The effects of disturbance on the microbial mediation of sediment stability
The effects of disturbance on the microbial mediation of sediment stability
In coastal areas, biofilms are often subject to disturbance by hydrodynamic forcing, bioturbation and human activities. These factors affect the influences biofilms have on the sediment. To reveal these effects, we studied laboratory-incubated and field-collected biotic sediments reworked by disturbances, and examined their stabilities and three-dimensional microstructures using laboratory annular flume tests and a wet-staining X-ray microcomputed tomography method. We find that, when subject to disturbance, biofilms do not always establish mat-like matrices that firmly armor the seabed and bio-stabilize sediments, but instead, have a range of effects on sediment stability, including both bio-stabilization and destabilization. Disturbance considerably alters microbial influences on sediment stability, but is not the only control. Given equal disturbance, whether or not sediments are bio-stabilized largely depends on the state of bio-sediment formation. At a relatively well-developed state, an organic-rich, adhesive polymer network tightly interconnects large amounts of sediment particles into aggregates, forms complex internal structures, and enhances sediment stability. By contrast, some bio-sediment formations only ever reach a less well-developed state, where scattered organic patches bind relatively few particles into aggregates and reduce sediment stability. Microbial growth likely has two opposing effects on sediment stability, by enhancing either weight/friction or lift/drag on aggregated particles. The former has the positive effect of enhancing sediment stability, whereas the latter can result in greater flow resistance and so have the opposite effect. A conceptual framework is put forward to characterize the different states of bio-sediment formation and their distinct effects on sediment stability.
1567-1579
Zhang, Naiyu
9af1e237-8e4a-4008-af76-ee29007aa7fb
Thompson, Charlie
2a304aa6-761e-4d99-b227-cedb67129bfb
Townend, Ian
f72e5186-cae8-41fd-8712-d5746f78328e
July 2023
Zhang, Naiyu
9af1e237-8e4a-4008-af76-ee29007aa7fb
Thompson, Charlie
2a304aa6-761e-4d99-b227-cedb67129bfb
Townend, Ian
f72e5186-cae8-41fd-8712-d5746f78328e
Zhang, Naiyu, Thompson, Charlie and Townend, Ian
(2023)
The effects of disturbance on the microbial mediation of sediment stability.
Limnology and Oceanography, 68 (7), .
(doi:10.1002/lno.12368).
Abstract
In coastal areas, biofilms are often subject to disturbance by hydrodynamic forcing, bioturbation and human activities. These factors affect the influences biofilms have on the sediment. To reveal these effects, we studied laboratory-incubated and field-collected biotic sediments reworked by disturbances, and examined their stabilities and three-dimensional microstructures using laboratory annular flume tests and a wet-staining X-ray microcomputed tomography method. We find that, when subject to disturbance, biofilms do not always establish mat-like matrices that firmly armor the seabed and bio-stabilize sediments, but instead, have a range of effects on sediment stability, including both bio-stabilization and destabilization. Disturbance considerably alters microbial influences on sediment stability, but is not the only control. Given equal disturbance, whether or not sediments are bio-stabilized largely depends on the state of bio-sediment formation. At a relatively well-developed state, an organic-rich, adhesive polymer network tightly interconnects large amounts of sediment particles into aggregates, forms complex internal structures, and enhances sediment stability. By contrast, some bio-sediment formations only ever reach a less well-developed state, where scattered organic patches bind relatively few particles into aggregates and reduce sediment stability. Microbial growth likely has two opposing effects on sediment stability, by enhancing either weight/friction or lift/drag on aggregated particles. The former has the positive effect of enhancing sediment stability, whereas the latter can result in greater flow resistance and so have the opposite effect. A conceptual framework is put forward to characterize the different states of bio-sediment formation and their distinct effects on sediment stability.
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MicrobialMediation2023
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Limnology Oceanography - 2023 - Zhang - The effects of disturbance on the microbial mediation of sediment stability
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Accepted/In Press date: 14 April 2023
e-pub ahead of print date: 22 May 2023
Published date: July 2023
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Funding Information:
This work was partially funded by the National Natural Science Foundation of China (grant no. 42206059), the BLUEcoast project (NE/N 015703/1), and the China Postdoctoral Science Foundation (2021M702472). The authors gratefully acknowledge Dr. Hachem Kassem for his help in flume setup instructions. The authors wish to thank Prof. David Paterson and Dr. Andrew Blight at St Andrews University for hosting field sampling work in Scotland. The authors wish to extend our thanks to Dr. Kathryn Rankin and Dr. Orestis Katsamenis for their assistance in performing the scans carried out at the μ-VIS X-ray Imaging Centre, University of Southampton. The authors also thank the editor and the two anonymous reviewers for their constructive comments, which makes the manuscript significantly improved.
Funding Information:
This work was partially funded by the National Natural Science Foundation of China (grant no. 42206059), the BLUEcoast project (NE/N 015703/1), and the China Postdoctoral Science Foundation (2021M702472). The authors gratefully acknowledge Dr. Hachem Kassem for his help in flume setup instructions. The authors wish to thank Prof. David Paterson and Dr. Andrew Blight at St Andrews University for hosting field sampling work in Scotland. The authors wish to extend our thanks to Dr. Kathryn Rankin and Dr. Orestis Katsamenis for their assistance in performing the scans carried out at the ‐VIS X‐ray Imaging Centre, University of Southampton. The authors also thank the editor and the two anonymous reviewers for their constructive comments, which makes the manuscript significantly improved. μ
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© 2023 Association for the Sciences of Limnology and Oceanography.
Identifiers
Local EPrints ID: 477223
URI: http://eprints.soton.ac.uk/id/eprint/477223
ISSN: 0024-3590
PURE UUID: 212f9c4b-dc4d-43e3-accb-7f0f9481e23b
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Date deposited: 01 Jun 2023 16:50
Last modified: 15 Apr 2024 04:01
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Naiyu Zhang
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