草型湖泊中沉水植物大面积分布，其表面常富集大量藻类、细菌、真菌、有机和无机碎屑，形成附植生物膜，是生物地球化学过程热区，对水环境质量具有重要影响。附植生物膜有机体间联系紧密，但藻类与反硝化菌群落及功能间的关系尚不清楚。据研究，生物膜中藻类数量最多的反硝化速率最大，反硝化菌群落结构也不同。我们认为，附植生物膜藻类与反硝化菌之间的这种协同关系与藻类种间分泌物不同有关。为此，本项目拟通过对草型湖泊中典型沉水植物附植生物膜藻类、反硝化菌群落及功能的研究，找出影响反硝化作用的藻类，并应用指纹图谱辨识藻类种间分泌物差异；在此基础上，通过模拟试验，研究藻类分泌物与反硝化菌群落及反硝化作用的关系，揭示藻类对反硝化菌群落及功能的影响机制。结果将增加附植生物膜有机体间互作关系的理解，对于正确认识和利用沉水植物的生态调控功能、改善水环境质量具有重要意义。

In macrophtic lakes, various kinds of substances, including algae, fungi, bacteria, and organic and inorganic detrital material etc., form epiphytic biofilms on surfaces of a wide variety of submerged macrophytes. These biofilms are hot spots of biogeochemical processes and have important influence on water environmental quality. Currently, the interactions between epiphytic-biofilm algae and bacteria, and the related metabolic processes are affteced by a number of factors, while it is still unclear what impact these algae will have on denitrifying bacteria communities. According to past studies, in the biofilms, the increment in the population of algae can speed the rate of denitrification and change the structure of denitrifying bacteria communities.Based on our studies, the synergistc relationship between epiphytic-biofilm algae and denitrifying bacteria epiphytic is related to the different secretion of algae. Thus, this project aims to study on typical submerged macrophytes, epiphytic biofilms and denitrifying bacteria communities, then find out what kinds of algae afftect denitrifying. The difference in the secretion of different algae will be distinguished by using fingerprint technology.The relationship between the secretion of algae and denitrifying bacteria communities ,and their functions will be studied by using simulation , and then the influence mechanism of epiphytic biofilms on denitrifying bacteria communities and denitrification will be researched. The achievement of this study will indicate the interaction of organisms in epiphytic biofilms, and it is important that submerged macrophytes will be used for ecological regulation and improving wate quality.