Chang Yongkai, Fan Jingfeng, Su Jie, Ming Hongxia, Zhao Wen, Shi Yan, Ji Fengyun, Guo Limei, Zan Shuaijun, Li Bochao, Guo Hao, Guan Daoming
Key Laboratory for Ecological Environment in Coastal Areas (SOA), National Marine Environmental Monitoring Center, 42 Linghe Street, Dalian, 116023, China.
College of Fisheries and Life Science, Dalian Ocean University, Dalian, 116023, China.
Curr Microbiol. 2017 May;74(5):632-640. doi: 10.1007/s00284-017-1226-x. Epub 2017 Mar 14.
Ammonia-oxidizing bacteria (AOB) play an important role in nitrification in estuaries. The aim of this study was to examine the spatial abundance, diversity, and activity of AOB in coastal sediments of the Liaohe Estuary using quantitative PCR, high-throughput sequencing of the amoA gene coding the ammonia monooxygenase enzyme active subunit, and sediment slurry incubation experiments. AOB abundance ranged from 8.54 × 10 to 5.85 × 10 copies g of wet sediment weight and exhibited an increasing trend from the Liaohe Estuary to the open coastal zone. Potential nitrification rates (PNRs) ranged from 0.1 to 336.8 nmol N g day along the estuary to the coastal zone. Log AOB abundance and PNRs were significantly positively correlated. AOB richness decreased from the estuary to the coastal zone. High-throughput sequencing analysis indicated that the majority of amoA gene sequences fell within the Nitrosomonas and Nitrosomonas-like clade, and only a few sequences were clustered within the Nitrosospira clade. This finding indicates that the Nitrosomonas-related lineage may be more adaptable to the specific conditions in this estuary than the Nitrosospira lineage. Sites with high nitrification rates were located in the southern open region and were dominated by the Nitrosomonas-like lineage, whereas the Nitrosospira lineage was found primarily in the northern estuary mouth sites with low nitrification rates. Thus, nitrification potentials in Liaohe estuarine sediments in the southern open region were greater than those in the northern estuary mouth, and the Nitrosomonas-related lineage might play a more important role than the Nitrosospira lineage in nitrification in this estuary.
氨氧化细菌（AOB）在河口硝化作用中发挥着重要作用。本研究旨在利用定量PCR、编码氨单加氧酶活性亚基的amoA基因的高通量测序以及沉积物泥浆培养实验，研究辽河河口海岸沉积物中AOB的空间丰度、多样性和活性。AOB丰度范围为每克湿沉积物重量8.54×10至5.85×10拷贝，并呈现出从辽河河口到开阔海岸带增加的趋势。沿河口到海岸带，潜在硝化速率（PNR）范围为0.1至336.8 nmol N g天。AOB丰度对数与PNR显著正相关。AOB丰富度从河口到海岸带降低。高通量测序分析表明，大多数amoA基因序列属于亚硝化单胞菌属和亚硝化单胞菌属样分支，只有少数序列聚集在亚硝化螺菌属分支内。这一发现表明，与亚硝化单胞菌相关的谱系可能比亚硝化螺菌谱系更适应该河口的特定条件。硝化速率高的位点位于南部开阔区域，以亚硝化单胞菌属样谱系为主，而亚硝化螺菌谱系主要在北部河口口位点发现，硝化速率较低。因此，辽河河口南部开阔区域沉积物中的硝化潜力大于北部河口口，与亚硝化单胞菌相关的谱系在该河口硝化作用中可能比亚硝化螺菌谱系发挥更重要的作用。
