Agricultural impact on the pelagic ecosystem of the small temporarily open/closed Seteni Estuary, South Africa
N. K. Carrasco A C , R. Perissinotto A and A. Whitehead A B
+ Author Affiliations
- Author Affiliations
A School of Life Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban, 4000, South Africa.
B Sustainable Development Projects cc., PO Box 1016, Ballito, 4420, South Africa.
C Corresponding author. Email: nicola.carrasco@gmail.com
Marine and Freshwater Research 64(10) 938-950 https://doi.org/10.1071/MF12310
Submitted: 29 October 2012 Accepted: 11 April 2013 Published: 23 July 2013
Abstract
The encroachment of agriculture and human population is placing increasing levels of stress on estuarine ecosystems worldwide. The catchment of the Seteni Estuary, a small temporarily open/closed estuary in South Africa, has been under extensive sugar cultivation for over 60 years. The present study reports on the impact of agricultural practices on the structure and dynamics of its pelagic communities over a 1-year period, from April 2008 to March 2009. The physico-chemical characteristics of the system were strongly linked to seasonality, with the system exhibiting a distinct open- and closed-mouth phase in response to rainfall. Concentrations of dissolved inorganic nitrogen (DIN) were exceptionally high in comparison to concentrations of dissolved inorganic phosphorus (DIP), resulting in high DIN : DIP ratios. Despite this, microalgal biomass remained relatively low, exhibiting maximum values of 91.7 mg chl a m–2 and 18.0 mg chl a m–3 for microphytobenthos and phytoplankton, respectively. Zooplankton abundance and biomass were significantly higher during the dry phase, with Pseudodiaptomus hessei dominating the zooplankton community both in terms of abundance and biomass throughout the study period. The ichthyofaunal community was dominated by Ambassis ambassis and Myxus capensis in terms of abundance and biomass, respectively. Results suggest that the system remains functional, but there is potential for deterioration, should the catchment become more nutrient-rich through poor management or land-use changes.
Additional keywords: estuarine ecology, fish, microalgae, nutrients, pesticides, seasonality, zooplankton.
References
Adams, J. B., and Bate, G. (1999). Primary producers: estuarine microalgae. In ‘Estuaries of South Africa’. (Eds BR Allanson and D Baird.) pp. 91–100. (Cambridge University Press, Cambridge, United Kingdom)Ansotegui, A., Trigueros, J. M., and Orive, E. (2001). The use of pigment signatures to assess phytoplankton assemblage structure in estuarine waters. Estuarine, Coastal and Shelf Science 52, 689–703.
| The use of pigment signatures to assess phytoplankton assemblage structure in estuarine waters.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXltlGhsbk%3D&md5=d5a3b765675e194ecfad8e95fccb4d58CAS |
Begg, G. W. (1978). ‘The estuaries of Natal. Natal Town and Regional Planning Report 41’. (Blackhouse, Pietermaritzburg, South Africa.)
Begg, G. W. (1984a). ‘The comparative ecology of Natal's smaller estuaries. Natal Town and Regional Planning Report 62’. (Natal Town and Regional Planning Commission, Pietermaritzburg, South Africa)
Begg, G. W. (1984b). ‘The estuaries of Natal, part 2. Natal Town and Regional Planning Report 55’. (Pietermatitzburg, South Africa)
Bonilla, S., Conde, D., Aubriot, L., and del Carmen Pérez, M. (2005). Influence of hydrology on phytoplankton species composition and life strategies in a subtropical coastal lagoon periodically connected with the Atlantic Ocean. Estuaries 28, 884–895.
| Influence of hydrology on phytoplankton species composition and life strategies in a subtropical coastal lagoon periodically connected with the Atlantic Ocean.Crossref | GoogleScholarGoogle Scholar |
Boyd, R., Dalrymple, R., and Zaitlin, B. A. (1992). Classification of clastic coastal depositional environments. Sedimentary Geology 80, 139–150.
| Classification of clastic coastal depositional environments.Crossref | GoogleScholarGoogle Scholar |
Bundy, S. C. (2004). The influence of anthropogenic impacts from development and human activity in and around foredune plant communities along a portion of the KwaZulu–Natal Coastline. Msc Thesis, University of KwaZulu-Natal, South Africa.
Burns, N. M., Rutherford, J. C., and Clayton, J. S. (1999). A monitoring and classification system for New Zealand lakes and reservoirs. Lake and Reservoir Management 15, 255–271.
| A monitoring and classification system for New Zealand lakes and reservoirs.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3cXhvFOns7k%3D&md5=01d37deb076383e61b8ebbdef4cf16e6CAS |
Burns, N. M., Bryers, G., and Bowman, E. (2000). ‘Protocols for Monitoring Trophic Levels of New Zealand Lakes and Reservoirs.’ (NZ Ministry for the Environment: Wellington, NZ.) Available at http://www.mfe.govt.nz/publications/water [Accessed March 2013].
Carrasco, N. K., Perissinotto, R., and Pillay, D. (2010). Zooplankton of the St Lucia Estuary during the current drought cycle: a comparison between open- and closed-mouth conditions. Marine Ecology Progress Series 399, 157–171.
| Zooplankton of the St Lucia Estuary during the current drought cycle: a comparison between open- and closed-mouth conditions.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXpvFOmu7g%3D&md5=9c6d4ae57dbff0b59a13dcfeda9f65eaCAS |
Conley, D. J., Paerl, H. W., Horwarth, R. W., Boesch, D. F., Seitzinger, S. P., Havens, K. E., Lancelot, C., and Likens, G. E. (2009). Controlling eutrophication: nitrogen and phosphorus. Science 323, 1014–1015.
| Controlling eutrophication: nitrogen and phosphorus.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD1MXisVCjtrc%3D&md5=a4c159439d64f965b0ae644b2cd49727CAS | 19229022PubMed |
Cooper, J. A. G. (2001). Geomorphological variability among microtidal estuaries from the wave-dominated South African coast. Geomorphology 40, 99–122.
| Geomorphological variability among microtidal estuaries from the wave-dominated South African coast.Crossref | GoogleScholarGoogle Scholar |
Cooper, J. A. G., Harrison, T. D., Ramm, A. E. L., and Singh, R. A. (1993). Refinement, enhancement and application of the Estuarine Health Index to Natal’s estuaries, Tugela–Mtamvuna. Technical report, Department of Environment Affairs, Pretoria, South Africa.
DeLorenzo, M. E., Scott, G. I., and Ross, P. E. (1999). Effects of the agricultural pesticides atrazine, deethylatrazine, endosulfan, and chlorpyrifos on an estuarine microbial food web. Environmental Toxicology and Chemistry 18, 2824–2835.
| Effects of the agricultural pesticides atrazine, deethylatrazine, endosulfan, and chlorpyrifos on an estuarine microbial food web.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1MXns1Gltrw%3D&md5=8260ef448c125672ec52156dc1d496cbCAS |
DeLorenzo, M. E., Scott, G. I., and Ross, P. E. (2001). Toxicity of pesticides to aquatic microorganisms: a review. Environmental Toxicology and Chemistry 20, 84–98.
| Toxicity of pesticides to aquatic microorganisms: a review.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXitlOq&md5=443eaee2782b5ee1a46e9ca230ec635cCAS | 11351418PubMed |
Downing, H. F., DeLorenzo, M. E., Fulton, M. H., Scott, G. I., Madden, C. J., and Kucklick, J. R. (2004). Effects of the agricultural pesticides atrazine, chlorothalonil, and endosulfan on South Florida microbial assemblages. Ecotoxicology 13, 245–260.
| Effects of the agricultural pesticides atrazine, chlorothalonil, and endosulfan on South Florida microbial assemblages.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2cXjtVShurg%3D&md5=c523db2a0c4a4e5edce7c0fadd1f7f6dCAS | 15217248PubMed |
Fisher, T. R., Peele, E. R., Ammerman, J. W., and Harding, L. W. (1992). Nutrient limitation of phytoplankton in Chesapeake Bay. Marine Ecology Progress Series 82, 51–63.
| Nutrient limitation of phytoplankton in Chesapeake Bay.Crossref | GoogleScholarGoogle Scholar |
Fong, P., Donohoe, R. M., and Zedler, J. B. (1993). Competition with macroalgae and benthic cyanobacterial mats limits phytoplankton abundance in experimental microcosms. Marine Ecology Progress Series 100, 97–102.
| Competition with macroalgae and benthic cyanobacterial mats limits phytoplankton abundance in experimental microcosms.Crossref | GoogleScholarGoogle Scholar |
Gobler, C. J., Cullison, L. A., Koch, F., Harder, T. M., and Krause, J. W. (2005). Influence of freshwater flow, ocean exchange, and seasonal cycles on phytoplankton and nutrient dynamics in a temporarily open estuary. Estuarine, Coastal and Shelf Science 65, 275–288.
| Influence of freshwater flow, ocean exchange, and seasonal cycles on phytoplankton and nutrient dynamics in a temporarily open estuary.Crossref | GoogleScholarGoogle Scholar |
Gordon, D. M., and McComb, A. J. (1989). Growth and production of the green-alga Cladophora montagneana in a eutropohic Australian estuary and its interpretation using a computer program. Water Research 23, 633–645.
| Growth and production of the green-alga Cladophora montagneana in a eutropohic Australian estuary and its interpretation using a computer program.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaL1MXlsF2kt7w%3D&md5=fbadeae41f8441096d79a29a41ed26d4CAS |
Haese, R. R., and Pronk, G. J. (2011). Intra-annual variability in primary producer groups and nitrogen dynamics in an intermittently closed estuary exposed to Mediterranean climate. Estuaries and Coasts 34, 557–568.
| Intra-annual variability in primary producer groups and nitrogen dynamics in an intermittently closed estuary exposed to Mediterranean climate.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3MXjvVOjtrw%3D&md5=9f1fc8eaeffe25fcbcd9d85dbb668cc1CAS |
Harrison, T. D., Cooper, J. A. G., and Ram, A. E. L. (2000). ‘Geomorphology, Ichthyofauna, Water Quality and Aesthetics of South African Estuaries.’ (Department of Environmental Affairs and Tourism: Pretoria, South Africa.)
Jezewski, W. A., Pyke, P. D., and Roberts, C. P. R. (1984). Estuarine and lake freshwater requirements. Technical report no. TR123. Department of Water Affairs and Forestry.
Kibirige, I., and Perissinotto, R. (2003). The zooplankton community of the Mpenjati Estuary, a South African temporarily open/closed system. Estuarine, Coastal and Shelf Science 58, 727–741.
| The zooplankton community of the Mpenjati Estuary, a South African temporarily open/closed system.Crossref | GoogleScholarGoogle Scholar |
Kibirige, I., Perissinotto, R., and Thwala, X. (2006). A comparative study of zooplankton dynamics in two subtropical temporarily open/closed estuaries, South Africa. Marine Biology 148, 1307–1324.
| A comparative study of zooplankton dynamics in two subtropical temporarily open/closed estuaries, South Africa.Crossref | GoogleScholarGoogle Scholar |
Lee, V., and Olsen, S. (1985). Eutrophication and management initiatives for the control of nutrient inputs to Rhode Island coastal lagoons. Estuaries 8, 191–202.
| Eutrophication and management initiatives for the control of nutrient inputs to Rhode Island coastal lagoons.Crossref | GoogleScholarGoogle Scholar |
Lill, A. W. T., Closs, G. P., Schallenberg, M., and Savage, C. (2012). Impact of berm breaching on hyperbenthic macroinvertebrate communities in intermittently closed estuaries. Estuaries and Coasts 35, 155–168.
| Impact of berm breaching on hyperbenthic macroinvertebrate communities in intermittently closed estuaries.Crossref | GoogleScholarGoogle Scholar |
Lotze, H. K., Lenihan, H. S., Bourque, B. J., Bradbury, R. H., Cooke, R. G., Kay, M. C., Kidwell, S. M., Kirby, M. X., Peterson, C. H., and Jackson, J. B. C. (2006). Depletion, degradation, and recovery potential of estuaries and coastal seas. Science 312, 1806–1809.
| Depletion, degradation, and recovery potential of estuaries and coastal seas.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XmtVSnt7Y%3D&md5=439b345db416a2468853f7e3b09f8be4CAS |
Morant, P., and Quinn, N. (1999). Influences of man and management of South African estuaries. In ‘Estuaries of South Africa’. (Eds BR Allanson and D Baird.) pp. 289–320. (Cambridge University Press, Cambridge, United Kingdom.)
Mundree, S., Perissinotto, R., and Nozais, C. (2003). Seasonal variations in the vertical distribution of benthic microalgae in the upper sediment of the Mdloti Estuary, South Africa. Botanica Marina 46, 323–331.
| Seasonal variations in the vertical distribution of benthic microalgae in the upper sediment of the Mdloti Estuary, South Africa.Crossref | GoogleScholarGoogle Scholar |
Nozais, C., Perissinotto, R., and Mundree, S. (2001). Annual cycle of microalgal biomass in a South African temporarily-open estuary: nutrient versus light limitation. Marine Ecology Progress Series 223, 39–48.
| Annual cycle of microalgal biomass in a South African temporarily-open estuary: nutrient versus light limitation.Crossref | GoogleScholarGoogle Scholar |
Paerl, H. W., Rossignol, K. L., Hall, S. N., Peierls, B. L., and Wetz, M. S. (2010). Phytoplankton community indicators of short- and long-term ecological change in the anthropogenically and climatically impacted Neuse River Estuary, North Carolina, USA. Estuaries and Coasts 33, 485–497.
| Phytoplankton community indicators of short- and long-term ecological change in the anthropogenically and climatically impacted Neuse River Estuary, North Carolina, USA.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXivFKiurg%3D&md5=29f4991f7723fb7821e587ceefe2d2d7CAS |
Perissinotto, R., Nozais, C., and Kibirge, I. (2002). Spatio-temporal dynamics of phytoplankton and microphytobenthos in a South African temporarily open estuary. Estuarine, Coastal and Shelf Science 55, 47–58.
| Spatio-temporal dynamics of phytoplankton and microphytobenthos in a South African temporarily open estuary.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XmsFWmsb4%3D&md5=67956cf537b41dd815d666bb2236b032CAS |
Perissinotto, R., and Wooldridge, T. (1989). Short term thermal effects of a power generating plant on zooplankton of the Swartkops Estuary, South Africa. Marine Ecology 10, 205–219.
| Short term thermal effects of a power generating plant on zooplankton of the Swartkops Estuary, South Africa.Crossref | GoogleScholarGoogle Scholar |
Perissinotto, R., Nozais, C., Kibirige, I., and Anandraj, A. (2003). Planktonic food webs and benthic–pelagic coupling in three South African temporarily-open estuaries. Acta Oecologia 24, S307–S316.
| Planktonic food webs and benthic–pelagic coupling in three South African temporarily-open estuaries.Crossref | GoogleScholarGoogle Scholar |
Perissinotto, R., Iyer, K., and Nozais, C. (2006). Response of microphytobenthos to flow and trophic variation in two South African temporarily open/closed estuaries. Botanica Marina 49, 10–22.
| Response of microphytobenthos to flow and trophic variation in two South African temporarily open/closed estuaries.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28Xis1yhu7w%3D&md5=178c0771e1ab119732178f69b80ca997CAS |
Perissinotto, R., Stretch, D., Whitfield, A. K., Adams, J. B., Forbes, A. T., and Demetriades, N. T. (2010). ‘Temporarily Open/Closed Estuaries in South Africa.’ (Nova Science Publishers: New York.)
Pinckney, J. L., Ornolfsdottir, E. B., and Lumsden, S. E. (2002). Estuarine phytoplankton group-specific responses to sublethal concentrations of the agricultural herbicide, atrazine. Marine Pollution Bulletin 44, 1109–1116.
| Estuarine phytoplankton group-specific responses to sublethal concentrations of the agricultural herbicide, atrazine.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38XosVSmu7w%3D&md5=905f2e1f20821a848609e1eb49a477f2CAS | 12474972PubMed |
Ranasinghe, R., and Pattiaratchi, C. (2003). The seasonal closure of tidal inlets: causes and effects. Coastal Engineering Journal 45, 601–627.
| The seasonal closure of tidal inlets: causes and effects.Crossref | GoogleScholarGoogle Scholar |
Roy, P. S., Williams, R. J., Jones, A. R., Yassini, I., Gibbs, P. J., Coates, B., West, R. J., Scanes, P. R., Hudson, J. P., and Nichol, S. (2001). Structure and function of south-east Australian estuaries. Estuarine, Coastal and Shelf Science 53, 351–384.
| Structure and function of south-east Australian estuaries.Crossref | GoogleScholarGoogle Scholar |
Santangelo, J. M., Roche, A. D. M., Bozelli, R. L., Carneiro, L. S., and Esteves, F. D. A. (2007). Zooplankton responses to sandbar opening in a tropical eutrophic coastal lagoon. Estuarine, Coastal and Shelf Science 71, 657–668.
| Zooplankton responses to sandbar opening in a tropical eutrophic coastal lagoon.Crossref | GoogleScholarGoogle Scholar |
Schallenberg, M., Larned, S. T., Hayward, S., and Arbuckle, C. (2010). Contrasting effects of managed opening regimes on water quality in two intermittently closed and open coastal lakes. Estuarine, Coastal and Shelf Science 86, 587–597.
| Contrasting effects of managed opening regimes on water quality in two intermittently closed and open coastal lakes.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC3cXhsVSru7Y%3D&md5=67da31c6d45befc1b3fe4d15c26744a7CAS |
Sebastiá, M. T., Rodilla, M., Sanchis, J. A., Altur, V., Gadea, I., and Falco, S. (2012). Influence of nutrient inputs from a wetland dominated by agriculture on the phytoplankton community in a shallow harbour at the Spanish Mediterranean coast. Agriculture, Ecosystems & Environment 152, 10–20.
| Influence of nutrient inputs from a wetland dominated by agriculture on the phytoplankton community in a shallow harbour at the Spanish Mediterranean coast.Crossref | GoogleScholarGoogle Scholar |
Snyman, K. (2007). Natural resources and agricultural land capability of a portion of Addington Farm – Tinley Manor (Farm No. 1385, Kwadukuza). Unpublished report to Ushukhela Milling (Pty) Ltd, Keith Snyman and Associates.(Pietermaritzburg, South Africa.)
South African Sugar Association (2010). ‘Farming Calendar.’ Available at http://www.sugar.org.za [Accessed April 2013].
Southwick, L. M., Grigg, B. C., Kornecki, T. S., and Fouss, J. L. (2002). Potential influence of sugarcane cultivation on estuarine water quality of Louisiana’s Gulf coast. Journal of Agricultural and Food Chemistry 50, 4393–4399.
| Potential influence of sugarcane cultivation on estuarine water quality of Louisiana’s Gulf coast.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xks12rsLY%3D&md5=15c0772677064162257a247d119e48a3CAS | 12105976PubMed |
Terörde, A. I., and Turpie, J. K. (2012). Use of a small, intermittently-open estuary by waterbirds: a case study of the East Kleinemonde Estuary, Eastern Cape, South Africa. African Journal of Aquatic Science 37, 183–190.
| Use of a small, intermittently-open estuary by waterbirds: a case study of the East Kleinemonde Estuary, Eastern Cape, South Africa.Crossref | GoogleScholarGoogle Scholar |
Thomas, C. M., Perissinotto, R., and Kibirige, I. (2005). Phytoplankton biomass and size structure in two South African eutrophic, temporarily open/closed estuaries. Estuarine, Coastal and Shelf Science 65, 223–238.
| Phytoplankton biomass and size structure in two South African eutrophic, temporarily open/closed estuaries.Crossref | GoogleScholarGoogle Scholar |
Turpie, J. K., Adams, J. B., Joubert, A., Harrison, T. D., Colloty, B. M., Maree, R. C., Whitfield, A. K., Wooldridge, T. H., Lamberth, S. J., Taljaard, S., and Van Niekerk, L. (2002). Assessment of the conservation priority status of South African estuaries for use in management and water allocation. Water SA 28, 191–206.
| Assessment of the conservation priority status of South African estuaries for use in management and water allocation.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD38Xkt12ru74%3D&md5=b8e3004584ac9f22a3a046f81e7ffc87CAS |
Twomey, L., and Thompson, P. (2001). Nutrient limitation of phytoplankton in a seasonally open bar-built estuary: Wilson Inlet, Western Australia. Journal of Phycology 37, 16–29.
| Nutrient limitation of phytoplankton in a seasonally open bar-built estuary: Wilson Inlet, Western Australia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD3MXitF2nsrc%3D&md5=635ab93d4b00fe3e19167beace0b8c78CAS |
Villena, M. J., and Romo, S. (2003). Phytoplankton changes in a shallow Mediterranean lake (Albufera of Valencia, Spain) after sewage diversion. Hydrobiologia 506–509, 281–287.
| Phytoplankton changes in a shallow Mediterranean lake (Albufera of Valencia, Spain) after sewage diversion.Crossref | GoogleScholarGoogle Scholar |
Vitousek, P. M., Mooney, H. A., Lubchenco, J., and Melillo, J. M. (1997). Human domination of Earth’s ecosystems . Science 277, 494–499.
| 1:CAS:528:DyaK2sXkvVektLs%3D&md5=deb81a2984e06ade9c293d4d703394f2CAS |
Vorwerk, P. D., Whitfield, A. K., Cowley, P. D., and Paterson, A. W. (2003). The influence of selected environmental variables on fish assemblage structure in a range of southeast African estuaries. Environmental Biology of Fishes 66, 237–247.
Watt, D. A. (1998). Estuaries of contrasting trophic status in Kwazulu–Natal, South Africa. Estuarine, Coastal and Shelf Science 47, 209–216.
| Estuaries of contrasting trophic status in Kwazulu–Natal, South Africa.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DyaK1cXlslCitrw%3D&md5=b5ab71b70b2b36f0cc37ac8f73b5e49aCAS |
Wedderburn, S. D., Hammer, M. P., and Bice, C. M. (2012). Shifts in small-bodied fish assemblages resulting from drought-induced water level recession in terminating lakes of the Murray–Darling Basin, Australia. Hydrobiologia 691, 35–46.
| Shifts in small-bodied fish assemblages resulting from drought-induced water level recession in terminating lakes of the Murray–Darling Basin, Australia.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC38XnvFOmsLo%3D&md5=dcd3b29d98493e789990ae7a84918207CAS |
Whitfield, A. K. (1992). A characterisation of southern African estuarine systems. Southern African Journal of Aquatic Sciences 18, 89–103.
| A characterisation of southern African estuarine systems.Crossref | GoogleScholarGoogle Scholar |
