大型水库水温季节性分层对水体富营养化的影响研究

Water supply reservoirs play a key role in social and economic development in our country. The main threat for most of reservoirs in China is eutrophication which can dramatically influence water quality. It is important for water environment protection to clarify the drivers of the trophic state and harmful algal bloom in reservoirs. The annual variation of trophic state is closely related to the spatial distribution of water temperature. Thermal stratification can significantly influence not only bottom-layer dissolved oxygen and nutrient exchange between water and sediment but also phytoplankton structure and dynamics. Xinanjiang reservoir which is the largest reservoir in Yangtze River Delta is selected as a case study. To clarify the thermal stratification process, we analyze historical data obtained from pre-projects and collect the high-frequent observational data from thermal chain. On the basis of dissolved oxygen, nutrient and phytoplankton monitoring, we will use ELCOM-CAEDYM developed by the University of Western Australia to describe the details of formation and destruction process of thermal stratification . Through scenario analysis, we will focus on the mechanism of effects of thermal stratification changes on trophic state and phytoplankton structure.

我国是水资源短缺的国家，水库供水在国民经济发展中发挥着重要作用。富营养化是我国多数水库面临的主要环境问题，严重影响水库的供水安全。阐明水库富营养化的发生机制，特别是有害藻类异常增殖甚至出现水华的规律，对水库的水环境保护及水资源有效管理具有重要意义。水库水华的发生与水体温度的空间分布密切相关，水温分层现象严重影响库底溶解氧含量及水-沉积物界面物质交换、浮游植物的群落结构。本申请拟以长三角地区最大的水库新安江水库为研究对象，通过对历史数据的分析，以及水温、水质和浮游植物群落演替的高频监测，阐述水温分层的形成和破坏规律；同时针对新安江水库岛屿众多、地形复杂的特点，以ELCOM-CAEDYM模型为基础，构建千岛湖三维生态系统动力学模型，模拟水体季节性分层和混合的规律，并进一步揭示营养盐内源释放和藻类异常增殖对水温分层变化的响应规律，为水库富营养化灾害及蓝藻水华暴发预测预警提供科学依据。

我国是水资源短缺的国家，水库供水在国民经济发展中发挥着重要作用。富营养化是我国多数水库面临的主要环境问题，严重影响水库的供水安全。阐明水库富营养化的发生机制，特别是有害藻类异常增殖甚至出现水华的规律，对水库的水环境保护及水资源有效管理具有重要意义。水库水华的发生与水体温度的空间分布密切相关，水温分层现象严重影响库底溶解氧含量及水-沉积物界面物质交换、浮游植物的群落结构。以长三角地区最大的水库新安江水库和苏南地区主要大型水库之一的天目湖-沙河水库为研究对象，通过对历史数据的分析，以及水温、水质和浮游植物群落演替的高频监测，阐述水温分层的形成和破坏规律；以ELCOM-CAEDYM模型为基础，构建三维水动力水质模型，模拟水体季节性分层和混合的规律，并进一步揭示营养盐内源释放和藻类异常增殖对水温分层变化的响应规律，为水库富营养化灾害及蓝藻水华暴发预测预警提供科学依据。