鄱阳湖夏季有色可溶有机物空间分布及其和浮游藻类的关系分析

有色可溶有机物(CDOM)的分布及光学性质对于研究湖泊水体富营养化和水色遥感具有重要的科学意义.该文通过紫外分光光度法定量研究了2016年夏季鄱阳湖水体不同区域的有色可溶有机物光吸收特性,分析了a_CDOM(440)与光谱斜率比值(S)的关系,讨论了CDOM吸收系数与藻类及其他环境因子之间的关系,并与其他湖泊和水库相比较.研究结果表明:鄱阳湖水体在440 nm波长处的吸收系数为0.13～2.17 m^-1,均值为(0.93±0.54)m^-1.不同区域的CDOM含量差异显著,排序依次为主航道>珠湖区>南矶山水域,表现为3种典型吸收光谱曲线.夏季在300～440nm波长处S与CDOM有很好的相关性.鄱阳湖CDOM分别来源于藻类降解、沉积物扰动和河流流入.珠湖区CDOM来源主要为内源性,由浮游植物降解所产生.南矶山水域CDOM来源于赣江等河流汇入以及养殖肥水排入,其吸收系数与水体总磷关系密切.

The Spatial Distribution of Chromophoric Dissolved Organic Matter and Its Relationship with Algae During the Summer in the Poyang Lake

The distribution and optical properties of colored dissolved organic matter(CDOM)are of great scientific significance for the study of lake eutrophication and water color remote sensing.The optical absorption properties of chromophoric dissolved organic matter(CDOM)in the different sections of the Poyang Lake are investigated during the summer of 2016.The relationship between a_CDOM(440) and spectral slope ratio(S)is analyzed and the relationship between CDOM absorption coefficient and the environmental factors is discussed and compared with other lakes and reservoirs.The results show that the absorption coefficient of Poyang Lake water at the wavelength of 440 nm is 0.13—2.17 m^-1,with an average value of(0.93±0.54)m^-1 and the concentrations of CDOM in different regions are obviously different.Its absorption spectral curves are clearly divided into three typical spectral curves.The concentration in main channel is higher than others,while the lowest is in Nanjishan region.S has a great correlation with CDOM at 300—440 nm in the summer.CDOM in Poyang Lake is derived from algal degradation,sediment disturbance and river inflow,respectively.The source of CDOM in Zhuhu region is mainly endogenous,which is generated by phytoplankton degradation.CDOM in Nanjishan region is derived from the inflow of Ganjiang river and other rivers and the discharge of aquaculture fertilizer water,and the absorption coefficient is closely related to the total phosphorus in the water.