title: Diversity, abundance, and spatial distribution of ammonia-oxidizing β-proteobacteria in sediments from Changjiang Estuary and its adjacent area in East China Sea.
abstract: Changjiang Estuary, the largest estuary in China, encompasses a wide range of nutrient loading and trophic levels from the rivers to the sea, providing an ideal natural environment to explore relationships between functional diversity, physical/chemical complexity, and ecosystem function. In this study, molecular biological techniques were used to analyze the community structure and diversity of ammonia-oxidizing bacteria (AOB) in the sediments of Changjiang Estuary and its adjacent waters in East China Sea. The amoA gene (encoding ammonia monooxygenase subunit A) libraries analysis revealed extensive diversity within the β-Proteobacteria group of AOB, which were grouped into Nitrosospira-like and Nitrosomonas-like lineages. The majority of amoA gene sequences fell within Nitrosospira-like clade, and only a few sequences were clustered with the Nitrosomonas-like clade, indicating that Nitrosospira-like lineage may be more adaptable than Nitrosomonas-like lineage in this area. Multivariate statistical analysis indicated that the spatial distribution of the sedimentary β-Proteobacterial amoA genotype assemblages correlated significantly with nitrate, nitrite, and salinity. The vertical profile of amoA gene copies in gravity cores showed that intense sediment resuspension led to a deeper mixing layer. The horizontal distribution pattern of amoA gene copies was nearly correlated with the clayey mud belt in Changjiang Estuary and its adjacent area in East China Sea, where higher β-Proteobacteria phylogenetic diversity was observed. Meanwhile, those areas with high amoA copies in the surface sediments nearly matched those with low concentrations of dissolved oxygen and ammonium in the bottom water.
authors.affiliation: College of Environmental Science and Engineering, Ocean University of China, 238 Songling Road, Qingdao, 266100, People's Republic of China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Chen
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhen
authors.forename: Hui
authors.initials: H
authors.lastname: He
authors.forename: Xinglan
authors.initials: X
authors.lastname: Lu
authors.forename: Tiezhu
authors.initials: T
authors.lastname: Mi
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Yu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D020562:Betaproteobacteria / Q000145:classification / Q000201:enzymology / Q000235:genetics / Q000502:physiology*; D044822:Biodiversity; D002681:China; D063366:Estuaries; D019015:Geologic Sediments / Q000382:microbiology*; D008969:Molecular Sequence Data; D009792:Oceans and Seas; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D010088:Oxidoreductases; C045582:ammonia monooxygenase