Major role of ammonia-oxidizing bacteria in N 2 O production in the Pearl River estuary
Biogeosciences(2019)
摘要
Abstract. Nitrous oxide ( N2O ) has significant global warming
potential as a greenhouse gas. Estuarine and coastal regimes are the major
zones of N2O production in the marine system. However, knowledge on
biological sources of N2O in estuarine ecosystems remains controversial but is of great importance for understanding global N2O emission
patterns. Here, we measured concentrations and isotopic compositions of
N2O as well as distributions of ammonia-oxidizing bacterial and
archaeal amoA and denitrifier nirS genes by quantitative polymerase chain reaction
along a salinity gradient in the Pearl River estuary, and we performed in situ
incubation experiments to estimate N2O yields. Our results indicated
that nitrification predominantly occurred, with significant N2O
production during ammonia oxidation. In the hypoxic waters of the upper
estuary, strong nitrification resulted in the observed maximum N2O and
Δ N2O excess concentrations, although minor denitrification
might be concurrent at the site with the lowest dissolved oxygen.
Ammonia-oxidizing β -proteobacteria (AOB) were significantly
positively correlated with all N2O -related parameters, although their amoA
gene abundances were distinctly lower than ammonia-oxidizing archaea (AOA)
throughout the estuary. Furthermore, the N2O production rate and the
N2O yield normalized to amoA gene copies or transcripts estimated a higher
relative contribution of AOB to the N2O production in the upper
estuary. Taken together, the in situ incubation experiments, N2O
isotopic composition and concentrations, and gene datasets suggested that
the high concentration of N2O (oversaturated) is mainly produced from
strong nitrification by the relatively high abundance of AOB in the upper
reaches and is the major source of N2O emitted to the atmosphere in the Pearl River estuary.
更多查看译文
AI 理解论文
溯源树
样例
![](https://originalfileserver.aminer.cn/sys/aminer/pubs/mrt_preview.jpeg)
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要