亚热带分层水库营养状态波动的时空特征与微生态学机理

Reservoirs in southeast China are important water resources for economic and social sustainable development, although few have been studied previously. During the past decade, growing population and increasing demands for water shifted the focus of many reservoirs from flood control and irrigation water to drinking water. However, eutrophication has become the most prominent and serious pollution problem for drinking water sources in China. Many studies have been made on eutrophication in large shallow lakes, but little is known about deep reservoirs in Fujian province, subtropical China. This project will investigate the tempo-spatial characteristics and microbial mechanisms of trophic state variation in the stratified reservoirs based on multi-parameters (nitrogen, phosphorus, chlorophyll a, Secchi disk transparency and microbial community) with emphasis on both structure and function of microorganisms (algae, bacteria and protozoa) in the subtropical Fujian province. This study will fill a major gap in the knowledge of the trophic state variation of Fujian stratified reservoirs while also contributing to research on microbial ecology and diversity during eutrophication process. This study will have direct theoretical implication for the eutrophication management and algal bloom control and practical implication for sustainable reservoir management and protection, water quality biomonitoring and early warning.

近十年来，我国水库逐步成为越来越多城镇的饮用水水源地，尽管富营养化是湖库型水源地最突出的污染问题，严重威胁水生态健康与供水安全，但是对亚热带分层水库营养状态波动的时空规律及其机理的认知非常有限。本项目拟选择福建省厦门、漳州、泉州典型水库型水源地考察气候、水文、水质特征；综合利用氮、磷、透明度、叶绿素、以及微型生物（藻类、细菌、原生动物）等多指标研究水体营养状态时空变化的特征与规律，确定藻类水华发生的敏感库区和敏感时期；在分子、种群、群落水平研究微型生物群落结构与功能对分层水库富营养化的响应与反馈，揭示营养状态变动的微生态学机理和内源驱动机制。在理论方面，本研究将为我国海峡西岸地区水库富营养化和藻类水华防控提供科技支持；在实践方面，将为水库型水源地生态管理与保护、水质生物监测与预警提供可靠的数据支持。

水库型饮用水水源保护是我国当前城市化进程中亟需研究和解决的问题，浮游生物是水库生态系统的重要组成部分，在水体自净和物质循环过程中发挥着关键作用。但是由于研究条件和难度的限制，浮游生物群落研究相对缺乏和滞后。本项目以东圳水库、汀溪水库、石兜水库、坂头水库等福建典型水库型水源地为例，通过长期观测和实验室分析，研究了氮、磷元素和藻类等微型浮游生物的时空动态特征、水库的富营养化趋势，定量分析了藻类、细菌、真菌、原生动物等微型浮游生物功能类群群落特征与水体营养要素的关系；分析了水体分层对富营养化的利弊，发现所调查的水库具有磷限制型富营养化水体特征；揭示了分层水库优势水华藻类（拟柱胞藻）对环境变化的响应规律，发现水库浮游藻类较浮游细菌具有更大幅的方向性演替，归纳出丝状蓝藻水华发生敏感时期和敏感地区分别是春夏和大坝前湖泊区，提出限制营养盐和水利调度是控制水华发生和保障水质安全的有效途径；首次揭示了内陆水体稀有浮游细菌的地理分布格局，定量区分空间随机过程和环境决定因子对群落构建的影响。项目执行期间，收集样本13000份，建立了水库系统长期定位观测站、样品库和数据库；在ISME Journal、Water Research、Environmental Science & Technology、湖泊科学等国内外学术期刊发表论文23篇（SCI收录21篇）；培养博士3名、硕士3名。研究成果还取得了良好的社会效益，在东圳水库分层取水和厦门金砖会晤期间水源地水质保障方面发挥了积极作用。