AUTHOR=Teng Zhenzhen , Zhen Yu , Yu Zhigang , Mi Tiezhu , Cai Tao 

TITLE=Nitrogen-loss and associated microbial communities in sediments from the Yangtze Estuary and adjacent sea

JOURNAL=Frontiers in Marine Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2022.1078653

DOI=10.3389/fmars.2022.1078653

ISSN=2296-7745

ABSTRACT=<sec><title>Introduction</title><p>Denitrification and anammox play the crucial role for N removal processes in coastal ecosystems, but the ecological distribution of denitrifying and anammox microorganisms and their N removal rates in the Yangtze Estuary and its adjacent sea are required in-depth analysis.</p></sec><sec><title>Methods</title><p>Here, we utilized high-throughput sequencing, qPCR, and <sup>15</sup>N isotope to reveal the community structure and function of denitrifying and anammox microorganisms in the surface sediments from Yangtze Estuary and adjacent sea.</p></sec><sec><title>Results</title><p>The results suggested that the gene abundances of <italic>nir</italic>S and <italic>nir</italic>K for denitrifiers were higher than AMX 16S rRNA for anammox bacteria. The genera composition of <italic>nir</italic>S- and <italic>nir</italic>K-encoding denitrifiers communities showed different distribution patterns. Furthermore, <italic>Candidatus</italic> Anammoximicrobium dominated the anammox community, implying the anammox oxidation capacity of the other genera should be noted in marine sediments.</p></sec><sec><title>Discussion</title><p>Compared to anammox, denitrification was the dominant contributor of nitrogen removal process and contributed 73.5% on average. The sediment Chl<italic>a</italic> was the key factor to regulate denitrification and anammox rates, indicating the fresh organic matter was more labile and easier to be utilized by NO<sub>x</sub><sup>−</sup> removal processes.</p></sec>