Stabilizing effects of bacterial biofilms: EPS penetration and redistribution of bed stability down the sediment profile

X. D. Chen, C. K. Zhang, Z. Zhou, Z. Gong, J. J. Zhou, J. F. Tao, D. M. Paterson, Q. Feng

Research output: Contribution to journalArticlepeer-review

47 Citations (Scopus)
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Abstract

Biofilms, consisting of microorganisms and their secreted extracellular polymeric substances (EPS), serve as “ecosystem engineers” stabilizing sedimentary environments. Natural sediment bed provides an excellent substratum for biofilm growth. The porous structure and rich nutrients allow the EPS matrix to spread deeper into the bed. A series of laboratory-controlled experiments were conducted to investigate sediment colonization of Bacillus subtilis and the penetration of EPS into the sediment bed with incubation time. In addition to EPS accumulation on the bed surface, EPS also penetrated downwards. However, EPS distribution developed strong vertical heterogeneity with a much higher content in the surface layer than in the bottom layer. Scanning Electron Microscope (SEM) images of vertical layers also displayed different micro-morphological properties of sediment-EPS matrix. In addition, colloidal and bound EPS exhibited distinctive distribution patterns. After the full incubation, the bio-sedimentary beds were eroded to test the variation of bed stability induced by biological effects. This research provides an important reference for the prediction of sediment transport, and hence deepens the understanding of the biologically mediated sediment system and broadens the scope of the burgeoning research field of “biomorphodynamics”.
Original languageEnglish
Pages (from-to)3113-3125
Number of pages12
JournalJournal of Geophysical Research - Biogeosciences
Volume122
Issue number12
Early online date4 Dec 2017
DOIs
Publication statusPublished - 12 Jan 2018

Keywords

  • EPS vertical distribution
  • Bio-sedimentary system
  • Bed stability
  • Biostabilization

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