水源生态净化系统浮游藻类功能群生境响应及调控机制

It is of great significance to construct an ecological purification system with water purification and emergency water storage functions to ensure the safety of river source drinking water. However, regional algae bloom often occurs because of the high heterogeneity of temporal and spatial distribution of water and ecological conditions within the ecological purification system. This project will investigate the temporal and spatial distribution characteristics of planktonic algae functional groups by tracking and monitoring of a large-scale water ecological purification system. Furthermore, it will reveal habitat type diversity and identify the dominant functional groups applied to the habitat characteristics and key control factors in the ecological purification system by determining the dominant functional group growth strategy and its water and energy needs. A rapid evaluation and early warning method of algae bloom in the ecological purification system will be established based on the spatial migration characteristics of planktonic algae function groups in each unit and the cumulative algae growth kinetic model. The proposed project will combine in situ confinement experiments and laboratory simulation experiments to analyze the effects of key components on planktonic algae habitat and the response characteristics of planktonic algae functional groups. In addition, it will characterize the variances of spatial distribution of habitat within the ecological purification system to establish the ecological regulation method of planktonic algae functional group from the perspective of habitat stress. The prosed project will provide scientific basis and technical support for the construction of the dynamic balance of key components of the water purification system and for the safety of drinking water.

构建兼备水质净化及应急蓄水功能的水源生态净化系统对保障河流型饮用水安全具有重要的意义。然而，水源生态净化系统内部水体生态环境时空分布的高度异质性，易出现局部区域藻类水华问题。本项目以浮游藻类功能群时空分布特征为切入点，基于规模化饮用水源生态净化系统的跟踪监测，从优势功能群组生长策略及其对水体能量和物质的需求情况，揭示水源生态净化系统内部生境类型多样性，识别优势功能群组所适宜的生境特征及关键控制因子。根据各单元浮游藻类功能群组空间迁移特征，基于藻类生长累积动力学模型，建立水源生态净化系统藻类水华快速评价与预警方法。通过原位围隔结合实验室模拟实验，解析生态净化系统关键可控要素对浮游藻类生境条件的影响及浮游藻类功能群组响应特征，结合生态净化系统内部生境空间分布差异性，从生境胁迫角度建立浮游藻类功能群生境调控方法，为水源生态净化系统关键组成要素动态平衡的构建及饮用水安全保障提供科学依据和技术支撑。

兼备水质净化及应急蓄水功能的水源生态净化系统的建立对保障河流型饮用水安全具有重要的意义。然而，水源生态净化系统内部水体生态环境时空分布的高度异质性，易出现局部区域藻类水华问题。本项目选择大规模水源生态净化工程——盐龙湖工程为研究对象，以浮游藻类功能群时空分布特征为切入点，开展浮游藻类功能群生境响应及调控机制研究。主要研究成果如下：. （1）探明不同季节水源生态净化系统内部生境异质性及影响因素。水源生态净化系统能够有效提升水体DO、透明度，去除水体营养盐及有机物，其中DO、SD的提升及有机物的去除主要作用单元为预处理单元及深度净化区，氮磷营养盐的去除主要作用单元为生态湿地净化区，不同季节各单元水质具有显著的空间差异性，其中夏季及秋季水质空间差异性最显著，系统关键构成要素水生植物、鱼类群落时空差异性及运行管理条件是影响生态净化系统内部生境异质性变化的关键驱动因素。. （2）揭示水源生态净化系统浮游藻类功能群生境响应特征。盐龙湖水源生态净化系统内共划分出23个FG功能群，在全年占优势的功能群为B、D、P、MP、X1、J和Lo；共划分出7个MBFG功能群，全年中占优势的功能群为GroupⅠ、GroupⅣ、GroupⅤ和GroupⅥ；通过比较盐龙湖水源生态净化系统中FG和MBFG这两种功能群与环境因子的冗余分析结果发现，MBFG的生境响应性优于FG。. （3）阐明生态系统关键组成要素水生植物、鱼类群落对浮游藻类功能群生存环境的胁迫作用。水生植物本身的C、N、P含量，与其溶解释放出的TDC、TDN和TDP具有显著的正相关性；沉水植物与漂浮植物的在腐解时释放营养盐的能力更强，腐解前期有机物被快速释放，同时消耗水体中大量的氧气，使水体呈现缺氧状态。基于鱼类捕食作用、营养盐的排泄作用和对沉积物的扰动作用浮游藻类功能群影响的综合效果，进行鱼类群落结构调控及优化，调控后盐龙湖鱼类多样性由21种增加至38种，对优势浮游藻类功能群的生境胁迫作用显著提升。