DOI: 10.1038/ngeo1891
论文题名: Erosion of biofilm-bound fluvial sediments
作者: Vignaga E. ; Sloan D.M. ; Luo X. ; Haynes H. ; Phoenix V.R. ; Sloan W.T.
刊名: Nature Geoscience
ISSN: 17520894
出版年: 2013
卷: 6, 期: 9 起始页码: 770
结束页码: 774
语种: 英语
Scopus关键词: alluvial deposit
; bacterium
; biofilm
; elastic modulus
; entrainment
; incompressible flow
; laboratory method
; membrane
; numerical model
; polysaccharide
; river flow
; river system
; shear flow
; Cyanobacteria
英文摘要: The movement of fluvial sediment shapes our rivers. Understanding sediment entrainment has been a goal of hydraulic engineers for almost a century. Previous sediment entrainment models have been informed by laboratory experiments using grains that were free from biological material. In natural river settings, however, sediments are invariably covered by bacteria, often forming visible biofilms, which comprise diverse consortia of species housed in sticky extracellular polysaccharides. Here we report experiments in a laboratory flume with cyanobacteria grown over sediment. We show that the prevailing model, where grains roll over one another at some critical threshold in shear velocity, does not hold for biofilm-bound sediments. Instead, biostabilized sediment behaves more like an elastic membrane. Fluid flow produces oscillations in the membrane, which can become unstable. Beyond a particular threshold in velocity, the membrane fails catastrophically by ripping and clumps of biofilm-bound sediment become entrained. We use a mathematical model of an oscillating membrane in incompressible flow to show that unstable oscillations will occur over a wide range of elastic material properties at realistic river flow velocities. We find that the horizontal length scale over which oscillations occur is a controlling factor for incipient sediment entrainment of biostabilized sediments. © 2013 Macmillan Publishers Limited. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/106706
Appears in Collections: 气候减缓与适应 科学计划与规划
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作者单位: School of Engineering, University of Glasgow, G12 8QQ, United Kingdom; Department of Mathematics, University of Strathclyde, G1 1XQ, United Kingdom; School of Mathematics and Statistics, University of Glasgow, G12 8QQ, United Kingdom; School of the Built Environment, HeriotWatt University, EH14 1AS, United Kingdom; School of Geography and Earth Sciences, University of Glasgow, G12 8QQ, United Kingdom
Recommended Citation:
Vignaga E.,Sloan D.M.,Luo X.,et al. Erosion of biofilm-bound fluvial sediments[J]. Nature Geoscience,2013-01-01,6(9)