摘要
以黄河上游干旱半干旱区典型河流清水河为研究对象,结合宏基因组技术揭示土地利用方式对流域水体碳氮循环微生物影响.结果发现,林地用地对水体污染较小,其中 NH4+-N、NO3--N、TN、COD 平均浓度分别为 0.19、1.35、1.66、21.92mg/L,城乡用地造成水体 NH4+-N(4.23mg/L)、COD(48.8mg/L)浓度增加,农田用地导致水体NO3-N(21.62mg/L)、TN(31.59mg/L)浓度增加.硝化基因amoAB、nxrAB与碳循环基因sucCD、IDH13、mdh、porAB、gap2在林区河段的相对丰度较高;而反硝化基因napAB、nirKS、nosZ在城乡区河段、农田区河段相对丰度较高.林区河段、城乡区河段碳氮功能优势微生物种类(＞20种)高于农田区河段(15种).微生物网络关系表明,城乡区河段和农田区河段相关性边数小于35,林区河段大于35,林区河段微生物网络结构更加复杂.城乡区河段,Paracoccus、Sphingomonas菌属与NH4+-N呈显著负相关,Thalassiosira菌属与NO3--N呈显著正相关;农田区河段,Leptothrix、Methylocystis 与 NH4+-N、COD 呈显著负相关,Acidovorax、Flavobacterium、Hydrogenophaga 与 NO3--N 呈显著负相关.
Abstract
In this study,the Qingshui River,a typical river in arid and semi-arid areas of the upper reaches of the Yellow River,was investigated.The metagenomic technology was used to reveal the impact of land use on carbon and nitrogen cycling microorganisms in the water bodies.The findings revealed the water quality was less polluted in forest reaches,the average concentrations of NH4+-N,NO3--N,TN,and COD were 0.19,1.35,1.66,and 21.92mg/L,respectively.Conversely,the NH4+-N(4.23mg/L)and COD(48.8mg/L)concentration elevated in the water body in urban and rural reaches,while NO3--N(21.62mg/L)and TN(31.59mg/L)contents increased in agricultural reaches.The relative abundance of the nitrification genes amoAB,nxrAB and the carbon cycling genes sucCD,IDH13,mdh,porAB,and gap2 was higher in forested reaches,while the relative abundance of the denitrification genes napAB,nirKS,and nosZ was higher in urban and rural area reaches,and in agricultural area reaches.The dominant microbial species of carbon and nitrogen functional were higher in forested reaches and urban and rural reaches with 20 species than in agricultural reaches with 15species.The microbial network showed that the number of correlation edges was less than 35 in urban and rural reaches and agricultural reaches,and more than 35 in forested reaches,thus the microbial network structures were notably more complex in forested reaches.In urban and rural reaches,Paracoccus and Sphingomonas were significantly negatively correlated with NH4+-N concentration,while Thalassiosira were significantly positively correlated with NO3--N concentration.In agricultural reaches,Leptothrix and Methylocystis were significantly negatively correlated with NH4+-N and COD contents;while Acidovorax,Flavobacterium,and Hydrogenophaga were significantly negatively correlated with NO3--N concentration.
维普
万方数据