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Research On Abundance,Community Structure And Influencing Factors Of Complete Ammonia Oxidizing (Comammox) Bacteria In Different Habitats

Posted on:2021-05-26Degree:MasterType:Thesis
Country:ChinaCandidate:Y Y JiangFull Text:PDF
GTID:2370330623470959Subject:Ecology
Abstract/Summary:PDF Full Text Request
Nitrification is the only biological process that connects oxidized and reduced inorganic nitrogen pools in nature.Nitrifying microorganisms play a key role in maintaining the global nitrogen balance.The discovery of complete ammonia oxidation?comammox?has given us new insights into nitrification and nitrogen cycling.Completely ammonia-oxidizing bacteria are autotrophic nitrifying microorganisms which provide substrates for denitrification.Therefore,it is important for the environmental nitrogen cycle to investigate comammox process in different habitats.In this study,the abundance and community structure of comammox bacteria of vertical paddy soils?0-1 m?samples from Guangdong and Dongbei,surface soils?0-10 cm?samples from Tibetan Plateau and surface sediment samples which were selected?010 cm?from Chaohu Lake in winter and summer were studied by high-throughput sequencing and Real-time quantitative PCR?qPCR?.The results were as follows:?1?In the paddy soil samples,the absolute abundance of comammox bacteria was1.76×1041.18×107 copies·g-1,the absolute abundance of ammonia-oxidizing archaea?AOA?was 1.26×1041.41×108copies·g-1and the absolute abundance of ammonia oxidizing bacteria?AOB?was 6.63×1051.21×107 copies·g-1.The abundance of comammox bacteria in all samples was significantly lower than AOB.In surface soil samples of Tibetan Plateau,the absolute abundance of comammox was 1.04×1061.46×107copies·g-1,the absolute abundance of AOA was 1.32×1056.92×108 copies·g-11 and the absolute abundance of AOB was 4.82×1051.36×108 copies·g-1.In surface sediments of Chaohu Lake,the absolute abundance of comammox bacteria was 5.20×1064.06×107copies·g-1,the abundance of AOA was 5.39×1051.60×107 copies·g-1,the abundance of AOB was 6.16×1054.30×106 copies·g-1.It was obviously the absolute abundance of comammox was significantly higher than AOA and AOB in surface sediments of Chaohu Lake.?2?The diversity analysis indicated that the species diversity of comammox bacteria in winter was greater than that in summer.The highest relative abundances of Candidatus Nitrospira nitrificans,Candidatus Nitrospira nitrosa and Candidatus Nitrospira inopinata were 78.72%,49.80%and 6.28%,respectively.The relative abundance of Candidatus Nitrospira inopinata was higher in summer than that in winter.The community structure analysis showed that Ca.N.inopinata was the main bacteria in surface soil sample of Guangdong,accounting for 74.82%.Ca.N.nitrificans was the main bacteria in subsurface and deep soil sample and the highest relative abundance was 99.21%.There were no differences in the community composition in Dongbei and the main bacteria were Ca.N.nitrificans and Ca.N.nitrosa.The highest relative abundance of Ca.N.nitrificans in the DB10 and DB9samples were 57.93%and 73.97%,respectively.In surface soil of Tibetan Plateau,the main composition of comammox bacteria is Ca.N.nitrificans and the relative abundance of Ca.N.nitrificans in RWMT samples was 99.87%.?3?The results of Principle Coordinate Analysis?PcoA?showed that the community structure of comammox bacteria had obvious spatial and temporal heterogeneity.?4?Among the physical and chemical factors,NH4+and pH are important factors affecting the abundance of comammox bacteria.?5?Analysis of molecular ecological network showed that Ca.N.nitrificans was most closely connected with other species which was the key genus in the network diagram.
Keywords/Search Tags:comammox, ammonia-oxidizing archaea, ammonia-oxidizing bacteria, high-throughput, diversity
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