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dc.contributor.advisorMalherbe, W.
dc.contributor.advisorTaylor, J.
dc.contributor.authorKock, Anrich
dc.date.accessioned2017-08-29T12:06:29Z
dc.date.available2017-08-29T12:06:29Z
dc.date.issued2017
dc.identifier.urihttp://hdl.handle.net/10394/25444
dc.descriptionMSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2017en_US
dc.description.abstractAll forms of life are dependent on water for survival. South Africa is a water scare country, due to seasonal rainfall and high temperatures, thus it is important to manage water resources in such a way that it benefits the needs of humans and maintains the integrity of aquatic ecosystems. Agriculture activities, industrial activities and poor sanitation are some of the threats to water resources. Biomonitoring is one of several methods used to evaluate changes within aquatic ecosystems and makes use of the organisms found within the ecosystem to monitor the ecological integrity of that ecosystem — terrestrial or aquatic. As the aquatic organisms are continuously exposed to the environmental conditions within the ecosystem they are constantly exposed to the effects of pollution in the ecosystem which in turn modifies community structure. Biomonitoring could potentially be applied to all aquatic ecosystems including rivers, lakes, oceans, estuaries and wetlands. Wetlands are important ecosystems as they are areas with a large variety of biota and provide numerous resources and ecological services for humans. However, wetlands are susceptible to nutrient enrichment and pollution as materials are brought into the ecosystem by water, wind and humans in the catchment area. As wetlands acts as ‘sinks’ sediment and pollutants, including nutrients, accumulate in wetland ecosystems. These pollutants enter the ecosystem through runoff, seepage, direct application or are wind driven. As humans make use wetlands as a source of food and water and wetlands support an abundance of biota it is important to monitor the health of these aquatic ecosystems. Monitoring of wetland biota can be problematic at times as the variability in depth and inundation time does not allow some systems to support fish and/or macroinvertebrates. For this reason, diatoms are useful as biological indicators to monitor wetlands as they are microorganisms. Furthermore, diatom communities are species rich, respond rapidly to changes in the environment, are easy to collect, abundant and are the most diverse algae group. There is a paucity of aquatic biodiversity information on South Africa’s Ramsar wetlands and specifically the diatom communities. The present study focused on two Ramsar wetlands in South Africa namely Lake Sibaya and the Makuleke Wetlands. The aims of the study were to determine the distribution and occurrence of diatoms in the Makuleke Wetlands and Lake Sibaya in relations to water quality and secondly, to determine if European diatom-based indices for indicating wetland water quality conditions. Water and diatom samples were collected from the Makuleke Wetlands during a wet (April 2015) and dry season (September 2015). Lake Sibaya was sampled during a winter (July 2015) and two summer seasons (November 2015 and February 2016). The nutrient concentrations present in the water column were measured. Diatom taxa from both wetlands were identified and indicator species were used to determine the trophic level and ecosystem quality of these wetlands. Measured phosphate and inorganic nitrogen concentrations indicated both Lake Sibaya and the Makuleke Wetlands as nutrient enriched. The diatom community and indices (Specific Pollution sensitivity Index (SPI) and Generic Diatom Index (GDI)) correlated with the measured water quality and indicated both sites as nutrient enriched. The measured water quality variables indicated the wetlands to be either mesotrophic, eutrophic or hypertrophic. Diatom indices indicated that the study sites were in a bad/poor quality state with dominant diatom species occurring in polluted and nutrient enriched ecosystems. Thus, both wetlands are undoubtedly enriched with nutrients, however, it is unsure if these levels can be considered natural for these systems as nutrient accumulation is a key feature of wetlands. Diatom taxa identified in the Makuleke Wetlands ranged from 12 – 20 species between the pans with a total of 70 species identified in the wetland as a whole. A total of 59 species were identified in Lake Sibaya with a ranging from 20 – 35 species identified at the sampling sites. Dominant diatom species in the Makuleke Wetlands included Aulacoseira granulata, Gomphonema parvulum, Navicula sp. and Nitzschia sp. Dominant species at Lake Sibaya included Cocconeis placentula, Epithemia adnata and Gomphonema sp. Dominant species for both wetlands were indicators of nutrient enriched ecosystems and tolerant of generally polluted conditions. The diatom community (dominant species and diatom indices) and water quality indicated increased nutrients in the studies wetlands, suggesting a declining ecosystem quality. It is concluded that methods for diatom community analysis and water quality analysis were successfully applied and indicated both wetland ecosystems as nutrient enriched, however there are doubts as to whether this can in turn be viewed as indicating poor ecosystem health in general. Thus it is recommended that further in-depth studies be completed on diatom community structure and water quality of wetland ecosystems to determine how to define natural conditions. This will enable better understanding of the nutrient levels within wetlands as well as the use of diatoms as bio-indicators for wetland ecosystemsen_US
dc.language.isoenen_US
dc.publisherNorth-West University (South Africa), Potchefstroom Campusen_US
dc.subjectBiomonitoringen_US
dc.subjectWetlandsen_US
dc.subjectDiatomsen_US
dc.subjectWater qualityen_US
dc.subjectNutrient enrichmenten_US
dc.titleDiatom diversity and response to water quality within the Makuleke Wetlands and Lake Sibayaen_US
dc.typeThesisen_US
dc.description.thesistypeMastersen_US
dc.contributor.researchID11331798 - Taylor, Jonathan Charles (Supervisor)


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