水库调度下生境扰动对浮游植物生物多样性的影响

Algal bloom, happening in some tributaries of Three Gorges Reservoir (TGR), has been the most serious environmental problem needed to solve. Although some researches indicated that there were negative correlation relationships between algal bloom and reservoir regulation, the quantitative relationship between them and it’s mechanism are still unclear. And, now those researches always focus on the static effects of the environmental factors on phytoplankton, there is relatively little research from the aspect of relationships between habitat disturbance and phytoplankton biodiversity. In this application, the “intermediate disturbance theory” would be used to study the algal bloom in the TGR. The aims of the study are to find the mechanism why and how the habitat disturbance can affect the phytoplankton biodiversity, to established quantitative relations between the habitat disturbance and phytoplankton diversity, and to propose some ecological thresholds of habitat disturbance to control the algal bloom. Those above could be really great and very meaningful to research the mechanism of the algal bloom , it's prediction and controlled methods in the TGR and some other reservoirs.

三峡水库蓄水带来的支流库湾水华现象已成为当前普遍关注和亟待解决的环境问题。研究发现三峡水库调度对支流水华影响显著，但尚未很好揭示二者之间的作用机制和定量关系，且已有研究多关注生境因子与水华之间的静态关系，未从生境扰动与生物多样性关系的角度来研究水华机理及其防控问题。本项目将借鉴中度扰动理论，以三峡水库典型支流库湾水华为研究对象，弄清对浮游植物生物多样性及水华生消有显著影响的生境因子扰动模式，建立敏感生境因子扰动与浮游植物生物多样性及水华的定量关系，提出能有效防控支流水华的生境扰动模式及强度。该研究对深化我国水库藻类水华生消机理的认识，实现水华预测预报及防治具有重要的理论价值和实践意义。

项目针对三峡水库支流水华问题，系统开展了跟踪监测和室内模拟，确定了不同调度情况下香溪河库湾环境因子及藻类水华变化或演替过程；系统开展了水温、营养盐、光照、水体层化结构等因素与藻类生长的关系实验；结合中度扰动理论和理论临界层理论，提出了决定支流水华生消的环境因子判定条件；结合水流、水质数值模拟，确定了三峡水库水位扰动是如何通过改变三峡水库干支流水流循环模式进而影响支流水华生消的作用机制；以此，提出了基于环境因子控制和藻类水华生消的水库调度需求。以香溪河库湾为例，开展多年调度方案模拟示范，2017年汛期调度模拟示范和2017年汛期实际调度示范及跟踪监测；结果表明，项目关于“防控支流库湾水华的生境扰动模式”具有一定的可操作性，且对水华控制效果显著。