湖泊蓝藻胞外聚合物的分布特征、组分变化及其对水华形成的机理研究

Cyanobacteria extracellular polymeric substances (EPS) play a significant role on the formation of lake bloom, while its specific functional mechanisms for the bloom forming are hardly discussed.Investigations on the spatial and temporal variations of cyanobacteria EPS would be contributable to the deep insights of the forming process and EPS functional mechanisms. In the past studies, we had obtained an optimized method to characterize the matrix structure of cyanobacterial EPS. Based on the obtained results, bloom-forming cyanobacteria in Taihu lake will be adopted in this study for further study. We will combine the multiple fluorescence labeling-confocal laser scanning microscopy with two dimensional correlation spectroscopy technique to investigate the distribution and dyanamic changes of cyanobacteria EPS during bloom period through field observation and indoor culture, and also to probe into the interactional effects of cyanobacterial EPS and environmental factors (such as temperature and nutrients) on the cyanobacteria growth and bloom forming. Through the application of this project, we would obtain the information on the distribution heterogeneity of EPS matrix during bloom forming and acquire the specific EPS compositions which are responsible for the cyanobacterial blooms. Also, we could ascertain the responsive relationship between environmental factors, EPS and cyanobacterial bloom, and ultimately elucidate the functional mechanisms of EPS for cyanobacterial blooms. This study will provide novel theoretical supports for the deeper understanding of the formation processes and mechanisms of cyanobacterial blooms and could give a significant direction for theoretically forecasting and efficiently preventing the cyanobacterial blooms.

蓝藻胞外聚合物(EPS)在湖泊水华形成过程中起重要作用，但目前对其具体作用机理的认识还相对薄弱。通过分析蓝藻水华期间EPS的时序变化特征，必将有助于剖析水华形成过程及EPS关键作用。项目在优化蓝藻EPS絮体结构表征的基础上，拟以太湖水华蓝藻为研究对象，通过野外原位观测及室内培养实验，结合多重荧光染色-共聚焦激光显微镜和二维相关光谱技术，分析富营养化湖泊水华形成过程中蓝藻EPS的分布特征及各组分物质的动态变化，并研究EPS关键作用物质与温度及营养盐等环境因子对水华形成的交互作用；获取湖泊水华期间蓝藻EPS的分布特异性信息，探明水华形成及解聚过程中EPS的关键作用物质；建立环境因子、EPS与蓝藻水华三者的响应关系，以期揭示蓝藻EPS对水华形成的作用机理。项目研究可加深对蓝藻水华形成过程及机理的理解，对科学预测并有效预防水华发生也具有重要的理论指导意义。

通过比较不同提取方法对水华蓝藻EPS提取效率的影响，获得了一种水华蓝藻EPS的无破坏优化提取操作。通过追踪我国典型富营养湖泊蓝藻水华发生过程中藻颗粒聚集体EPS有机质的含量及组成变化，明确了蛋白质和多糖等有机质在蓝藻水华形成过程中的重要作用。基于EPS提取前后蓝藻颗粒聚集体团聚性能的变化情况，并运用扩展DLVO理论，定量探讨了EPS对蓝藻水华形成的能量贡献，发现松散结合EPS和紧密结合EPS在蓝藻水华形成过程中的能量演变规律。通过比较标准培养基及低浓度培养基铜绿微囊藻的生长及EPS变化情况，构建了蓝藻生长与EPS作用的初步模型。基于EPS对蓝藻颗粒聚集性能的重要性，研究了EPS在环境条件下的变化(降解)行为，探讨了不同组分的降解速率及机理及其对蓝藻水华的环境适应性机制。通过分析EPS与环境中污染物的作用过程，发现结合过程不仅与EPS和污染物种类有关，还与环境因子(pH、温度、离子强度)显著相关，并解析了EPS对蓝藻细胞维持其自身完整性及环境抗干扰性能的作用。研究结果对加深理解富营养化湖泊蓝藻水华的形成机理具有显著的理论意义，对湖泊污染治理工程的研发也具有重要的指导作用。