武汉东湖沉积物好氧氨氧化微生物时空分布

Spatiotemporal distribution of aerobic ammonia-oxidizing microorganisms in sediments of Lake Donghu,Wuhan

采用实时荧光定量PCR(qPCR)技术,测定了武汉东湖沉积物中氨氧化古菌(AOA)和氨氧化细菌(AOB)氨单加氧酶基因(amoA)的丰度,并结合沉积物水体环境中各形态氮素的含量,分析氮素含量对AOA和AOB的时空分布的影响.结果显示,AOA amoA基因丰度大于AOB amoA基因丰度,表明AOA对氨氧化过程的贡献较大.同时,AOA和AOB amoA基因丰度都随深度增加而降低.此外,间隙水的总氮、氨氮、硝酸盐氮以及亚硝酸盐氮浓度分别为6.28~33.56、2.71~22.7、0.12~0.98、0.01~0.13mg/L;上覆水的总氮、氨氮、硝酸盐氮以及亚硝酸盐氮平均浓度分别为1.68,0.79,0.16,0.04mg/L;表层水的总氮、氨氮、硝酸盐氮以及亚硝酸盐氮平均浓度分别为1.34,0.62,0.11,0.03mg/L,表明东湖东湖沉积物相对于水体呈营养盐可释放状态.相关性分析表明:AOA amoA基因丰度与间隙水氨氮和亚硝酸盐氮浓度呈显著正相关(P<0.05),AOB amoA基因丰度与间隙水亚硝酸盐氮(NO2--N)浓度呈显著正相关(P<0.05).

The amoA gene abundances of ammonia-oxidizing archaea(AOA-amoA)and bacteria(AOB-amoA)in the sediments of Lake Donghu,Wuhan,was determined by the real-time quantitative polymerase chain reaction(qPCR).Moreover,the influence of nitrogen content on the temporal and spatial distribution of AOA and AOB was analyzed.The results showed that the abundance of AOA-amoA was higher than that of AOB-amoA,indicating greater contribution of AOA-amoA to the ammonia oxidation process.Meanwhile,the abundances of AOA-amoA and AOB-amoA decreased with elevated sediment depth.In addition,the concentrations of total nitrogen(TN),ammonia nitrogen(NH4+-N),nitrate nitrogen(NO3--N)and nitrite nitrogen(NO2--N)in interstitial water were 6.28~33.56,2.71~22.7,0.12~0.98 and 0.01~0.13mg/L,respectively.The average concentrations of TN,NH4+-N,NO3--N and NO2--N in overlying water were 1.68,0.79,0.16 and 0.04mg/L,respectively,while in surface water were 1.34,0.62,0.11 and 0.03mg/L,respectively.These results suggested that the sediments of Lake Donghu were important sources of nutrient.In addition,the abundance of AOA-amoA was positively correlated with the concentrations of NH4+-N and NO2--N in interstitial water(P<0.05),while the abundance of AOB-amoA was positively correlated with the concentration of NO2--N in interstitial water(P<0.05).