Browsing by Author "Naidoo, Kubendran Kista."

Now showing 1 - 3 of 3

Assessment of the impact of agriculture and industry on the changing geochemical regimes, macro invertebrate communities and wetland areas : a case study of Sezela estuary and wetland areas, KwaZulu-Natal.
(2017) Hoosen, Suheil Malek.; Pillay, Srinivasan Seeni.; Naidoo, Kubendran Kista.
The Sezela estuary and wetlands make up a vast area of the Sezela in which these environments impacted by anthropogenic activities. The Sezela area is located along the south coast of KwaZulu-Natal province of South Africa in which the predominant land uses are commercial dryland sugarcane plantation cultivation and the Sezela Sugar Mill. Due to the anthropogenic activities in the area, several coastal environments have been degraded. The degradation of these environments can be detrimental to the organisms that are dependent on them for ecosystem services and even poverty-stricken people that require these environments for basic needs (Kotze et al., 2007). In addition, due to the water crisis currently in South Africa, further degrading these estuarine and wetland environments can rapidly increase the processes of drought. Therefore, assessing the quality of these environments is imperative to identify their functionality and need for rehabilitation (Macfarlane et al., 2007). The identification of estuarine and wetland functionality are conducted through field, laboratory analysis and statistical analysis. The determination of the health of the Sezela estuary was conducted through a step-by-step method which involved sediment granulometric analysis, sediment and water quality (utilisation of ICP-OES) and macro invertebrate indicators in the sediment. The health status of wetlands were determined through the PES and ecological services provided by the wetland utilising tools such as WET-Health and WET-EcoServices. It was determined that the Sezela estuary contained relatively coarse material and lacked species composition and richness due to past pollution of the estuary by the mill. The Sezela wetland areas were degraded as a result of dryland sugarcane plantation in which two of the three wetlands were predominantly impacted drastically which were the channelled valley bottom wetlands and not the floodplain wetland. It was necessary for the Sezela estuary and wetlands to be mitigated and rehabilitated in order to re-establish past conditions or conditions that will promote the return of organisms into the estuary and wetland environments. The measures that can be implemented are improve sediment and water quality, removal of alien invasive vegetation and re-vegetation with indigenous vegetation.
The ecological and functional assessment of wetlands : case study of a constructed wetland, Dundee, KwaZulu-Natal.
(2018) Naidoo, Nivarya.; Pillay, Srinivasan Seeni.; Naidoo, Kubendran Kista.
This dissertation focused on the constructed wetland at a disused coal mine in Dundee, KwaZulu-Natal. A sequence of 10 wetland cells was constructed by the Department of Water and Sanitation (DWS) to remediate seepage from the mine. The main aspects that this dissertation is focused on are the water quality and geochemistry of the wetland; the ability of the wetland in providing ecological goods and services, and the rehabilitation of the wetland system. The results of the water quality analysis revealed that the water in the system is of inferior quality. Several of the parameters exceeded South African water quality standards indicating that the water is detrimental to aquatic health and neither is it suitable for human consumption. The geochemical analysis revealed that whilst heavy metals are present in the sediments the enrichment factor (EF) values are low although certain elements may be bioavailable. This possibility is enhanced by the predominance of larger grained sediment which have low adsorption capacities, allowing for relatively easy remobilisation into the water column. PCA analysis indicated a predominance of some heavy metals in the wetland cells but that this was influenced by anthropogenic impacts via discard coal. The ability of the wetland system in providing ecosystem goods and services was found to be compromised due to the wetland being in a state of malfunction. The final part of this dissertation comprises of a proposed rehabilitation plan for the constructed wetland. The rehabilitation plan focuses on the causes of degradation of the system due to the prolonged lack of maintenance and monitoring resulting in dysfunctional connectivity of wetland cells; inhibition of wetland conditions; the proliferation of terrestrial and alien invasive plants and, the inappropriate original structural composition of the basal sediments used which initially would have worked counter to the original intention to reduce acidity of mine derived groundwater. The rehabilitation plan is intended to aid in the re-establishment of hydrological, geomorphological and ecological processes in the wetland system.
Ecophysiological studies of the invasive weed Chromolaena odorata (L.) King and Robinson and its control in KwaZulu-Natal.
(2013) Naidoo, Kubendran Kista.; Naidoo, Gonasageran.; Naidoo, Yougasphree.
Despite increased interest in the control and spread of the alien weed, Chromolaena odorata, little is known of its photosynthetic characteristics under field conditions. The aim of the study was to obtain a better understanding of the ecophysiological attributes of C. odorata that contribute to its invasive success. Photosynthetic performance of C. odorata was evaluated by monitoring diurnal changes in gas exchange, chlorophyll a fluorescence and plant water relations. Gas exchange characteristics of plants growing in exposed and shaded environments, as well as seasonal patterns, were evaluated. The response of C. odorata to water stress was also determined. Chromolaena odorata exhibited high CO2 uptake rates with no light saturation. Shade plants had significantly larger leaf surface areas and greater concentrations of total chlorophyll, total carotenoids and chlorophylls a and b than sun plants. Relatively high photosynthetic uptake rates in C. odorata may allow for greater carbon gain in high light environments thus contributing to increased growth and spread of the species. Chromolaena odorata can successfully acclimatise to low photosynthetic photon flux density (PPFD), thus, outcompeting less tolerant species under low light conditions. Leaf conductance, CO2 uptake, transpiration and chlorophyll fluorescence parameters in winter were tightly coupled to summer. Plants had higher water use efficiency (WUE) in summer compared to winter, probably to maximise CO2 uptake and minimise water loss. There was a progressive decrease in leaf water potential with increase in water stress in water stressed (WS) plants. The leaves of WS plants showed signs of severe wilting 10 days after the onset of stress compared to well watered (WW) plants. Increased proline concentration and leaf wilting probably increase (WUE) and may be an adaptive strategy to protect against dehydration injury.The effects of the herbicide, glyphosate, on gas exchange and translocation were studied. Glyphosate treatment decreased leaf conductance leading to a reduction in CO2 uptake and transpiration. Glyphosate is a mobile herbicide that is transported from leaves to roots and caused death of plants within a week of treatment. The potential antimicrobial properties of the weed were evaluated using selected bacteria and fungi. Crude leaf extracts exhibited some antibacterial and antifungal activity. Extracts from the weed are unlikely to be useful antimicrobial sources due to low concentrations of active compounds. A co-ordinated strategy, taking into account the high plasticity of the weed, is needed to curtail the spread of C. odorata. The ecophysiological responses to environmental conditions should be considered when planning management and control strategies for C. odorata.