Cable bacteria extend the impacts of elevated dissolved oxygen into anoxic sediments

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DOI

  • Feifei Liu, Guangdong Academy of Agricultural Sciences
  • ,
  • Zhenyu Wang, Guangdong Academy of Agricultural Sciences
  • ,
  • Bo Wu, Sun Yat Sen Univ, Sun Yat Sen University, Inst Hypertens, Zhongshan Sch Med
  • ,
  • Jesper T Bjerg
  • Wenzhe Hu, Guangdong Academy of Agricultural Sciences
  • ,
  • Xue Guo, Central South University China
  • ,
  • Jun Guo, Guangdong Academy of Agricultural Sciences
  • ,
  • Lars Peter Nielsen
  • Rongliang Qiu, Sun Yat Sen Univ, Sun Yat Sen University, Inst Hypertens, Zhongshan Sch Med
  • ,
  • Meiying Xu, Guangdong Academy of Agricultural Sciences

Profound biogeochemical responses of anoxic sediments to the fluctuation of dissolved oxygen (DO) concentration in overlaying water are often observed, despite oxygen having a limited permeability in sediments. This contradiction is indicative of previously unrecognized mechanism that bridges the oxic and anoxic sediment layers. Using sediments from an urban river suffering from long-term polycyclic aromatic hydrocarbons (PAHs) contamination, we analyzed the physicochemical and microbial responses to artificially elevated DO (eDO) in the overlying water over 9 weeks of incubation. Significant changes in key environmental parameters and microbial diversity were detected over the 0-6 cm sediment depth, along with accelerated degradation of PAHs, despite that eDO only increased the porewater DO in the millimeter subfacial layer. The dynamics of physicochemical and microbial properties coincided well with significantly increased presence of centimeter-long sulfide-oxidizing cable bacteria filaments under eDO, and were predominantly driven by cable bacteria metabolic activities. Phylogenetic ecological network analyses further revealed that eDO reinforced cable bacteria associated interspecific interactions with functional microorganisms such as sulfate reducers, PAHs degraders, and electroactive microbes, suggesting enhanced microbial syntrophy taking advantage of cable bacteria metabolism for the regeneration of SO42- and long-distance electron transfer. Together, our results suggest cable bacteria may mediate the impacts of eDO in anaerobic sediments by altering sediment physiochemical properties and by reinforcing community interactions. Our findings highlight the ecological importance of cable bacteria in sediments.

OriginalsprogEngelsk
TidsskriftThe ISME Journal
ISSN1751-7362
DOI
StatusE-pub ahead of print - 21 jan. 2021

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