Lu Shimin, Liu Xingguo, Ma Zhuojun, Liu Qigen, Wu Zongfan, Zeng Xianlei, Shi Xu, Gu Zhaojun
Fishery Machinery and Instrument Research Institute, Chinese Academy of Fishery SciencesShanghai, China; College of Fisheries and Life, Shanghai Ocean UniversityShanghai, China.
Fishery Machinery and Instrument Research Institute, Chinese Academy of Fishery Sciences Shanghai, China.
Front Microbiol. 2016 Jan 20;6:1539. doi: 10.3389/fmicb.2015.01539. eCollection 2015.
Pond aquaculture is the major freshwater aquaculture method in China. Ammonia-oxidizing communities inhabiting pond sediments play an important role in controlling culture water quality. However, the distribution and activities of ammonia-oxidizing microbial communities along sediment profiles are poorly understood in this specific environment. Vertical variations in the abundance, transcription, potential ammonia oxidizing rate, and community composition of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in sediment samples (0-50 cm depth) collected from a freshwater aquaculture pond were investigated. The concentrations of the AOA amoA gene were higher than those of the AOB by an order of magnitude, which suggested that AOA, as opposed to AOB, were the numerically predominant ammonia-oxidizing organisms in the surface sediment. This could be attributed to the fact that AOA are more resistant to low levels of dissolved oxygen. However, the concentrations of the AOB amoA mRNA were higher than those of the AOA by 2.5- to 39.9-fold in surface sediments (0-10 cm depth), which suggests that the oxidation of ammonia was mainly performed by AOB in the surface sediments, and by AOA in the deeper sediments, where only AOA could be detected. Clone libraries of AOA and AOB amoA sequences indicated that the diversity of AOA and AOB decreased with increasing depth. The AOB community consisted of two groups: the Nitrosospira and Nitrosomonas clusters, and Nitrosomonas were predominant in the freshwater pond sediment. All AOA amoA gene sequences in the 0-2 cm deep sediment were grouped into the Nitrososphaera cluster, while other AOA sequences in deeper sediments (10-15 and 20-25 cm depths) were grouped into the Nitrosopumilus cluster.
池塘养殖是中国主要的淡水养殖方式。栖息于池塘沉积物中的氨氧化群落对控制养殖水质起着重要作用。然而，在这种特定环境中，沿沉积物剖面的氨氧化微生物群落的分布和活性仍知之甚少。本研究调查了从一个淡水养殖池塘采集的沉积物样本（深度0 - 50厘米）中氨氧化细菌（AOB）和氨氧化古菌（AOA）在丰度、转录水平、潜在氨氧化速率及群落组成方面的垂直变化。AOA氨单加氧酶基因（amoA）的浓度比AOB的高一个数量级，这表明与AOB相比，AOA是表层沉积物中数量上占优势的氨氧化生物。这可能是由于AOA对低溶解氧水平更具抗性。然而，在表层沉积物（深度0 - 10厘米）中，AOB氨单加氧酶信使核糖核酸（amoA mRNA）的浓度比AOA的高2.5至39.9倍，这表明表层沉积物中的氨氧化主要由AOB进行，而在仅能检测到AOA的较深层沉积物中则由AOA进行。AOA和AOB氨单加氧酶基因序列的克隆文库表明，AOA和AOB的多样性随深度增加而降低。AOB群落由两组组成：亚硝化螺菌属和亚硝化单胞菌属菌群，且亚硝化单胞菌属在淡水池塘沉积物中占主导。0 - 2厘米深沉积物中的所有AOA氨单加氧酶基因序列都归入亚硝化球形菌属菌群，而较深层沉积物（深度10 - 15厘米和20 - 25厘米）中的其他AOA序列则归入亚硝化侏儒菌属菌群。
