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The resilience of biofilm‐bound sandy systems to cyclic changes in shear stress

The resilience of biofilm‐bound sandy systems to cyclic changes in shear stress
The resilience of biofilm‐bound sandy systems to cyclic changes in shear stress
Sand-attached benthic biofilms drive many important biogeological processes and serve as cooperative “ecosystem engineers”. In aquatic environments, biofilms undergo periodic detachment and re-colonization due to the regular changes in hydrodynamic forcing. However, legacy impacts of past microbial actions on current biofilm formation and the biostabilization of the substratum sands are yet to be fully understood. In this study, a systematic set of flume experiments were conducted to investigate the effects of different depositional histories. Changes in the erosion threshold and rate of erosion were determined from the time sequences of suspended sediment concentrations. The contents of extracellular polymeric substances (EPS) and particle morphology of the biofilm-bound sandy matrix were analyzed. Surprisingly, biostabilization is disturbance-stimulated, rather than disturbance-limited, as previously thought. Bio-sandy beds cultivated under intensive disturbance presented an EPS accumulation in each cycle, and showed a more rapid increase in bed strength and stability than when rarely disturbed. All colonies from previous cycles exhibited traces of EPS as “footprints”. These stimulated and possibly accelerated the process of recolonization, thereby enhancing the erosion resistance of the bed. In contrast, a stabilized bed was better suited to mature microbial communities. A modified “Windows of Opportunity” framework was therefore put forward. Although biostabilization was not established within short quiescent periods, the system created the “opportunity” to become established in subsequent “windows” by seeding the colonization process. The stabilization, destabilization and re-stabilization of biofilm may imply a much more important role as ecosystem engineers and is relevant for a range of engineered bio-systems.
biofilm detachment and re-colonization, biostabilization, repeated disturbance, sediment erosion, system resilience, windows of opportunity
0043-1397
Chen, Xindi
79f07552-4abc-407b-805e-0a16ee40a98c
Zhang, Changkuan
dfdb560e-6606-4ba2-86be-f7068ef48393
Townend, Ian H.
f72e5186-cae8-41fd-8712-d5746f78328e
Gong, Zheng
8fec227f-4dcc-431e-85c3-13a520574886
Feng, Qian
e5bc45a3-f8ed-479f-bd3e-5e10a8bd7bf3
Yu, Xiping
a139885b-74cc-4427-94f5-fe7248d19b55
Chen, Xindi
79f07552-4abc-407b-805e-0a16ee40a98c
Zhang, Changkuan
dfdb560e-6606-4ba2-86be-f7068ef48393
Townend, Ian H.
f72e5186-cae8-41fd-8712-d5746f78328e
Gong, Zheng
8fec227f-4dcc-431e-85c3-13a520574886
Feng, Qian
e5bc45a3-f8ed-479f-bd3e-5e10a8bd7bf3
Yu, Xiping
a139885b-74cc-4427-94f5-fe7248d19b55

Chen, Xindi, Zhang, Changkuan, Townend, Ian H., Gong, Zheng, Feng, Qian and Yu, Xiping (2022) The resilience of biofilm‐bound sandy systems to cyclic changes in shear stress. Water Resources Research, 58 (3), [e2021WR031098]. (doi:10.1029/2021WR031098).

Record type: Article

Abstract

Sand-attached benthic biofilms drive many important biogeological processes and serve as cooperative “ecosystem engineers”. In aquatic environments, biofilms undergo periodic detachment and re-colonization due to the regular changes in hydrodynamic forcing. However, legacy impacts of past microbial actions on current biofilm formation and the biostabilization of the substratum sands are yet to be fully understood. In this study, a systematic set of flume experiments were conducted to investigate the effects of different depositional histories. Changes in the erosion threshold and rate of erosion were determined from the time sequences of suspended sediment concentrations. The contents of extracellular polymeric substances (EPS) and particle morphology of the biofilm-bound sandy matrix were analyzed. Surprisingly, biostabilization is disturbance-stimulated, rather than disturbance-limited, as previously thought. Bio-sandy beds cultivated under intensive disturbance presented an EPS accumulation in each cycle, and showed a more rapid increase in bed strength and stability than when rarely disturbed. All colonies from previous cycles exhibited traces of EPS as “footprints”. These stimulated and possibly accelerated the process of recolonization, thereby enhancing the erosion resistance of the bed. In contrast, a stabilized bed was better suited to mature microbial communities. A modified “Windows of Opportunity” framework was therefore put forward. Although biostabilization was not established within short quiescent periods, the system created the “opportunity” to become established in subsequent “windows” by seeding the colonization process. The stabilization, destabilization and re-stabilization of biofilm may imply a much more important role as ecosystem engineers and is relevant for a range of engineered bio-systems.

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The Resilience of Biofilm-Bound Sandy Systems to Cyclic Changes in Shear Stress - Accepted Manuscript
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Accepted/In Press date: 28 February 2022
Published date: 15 March 2022
Additional Information: Funding Information: Funding for this project was provided by the National Natural Science Foundation of China (41961144014, 52101318), and the China Postdoctoral Science Foundation (2021T140383, 2020M680580). Our thanks go to Jia Xu, Shibai Yu and all our laboratory assistants for their help with the flume setup. Our thanks also go to Dr. Xueer Zhang for designing Figure 7 . The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Publisher Copyright: © 2022. American Geophysical Union. All Rights Reserved.
Keywords: biofilm detachment and re-colonization, biostabilization, repeated disturbance, sediment erosion, system resilience, windows of opportunity

Identifiers

Local EPrints ID: 457471
URI: http://eprints.soton.ac.uk/id/eprint/457471
ISSN: 0043-1397
PURE UUID: fe366f9b-9502-4c68-9765-64204f8ec362
ORCID for Ian H. Townend: ORCID iD orcid.org/0000-0003-2101-3858

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Date deposited: 09 Jun 2022 16:54
Last modified: 10 Jun 2022 01:36

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Contributors

Author: Xindi Chen
Author: Changkuan Zhang
Author: Ian H. Townend ORCID iD
Author: Zheng Gong
Author: Qian Feng
Author: Xiping Yu

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