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Diversity, abundance, and distribution of NO-forming nitrite reductase–encoding genes in deep-sea subsurface sediments of the South China Sea

Authors

  • M. Li,

    1. Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
    Current affiliation:
    1. Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
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  • Y. Hong,

    1. State Key Laboratory of Tropical Oceanography (LTO), South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China
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  • H. Cao,

    1. Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
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  • M. G. Klotz,

    1. Department of Biology, University of North Carolina at Charlotte, Charlotte, NC, USA
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  • J.-D. Gu

    Corresponding author
    1. The Swire Institute of Marine Science, The University of Hong Kong, Hong Kong SAR, China
    • Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
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Corresponding author: J.-D. Gu. Tel.: +1 852 2299 0605; fax: +1 852 2559 9114; e-mail: jdgu@hkucc.hku.hk

Abstract

In marine ecosystems, both nitrite-reducing bacteria and anaerobic ammonium-oxidizing (anammox) bacteria, containing different types of NO-forming nitrite reductase–encoding genes, contribute to the nitrogen cycle. The objectives of study were to reveal the diversity, abundance, and distribution of NO-forming nitrite reductase–encoding genes in deep-sea subsurface environments. Results showed that higher diversity and abundance of nirS gene than nirK and Scalindua-nirS genes were evident in the sediments of the South China Sea (SCS), indicating bacteria containing nirS gene dominated the NO-forming nitrite-reducing microbial community in this ecosystem. Similar diversity and abundance distribution patterns of both nirS and Scalindua-nirS genes were detected in this study sites, but different from nirK gene. Further statistical analyses also showed both nirS and Scalindua-nirS genes respond similarly to environmental factors, but differed from nirK gene. These results suggest that bacteria containing nirS and Scalindua-nirS genes share similar niche in deep-sea subsurface sediments of the SCS, but differed from those containing nirK gene, indicating that community structures of nitrite-reducing bacteria are segregated by the functional modules (NirS vs. NirK) rather than the competing processes (anammox vs. classical denitrification).

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