浮游植物降解过程中的水体光学吸收特性变化研究

通过配制3组不同浓度浮游植物,在室内进行长时间(37d)降解实验,分析水体光学吸收特性变化规律.结果表明:降解速度前3d最快,25d后逐渐趋于稳定;浮游植物色素吸收系数( aph)随时间变化不断减小趋势明显,在分解过程中不同波段aph(440)、aph(624)、aph(675)与叶绿素浓度(Cchl)显著相关(R2>0.5984,P<0.05),悬浮颗粒物吸收系数ap(440)、ap(675)和总悬浮颗粒物浓度仅呈弱相关性(R2<0.4613); 有色可溶性有机物CDOM构成比较复杂且相对不稳定,非藻类颗粒物吸收系数ad(440)和光谱斜率Sd随时间变化均呈现不规律性.另外,与太湖同期野外采样点相比,室内降解实验的总颗粒物和浮游藻类色素吸收光谱更相似,Sd和Sg更大.通过研究浮游植物死亡分解过程中水体吸收特性的变化规律,有助于构建高精度的黑水团遥感监测模型,及时掌握黑水团信息.

Variability of absorption of inherent optical properties (IOPs) in the presence of phytoplankton degradation

We examine the long term (37days) changes in the optical dynamics of phytoplankton concentrations during senescence and degradation. The results show that: 1) The degradation rate is fastest in the first three days and optical properties reach a steady state after 25days; 2) A significant production of inorganic particulates are formed during the degradation process at higher concentrations of algal biomass; 3) The temporal dynamics between optical properties of phytoplankton (aph(440)、aph(624)、aph(675)) and chlorophyll concentrations (Cchl) were significantly correlated (R2>0.5984,P<0.05) while those of particulates (ap(440)、ap(675)) and total suspended particles concentrations were only weakly correlated(R2<0.4613); The structure of CDOM is complex and relatively unstable while ad (440) and Sd changed not regularly with time. The optical properties of the particulate fraction and phytoplankton measured in the degradation experiment was more similar than those measured in black water masses in Taihu Lake. Optical properties of dissolved components (Sd and Sg) were greater. These optical properties of the particulate and dissolved fractions provide needed information for algorithm development for remote sensing monitoring and modeling of these important phenomena.