水动力输移对大型浅水富营养化湖泊环境要素时空分异格局的影响机制

There is high spatial varibility of environmental factors and ecosystem structure in large shallow eutrophic lakes. In addition to effcet by rivine inputs of nutrients and the lake physical characteristics (i.e.,water depth,lake shape,and predominent winds), this spatial variation pattern is also resulted from the wind-induced currents. In this project, the hydrodynamics-caused transportation process of organic matter in Lake Taihu will be focused on. In order to provide insight into how hydrodynamics affects the accumulation and transportation process of nutrients, algal detritus and suspended particles,the field observation, high-frequency monitoring and numerical modeling will be conducted for revealing spatial variation of currents, waves and their controlling conditions at different regions of the lake. The special attention will be concentrated on the process of hydrodynamics-caused organic matter transportation and redistribution, which consequent effected on several environment facrors, i.e., nutrient regeneration and cycling, dissolved oxygen, underwater light climate, and finally effected on the communities of phytoplankton, zooplankton, bacteria, benthos, and macrophyte. The Impact mechanism of hydrodynamics transportation on the temporal and spatial environmental heterogeneity in large shallow eutrophic lakes will also be displayed.

大型浅水富营养化湖泊，无论是水环境要素还是生态系统结构，大都呈现出高度的空间异质性。这种高度的空间不均匀性除源自外源输入及地理环境（盛行风场、水深和湖底地形、岸线等）的影响外，还与湖流的输送、扩散过程密切相关。本申请拟以大型浅水富营养化湖泊－太湖为对象，以水动力驱动下物质的输移、扩散过程为主线，以悬浮颗粒物为载体，通过采用野外连续、高频监测的技术手段，研究太湖不同湖区湖流、波浪等水动力要素的时空分布特征、控制因素，及其对水体中营养盐、藻类颗粒物、悬浮颗粒物迁移和积聚过程的影响。重点关注湖泊水动力通过影响藻类颗粒物为主的有机颗粒物的输移和空间再分配，进而影响水体中营养盐的循环和再生、溶解氧、水下光场等环境要素，并最终影响水体中浮游植物、微生物、底栖生物和沉水植物的过程、途径和规律，揭示水动力对大型浅水富营养化湖泊生态环境要素空间异质性格局的影响机制。

本项目以大型浅水富营养化湖泊——太湖为对象，通过研究太湖不同湖区湖流、波浪等水动力要素的时空分布特征及控制因素，揭示水动力特征对太湖生态环境空间异质性格局形成的影响。项目取得了显著的成果：①揭示了影响浮游植物生长、生态系统演化的太湖及周边地区太阳辐射、风速等气象条件长期变化趋势及形成机制；②厘清了太湖波浪波动特征及时空分布规律，开拓了太湖动力过程与生态过程耦合模拟研究的新局面；③阐明了风浪扰动对太湖水环境理化因子格局和生物组成与分布的作用机制，揭示了水动力是造成太湖蓝藻水华迁移、分布和生消过程具有高度时空异质性的根本原因；④揭示了河流输入和藻华暴发过程对太湖有机质与营养盐的来源、浓度及长期变化等理化因子和蓝藻水华时空分异的驱动机制，提出了“氮磷双控”的外源负荷削减与蓝藻水华控制方案；⑤发现了太湖藻类生物量与主要水环境因子在不同时间尺度上的响应与反馈过程，提出太湖蓝藻水华暴发的动力学新机制；⑥构建和验证太湖三维水动力数值模型，科学地指导了太湖蓝藻水华预测预警与湖泛灾害防控。基于本项目的研究开展了广泛的国内外学术交流与合作，形成了一支高水平湖泊系统动力及生态响应研究队伍；近5年来共发表了SCI论文67篇，EI/CSCD论文23篇；获得授权发明专利2项、已登记软件著作权8项；培养了博士后2名、博士生16名、硕士生14名。