Department of Environmental Engineering, Zhejiang University, Hangzhou, China.
Appl Environ Microbiol. 2013 Jul;79(13):4065-71. doi: 10.1128/AEM.00543-13. Epub 2013 Apr 26.
Ammonia oxidation is performed by both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). However, the current knowledge of the distribution, diversity, and relative abundance of these two microbial groups in freshwater sediments is insufficient. We examined the spatial distribution and analyzed the possible factors leading to the niche segregation of AOA and AOB in the sediments of the Qiantang River, using clone library construction and quantitative PCR for both archaeal and bacterial amoA genes. pH and NH4(+)-N content had a significant effect on AOA abundance and AOA operational taxonomy unit (OTU) numbers. pH and organic carbon content influenced the ratio of AOA/AOB OTU numbers significantly. The influence of these factors showed an obvious spatial trend along the Qiantang River. This result suggested that AOA may contribute more than AOB to the upstream reaches of the Qiantang River, where the pH is lower and the organic carbon and NH4(+)-N contents are higher, but AOB were the principal driver of nitrification downstream, where the opposite environmental conditions were present.
氨氧化由氨氧化古菌（AOA）和氨氧化细菌（AOB）共同完成。然而，目前对于淡水沉积物中这两类微生物的分布、多样性和相对丰度的了解还不够充分。本研究采用克隆文库构建和定量 PCR 方法，对钱塘江沉积物中 AOA 和 AOB 的空间分布进行了研究，并分析了导致它们生态位分离的可能因素。结果表明，pH 和 NH4(+)-N 含量对 AOA 的丰度和 OTU 数量有显著影响，而 pH 和有机碳含量则显著影响 AOA/AOB OTU 数量的比值。这些因素的影响沿钱塘江呈现出明显的空间趋势。这表明，在钱塘江上游地区，由于 pH 值较低，有机碳和 NH4(+)-N 含量较高，AOA 的贡献可能大于 AOB，但在下游地区，由于环境条件相反，AOB 是硝化作用的主要驱动因素。
