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Quantifying biostabilisation effects of biofilm-secreted and extracted extracellular polymeric substances (EPSs) on sandy substrate

Van De Lageweg, Wietse I.; McLelland, Stuart J.; Parsons, Daniel R.

Authors

Wietse I. Van De Lageweg

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Dr Stuart McLelland S.J.McLelland@hull.ac.uk
Deputy Director of the Energy and Environment Institute

Daniel R. Parsons



Abstract

© Author(s) 2018. Microbial assemblages ( < q > biofilms < /q > ) preferentially develop at water-sediment interfaces and are known to have a considerable influence on sediment stability and erodibility. There is potential for significant impacts on sediment transport and morphodynamics, and hence on the longer-term evolution of coastal and fluvial environments. However, the biostabilisation effects remain poorly understood and quantified due to the inherent complexity of biofilms and the large spatial and temporal (i.e. seasonality) variations involved. Here, we use controlled laboratory tests to systematically quantify the effects of natural biofilm colonisation as well as extracted extracellular polymeric substances (EPSs) on sediment stability. Extracted EPSs may be useful to simulate biofilm-mediated biostabilisation and potentially provide a method of speeding up timescales of physical modelling experiments investigating biostabilisation effects. We find a mean biostabilisation effect due to natural biofilm colonisation and development of almost 4 times that of the uncolonised sand. The presented cumulative probability distribution of measured critical threshold for erosion of colonised sand reflects the large spatial and temporal variations generally seen in natural biostabilised environments. For identical sand, engineered sediment stability from the addition of extracted EPSs compares well across the measured range of the critical threshold for erosion and behaves in a linear and predictable fashion. Yet, the effectiveness of extracted EPSs to stabilise sediment is sensitive to the preparation procedure, time after application and environmental conditions such as salinity, pH and temperature. These findings are expected to improve biophysical experimental models in fluvial and coastal environments and provide much-needed quantification of biostabilisation to improve predictions of sediment dynamics in aquatic ecosystems.

Citation

Van De Lageweg, W. I., McLelland, S. J., & Parsons, D. R. (2018). Quantifying biostabilisation effects of biofilm-secreted and extracted extracellular polymeric substances (EPSs) on sandy substrate. Earth surface dynamics ESURF ; an interactive open access journal of the European Geosciences Union, 6(1), 203-215. https://doi.org/10.5194/esurf-6-203-2018

Journal Article Type Article
Acceptance Date Feb 18, 2018
Online Publication Date Mar 16, 2018
Publication Date Mar 16, 2018
Deposit Date Aug 26, 2018
Publicly Available Date Aug 28, 2018
Journal Earth Surface Dynamics
Print ISSN 2196-632X
Electronic ISSN 2196-632X
Publisher European Geosciences Union
Peer Reviewed Peer Reviewed
Volume 6
Issue 1
Pages 203-215
DOI https://doi.org/10.5194/esurf-6-203-2018
Keywords Earth-Surface Processes; Geophysics
Public URL https://hull-repository.worktribe.com/output/755332
Publisher URL https://www.earth-surf-dynam.net/6/203/2018/

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