Responses of Active Ammonia Oxidizers to Eutrophication and Oxygen Statuses in Taihu Freshwater Sediments

Wu, Lianghuan; Han, Cheng; Qin, Hongyi; Zhu, Guangwei; Zhong, Wang

doi:10.1080/01490451.2018.1479806

Cited by 4 publications

(2 citation statements)

References 62 publications

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“…Temperature affected the ammonia-oxidizing activity through its effect on community composition, as observed by Urakawa et al (43). We found that AOB in the contrasting eutrophic sediments were exclusively dominated by the Nitrosomonas cluster following SIP culture at different nitrogen inputs and temperatures, as reported in previous studies (11,33) but in contrast to the findings of Dai et al (21), possibly due to differences in sampling season. Our study illustrated that the compositions of communities of active AOB within the Nitrosomonas cluster changed with N input and temperature; in most sediments, they were mainly associated with the Nitrosomonadaceae-like lineage, which represents a monophyletic phylogenetic group within the betaproteobacteria, all of whose cultivated representa-tives are lithoautotrophic ammonia oxidizers (44).…”

Section: Discussionsupporting

confidence: 79%

“…Differences in cell size, activity, and physiology of archaea and bacteria drive differences in their nitrification activities and, although AOA tend to be more abundant than AOB in soils and marine ecosystems (2,(5)(6)(7)(8), AOB growth correlates with nitrification activity, while archaea do not respond to increased levels of nitrogen fertilizer (9,10). Moreover, the concentration of ammonium is a key driver of population dynamics and community composition for ammonia oxidizers in sediments and soils (11)(12)(13)(14); the activity of AOB is always enhanced in soils with high concentrations of ammonium (9,10), AOB growth (measured as dynamic activity) increases in sediments or biofilms with high concentrations of ammonium (15,16), and Nitrosomonas AOB are found in ammonium-rich coastal sediments (17). In contrast, AOA occur where ammonium concentrations are low (Յ10 M), such as in marine ecosystems and in oligotrophic or slightly eutrophic lakes (2,5), while Nitrosopumilus maritimus AOA show high rates of ammonia oxidization in low-ammonia environments (14).…”

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confidence: 99%

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Responses of Active Ammonia Oxidizers and Nitrification Activity in Eutrophic Lake Sediments to Nitrogen and Temperature

Han

Zhu

et al. 2019

Appl Environ Microbiol

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Ammonium concentrations and temperature drive the activities of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB), but their effects on these microbes in eutrophic freshwater sediments are unclear. In this study, surface sediments collected from areas of Taihu Lake (China) with different degrees of eutrophication were incubated under three levels of nitrogen input and temperature, and the autotrophic growth of ammonia oxidizers was assessed using 13C-labeled DNA-based stable-isotope probing (SIP), while communities were characterized using MiSeq sequencing and phylogenetic analysis of 16S rRNA genes. Nitrification rates in sediment microcosms were positively correlated with nitrogen inputs, but there was no marked association with temperature. Incubation of SIP microcosms indicated that AOA and AOB amoA genes were labeled by 13C at 20°C and 30°C in the slightly eutrophic sediment, and AOB amoA genes were labeled to a much greater extent than AOA amoA genes in the moderately eutrophic sediment after 56 days. Phylogenetic analysis of 13C-labeled 16S rRNA genes revealed that the active AOA were mainly affiliated with the Nitrosopumilus cluster, with the Nitrososphaera cluster dominating in the slightly eutrophic sediment at 30°C with low ammonium input (1 mM). Active AOB communities were more sensitive to nitrogen input and temperature than were AOA communities, and they were exclusively dominated by the Nitrosomonas cluster, which tended to be associated with Nitrosomonadaceae-like lineages. Nitrosomonas sp. strain Is79A3 tended to dominate the moderately eutrophic sediment at 10°C with greater ammonium input (2.86 mM). The relative abundance responses of the major active communities to nitrogen input and temperature gradients varied, indicating niche differentiation and differences in the physiological metabolism of ammonia oxidizers that are yet to be described. IMPORTANCE Both archaea and bacteria contribute to ammonia oxidation, which plays a central role in the global cycling of nitrogen and is important for reducing eutrophication in freshwater environments. The abundance and activities of ammonia-oxidizing archaea and bacteria in eutrophic limnic sediments vary with different ammonium concentrations or with seasonal shifts, and how the two factors affect nitrification activity, microbial roles, and active groups in different eutrophic sediments is unclear. The significance of our research is in identifying the archaeal and bacterial responses to anthropogenic activity and climate change, which will greatly enhance our understanding of the physiological metabolic differences of ammonia oxidizers.

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