A comparison study on the sediment flocculation process between a bare tidal flat and a clam aquaculture mudflat: The important role of sediment concentration and biological processes
A comparison study on the sediment flocculation process between a bare tidal flat and a clam aquaculture mudflat: The important role of sediment concentration and biological processes
The flocculation process of cohesive sediment impacts upon estuaries and tidal flats by affecting the sediment dynamics, modifying the biogeochemical exchanges, and playing an essential role in coastal ecosystems and geomorphologic evolution. To understand the roles of biological activity on flocculation processes in aquaculture areas, here we undertook in situ measurements over a bare tidal flat and a nearby clam aquaculture mudflat on the Jiangsu coast, China. Near-bed in situ floc size, the grain size distribution of suspended particles in seawater, suspended sediment concentration (SSC), and currents were obtained for nine consecutive semidiurnal tidal cycles simultaneously at the two sites. Correlation analysis indicated that the flocculation and its break-up process in this study appeared to be controlled by the variations in SSC and bottom shear stress due to combined wave and current. The floc sizes showed less difference between the two sites under calm conditions. However, the near-bed in situ floc size in the aquaculture mudflat was 23% larger than that in the bare tidal flat in the severe erosion events, suggesting modulation of the flocculation process due to the extracellular polymeric substances (EPS) eroded from the seabed sediments at the aquaculture site, as the hydrodynamics were very similar between the two sites. A higher EPS content was observed in the sediment layer below the surface seabed at the aquaculture site. We conclude that abundant filter feeders alter floc properties and enhance flocculation by excretion of exopolymer particles.
Aquaculture, Biological activities, Flocculation, Suspended sediment, Tidal flat, Turbulence
Li, Jiasheng
a8a60f6a-a00a-4289-a2fa-8e3a74cee31b
Chen, Xindi
79f07552-4abc-407b-805e-0a16ee40a98c
Townend, Ian
f72e5186-cae8-41fd-8712-d5746f78328e
Shi, Benwei
855bf191-9749-44a9-80b1-b20be968c61a
Du, Jiabi
13dba676-c089-46cc-9325-d0e8a57f2df7
Gao, Jianhua
5cf171d3-075d-4d7c-80e7-c3ce512cc5d1
Chuai, Xiaowei
89eb4626-9eb1-44ee-85ff-f58c60ae6c1c
Gong, Zheng
8fec227f-4dcc-431e-85c3-13a520574886
Wang, Ya Ping
39ca2e13-2d50-4fef-9258-f0c1a1f7681b
1 April 2021
Li, Jiasheng
a8a60f6a-a00a-4289-a2fa-8e3a74cee31b
Chen, Xindi
79f07552-4abc-407b-805e-0a16ee40a98c
Townend, Ian
f72e5186-cae8-41fd-8712-d5746f78328e
Shi, Benwei
855bf191-9749-44a9-80b1-b20be968c61a
Du, Jiabi
13dba676-c089-46cc-9325-d0e8a57f2df7
Gao, Jianhua
5cf171d3-075d-4d7c-80e7-c3ce512cc5d1
Chuai, Xiaowei
89eb4626-9eb1-44ee-85ff-f58c60ae6c1c
Gong, Zheng
8fec227f-4dcc-431e-85c3-13a520574886
Wang, Ya Ping
39ca2e13-2d50-4fef-9258-f0c1a1f7681b
Li, Jiasheng, Chen, Xindi, Townend, Ian, Shi, Benwei, Du, Jiabi, Gao, Jianhua, Chuai, Xiaowei, Gong, Zheng and Wang, Ya Ping
(2021)
A comparison study on the sediment flocculation process between a bare tidal flat and a clam aquaculture mudflat: The important role of sediment concentration and biological processes.
Marine Geology, 434, [106443].
(doi:10.1016/j.margeo.2021.106443).
Abstract
The flocculation process of cohesive sediment impacts upon estuaries and tidal flats by affecting the sediment dynamics, modifying the biogeochemical exchanges, and playing an essential role in coastal ecosystems and geomorphologic evolution. To understand the roles of biological activity on flocculation processes in aquaculture areas, here we undertook in situ measurements over a bare tidal flat and a nearby clam aquaculture mudflat on the Jiangsu coast, China. Near-bed in situ floc size, the grain size distribution of suspended particles in seawater, suspended sediment concentration (SSC), and currents were obtained for nine consecutive semidiurnal tidal cycles simultaneously at the two sites. Correlation analysis indicated that the flocculation and its break-up process in this study appeared to be controlled by the variations in SSC and bottom shear stress due to combined wave and current. The floc sizes showed less difference between the two sites under calm conditions. However, the near-bed in situ floc size in the aquaculture mudflat was 23% larger than that in the bare tidal flat in the severe erosion events, suggesting modulation of the flocculation process due to the extracellular polymeric substances (EPS) eroded from the seabed sediments at the aquaculture site, as the hydrodynamics were very similar between the two sites. A higher EPS content was observed in the sediment layer below the surface seabed at the aquaculture site. We conclude that abundant filter feeders alter floc properties and enhance flocculation by excretion of exopolymer particles.
Text
LiJS2021MGfinal
- Accepted Manuscript
More information
Published date: 1 April 2021
Keywords:
Aquaculture, Biological activities, Flocculation, Suspended sediment, Tidal flat, Turbulence
Identifiers
Local EPrints ID: 448447
URI: http://eprints.soton.ac.uk/id/eprint/448447
ISSN: 0025-3227
PURE UUID: 701301c3-0fe9-43dd-9282-914420d7b720
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Date deposited: 22 Apr 2021 16:46
Last modified: 17 Mar 2024 06:26
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Contributors
Author:
Jiasheng Li
Author:
Xindi Chen
Author:
Benwei Shi
Author:
Jiabi Du
Author:
Jianhua Gao
Author:
Xiaowei Chuai
Author:
Zheng Gong
Author:
Ya Ping Wang
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