matter（CDOM）. The results show： The ab- sorption coefficient of tripton is higher than that of phytoplankton pigment except for red wavelength at 675 nm. Absorption coeffi- cient of tripton spectrum becomes lower at the longer wavelength, and absorption of total particulates has the similar characteristics as that of tripton; Absorption coefficients of tripton and CDOM approximate exponential attenuation with increases of the wave- length, in which show certain relationships in different bands, and absorption coefficients of tripton at 400 nm and at 440 nm have good polynomial relationships with total particulate concentration ; Relationships of the specific absorption coefficients between phy- toplankton pigment and chlorophyU-a concentration also can be well expressed by a polynomial function; Absorption coefficients from different sites of Lake Kuncheng sites show four different types of contributions to the total absorption coefficients.