橡胶坝对河流沉积物氮转化功能基因丰度和营养盐的影响

Effects of rubber dam on functional gene abundance of nitrogen transformation and nutrient accumulation in sediments in Yi River

沉积物氮转化功能微生物是河流脱氮和水体净化的重要生物因素.为探讨橡胶坝对沉积物氮转化功能基因丰度及氮营养盐的影响,本研究以沂河沂水城区蓄水段为研究对象,从橡胶坝前不同距离采集沉积物,利用实时荧光定量PCR(qPCR)方法研究了沉积物的反硝化功能基因(nirS、nirK、nosZ)、厌氧氨氧化功能基因(AMX)和反硝化型甲烷厌氧氧化功能基因(pmoA)的丰度及沉积物营养盐特征.结果表明:橡胶坝促进了沉积物中nirK、nirS、nosZ和pmo A基因的聚集,反硝化功能基因nirK、nirS、nosZ丰度在坝前120~330 m范围内较高;橡胶坝促进了沉积物NH_(4)^(+)、NO_(3)^(-)、TN、TP、TOC、有机质(OM)等营养盐的滞留,主要在120~360 m区域聚集,多元线性回归模型拟合度较高.相关分析表明,16S rRNA、nirK、nirS、nosZ、pmoA基因丰度与环境因子NH_(4)^(+)、NO_(3)^(-)、TN、OM、TOC、孔隙度呈正相关;PCA分析结果表明,随着沉积物环境因子主成分的增长,氮转化功能基因丰度主成分呈升高趋势.橡胶坝可促进沂河沉积物氮素等营养盐的滞留和氮转化功能微生物的聚集.

Nitrogen transformation functional microbiota play an important role in biodenitrogenation and water purification in river ecosystems.Rubber dams are widely constructed for water storage and landscaping in urban rivers in China.Rubber dammed river would affect nitrogen removal functional microbes and nutrient in sediments.In this study,the surface sediment samples were selected along the Yi river at different distances pre-dam(12sites)in Yishui urban area.The characteristics of the functional genes abundance of denitrification(nirS,nirK,nosZ),anammox(AMX),denitrifying anaerobiac methane oxidation(DAMO)(pmoA),and nutrient in sediment were explored by rea-time fluorescence quantitative PCR(qPCR)technology.Results showed that rubber dam construction enhanced the enrichment of nirK,nirS,nosZ,and pmoA in front of the dam.The results showed that rubber dam enhanced the enrichment of nirK,nirS,nosZ,and pmoA in front of the dam.The denitrification functional genes abundance displayed higher levels and mainly concentrated in the range of 120 m to 330 m.Rubber dam accelerated the enrichment of NH_(4)^(+),NO_(3)^(-),TN,TP,TOC,and organic matter(OM)in sediments distance from 120 m to 360 m in front of the dam,and multivariable linear regression model worked very well.Moreover,the correlation analysis indicated that TN,OM,TOC,porosity,and moisture content had the significantly(p<0.05)positive correlations with the genes abundance of 16S rRNA,nirK,nosZ,and pmoA.There was significant positive correlation among functional genes abundance in sediment,and the same was true for environmental factors.PCA analysis results showed that the abundance of nitrogen transformation functional genes increased with the increase of sediment environmental factors.Therefore,the rubber dam may promote the accumulation of nitrogen transformation microbes and nutrients in sediments in Yi River.