Triggering biodegradation of low-density polyethylene films containing biobased additives for ecological applications
- Authors: Gada, Abongile
- Date: 2019
- Subjects: Refuse and refuse disposal , Plastics industry and trade -- Waste disposal Polyethylene Polyurethanes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39796 , vital:35460
- Description: The aims of the present study are focused on the investigation of low-density polyethylene (LDPE) films that contain biobased pro-oxidizing additives (CSIR1% and CSIR3% (w/w)) for environmental degradation in different abiotic and biotic conditions in comparison to non-biodegradable commercially available Pick n Pay (PnP) PE grocery bags. In this project, a biobased pro-oxidant additive master batch was prepared in a heat kneader mixer. A mixture of biobased radical reaction initiators and natural polymers were melt processed as a master batch. The biobased pro-oxidant additive master batch CSIR1% and CSIR3% and LDPE components were melt-extruded to form biobased pro-oxidant additive LDPE pellets using a twin screw melt extruder. The pelletized biobased pro-oxidant additive LDPE was blown into a 25 -27 μm thick film using a melt blower machine. The LDPE containing biobased pro-oxidant additive CSIR 1% and 3% test samples and the PnP polyethylene carrier bags were submitted to thermal oxidizing test conditions in a 70°C air ventilated oven and direct sunlight (photo oxidation) for a period of six months (180 days). The thermal and photo-oxidized LDPE film test samples were further subjected to biotic degradation tests in aqueous, soil and compost environments for varying periods of 180 days to 263 days in biodegradation evaluation studies. The oxidation degradation rates of the test samples were monitored and determined by evaluating carbonyl index (COi) using FT-IR spectroscopy; molecular weight determination and distribution of the test materials were analyzed by Gel Permeation Chromatography (GPC); compounds analysis was done by GC-MS; percentage crystallinity (Xc%) was quantified by DSC; thermal stability by TGA and morphological surfaces were examined by SEM analytical techniques. Biodegradation tests simulating marine salt water, burial in soil and compost conditioning methods were used to determine the “potential biodegradability” of the thermally and photo-oxidized test samples after the oxidation period. The oxidation extent and rate of LDPE films containing CSIR3% biobased additives was higher than that of LDPE films containing CSIR1% biobased additives. GPC molecular weight determination and distribution results showed a decrease for all the test samples exposed to oxidation. The molecular weight of LDPE films containing CSIR1% biobased additives decreased from 404K Mw to 111K Mw for sunlight oxidized samples and to 16KMw for the thermally oxidized LDPE samples after 200 days of oxidation exposure. Molecular weight of LDPE films containing CSIR3% biobased additives showed the most reduction from 293K Mw to 22K Mw for sunlight oxidized samples and to 2K Mw for thermally oxidized samples after 100 days of oxidation exposure. DSC analysis showed that crystallinity degree decreased after exposure to thermal and photo-oxidation. TGA results showed a reduction of initial degradation temperature by almost half compared to zero-days untreated CSIR3% samples, with higher degree temperatures observed in samples exposed to thermal oxidation than those exposed to photo-oxidation. GC-MS revealed peaks of carbonyls such as alcohols, aldehydes, ketones, carboxylic and anionic acids, and very short chain alkenes and alkanes. The SEM showed heterogeneous morphological modifications in surfaces of samples even though they were not severe. After 172 days the oxidized LDPE samples containing CSIR3% biobased additives, were investigated for potential biodegradation in aqueous, soil and composting environments. Thermally oxidized and photo-oxidized CSIR3% samples showed a mineralization degree of 10.4% and 10.7% respectively, when oxidized in 181 days aqueous biodegradation, 20% and 7.7% respectively, when oxidized in 233 days of soil burial, and 52.6% and 62% respectively, oxidized in 263 days of compost. The obtained results confirmed the abiotic oxidation step as the initiation step for PE degradation, succeeded by assimilation, by action of microorganisms (ultimate biodegradation), of lower weight molecular compounds of oxidized LDPE samples in aqueous medium, soil and composting conditions to final end products of CO2, H2O and new microbial cell biomass.
- Full Text:
- Date Issued: 2019
- Authors: Gada, Abongile
- Date: 2019
- Subjects: Refuse and refuse disposal , Plastics industry and trade -- Waste disposal Polyethylene Polyurethanes
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/39796 , vital:35460
- Description: The aims of the present study are focused on the investigation of low-density polyethylene (LDPE) films that contain biobased pro-oxidizing additives (CSIR1% and CSIR3% (w/w)) for environmental degradation in different abiotic and biotic conditions in comparison to non-biodegradable commercially available Pick n Pay (PnP) PE grocery bags. In this project, a biobased pro-oxidant additive master batch was prepared in a heat kneader mixer. A mixture of biobased radical reaction initiators and natural polymers were melt processed as a master batch. The biobased pro-oxidant additive master batch CSIR1% and CSIR3% and LDPE components were melt-extruded to form biobased pro-oxidant additive LDPE pellets using a twin screw melt extruder. The pelletized biobased pro-oxidant additive LDPE was blown into a 25 -27 μm thick film using a melt blower machine. The LDPE containing biobased pro-oxidant additive CSIR 1% and 3% test samples and the PnP polyethylene carrier bags were submitted to thermal oxidizing test conditions in a 70°C air ventilated oven and direct sunlight (photo oxidation) for a period of six months (180 days). The thermal and photo-oxidized LDPE film test samples were further subjected to biotic degradation tests in aqueous, soil and compost environments for varying periods of 180 days to 263 days in biodegradation evaluation studies. The oxidation degradation rates of the test samples were monitored and determined by evaluating carbonyl index (COi) using FT-IR spectroscopy; molecular weight determination and distribution of the test materials were analyzed by Gel Permeation Chromatography (GPC); compounds analysis was done by GC-MS; percentage crystallinity (Xc%) was quantified by DSC; thermal stability by TGA and morphological surfaces were examined by SEM analytical techniques. Biodegradation tests simulating marine salt water, burial in soil and compost conditioning methods were used to determine the “potential biodegradability” of the thermally and photo-oxidized test samples after the oxidation period. The oxidation extent and rate of LDPE films containing CSIR3% biobased additives was higher than that of LDPE films containing CSIR1% biobased additives. GPC molecular weight determination and distribution results showed a decrease for all the test samples exposed to oxidation. The molecular weight of LDPE films containing CSIR1% biobased additives decreased from 404K Mw to 111K Mw for sunlight oxidized samples and to 16KMw for the thermally oxidized LDPE samples after 200 days of oxidation exposure. Molecular weight of LDPE films containing CSIR3% biobased additives showed the most reduction from 293K Mw to 22K Mw for sunlight oxidized samples and to 2K Mw for thermally oxidized samples after 100 days of oxidation exposure. DSC analysis showed that crystallinity degree decreased after exposure to thermal and photo-oxidation. TGA results showed a reduction of initial degradation temperature by almost half compared to zero-days untreated CSIR3% samples, with higher degree temperatures observed in samples exposed to thermal oxidation than those exposed to photo-oxidation. GC-MS revealed peaks of carbonyls such as alcohols, aldehydes, ketones, carboxylic and anionic acids, and very short chain alkenes and alkanes. The SEM showed heterogeneous morphological modifications in surfaces of samples even though they were not severe. After 172 days the oxidized LDPE samples containing CSIR3% biobased additives, were investigated for potential biodegradation in aqueous, soil and composting environments. Thermally oxidized and photo-oxidized CSIR3% samples showed a mineralization degree of 10.4% and 10.7% respectively, when oxidized in 181 days aqueous biodegradation, 20% and 7.7% respectively, when oxidized in 233 days of soil burial, and 52.6% and 62% respectively, oxidized in 263 days of compost. The obtained results confirmed the abiotic oxidation step as the initiation step for PE degradation, succeeded by assimilation, by action of microorganisms (ultimate biodegradation), of lower weight molecular compounds of oxidized LDPE samples in aqueous medium, soil and composting conditions to final end products of CO2, H2O and new microbial cell biomass.
- Full Text:
- Date Issued: 2019
Truth and reconciliation and other stories: a critical multimodal investigation of representations of post-apartheid South Africa in children's picturebooks: volume 1
- Authors: Smith, Jade
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97614 , vital:31458
- Description: Expected release date-April 2021
- Full Text: false
- Date Issued: 2019
- Authors: Smith, Jade
- Date: 2019
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/97614 , vital:31458
- Description: Expected release date-April 2021
- Full Text: false
- Date Issued: 2019
Using captive seabirds to assess knowledge gaps in stable isotope analysis of diets
- Authors: Micklem, Isabel Andrea
- Date: 2019
- Subjects: Stable isotopes -- Analysis African penguin -- South Africa Breeding
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/65101 , vital:28686
- Description: Stable isotope (SI) ratios of carbon (δ13C) and nitrogen (δ15N) are now widely used as biomarkers in ecological studies to provide information about food web structuring. However, understanding trophic relationships using SI analysis requires not only knowledge of SI values of predator and prey, but also accurate discrimination factors (DFs), which can differ among species and by physiological state. This thesis examined three questions using captive birds from the South African Foundation for the Conservation of Coastal Birds (SANCCOB). First, the effects of ontogeny on δ13C and δ15N ratios of African penguins (Spheniscus demersus) were assessed. Blood samples were collected from penguins in four age classes (P3 chicks, blues, juveniles and adults) concurrently with their diet (sardine (Sardinops sagax) and formula). Second, to assess the influence of breeding physiology on SI ratios, the blood of ten breeding pairs of penguins was sampled over a five-month period from June to October 2016. Following laying, each pair was categorised into one of three (four for whole blood) egg production phases (initial yolk deposition, rapid yolk deposition and post-laying) and their influences on SI ratios were tested. Third, species differences in DFs were evaluated for African penguins, kelp and Hartlaub’s gulls (Larus dominicanus and L. hartlaubii), greater crested terns (Thalasseus bergii) and Cape cormorants (Phalacrocorax capensis). Flying birds were mostly fed sardine with a small but unknown amount of sardinella (Sardinella aurita), DFs were therefore estimated for a 50:50 sardine:sardinella diet, a 75:25 sardine:sardinella diet and a 100% sardine diet for each flying bird species. The DFs were assessed for the whole blood (WB), red blood cells (RBC), plasma (PL) and delipidated plasma of the penguins, and only WB for the flying birds as well as flesh, whole fish, delipidated flesh and delipidated whole fish for fish species, and for formula. Results indicated that age influenced both the δ13C and δ15N of WB, only the δ15N of RBC and the δ13C of delipidated PL. The assessment of breeding physiology yielded a significant interaction between the effects of egg production phase and sex on the δ13C of WB; females had significantly lower δ13C in the rapid yolk deposition phase than the other two phases and all males. The δ13C of PL was affected only by sex, with females having a significantly lower δ13C value than males. Neither physiological state nor sex influenced the other blood components. Differences were found among the three DFs in the non-penguin species, but not for all consumer – prey tissue combinations. There were also significant differences among species with a DF calculated from a diet with the most probable prey proportions eaten. Depending on the combination of consumer and prey tissue used to calculate the DF, a different conclusion regarding trophic information can be reached. A literature review updated with the present data showed that no general pattern or grouping of similar species with regards to DF values could be drawn, highlighting the importance of determining species- and tissue-specific DFs. Thus age, egg production, tissue and species all influenced the SI values of bird blood and therefore their DFs. Not all physiological conditions affect all blood components in the same way, making different components more or less sensitive to physiological influences. Though their influence is at a small enough scale that it is unlikely to hamper correct conclusion in ecological studies, it is crucial that these factors are considered when using SI analysis (SIA). When uncertainties exist for some coefficients in wild studies, SIA should therefore be combined to other dietary techniques to determine the food web structure as best as possible.
- Full Text:
- Date Issued: 2019
- Authors: Micklem, Isabel Andrea
- Date: 2019
- Subjects: Stable isotopes -- Analysis African penguin -- South Africa Breeding
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/65101 , vital:28686
- Description: Stable isotope (SI) ratios of carbon (δ13C) and nitrogen (δ15N) are now widely used as biomarkers in ecological studies to provide information about food web structuring. However, understanding trophic relationships using SI analysis requires not only knowledge of SI values of predator and prey, but also accurate discrimination factors (DFs), which can differ among species and by physiological state. This thesis examined three questions using captive birds from the South African Foundation for the Conservation of Coastal Birds (SANCCOB). First, the effects of ontogeny on δ13C and δ15N ratios of African penguins (Spheniscus demersus) were assessed. Blood samples were collected from penguins in four age classes (P3 chicks, blues, juveniles and adults) concurrently with their diet (sardine (Sardinops sagax) and formula). Second, to assess the influence of breeding physiology on SI ratios, the blood of ten breeding pairs of penguins was sampled over a five-month period from June to October 2016. Following laying, each pair was categorised into one of three (four for whole blood) egg production phases (initial yolk deposition, rapid yolk deposition and post-laying) and their influences on SI ratios were tested. Third, species differences in DFs were evaluated for African penguins, kelp and Hartlaub’s gulls (Larus dominicanus and L. hartlaubii), greater crested terns (Thalasseus bergii) and Cape cormorants (Phalacrocorax capensis). Flying birds were mostly fed sardine with a small but unknown amount of sardinella (Sardinella aurita), DFs were therefore estimated for a 50:50 sardine:sardinella diet, a 75:25 sardine:sardinella diet and a 100% sardine diet for each flying bird species. The DFs were assessed for the whole blood (WB), red blood cells (RBC), plasma (PL) and delipidated plasma of the penguins, and only WB for the flying birds as well as flesh, whole fish, delipidated flesh and delipidated whole fish for fish species, and for formula. Results indicated that age influenced both the δ13C and δ15N of WB, only the δ15N of RBC and the δ13C of delipidated PL. The assessment of breeding physiology yielded a significant interaction between the effects of egg production phase and sex on the δ13C of WB; females had significantly lower δ13C in the rapid yolk deposition phase than the other two phases and all males. The δ13C of PL was affected only by sex, with females having a significantly lower δ13C value than males. Neither physiological state nor sex influenced the other blood components. Differences were found among the three DFs in the non-penguin species, but not for all consumer – prey tissue combinations. There were also significant differences among species with a DF calculated from a diet with the most probable prey proportions eaten. Depending on the combination of consumer and prey tissue used to calculate the DF, a different conclusion regarding trophic information can be reached. A literature review updated with the present data showed that no general pattern or grouping of similar species with regards to DF values could be drawn, highlighting the importance of determining species- and tissue-specific DFs. Thus age, egg production, tissue and species all influenced the SI values of bird blood and therefore their DFs. Not all physiological conditions affect all blood components in the same way, making different components more or less sensitive to physiological influences. Though their influence is at a small enough scale that it is unlikely to hamper correct conclusion in ecological studies, it is crucial that these factors are considered when using SI analysis (SIA). When uncertainties exist for some coefficients in wild studies, SIA should therefore be combined to other dietary techniques to determine the food web structure as best as possible.
- Full Text:
- Date Issued: 2019
Using four different methods to reach a taxonomic conclusion in dung beetles (Scarabaeinae)
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
- Authors: Deschodt, Christian Michel
- Date: 2019
- Subjects: Dung beetles -- Classification , Scarabaeidae -- Classification
- Language: English
- Type: text , Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10962/67845 , vital:29156
- Description: Four different techniques to make taxonomic decisions concerning different species in Scarabaeinae are being investigated. Firstly, I made measurements of the body dimensions which are plotted on a two dimensional graph. This method is successfully used to erect one new species, Copris crassus Deschodt and Davis, 2015, and to establish the synonymy of Copris bihamatus Balthasar, 1965 with Copris fidius (Olivier, 1789). Thereafter the classical or traditional comparative method is used to propose seven new species Scarabaeolus soutpansbergensis (Deschodt and Davis 2015), Scarabaeolus megaparvulus (Davis and Deschodt 2015), Scarabaeolus niemandi (Deschodt and Davis 2015), Scarabaeolus carniphilus (Davis and Deschodt 2015), Scarabaeolus ermienae (Deschodt and Davis 2015), Scarabaeolus planipennis (Davis and Deschodt 2015) and Scarabaeolus afronitidus (Davis and Deschodt 2015) and formally synonymise Scarabaeolus vansoni (Ferreira, 1958) with Scarabaeolus lucidulus (Boheman, 1860) and Scarabaeolus xavieri (Ferreira, 1968) with Scarabaeolus andreaei (zur Strassen, 1963). Morphometric measurements of external structures of a group of flightless relict beetles in the tribe Canthonini are used to compile a nexus file which is analysed with computer software. The interpretation of these results is used here to support the erection of a new genus Drogo Deschodt, Davis & Scholtz 2016, Lastly I analysed the DNA sequences of specimens from different species belonging to a species complex in the genus Epirinus Reiche, 1841 occurring over a wide geographic range. These sequences are used together with external morphological characters to propose the synonymy of Epirinus hluhluwensis Medina & Scholtz 2005 and Epirinus ngomae Medina & Scholtz 2005 with Epirinus davisi Scholtz & Howden 1987.
- Full Text:
- Date Issued: 2019
Using GIS and Remote Sensing to identify water-stressed areas in South Africa - A case study of the Raymond Mhlaba Local Municipality, Eastern Cape Province
- Authors: Malunda, Kasongo Benjamin
- Date: 2019
- Subjects: Water-supply Droughts
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17238 , vital:40868
- Description: The main purpose of this study is to identify water stressed areas as a response to climate variability (Drought), Aridity, and water exploitation in the Raymond Mhlaba Local Municipality (RMLM) using Geographical Information Systems (GIS) and Remote Sensing (RS). This study focused on evaluating whether it is best to address the issue of drought and water stress as a municipal problem instead of a community-based problem. To achieve this, the study was attempting to establish four things: the climate condition of the municipality, whether the municipality is a drought prone area, how the surface water is being exploited in the municipality, and identify areas that should be considered water stressed areas. There are several indices used to compute water stress and the study opted for indices that can monitor climate variability, and surface water resources. Therefore, the de Martone Aridity Index (MA) was used to compute the aridity of the municipality the Standardized Precipitation Evapotranspiration Index (SPEI) to compute drought, and the Water Exploitation Index (WEI) to measure population water exploitation. Data used was from 25 weather stations provided by the Meteoblue website and water data from the department of water and sanitation. Thereafter, the Analytical Hierarchy Process (AHP) was used to determine the weights of each variables’ contribution to water stress. For validation, the Shapiro, Jarqua Bera and Kolmogorov-Smirnov tests were used and results showed that the data was normally distributed and a two-sample t-test confirmed that there was no significant difference between the measured and simulated data. According to the de Martonne there are three main climatic regions in the Raymond Mhlaba Municipality namely: the Mediterranean, semi-humid and humid region. The Mediterranean region is equally prone to drought as the humid region while the semi-humid region was a wet prone. This was contradictory to literature that expected drier regions to experience more frequent drought. However, this may have been influenced by the number of weather points that cover the humid region that is far lower than the ones covering the Mediterranean region. In addition, the municipality is 50% drought prone and would experience extreme events about 30% of the time. The study discovered that towns such as Fort Beaufort, Alice, Adelaide, and Middle drift are water stressed areas. While most of the other regions are low water users. These challenges with water stress could be reduced with the implementation of water saving mechanisms such as water tanks and the avoidance of addressing water stress as municipal challenges as opposed to a town specific challenge.
- Full Text:
- Date Issued: 2019
- Authors: Malunda, Kasongo Benjamin
- Date: 2019
- Subjects: Water-supply Droughts
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/17238 , vital:40868
- Description: The main purpose of this study is to identify water stressed areas as a response to climate variability (Drought), Aridity, and water exploitation in the Raymond Mhlaba Local Municipality (RMLM) using Geographical Information Systems (GIS) and Remote Sensing (RS). This study focused on evaluating whether it is best to address the issue of drought and water stress as a municipal problem instead of a community-based problem. To achieve this, the study was attempting to establish four things: the climate condition of the municipality, whether the municipality is a drought prone area, how the surface water is being exploited in the municipality, and identify areas that should be considered water stressed areas. There are several indices used to compute water stress and the study opted for indices that can monitor climate variability, and surface water resources. Therefore, the de Martone Aridity Index (MA) was used to compute the aridity of the municipality the Standardized Precipitation Evapotranspiration Index (SPEI) to compute drought, and the Water Exploitation Index (WEI) to measure population water exploitation. Data used was from 25 weather stations provided by the Meteoblue website and water data from the department of water and sanitation. Thereafter, the Analytical Hierarchy Process (AHP) was used to determine the weights of each variables’ contribution to water stress. For validation, the Shapiro, Jarqua Bera and Kolmogorov-Smirnov tests were used and results showed that the data was normally distributed and a two-sample t-test confirmed that there was no significant difference between the measured and simulated data. According to the de Martonne there are three main climatic regions in the Raymond Mhlaba Municipality namely: the Mediterranean, semi-humid and humid region. The Mediterranean region is equally prone to drought as the humid region while the semi-humid region was a wet prone. This was contradictory to literature that expected drier regions to experience more frequent drought. However, this may have been influenced by the number of weather points that cover the humid region that is far lower than the ones covering the Mediterranean region. In addition, the municipality is 50% drought prone and would experience extreme events about 30% of the time. The study discovered that towns such as Fort Beaufort, Alice, Adelaide, and Middle drift are water stressed areas. While most of the other regions are low water users. These challenges with water stress could be reduced with the implementation of water saving mechanisms such as water tanks and the avoidance of addressing water stress as municipal challenges as opposed to a town specific challenge.
- Full Text:
- Date Issued: 2019
Vulnerability in surf tourism: surf break decline and its impact on Herold's Bay, South Africa
- Authors: Schröder, Klaus
- Date: 2019
- Subjects: Surfing -- South Africa , Tourism -- Environmental aspects Climatic changes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43501 , vital:36900
- Description: Surfing has increasingly become a mainstream and demographically diverse activity that holds substantial economic worth. It also holds substantial social, cultural and spiritual value for participants and related communities. It is therefore not surprising that the maintenance of surf breaks has become an important element of coastal tourism, and that tourism management has had a growing concern with anthropogenic impacts on the shoreline. In line with these developments, this study investigates the vulnerability of surf tourism given the general consensus that there has been a human-induced decline of the river-mouth surf break in Herold’s Bay. An adapted ecological services model is used, and in line with such models, the status of the three types of capital (natural (physical) capital, climatic capital, and built capital) and their effect on recreation capital (surfing’s participation, market, and non-market values) over a twenty-year period is tracked. The findings identified alterations to the river bed morphology, beach morphology, wind direction, and swell intensity and frequency as the main determinants in surf break decline. The corresponding increase in vulnerability of Herold’s Bay’s surf tourism industry is also given as having negative socio-economic impacts. This study has underlined both the potential and the imperative to conserve, utilise and develop surf breaks and the surf tourism industry within South Africa.
- Full Text:
- Date Issued: 2019
- Authors: Schröder, Klaus
- Date: 2019
- Subjects: Surfing -- South Africa , Tourism -- Environmental aspects Climatic changes -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43501 , vital:36900
- Description: Surfing has increasingly become a mainstream and demographically diverse activity that holds substantial economic worth. It also holds substantial social, cultural and spiritual value for participants and related communities. It is therefore not surprising that the maintenance of surf breaks has become an important element of coastal tourism, and that tourism management has had a growing concern with anthropogenic impacts on the shoreline. In line with these developments, this study investigates the vulnerability of surf tourism given the general consensus that there has been a human-induced decline of the river-mouth surf break in Herold’s Bay. An adapted ecological services model is used, and in line with such models, the status of the three types of capital (natural (physical) capital, climatic capital, and built capital) and their effect on recreation capital (surfing’s participation, market, and non-market values) over a twenty-year period is tracked. The findings identified alterations to the river bed morphology, beach morphology, wind direction, and swell intensity and frequency as the main determinants in surf break decline. The corresponding increase in vulnerability of Herold’s Bay’s surf tourism industry is also given as having negative socio-economic impacts. This study has underlined both the potential and the imperative to conserve, utilise and develop surf breaks and the surf tourism industry within South Africa.
- Full Text:
- Date Issued: 2019
Zoning the Southwestern Indian Ocean to mitigate impacts from ocean-based hydrocarbon exploration and production on sea turtles
- Authors: Pretorius, Dirk
- Date: 2019
- Subjects: Ocean zoning , Marine ecology -- Indian Ocean Sea turtles -- Indian Ocean Marine animals -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43303 , vital:36787
- Description: The conflict between sea turtles and the numerous socio-economic developments in the Southwestern Indian Ocean (SWIO) are set to intensify as countries are looking to develop their ocean-based economies. The Hydrocarbon Exploration and Production (HEP) industry is of particular importance, since many of the SWIO governments view it as catalyst for development. This has raised concerns about potentially significant environmental impacts from the HEP industry, to sea turtles and their habitats, based on international examples where sea turtles have been severely negatively impacted upon, like the Deepwater Horizon spill in the Gulf of Mexico. Given that the four sea turtles species in the SWIO are listed on the IUCN Red List of threatened species, the aim of this study was to derive priority areas for sea turtles in the face of HEP, that could be used in an ocean zoning strategy for sustainable economic development of HEP in the SWIO region. To achieve this, the study spatially represented the main life-history stages of sea turtles, i.e. the breeding, migrating and foraging areas of Caretta caretta (loggerhead turtles), Dermochelys coriacea (leatherback turtles), Chelonia mydas (green turtles) and Eretmochelys imbricata (hawksbill turtles), within a telemetry derived distribution for each species. This spatial representation was used to quantify the extent of Marine Protected Areas (MPAs) conserving sea turtles in the SWIO, which revealed that sea turtle breeding areas were well represented in MPAs, including C. caretta (~40 %), C. mydas (~53 %), E. imbricata (~59 %) and D. coriacea (~22 %), the latter being least protected by MPAs during breeding, possibly due to a far greater extent of their internesting areas than the other three species. MPA coverage of breeding areas could be positively correlated to the increasing population trends of C. caretta and C. mydas in the SWIO, and therefore the assumption was made that increasing population trends of sea turtles are in part related to MPA protection of their breeding areas. In addition, the potential impacts on sea turtles from existing and proposed HEP developments were assessed and mapped by using a novel, species-specific rating index. The results revealed the extensive nature of potential water pollution impacts on sea turtles, constituting 16 of the top 28 most significant impacts from HEP on sea turtles. Other significant impacts on sea turtles associated with the HEP industry, included habitat destruction, light pollution and noise pollution. Importantly, this study found that ~70 % of all potential HEP impacts (irrespective of significance) on adult nesting sea turtles could be avoided if seasonal sea turtle movement during critical life stages are included as species-specific HEP mitigation measures. The data and maps on the main life-history stages of sea turtles, and the potential cumulative impacts from the HEP industry, were used in a Systematic Conservation Planning process, to derive a concept ocean zoning. As final outcome of this study, the concept ocean zoning highlighted areas where increased protection to sea turtles, and management of the conflict between sea turtles and the HEP industry, will be required if the HEP industry is to develop in a sustainable manner in the SWIO.
- Full Text:
- Date Issued: 2019
- Authors: Pretorius, Dirk
- Date: 2019
- Subjects: Ocean zoning , Marine ecology -- Indian Ocean Sea turtles -- Indian Ocean Marine animals -- Ecology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/43303 , vital:36787
- Description: The conflict between sea turtles and the numerous socio-economic developments in the Southwestern Indian Ocean (SWIO) are set to intensify as countries are looking to develop their ocean-based economies. The Hydrocarbon Exploration and Production (HEP) industry is of particular importance, since many of the SWIO governments view it as catalyst for development. This has raised concerns about potentially significant environmental impacts from the HEP industry, to sea turtles and their habitats, based on international examples where sea turtles have been severely negatively impacted upon, like the Deepwater Horizon spill in the Gulf of Mexico. Given that the four sea turtles species in the SWIO are listed on the IUCN Red List of threatened species, the aim of this study was to derive priority areas for sea turtles in the face of HEP, that could be used in an ocean zoning strategy for sustainable economic development of HEP in the SWIO region. To achieve this, the study spatially represented the main life-history stages of sea turtles, i.e. the breeding, migrating and foraging areas of Caretta caretta (loggerhead turtles), Dermochelys coriacea (leatherback turtles), Chelonia mydas (green turtles) and Eretmochelys imbricata (hawksbill turtles), within a telemetry derived distribution for each species. This spatial representation was used to quantify the extent of Marine Protected Areas (MPAs) conserving sea turtles in the SWIO, which revealed that sea turtle breeding areas were well represented in MPAs, including C. caretta (~40 %), C. mydas (~53 %), E. imbricata (~59 %) and D. coriacea (~22 %), the latter being least protected by MPAs during breeding, possibly due to a far greater extent of their internesting areas than the other three species. MPA coverage of breeding areas could be positively correlated to the increasing population trends of C. caretta and C. mydas in the SWIO, and therefore the assumption was made that increasing population trends of sea turtles are in part related to MPA protection of their breeding areas. In addition, the potential impacts on sea turtles from existing and proposed HEP developments were assessed and mapped by using a novel, species-specific rating index. The results revealed the extensive nature of potential water pollution impacts on sea turtles, constituting 16 of the top 28 most significant impacts from HEP on sea turtles. Other significant impacts on sea turtles associated with the HEP industry, included habitat destruction, light pollution and noise pollution. Importantly, this study found that ~70 % of all potential HEP impacts (irrespective of significance) on adult nesting sea turtles could be avoided if seasonal sea turtle movement during critical life stages are included as species-specific HEP mitigation measures. The data and maps on the main life-history stages of sea turtles, and the potential cumulative impacts from the HEP industry, were used in a Systematic Conservation Planning process, to derive a concept ocean zoning. As final outcome of this study, the concept ocean zoning highlighted areas where increased protection to sea turtles, and management of the conflict between sea turtles and the HEP industry, will be required if the HEP industry is to develop in a sustainable manner in the SWIO.
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- Date Issued: 2019