洱海脱氮微生物种群稳定性及其鲁棒机制的研究

The ecological system of plateau lakes is fragile, and it is poor in its robustness which can not keep stability of both function and structure under the external pollutant interference, so it prones to become eutrophication and sensitive areas. A lot of studies including geochemical, climate, water physicochemical factors, nutritional balance, animal and plant ecology on the eutrophication have been carried out, but there is little study on the nitrogen removal microorganisms microorganisms and their robustness, which play an important role in the material energy cycle. .So this project puts forward the hypothesis: the function and structure robustness of nitrogen removal microorganisms microorganisms is the key to maintain the stability of water ecosystem. Once the robustness is destructed by disturbance of the outside pollutants (nutrients), the water will develop into eutrophication. nitrogen removal microorganisms adjustment can help to slow or prevent eutrophication. Taking Erhai lake as an example, this project is planned to analyse the water physicochemical factors, nitrogen removal microorganisms, physiological metabolism and carbon nitrogen phosphorus cycle related gene, to clarify their temporal and spatial distribution pattern. .Based on evaluation of the water quality, the metheds such as social network and principal component analysis are used to research the structure and function robustness. The eutrophication mechanism and ecological driving forces are researched by studying the module and structure stability, feedback, redundancy, nitrogen removal capacity of the nitrogen removal microorganisms system..It is very important in theoretical and practical value for protecting and developing Yunnan plateau lakes, and it is significant in reality to regulate the process and direction of the eutrophication by shaping the nitrogen removal microorganisms microorganism’s robustness.

高原湖泊生态脆弱，鲁棒性差，即在外界污染物干扰下，系统保持结构和功能稳定性能力差，是富营养化易发和敏感区。但洱海沉积物总氮偏高，与滇池接近，而水体相对保持较好。前期实验发现，这可能与洱海脱氮微生物种群稳定性有关。据此，本项目提出脱氮微生物鲁棒性在维持湖泊生态系统稳定性中作用的假说。在明确洱海可培养和不可培养微生物及环境因子、功能因子时空分布基础上，采用社会网络分析法，用ucinet构建脱氮微生物间关系的无向网络，从微生物种群关系及其整体生态学功能角度，研究富营养化相同条件下网络核心边缘结构、凝聚子群，分析微生物种群结构、角色、功能模块和冗余，探讨不同营养收支和富营养化下微生物系统结构的演化，解析系统对富营养化的反馈，阐释脱氮微生物维持种群结构和功能稳定性的鲁棒机制，并结合生物信息学、主成分及冗余分析等方法探讨其影响因子，为优化群落结构、调节群落功能从而治理云南高原湖泊富营养化提供理论依据。

本项目在明确洱海可培养和不可培养微生物及环境因子、功能因子时空分布基础上，采用社会网络分析法，系统阐释脱氮微生物维持种群结构和功能稳定性的鲁棒机制。执行结果如下：.1、当前洱海水质处于II类向III类转变关键时期，以TN、TP污染为主。Chla与SD呈负相关，富营养化指数与TN、CODMn正相关。.2、纯培养获得510株细菌，隶属于5个门7个纲25个目35个科和57个属，203个种。在属水平上优势类群有Micromonospora、Streptomyces、Microbacterium、Pseudomonas、Massilia和Pantoea。.3、高通量测序，共注释到64个门182个纲405个目579个科859个属1730个不同种。在属水平上优势种群为Sva0485、Thermodesulfovibrionia、Aminicenantales、Anaerolineaceae、Vicinamibacterales、Crenothrix等。不同样点中的物种组成结构存在较大差异。.4、硝化、反硝化的稀有类群拥有更高的网络参数(如网络节点数、特征向量中心度等)，可能在生态网络中具有更中心的地位，在维持微生物生态网络复杂性中起着更重要的作用，相比AOA和nirS型微生物，AOB和nirK型反硝化微生物对潜在硝化、反硝化速率的贡献更大，而其稀有类群的β而非a-多样性对潜在硝化、反硝化速率的影响更大。.5、SAR324_cladeMarine 和Cloacimonadota类群影响pH；类群Bacteroidota、Spirochaetota、Fibrobacterota、Bdellovibrionota、RCP2-54、Dependentiae影响总有机碳；类群NB1-j、Dependentiae影响总磷；类群RCP2-54、Bdellovibrionota影响总氮；类群Calditrichota影响铵态氮；类群Fibrobacterota、Dependentiae、WS2影响硝态氮：类群Campilobacterota、Dependentiae影响亚硝态氮。.6、硝化、反硝化微生物的α和β多样性具有明显的区域分布模式，分布模式趋势并不一致。.7、SCI论文6篇(第一作者3篇)，其它论文2篇。第一发明发明专利1项，实用新型1项，软件著作1项。独著1部。部分成果将在结题后发表。