Plastic particle characterization and concentrations found in the river and marine water environment of Algoa Bay, South Africa
- Authors: Moss, Kerry-Leigh
- Date: 2021-12
- Subjects: Marine pollution , Plastic marine debris --Environmental aspects , Algoa Bay -- Eastern Cape
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10948/55645 , vital:53403
- Description: With just 4% of published plastic pollution research, the African region remains one of the most poorly 221 understood areas, leaving a large knowledge gap in our understanding of this global pollution problem 222 (Hurley, Woodward, & Rothwell, 2018). It is estimated that 64 to 90% of the ocean’s plastics originate 223 from fluxes in the terrestrial environment, however determining the exact source is not a simple task 224 (Andrady, 2011; Hurley et al., 2018). Plastic items, including the biodegradable plastic items, 225 breakdown in the marine environment through mechanical action resulting in non-degradable 226 microscopic fragments of synthetic polymers (Thompson et al., 2004). However, the consequences of 227 these microplastic fragments.This research intends to address two aims; first, to provide an estimation of the quantity of plastic 235 transportation via African rivers to the greater body of knowledge of global plastic emissions. This aim 236 will specifically focus on determining plastic output via Port Elizabeth rivers into the Algoa Bay marine 237 environment. The second aim of this research is to quantify and characterize the amount of microplastic 238 in the marine environment of Algoa Bay. The second aim will focus on identifying microplastic (MP) 239 throughout the water column. 240 This research consists of six objectives; first, to identify, design and field test a cost-effective system for 241 monitoring macroplastic quantity output from riverine to marine environments. Second, to contribute to 242 the body of knowledge of African river plastic pollution through quantification and characterisation of 243 macroplastics in the Port Elizabeth rivers. Third, to compare three very different rivers with different 244 levels of urbanisation (industrial, urban, and remote) to ascertain the impact of population and 245 government pollution management protocols on plastic emissions. Fourth, to measure microplastic 246 quantities at three depths from eight locations across the marine environment of Algoa Bay. Fifth, quantitatively characterize the microplastics in Algoa Bay to highlight any patterns of distribution. Sixth, 248 to compare the Algoa Bay concentrations with published international marine microplastic findings. , Thesis (MSc) -- Faculty of Science, Ocean Science, 2021
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- Date Issued: 2021-12
Upwelling on the Southeast Madagascan shelf: frequency, extent, and driving mechanisms
- Authors: Collins, Matthew
- Date: 2020
- Subjects: Upwelling (Oceanography) -- Madagascar , Oceanography -- Research -- Madagascar Marine biology -- Indian Ocean
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/49060 , vital:41597
- Description: The southeast coast of Madagascar, namely the region surrounding the town of Fort Dauphin, is an area that regularly experiences upwelling events. Two unique high frequency data sets, UTR data, and wind data retrieved from a nearby airport, are the primary data sets used to investigate the nature of the upwelling, i.e. the area that experiences upwelling, how often it occurs, and its mechanisms. To complement the in-situ data, several different satellite data sources are used alongside the in-situ data to study this relatively remote region, i.e. SST, chlorophyll-a concentration, current, and wind data. The results refine upon previous literature on the topic. The upwelling covers an area of 1o latitude by 1.3o longitude, and occurs on average 14 times per annum. The mechanism driving the upwelling can be attributed to both wind and current, with wind the more dominant driver along the south coast, and current more dominant along the east coast. Separate to the main objective of the thesis is the importance of in-situ data when analysing small scale events such as upwelling events. While the in-situ wind data were found to be unreliable due to its location within a valley, the UTR data were of vital importance in identifying and studying the finer details of the upwelling events. The satellite SST data, by comparison, were lacking in their ability to investigate the upwelling events. The satellite derived wind data, however, did prove useful when analysing the wind as a driver of the upwelling.
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- Date Issued: 2020
Testing the application of coastal altimetry in two South-Eastern African bights: the relationship between mesoscale features and chlorophyll-a, cyclonic eddies in the Indian Ocean
- Authors: Ziegler, Lisa
- Date: 2018
- Subjects: Oceanography -- Remote sensing -- Indian Ocean
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/15225 , vital:28188
- Description: Enhanced coastal altimetry, adaptive Leading-Edge Subwaveform(ALES), was used to study wo well known eddies along the southeastern African coast, namely the Delagoa Bight Lee Eddy and the Durban Lee Eddy. I address a two part problem. Firstly, how well does the application of coastal altimetry techniques behave in the coastal region? Secondly, is there a relationship between the eddies’ presence and chlorophyll-a (chl-a). Sea level anomalies (SLA) were computed from the re-tracked ALES data of two satellite missions — Envisat (used for Delagoa Bight eddy) and Jason -2 (for the Durban eddy) with geophysical corrections removed. These datasets were compared with the original satellite, 1 Hz RADS, AND AVISO gridded data. Two regions were selected to see if there was a biophysical link. A centre region of the eddy and an outside region of the eddy were taken. Results indicate that coastal altimetrywas successful in delimiting both features. ALES was less noisey and able to recover more data that were missed by the 1 Hz RADS dataset. Hovmöller plots showed the Delagoa Bight eddy to be more of a transient feature than semi-permanent, as had previously been suggested. Results from the linear model indicate a negative correlation between SLA and chl-a. This influence could be through facilitation of chl-a in the bight or just retaining chla. This is hard to elucidate without in situ data. These results show a promising indication that coastal altimetry will be a useful and reliable product to further biophysical coupling research along the coast.
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- Date Issued: 2018
A critical study of the evidence of Andries Stockenstrom before the Aborigines Committee in 1835, viewed in the light of his statements and policies before 1935
- Authors: Urie, J M
- Date: 1953
- Subjects: Stockenstrom, Andries, 1792-1864 , Eastern Cape (South Africa) -- History -- 19th century
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:2617 , http://hdl.handle.net/10962/d1013416
- Description: In recent years, increasing interest has been taken in the career of Andries Stockenstrom. Detailed study of his policy as Landdrost of Graaff-Reinet , as Commissioner-General of the Eastern Districts, and as Lieutenant-Governor, has brought about a realization of the soundness and value of much of his work. This appreciation of the sterling qualities of Stockenstrom's character- despite his undoubtedly difficult temperament - has led to the tacit assumption that the accusations which were levelled against him, and the odium in which he was held in Albany, after his evidence before the Aborigines Committee 1835 -1836, were largely the result of unfortunate newspaper propaganda. That evidence, it is implied - coming as it did at a time when public opinion was peculiarly sensitive to criticism - was in fact, not as black as it had been painted. Yet the events of the period between the Commissioner-Generalship and the Lieutenant- Governorship have not only coloured the judgment upon Stockenstrom of almost every writer on South African history, but so influenced contemporary public opinion as to materially impair the efficiency of his Lieutenant-Governorship. In writing this thesis, it has heen my purpose to make a detailed study of such material as is available for the period 1833-1836, and to endeavour, by an analysis of the evidence more particularly in the light of the years before 1833, to set this significant period in Stockenstrom' s career in its right perspective.
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- Date Issued: 1953