A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system

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dc.contributor.authorWhitfield, A K
dc.contributor.authorAdams, J B
dc.contributor.authorBate, G C
dc.contributor.authorBezuidenhout, K
dc.contributor.authorBornman, T G
dc.contributor.authorCowley, P D
dc.contributor.authorFroneman, P W
dc.contributor.authorGama, P T
dc.contributor.authorJames, N C
dc.contributor.authorMackenzie, B
dc.contributor.authorRiddin, T
dc.contributor.authorSnow, G C
dc.contributor.authorStrydom, N A
dc.contributor.authorTaljaard, S
dc.contributor.authorTerörde, A I
dc.contributor.authorTheron, A K
dc.contributor.authorTurpi, J K
dc.contributor.authorvan Niekerk, L
dc.contributor.authorVorwerk, P D
dc.contributor.authorWooldridg, T H
dc.date.accessioned2017-06-23T09:53:19Z
dc.date.available2017-06-23T09:53:19Z
dc.date.issued2008
dc.date.updated2016-01-22T09:52:54Z
dc.description.abstractIn 2005/2006 a multidisciplinary research programme that included studies on the hydrodynamics, sediment dynamics, macronutrients, microalgae, macrophytes, zoobenthos, hyperbenthos, zooplankton, ichthyoplankton, fish and birds of the temporarily open/closed East Kleinemonde Estuary was conducted. Particular attention was given to the responses of the different ecosystem components to the opening and closing of the estuary mouth and how this is driven by both riverine and marine events. Using a complementary dataset of daily estuary mouth conditions spanning a 14-year period, five distinct phases of the estuary were identified, including closed (average = 90% of the days), outflow (<1%), tidal (9%) and semi-closed (<1%). The open-mouth phase is critical for the movements of a number of estuary-associated fish (e.g. Rhabdosargus holubi) and invertebrates (e.g. Scylla serrata) between the estuary and sea. The timing of this open phase has a direct influence on the ability of certain estuaryassociated fish (e.g. Lithognathus lithognathus) and invertebrates (e.g. Palaemon peringueyi) to successfully recruit into the system, with a spring opening (October/November) being regarded as optimal for most species. The type of mouth-breaching event and outflow phase is also important in terms of the subsequent salinity regime once the berm barrier forms. A deep mouth breaching following a large river flood tends to result in major tidal inputs of marine water prior to mouth closure and therefore higher salinities (15–25). Conversely, a shallow mouth breaching with reduced tidal exchange during the open phase often leads to a much lower salinity regime at the time of mouth closure (5–15). The biota, especially the submerged macrophytes, respond very differently to the above two scenarios, with Ruppia cirrhosa benefiting from the former and Potamogeton pectinatus from the latter. River flooding and the associated outflow of large volumes of water through the estuary can result in major declines in zooplankton, zoobenthos, hyperbenthos and fish populations during this phase. However, this resetting of the estuary is necessary because certain marine invertebrate and fish species are dependent on the opening of the estuary mouth in order to facilitate recruitment of larvae and post-larvae into the system from the sea. Slight increases in the numbers of certain piscivorous and resident wading bird species were recorded when the estuary mouth opened, possibly linked to increased feeding opportunities during that phase.
dc.identifierhttp://dx.doi.org/10.2989/AJMS.2008.30.3.2.636
dc.identifier.apacitationWhitfield, A. K., Adams, J. B., Bate, G. C., Bezuidenhout, K., Bornman, T. G., Cowley, P. D., ... Wooldridg, T. H. (2008). A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system. <i>African Journal of Marine Science</i>, http://hdl.handle.net/11427/24623en_ZA
dc.identifier.chicagocitationWhitfield, A K, J B Adams, G C Bate, K Bezuidenhout, T G Bornman, P D Cowley, P W Froneman, et al "A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system." <i>African Journal of Marine Science</i> (2008) http://hdl.handle.net/11427/24623en_ZA
dc.identifier.citationWhitfield, A. K., Adams, J. B., Bate, G. C., Bezuidenhout, K., Bornman, T. G., Cowley, P. D., ... & Riddin, T. (2008). A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system. African Journal of Marine Science, 30(3), 453-473.
dc.identifier.ris TY - AU - Whitfield, A K AU - Adams, J B AU - Bate, G C AU - Bezuidenhout, K AU - Bornman, T G AU - Cowley, P D AU - Froneman, P W AU - Gama, P T AU - James, N C AU - Mackenzie, B AU - Riddin, T AU - Snow, G C AU - Strydom, N A AU - Taljaard, S AU - Terörde, A I AU - Theron, A K AU - Turpi, J K AU - van Niekerk, L AU - Vorwerk, P D AU - Wooldridg, T H AB - In 2005/2006 a multidisciplinary research programme that included studies on the hydrodynamics, sediment dynamics, macronutrients, microalgae, macrophytes, zoobenthos, hyperbenthos, zooplankton, ichthyoplankton, fish and birds of the temporarily open/closed East Kleinemonde Estuary was conducted. Particular attention was given to the responses of the different ecosystem components to the opening and closing of the estuary mouth and how this is driven by both riverine and marine events. Using a complementary dataset of daily estuary mouth conditions spanning a 14-year period, five distinct phases of the estuary were identified, including closed (average = 90% of the days), outflow (<1%), tidal (9%) and semi-closed (<1%). The open-mouth phase is critical for the movements of a number of estuary-associated fish (e.g. Rhabdosargus holubi) and invertebrates (e.g. Scylla serrata) between the estuary and sea. The timing of this open phase has a direct influence on the ability of certain estuaryassociated fish (e.g. Lithognathus lithognathus) and invertebrates (e.g. Palaemon peringueyi) to successfully recruit into the system, with a spring opening (October/November) being regarded as optimal for most species. The type of mouth-breaching event and outflow phase is also important in terms of the subsequent salinity regime once the berm barrier forms. A deep mouth breaching following a large river flood tends to result in major tidal inputs of marine water prior to mouth closure and therefore higher salinities (15–25). Conversely, a shallow mouth breaching with reduced tidal exchange during the open phase often leads to a much lower salinity regime at the time of mouth closure (5–15). The biota, especially the submerged macrophytes, respond very differently to the above two scenarios, with Ruppia cirrhosa benefiting from the former and Potamogeton pectinatus from the latter. River flooding and the associated outflow of large volumes of water through the estuary can result in major declines in zooplankton, zoobenthos, hyperbenthos and fish populations during this phase. However, this resetting of the estuary is necessary because certain marine invertebrate and fish species are dependent on the opening of the estuary mouth in order to facilitate recruitment of larvae and post-larvae into the system from the sea. Slight increases in the numbers of certain piscivorous and resident wading bird species were recorded when the estuary mouth opened, possibly linked to increased feeding opportunities during that phase. DA - 2008 DB - OpenUCT DP - University of Cape Town J1 - African Journal of Marine Science LK - https://open.uct.ac.za PB - University of Cape Town PY - 2008 T1 - A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system TI - A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system UR - http://hdl.handle.net/11427/24623 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/24623
dc.identifier.vancouvercitationWhitfield AK, Adams JB, Bate GC, Bezuidenhout K, Bornman TG, Cowley PD, et al. A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system. African Journal of Marine Science. 2008; http://hdl.handle.net/11427/24623.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Biological Sciencesen_ZA
dc.publisher.facultyFaculty of Scienceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.sourceAfrican Journal of Marine Science
dc.source.urihttp://www.tandfonline.com/loi/tams20
dc.subject.otherEast Kleinemonde Estuary
dc.subject.otherestuarine biota
dc.subject.othermouth state
dc.subject.otherphysical conditions
dc.subject.otherriver flow
dc.subject.othersalinity regime
dc.titleA multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system
dc.typeJournal Article
uct.type.filetypeText
uct.type.filetypeImage
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