Tidally driven pore water exchange within offshore intertidal sandbanks: Part II numerical simulations

Gibbes, B., Robinson, C., Li, L., Lockington, David A. and Li, H. (2008) Tidally driven pore water exchange within offshore intertidal sandbanks: Part II numerical simulations. ESTUARINE COASTAL AND SHELF SCIENCE, 80 4: 472-482. doi:10.1016/j.ecss.2008.08.021


Author Gibbes, B.
Robinson, C.
Li, L.
Lockington, David A.
Li, H.
Title Tidally driven pore water exchange within offshore intertidal sandbanks: Part II numerical simulations
Journal name ESTUARINE COASTAL AND SHELF SCIENCE   Check publisher's open access policy
ISSN 0272-7714
Publication date 2008-01-01
Year available 2008
Sub-type Article (original research)
DOI 10.1016/j.ecss.2008.08.021
Open Access Status
Volume 80
Issue 4
Start page 472
End page 482
Total pages 11
Editor D S McClusky, D.S. ,
E. Wolanski, E.
Valiela, I.
Place of publication United Kingdom
Publisher Academic Press
Language eng
Subject C1
960902 Coastal and Estuarine Land Management
0905 Civil Engineering
Abstract Field measurements presented by [Gibbes, B., Robinson, C., Li, L, Lockington, D.A., Carey, H., 2008. Tidally driven pore water exchange within offshore intertidal sandbanks: Part I Field measurements. Estuarine, Coastal and Shelf Science 79, pp. 121-132.] revealed a tidally driven pore water flow system within an offshore intertidal sandbank in Moreton Bay, Australia. The field data suggested that this flow system might be capable of delivering nutrients, and in particular bio-available iron, across the sediment-water interface. Bio-available iron has been implicated as a key nutrient in the growth of the toxic marine cyanobacteria Lyngbya majuscula and therefore this pore water exchange process is of interest at sites where L majuscula blooms have been observed. In this study two-dimensional numerical simulations were used in conjunction with hydraulic data from field measurements to further investigate the tidally induced pore water flow patterns. Simulation results generally showed good agreement with the field data and revealed a more complex residual pore water flow system in the sandbank than shown by the field data. The flow system, strongly influenced by the geometry of the sandbank, was characterized by two circulation cells which resulted in pore water discharge at the bank edge and also to a permanently ponded area within the sandbank interior. Simulated discharge volumes in these two zones were in the order of 0.813 m(3) and 0.143 m(3) per meter width (along shore) of sandbank per tidal cycle at the bank edge and sandbank interior respectively. Transit times of pore water circulating through these cells were found to range from approximate to 17 days to > 60 years with an average time of 780 days. The results suggest that the tidally driven flow systems might provide a mechanism for transport of bio-available iron across the sediment-water interface. This flow could constitute a previously unrecognized source of bio-available iron for L. majuscula blooms in the Bay. (C) 2008 Elsevier Ltd. All rights reserved.
Keyword Marine & Freshwater Biology
Oceanography
Marine & Freshwater Biology
Oceanography
MARINE & FRESHWATER BIOLOGY
OCEANOGRAPHY
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP0772660
50425926
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Civil Engineering Publications
 
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Created: Fri, 27 Mar 2009, 20:48:14 EST by Katherine Montagu on behalf of School of Civil Engineering