白洋淀流域岸边带土壤全程氨氧化菌的分布特征及其生态网络研究  

Distribution characteristics and ecological network analysis of complete ammonia oxidizers and other nitrifiers in the riparian zone of Baiyangdian Basin

作　　者：余杰 李祎飞 王衫允 祝贵兵 YU Jie;LI Yifei;WANG Shanyun;ZHU Guibing(School of Environmental and Civil Engineering,Jiangnan University,Wuxi 214122;Key Laboratory of Drinking Water Science and Technology,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085)

机构地区：[1]江南大学环境与土木工程学院,无锡214122 [2]中国科学院饮用水科学与技术重点实验室,北京100085

出　　处：《环境科学学报》2023年第4期359-367,共9页Acta Scientiae Circumstantiae

基　　金：国家自然科学基金(No.42177063,91851204,42107418);中国科学院青年创新促进会项目。

摘　　要：氨氧化途径一直被认为是硝化过程的限速步骤.新型氨氧化微生物—全程氨氧化菌(Complete Ammonia O_(x)idizer,Comammox)的出现更新了人们的认识.虽然全程氨氧化过程已被发现于多种自然生态系统,但其在水位波动环境,尤其是工程引水的岸边带系统,尚缺乏报道.采用宏基因测序技术及氮循环基因特异性分析,研究南水北调典型受水区Comammox的时空特征和潜在生态网络关系.结果表明,在白洋淀流域尺度,入淀河流岸边带系统中,Comammox相对丰度具有明显的时空分布特征.时间尺度上,Comammox相对丰度在枯水期(1455 TPM)显著高于丰水期(1115 TPM);空间尺度上,Comammox在上游山区丰度最高(1403 TPM),显著高于中游(山区/平原生态过渡区;515 TPM)和下游平原区(653 TPM).Spearman相关性分析结果表明,MC对Comammox相对丰度具有显著影响(p<0.05).与其他好氧氨氧化微生物相比,Comammox相对丰度显著高于氨氧化细菌(Ammonia-oxidizing Bacteria,AOB),却低于氨氧化古菌(Ammonia-oxidizing Archaea,AOA).其中,AOB与Comammox时空分布规律相似,而AOA与Comammox仅在时间上分布规律一致.通过构建分子生态网络分析,发现在中游山区/平原过渡区,好氧氨氧化微生物具有最高模块化水平,其中,Comammox是关键物种,Nitrospira nitrificans是关键群落连接者.本研究结果将为我们认识生态补水背景下河流氨氧化过程时空演替和功能趋势提供理论依据.Aerobic ammonia oxidation pathway is generally considered to be the first and rate-limiting step in the two-step nitrification process.The discovery of complete ammonia oxidizer(comammox),a novel ammonia oxidizing microorganism,has fundamentally upended our traditional perception.Although comammox process has been found in a variety of natural ecosystems,it has limited report in water-level-fluctuation zone,especially in riparian zone influenced by water-diversion projects.In this study,we investigated the spatio-temporal distribution and potential ecological relationships of comammox and other ammonia oxidizers in the riparian zone of Baiyangdian basin,a typical water received region of the South-North Water Diversion Project(SNWDP),by using metagenomics and ecological network analyses.Temporal-scale results showed that the relative abundances of comammox was significantly higher in the low-water-level period(1455 TPM)than those in the high-water-level period(1115 TPM).On the spatial scale,comammox abundance was highest in the upper reaches(mountain area;1403 TPM)and significantly higher than in the middle(mountain/plain transition area;515 TPM)and lower reaches(plain area;653 TPM).Correlation analysis showed that soil moisture content(MC)was significantly positive influence on comammox abundance(p<0.05).Compared with other aerobic ammonia oxidizers,comammox abundance was significantly higher than ammonia-oxidizing bacteria(AOB),but less than ammonia-oxidizing archaea(AOA).The spatio-temporal distribution characteristics of AOB were similar to comammox,while AOA were only similar on temporal scale.Furthermore,ecological network analysis showed comammox was the key community with comammox Nitrospira nitrificans as the key species affecting the complex community of aerobic ammonia oxidizers.This study provides us a new understanding of the spatio-temporal succession and function of riverine nitrification processes under the background of ecological recharge.

关 键 词：全程氨氧化 好氧氨氧化 氨单加氧酶功能基因 白洋淀流域 生态补水 分子生态网络 

分 类 号：X171[环境科学与工程—环境科学] X172