ORCID
- Bass, Sarah: 0000-0001-7794-4366
Abstract
Sediment fluxes in aquatic environments are crucially dependent on bedform dynamics. However, sediment-flux predictions rely almost completely on clean-sand studies, despite most environments being composed of mixtures of non-cohesive sands, physically cohesive muds and biologically cohesive extracellular polymeric substances (EPS) generated by microorganisms. EPS associated with surficial biofilms are known to stabilize sediment and increase erosion thresholds. Here we present experimental data showing that the pervasive distribution of low levels of EPS throughout the sediment, rather than the high surficial levels of EPS in biofilms, is the key control on bedform dynamics. The development time for bedforms increases by up to two orders of magnitude for extremely small quantities of pervasively distributed EPS. This effect is far stronger than for physical cohesion, because EPS inhibit sand grains from moving independently. The results highlight that present bedform predictors are overly simplistic, and the associated sediment transport processes require re-assessment for the influence of EPS.
DOI
10.1038/ncomms7257
Publication Date
2015-02-06
Publication Title
Nat Commun
Volume
6
Organisational Unit
School of Geography, Earth and Environmental Sciences
Keywords
Biopolymers, Extracellular Space, Geologic Sediments, Motion, Time Factors
Recommended Citation
Malarkey, J., Baas, J., Hope, J., Aspden, R., Parsons, D., Peakall, J., Paterson, D., Schindler, R., Ye, L., Lichtman, I., Bass, S., Davies, A., Manning, A., & Thorne, P. (2015) 'The pervasive role of biological cohesion in bedform development.', Nat Commun, 6. Available at: https://doi.org/10.1038/ncomms7257
