武汉东湖原生动物群落对“六湖连通”的生态响应

The assembly and maintenance of biodiversity has historically been a hot topic in ecology studies, but most of studies focused on the adaptive evolution and spatio-temporal turnover of animals/plants at regional or world-scales. Little is known about the ecological response of the single-celled protozoa to the anthropogenic disturbances. However, the protozoa in the aquatic ecosystems not only play fundamental ecological roles in the biogeochemical cycling, but its ecosystem functioning in aquaculture, water purification and environmental monitoring are also very important. By using the newly developed high-throughput sequencing technologies, as well as traditional taxonomic methods, this project intend to study the spatio-temporal patterns and the community succession of protozoa in Lake Donghu after the ecological project of connecting six lakes in Wuhan. With meta-analysis using the sequencing, taxonomical and geochemical data, we aimed at revealing how protozoa communities respond to the ecological water project of connecting the six lakes in Wuhan. This study will not only improve our understanding on how aquatic microorganisms in response to anthropogenic disturbances, but will also shed new insights for environmental assessment.

生物多样性的形成和维持机制一直都是生态学研究的重点课题，不过绝大多数研究集中在大尺度范围高等动、植物群落的时空演替规律及其适应性进化，而就自然界中最原始、最低等的动物类群—原生动物对人类干扰的生态响应研究相对较少。该单细胞类群不仅对水体生态系统物质循环和能量流动非常重要，而且在水产养殖、水质净化和水环境监测等方面均具有很好的应用价值。本申请课题拟以 “大东湖”生态水网工程实施“六湖连通”后的武汉东湖为主要研究对象，采用近期发展起来的高通量测序技术与传统的形态学方法相结合，从系统进化和物种多样性层面揭示武汉东湖与连通湖泊及通道内原生动物群落时空格局及演替规律。在此基础上结合相关环境指标通过结构方程模型和小波分析解析并预测原生动物生态群落对“六湖连通”的生态响应规律。本项研究不仅能增强我们对水生生物重要类群对人工干扰的生态响应规律的认识，而且也能为水环境生态评估和保护提供依据。

探索人类活动影响下生物多样性的时空分布和演替规律是生态学研究的重要内容，然而对原生生物类群影响的相关研究尚处于起步阶段。本项目采用高通量测序技术与传统的形态鉴定方法相结合，揭示了“大东湖”生态水网工程实施“六湖连通”后的东湖各子湖区及连通通道内原生生物群落时空格局及演替规律。研究结果表明：（1）“大东湖”生态水网工程实施后浮游原生生物的季节性变化与天然湖泊仍然相似，影响其群落结构的主要因素是水温、pH和亚硝酸盐浓度；（2）不同个体大小（0.22-20μm和20μm以上）的原生生物群落结构存在显著差异，且不同湖区间较小个体的原生生物（0.22-20μm）群落组成差异较大；（3）原生生物多样性仅在部分样点间存在显著差异，主要体现在不同连通区域间，且该差异与样点间的地理距离显著正相关；（4）获得了多种纤毛虫原生动物的活体形态、纤毛图式和标记基因序列，探讨了相关物种的系统演化关系。该研究表明连通工程在一定程度上影响了各湖区原有的原生生物群落，加深了对该类群落受人工干扰的生态响应规律的认识，为水环境生态评估和保护提供了参考依据。