湿地水质与水系浮游细菌多样性关联研究

城市湿地水质受人类活动影响,其水系浮游细菌群落多样性也因水质状况不同而变化.以杭州西溪湿地国家公园为研究区,分析人类活动特征差异对河道水质及浮游细菌群落多样性的影响,测定溶解氧、氨氮、硝氮、总氮、总磷等主要理化指标,运用聚合酶链式反应与变性梯度凝胶电泳(PCR-DGGE)技术,分析各水样中浮游细菌群落多样性,通过主成分分析与典型对应分析等统计手段,比较各项理化指标与细菌群落结构的相关性.研究结果表明:湿地河道水质受人类活动影响显著,呈中度~重度富营养化;河道水域内细菌群落总体多样性较高,且多样性指数与硝态氮、总氮、TSI指数、电导率呈极显著负相关(r<-0.7,p<0 .01),与水温呈极显著正相关(r>0.8,p<0.01),相较于硝态氮、总氮等单项指标，综合营养状态指数与细菌多样性指数间具有最高负相关性(r=-0.90,p<0.01).浮游细菌群落结构变化受多种理化指标共同影响,其中限制性营养元素氨氮为主要调控因子.

Correlation analysis of water quality and the diversity of planktonic bacterial community in the wetland

The escalation of agricultural and industrial development,as well as the continuous growth of population,have caused a substantial impact to the environment,particularly in urban wetland.About 50% of the wetlands in the world have been lost and existing wetlands continue to be endangered due to human activities.Water quality of urban wetland is affected by human activities,and the diversity of planktonic bacterial communities in the affected water is governed by water quality.In this case study of Hangzhou Xixi Wetland national park in China,bacterial indicators coupled with physical and chemical parameters were used as multi-metric index for measuring wetland health conditions.Meanwhile,the relationship between environmental factors and the abundance of planktonic community was investigated.Nine water samples were collected to test water quality indicators including dissolved oxygen,ammonia nitrogen,nitrate nitrogen,total nitrogen,and total phosphorus.Polymerase chain reaction-based denaturing gradient gel electrophoresis analysis（PCR-DGGE）of 16 SrDNA genes was used to document changes in the phylogenetic diversity of bacterial communities.Statistical analysis methods including principal component analysis（PCA）and canonical corresponding analysis（CCA）were applied to analyze the correlation between environmental factors and the diversity of planktonic bacterial community.Results showed that the water quality of Xixi Wetland varied from hypertrophic（TSI（∑）：53.0）to eutrophic status（TSI（∑）：76.6）corresponding to various intensities of human activities.Total nitrogen（（1.01±0.14）~（4.10±0.06）mg·L-1）mainly existing in the form of nitrate nitrogen was proved to be the major pollution factor,and ammonia nitrogen（（0.11±0.01）-（0.68±0.00）mg·L-1）acted as the limited nutrients indicator.Planktonic bacterial community in Xixi Wetland watershowed a certain degree of richness,which was significantly influenced by the water quality.Compared with individual indicators