多营养层级淡水生态系统构建对微生物的影响

The effect of multi-trophic freshwater ecosystem construction on microorganisms

微生物是淡水生态系统的重要组成部分,其群落组成与水环境密切相关。在室内设置5个试验组,种植常绿型沉水植物苦草(Vallisneria natans)同时引入铜锈环棱螺(Bellamya aeruginosa)、三角帆蚌(Hyriopsis cumingii)和鲫(Carassius auratus)来模拟生态系统中的生物种群结构。通过构建多营养层级淡水生态系统,探究了不同水生生物对细菌群落结构的影响。结果表明,构建的几种淡水生态系统中优势细菌类群为变形菌门(Proteobacteria)、放线菌门(Actinobacteriota)、拟杆菌门(Bacteroidota)和蓝细菌门(Cyanobacteria),螺、蚌、鱼的存在极大地减少了水体中蓝细菌门的数量,能够有效控制蓝细菌过度繁殖。细菌多样性指数(Shannon指数)在草、草-螺-蚌组中较高,而在草-螺、草-螺-蚌-鱼组中较低。冗余分析(RDA)表明,各系统间微生物群落丰度存在明显的差异,不同水生生物的引入和溶解氧含量是影响微生物群落变化的直接因素,而营养盐浓度的变化主要依赖于水生生物与微生物的共同作用,是影响微生物群落变化的间接因素。综上,多营养层级生态系统的构建不仅可以改善水质,也可以提高水体中细菌的多样性,改变水体中细菌的群落结构,使之向更加健康、稳定的方向发展。

Microorganism is an important part of freshwater ecosystem and its community composition is closely related to water environment.Five experimental groups were set up in the laboratory to simulate the population structure of the ecosystem by planting the evergreen submersible plant Vallisnerianatansand introducing the Bellamyaaeruginosa,Hyriopsiscumingii and Carassiusauratus.In this paper,the effects of different aquatic organisms on bacterial community structure were explored by constructing a multi-trophic freshwater ecosystem.The results showed that the dominant bacteria groups in the freshwater ecosystem were Proteobacteria,Actinobacteriota,Bacteroidota and Cyanobacteria.The existence of snails,mussels and fish greatly reduced the number of Cyanobacteria in the water,which could effectively control the overreproduction of Cyanobacteria.The bacterial Shannon index was higher in Vallisnerianatans and Vallisnerianatans-Bellamyaaeruginosa-Hyriopsiscumingii,but lower in Vallisnerianatans-Bellamyaaeruginosa and Vallisnerianatans-Bellamyaaeruginosa-Hyriopsiscumingii-Carassiusauratus.RDA results showed that there were significant differences in the abundance of microbial communities among different systems.The introduction of different aquatic organisms and the content of DO are the direct factors affecting the change of microbial community,and the change of nutrient concentration is mainly dependent on the interaction between aquatic organisms and microorganisms,which is an indirect factor affecting the change of microbial community.In conclusion,the construction of multi-trophic ecosystem can not only improve the water quality,but also increase the diversity of bacteria in the water,change the community structure of bacteria in the water,and make it more healthy and stable.