Microalgae as indicators of environmental change in the St Lucia estuarine system
- Authors: Nunes, Monique
- Date: 2019
- Subjects: Microalgae -- South Africa -- St Lucia estuarine
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31165 , vital:31333
- Description: The St Lucia system represents 56% of the estuarine habitat area in South Africa. This dynamic estuarine lake responds to a complex interaction of climatic and anthropogenic drivers. There has been a long history of human interventions and the extended drought (2002-2012) led to major changes. In 1952, the inlet shared between the estuarine system and the Mfolozi River was artificially separated, which significantly reduced freshwater inflow. The systems were separated because of the silt load from the expanding agricultural activities in the Mfolozi River catchment. The drought prompted a critical review of re-establishing the historic connection, and in July 2012, the beach spillway was excavated marking the start of restoring connectivity. Increased rainfall coupled with the partial re-connection with the agriculturally-impacted Mfolozi River shifted the St Lucia estuarine system to a new wet phase. This study investigated the microalgal dynamics of the estuarine system as it transitioned to this new wet phase. Results showed that the phytoplankton and microphytobenthos (MPB) biomass was low (< 5 ug l-1 and < 60 mg m-2 respectively) throughout the system due to nutrient and light availability, water residence time and sediment type. The increased freshwater inflow from the Mfolozi River was limited to the Narrows and available nutrients promoted the growth of cyanobacteria and dinophytes in the water column. Of interest was the presence of the potentially harmful algal species Prorocentrum minimum. A weekly study investigated the relationship between freshwater inflow, phytoplankton succession and the introduction and persistence of harmful microalgal species in the lower reaches. The increased freshwater inflow received from the Mfolozi River has led to a system in a constant state of flux. The changes in salinity, light availability and water residence time, shifted the phytoplankton functional group structure to one where chlorophytes and euglenoids were dominant. The persistence of the nutrient tolerant euglenoids highlighted the influence of the nutrient-enriched freshwater inflow on the phytoplankton functional groups. However, the relative abundance of all functional groups remained low due to the rapid change in environmental conditions. The next step was to test the use of an artificial substrate as a monitoring method to detect nutrient induced change. Findings from the 28-day study showed that epilithic diatom communities growing on glass slides were good indicators of nutrient enrichment. The epilithic algal biomass increased significantly from 1.5 mg m-2 (Day 14) to 6 mg m-2 (Day 21), following peak river inflow. In contrast, the phytoplankton and MPB showed no discernible increase in biomass. Epilithic diatom community diversity, richness and evenness scores declined due to the increasing relative abundance of a single nutrient tolerant species, Cocconeis placentula var. euglypta. The use of diatoms as indicators of change depends on the accuracy of identification to species level. This can be a slow process requiring a high level of taxonomic expertise. Considering that molecular phylogenetic methods are readily used to produce a reliable taxonomic list, the suitability of DNA metabarcoding for diatom monitoring in the St Lucia Estuary was tested. Comparisons between the molecular and morphological method indicated that the diatom taxonomic composition was similar at 9 to 27% for genus level and 2 to 9% at species level. The low taxonomic similarity was related to the large number of unclassified DNA representative sequences included in the molecular inventory due to the incomplete DNA library database. However, the available operational taxonomic units (OTUs) from the molecular method did provide an effective alternative to determine the relevant community diversity estimates required for the application of the South African Estuarine Health Index (EHI). This research has highlighted the dynamic nature of the St Lucia estuarine system and the effectiveness of the microalgal communities to differentiate between the cyclical climatic phases and anthropogenic stressors such as nutrient enrichment.
- Full Text:
- Date Issued: 2019
- Authors: Nunes, Monique
- Date: 2019
- Subjects: Microalgae -- South Africa -- St Lucia estuarine
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/31165 , vital:31333
- Description: The St Lucia system represents 56% of the estuarine habitat area in South Africa. This dynamic estuarine lake responds to a complex interaction of climatic and anthropogenic drivers. There has been a long history of human interventions and the extended drought (2002-2012) led to major changes. In 1952, the inlet shared between the estuarine system and the Mfolozi River was artificially separated, which significantly reduced freshwater inflow. The systems were separated because of the silt load from the expanding agricultural activities in the Mfolozi River catchment. The drought prompted a critical review of re-establishing the historic connection, and in July 2012, the beach spillway was excavated marking the start of restoring connectivity. Increased rainfall coupled with the partial re-connection with the agriculturally-impacted Mfolozi River shifted the St Lucia estuarine system to a new wet phase. This study investigated the microalgal dynamics of the estuarine system as it transitioned to this new wet phase. Results showed that the phytoplankton and microphytobenthos (MPB) biomass was low (< 5 ug l-1 and < 60 mg m-2 respectively) throughout the system due to nutrient and light availability, water residence time and sediment type. The increased freshwater inflow from the Mfolozi River was limited to the Narrows and available nutrients promoted the growth of cyanobacteria and dinophytes in the water column. Of interest was the presence of the potentially harmful algal species Prorocentrum minimum. A weekly study investigated the relationship between freshwater inflow, phytoplankton succession and the introduction and persistence of harmful microalgal species in the lower reaches. The increased freshwater inflow received from the Mfolozi River has led to a system in a constant state of flux. The changes in salinity, light availability and water residence time, shifted the phytoplankton functional group structure to one where chlorophytes and euglenoids were dominant. The persistence of the nutrient tolerant euglenoids highlighted the influence of the nutrient-enriched freshwater inflow on the phytoplankton functional groups. However, the relative abundance of all functional groups remained low due to the rapid change in environmental conditions. The next step was to test the use of an artificial substrate as a monitoring method to detect nutrient induced change. Findings from the 28-day study showed that epilithic diatom communities growing on glass slides were good indicators of nutrient enrichment. The epilithic algal biomass increased significantly from 1.5 mg m-2 (Day 14) to 6 mg m-2 (Day 21), following peak river inflow. In contrast, the phytoplankton and MPB showed no discernible increase in biomass. Epilithic diatom community diversity, richness and evenness scores declined due to the increasing relative abundance of a single nutrient tolerant species, Cocconeis placentula var. euglypta. The use of diatoms as indicators of change depends on the accuracy of identification to species level. This can be a slow process requiring a high level of taxonomic expertise. Considering that molecular phylogenetic methods are readily used to produce a reliable taxonomic list, the suitability of DNA metabarcoding for diatom monitoring in the St Lucia Estuary was tested. Comparisons between the molecular and morphological method indicated that the diatom taxonomic composition was similar at 9 to 27% for genus level and 2 to 9% at species level. The low taxonomic similarity was related to the large number of unclassified DNA representative sequences included in the molecular inventory due to the incomplete DNA library database. However, the available operational taxonomic units (OTUs) from the molecular method did provide an effective alternative to determine the relevant community diversity estimates required for the application of the South African Estuarine Health Index (EHI). This research has highlighted the dynamic nature of the St Lucia estuarine system and the effectiveness of the microalgal communities to differentiate between the cyclical climatic phases and anthropogenic stressors such as nutrient enrichment.
- Full Text:
- Date Issued: 2019
The efficiency of budgeting for procurement of movable non-current assets in the absence of sound asset management
- Authors: Mtayisi, Nobuntu Rebecca
- Date: 2017
- Subjects: Assets (Accounting) -- Management , Asset management accounts , Budget
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/19651 , vital:28923
- Description: Movable non-current assets are physical and mobile assets that a municipality uses to provide services to the community directly or indirectly. Therefore, effective movable non-current asset management is necessary to ensure that these assets provide value to both the municipality and the community. This study seeks to determine whether poor asset management negatively affects capital budgeting for procurement of movable non-current assets. Mbhashe Local Municipality, a Category B municipality in the Eastern Cape Province was selected for the study. A desktop research method was utilised for this study. The analysis of secondary data includes policy documents (such as National Treasury asset management guidelines and Mbhashe budgeting policy), books, journals, internet data, newspapers and research documents in order to determine asset management guidelines and budgeting theories by noteworthy scholars. Auditor General South Africa (AGSA) and State of Local Government Finance reports were also analysed to establish the current practice and impact of the role of the municipal management in its finances as well as budget spending patterns at Mbhashe Local Municipality. The results of the study revealed that Mbhashe Local Municipality’s non-compliance with asset management and budgeting policies and procedures throughout the period of the study negatively affected their capital budgeting decisions. The consequences of instability in leadership and lack of approved movable non-current asset management policy resulted in partial asset information, incorrect recording and accounting systems for assets and unauthorised disposal of strategic movable non-current assets. Although, an approved budget policy existed at Mbhashe Local Municipality, the budgetary information was unrealistic because of negligence such as: lack of public participation, consultation and alignment of the Integrated Development Plan (IDP) with the municipality’s objectives. This resulted in habitual under-spending of capital assets compared to the capital budget throughout the period of the study.
- Full Text:
- Date Issued: 2017
- Authors: Mtayisi, Nobuntu Rebecca
- Date: 2017
- Subjects: Assets (Accounting) -- Management , Asset management accounts , Budget
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/19651 , vital:28923
- Description: Movable non-current assets are physical and mobile assets that a municipality uses to provide services to the community directly or indirectly. Therefore, effective movable non-current asset management is necessary to ensure that these assets provide value to both the municipality and the community. This study seeks to determine whether poor asset management negatively affects capital budgeting for procurement of movable non-current assets. Mbhashe Local Municipality, a Category B municipality in the Eastern Cape Province was selected for the study. A desktop research method was utilised for this study. The analysis of secondary data includes policy documents (such as National Treasury asset management guidelines and Mbhashe budgeting policy), books, journals, internet data, newspapers and research documents in order to determine asset management guidelines and budgeting theories by noteworthy scholars. Auditor General South Africa (AGSA) and State of Local Government Finance reports were also analysed to establish the current practice and impact of the role of the municipal management in its finances as well as budget spending patterns at Mbhashe Local Municipality. The results of the study revealed that Mbhashe Local Municipality’s non-compliance with asset management and budgeting policies and procedures throughout the period of the study negatively affected their capital budgeting decisions. The consequences of instability in leadership and lack of approved movable non-current asset management policy resulted in partial asset information, incorrect recording and accounting systems for assets and unauthorised disposal of strategic movable non-current assets. Although, an approved budget policy existed at Mbhashe Local Municipality, the budgetary information was unrealistic because of negligence such as: lack of public participation, consultation and alignment of the Integrated Development Plan (IDP) with the municipality’s objectives. This resulted in habitual under-spending of capital assets compared to the capital budget throughout the period of the study.
- Full Text:
- Date Issued: 2017
The physical activity and health-related fitness of female students at a South African university
- Authors: Baatjes, Tashrique
- Date: 2016
- Subjects: Physical fitness for women Physical education and training Women college students -- Health and hygiene Health behavior
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/5575 , vital:20909
- Description: Physical inactivity and resultant chronic diseases of lifestyle (CDLs) are becoming a global epidemic as secular modernization and the sedentary lifestyles it brings with it become universal. The importance of physical activity (PA) in reducing morbidity and mortality from CDLs and related conditions has been well established. Since it is generally significant that the onset of many CDLs lies in childhood through to adolescence, preventative strategies should start as early in life as possible. Currently, university students are failing to engage in the levels of PA recommended for better health outcomes over the short and long term. To make matters worse, there is increasing evidence of a decrease in PA during the transitional phase from adolescence to adulthood. This study aimed to determine the physical activity (PA) levels, sedentary behaviour and health-related fitness (HRF) characteristics of female university students. In addition, the participants‘ perceived barriers to PA were investigated. The study was exploratory-descriptive and employed a quantitative research design. Five hundred and thirty-one full-time female students, between the ages of 18 and 46, studying at Nelson Mandela Metropolitan University‘s (NMMU) South, North, Second Avenue and Missionvale campuses participated in the study. The participants (n=531) completed an online survey which determined their PA levels, sedentary behaviours and perceived barriers to PA participation. A health-related fitness (HRF) assessment was also administered to 68 participants who completed the online survey. Their height, weight, and waist and hip circumferences were measured, as well as their cardiovascular fitness (CF). The majority (88 percent) of the participants reported low and minimal levels of PA, and 44 percent were either overweight or obese. The participants had a low-risk waist-to-hip ratio (WHR) (M=0.70). The majority of the population (94 percent) had poor cardiovascular fitness (CF). A high prevalence of sitting time was recorded among the participants: on average 855 minutes (14 hours) on a usual weekday and 720 minutes (12 hours) on a usual weekend day. Students reported the greatest length of sitting time at work/attending lectures/studying. Cross tabulations and Chi2 tests indicated no significant relationships among PA and HRF (BMI, WHR and CF) and sedentary behaviour and HRF. The ANOVA and t-test results for PA, sedentary behaviour and HRF related to various demographic variables, found small (0.19 < d < 0.50) and medium (0.49 < d < 0.80) significant differences by race (d=0.43; d=0.52), home language (d=0.41; d=0.44) and living arrangement (d=0.38; d=0.28). No significant relationship was found to exist between age, year of study and faculty of registration and sedentary behaviour or HRF. The participants listed: Not enough time; too expensive to exercise; and, no friends who can exercise with me as the most important barriers to participation in PA. Academic obligations (3.08 mean) was found to be the most important barrier to PA.
- Full Text:
- Date Issued: 2016
- Authors: Baatjes, Tashrique
- Date: 2016
- Subjects: Physical fitness for women Physical education and training Women college students -- Health and hygiene Health behavior
- Language: English
- Type: Thesis , Masters , MA
- Identifier: http://hdl.handle.net/10948/5575 , vital:20909
- Description: Physical inactivity and resultant chronic diseases of lifestyle (CDLs) are becoming a global epidemic as secular modernization and the sedentary lifestyles it brings with it become universal. The importance of physical activity (PA) in reducing morbidity and mortality from CDLs and related conditions has been well established. Since it is generally significant that the onset of many CDLs lies in childhood through to adolescence, preventative strategies should start as early in life as possible. Currently, university students are failing to engage in the levels of PA recommended for better health outcomes over the short and long term. To make matters worse, there is increasing evidence of a decrease in PA during the transitional phase from adolescence to adulthood. This study aimed to determine the physical activity (PA) levels, sedentary behaviour and health-related fitness (HRF) characteristics of female university students. In addition, the participants‘ perceived barriers to PA were investigated. The study was exploratory-descriptive and employed a quantitative research design. Five hundred and thirty-one full-time female students, between the ages of 18 and 46, studying at Nelson Mandela Metropolitan University‘s (NMMU) South, North, Second Avenue and Missionvale campuses participated in the study. The participants (n=531) completed an online survey which determined their PA levels, sedentary behaviours and perceived barriers to PA participation. A health-related fitness (HRF) assessment was also administered to 68 participants who completed the online survey. Their height, weight, and waist and hip circumferences were measured, as well as their cardiovascular fitness (CF). The majority (88 percent) of the participants reported low and minimal levels of PA, and 44 percent were either overweight or obese. The participants had a low-risk waist-to-hip ratio (WHR) (M=0.70). The majority of the population (94 percent) had poor cardiovascular fitness (CF). A high prevalence of sitting time was recorded among the participants: on average 855 minutes (14 hours) on a usual weekday and 720 minutes (12 hours) on a usual weekend day. Students reported the greatest length of sitting time at work/attending lectures/studying. Cross tabulations and Chi2 tests indicated no significant relationships among PA and HRF (BMI, WHR and CF) and sedentary behaviour and HRF. The ANOVA and t-test results for PA, sedentary behaviour and HRF related to various demographic variables, found small (0.19 < d < 0.50) and medium (0.49 < d < 0.80) significant differences by race (d=0.43; d=0.52), home language (d=0.41; d=0.44) and living arrangement (d=0.38; d=0.28). No significant relationship was found to exist between age, year of study and faculty of registration and sedentary behaviour or HRF. The participants listed: Not enough time; too expensive to exercise; and, no friends who can exercise with me as the most important barriers to participation in PA. Academic obligations (3.08 mean) was found to be the most important barrier to PA.
- Full Text:
- Date Issued: 2016
Factors influencing employees to seek supervisory positions in manufacturing
- Authors: Ficker, Liezel
- Date: 2005
- Subjects: Supervisors, Industrial , Supervision of employees
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8539 , http://hdl.handle.net/10948/190 , Supervisors, Industrial , Supervision of employees
- Description: This research was undertaken at a hosiery manufacturing plant situated in Cape Town. The two research questions were: 1) What are the main factors that influenced, as well as previously discouraged, current supervisors to seek supervisory positions? and 2) What are the main factors that influence employees to want to become a supervisor, and what factors would discourage them from wanting to become a supervisor? Questionnaires were used as the measuring instrument. The results revealed that internal motivation was the most important factor that positively influenced current supervisors to seek a supervisory position. This was followed by self-perceived management ability, self-belief and confidence factors. Supervisors revealed a low social and affiliation need. Factors that discouraged current supervisors from seeking a supervisory position were limited management involvement, negative work related issues, and self-doubt factors. Most employees, who were not interested in seeking a supervisory position, indicated that there were no factors that would motivate them to want to become supervisors. Amongst the four content theories of motivation, the most relevant theory in interpreting the results was the Herzberg’s two factor theory. He stated that “employees are motivated by their own inherent need to succeed at a challenging task”. This is exactly what was also found in this research. One of the interesting findings is that Herzberg’s hygiene factors played almost no role as a motivator or demotivator for either current supervisors or employees. The significance of the findings for managers is that they should not strive to motivate employees to become supervisors, but rather select people who already have a high level of internal self-motivation. If they are simply looking for good workers, they should select a different type of employee who does not have a high need for achievement.
- Full Text:
- Date Issued: 2005
- Authors: Ficker, Liezel
- Date: 2005
- Subjects: Supervisors, Industrial , Supervision of employees
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8539 , http://hdl.handle.net/10948/190 , Supervisors, Industrial , Supervision of employees
- Description: This research was undertaken at a hosiery manufacturing plant situated in Cape Town. The two research questions were: 1) What are the main factors that influenced, as well as previously discouraged, current supervisors to seek supervisory positions? and 2) What are the main factors that influence employees to want to become a supervisor, and what factors would discourage them from wanting to become a supervisor? Questionnaires were used as the measuring instrument. The results revealed that internal motivation was the most important factor that positively influenced current supervisors to seek a supervisory position. This was followed by self-perceived management ability, self-belief and confidence factors. Supervisors revealed a low social and affiliation need. Factors that discouraged current supervisors from seeking a supervisory position were limited management involvement, negative work related issues, and self-doubt factors. Most employees, who were not interested in seeking a supervisory position, indicated that there were no factors that would motivate them to want to become supervisors. Amongst the four content theories of motivation, the most relevant theory in interpreting the results was the Herzberg’s two factor theory. He stated that “employees are motivated by their own inherent need to succeed at a challenging task”. This is exactly what was also found in this research. One of the interesting findings is that Herzberg’s hygiene factors played almost no role as a motivator or demotivator for either current supervisors or employees. The significance of the findings for managers is that they should not strive to motivate employees to become supervisors, but rather select people who already have a high level of internal self-motivation. If they are simply looking for good workers, they should select a different type of employee who does not have a high need for achievement.
- Full Text:
- Date Issued: 2005
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