三江平原湿地开垦对土壤微生物群落结构的影响

Effects of Wetland Reclamation on Soil Microbial Community Structure in the Sanjiang Plain

过度开垦会导致湿地生态系统的快速退化,湿地土壤微生物能够敏感地反映湿地土壤质量及湿地生态系统功能的演变.为研究土地利用变化对湿地微生物群落结构的影响,以黑龙江抚远三江湿地保护区为研究对象,采集其中的原始泥炭湿地、开垦后改种豆科植物及水稻的3种湿地土壤.采用基于细菌16S rRNA基因的高通量测序技术研究上述土壤细菌的群落结构,并探讨其与土壤环境因子间的关系.结果表明,不同土地利用方式湿地土壤中的优势菌门均为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)及酸杆菌门(Acidobacteria),但土地利用方式明显改变了湿地土壤细菌属的组成.改种豆科植物土壤中Blastocatella、Coxiella、Rickettsia丰度较高,水稻田土中Massilia、Nitrosomonas、Bradyrhizobium聚集较多,而泥炭湿地中含较高丰度的Rhizomicrobium、Arthrobacter、Bacillus.结合Chao值与Shannon指数,水稻田土微生物多样性高于改种豆科植物土壤及泥炭湿地土壤,而后两种土壤细菌群落多样性则未见明显差异.相关性分析表明,土壤p H及含水率是影响微生物群落组成的重要驱动因子,说明湿地土壤开垦后改变了土壤p H、含水率及土壤养分,从而对微生物群落结构产生影响.

Excessive reclamation leads to rapid degradation of wetland ecosystems.Microbial changes in wetland soils under the influence of human activities can sensitively indicate degradation of soil quality and ecosystem functions.To study the effects of different land use patterns on microbial community structure of wetlands,the Sanjiang Wetland Protected Area of Fuyuan,Heilongjiang Province,was selected as the research area.Soil samples were collected from replanting legume crop area,rice wetland,and primitive peat wetland.Then,the bacterial community structure in the soil was investigated with high-throughput sequencing based on the 16 S rRNA gene.The relationship between bacterial community and environmental factors was further explored.The results indicated that,based on the bacterial phylum,there are no significant differences between the microbial community structures of soils under different land use patterns.Nevertheless,at the genus level,higher abundance of Blastocatella,Coxiella,and Rickettsia were detected in the legume rhizospheric soil.In the paddy soil,the relative abundances of Massilia,Nitrosomonas,and Bradyrhizobium are higher,while in the peatand soil,the higher contents are of Rhizomicrobium,Arthrobacter,and Bacillus.The results of Chao1 and Shannon index indicate that the microbial diversity of the paddy soil was higher than in the legume rhizospheric soil and peatland soils.However,no significant differences on bacterial diversity between the legume rhizospheric soil and peatland soils were observed.The results of the correlation analysis indicate that soil reclamation triggers a shift in microbial community mainly because of its influence on soil p H,moisture,and nutrients.