List of Titles

Fish community response to increased river flow in the Kariega Estuary, a freshwater-deprived, permanently open southern African system

- Vorwerk, Paul D, Froneman, P William, Paterson, Angus W, Whitfield, Alan K

Authors: Vorwerk, Paul D , Froneman, P William , Paterson, Angus W , Whitfield, Alan K
Date: 2008
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/481886 , vital:78594 , https://doi.org/10.2989/AJAS.2008.33.3.1.613
Description: The littoral and demersal ichthyofaunal community structure in the freshwater-deprived, permanently open Kariega Estuary was investigated following heavy rain in November 2006 and was compared to low-flow condition data from 1991 and 1996. All surveys took place during the spring months and allowed for a comparison of a wet and a dry spring period.
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Floating sulphur biofilms structure, function and biotechnology

- Molwantwa, Jennifer Balatedi

Authors: Molwantwa, Jennifer Balatedi
Date: 2008
Subjects: Biofilms Sulfur Acid mine drainage -- South Africa Mine water -- Purification -- Biological treatment Microbial ecology
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:3958 , http://hdl.handle.net/10962/d1004017
Description: Mine wastewaters generated during active production operations, and decanting streams following mine closure have major environmental impacts, and volumes requiring treatment are expected to increase substantially as the South African mining industry matures. Biological treatment of mine waters has been the subject of increasing interest, where sulphate reducing bacteria are employed for the reduction of sulphate to sulphide, precipitation of metals and the production of alkalinity. However, the sulphide if not removed from the system can be oxidised back to sulphate. As a result there have been limitations especially in the provision of technological options that are sustainable over the long-term, where the total sulphur (in its different forms) can be removed from the system. These, however, are the subject of a number of constraints including, importantly, the process capability to remove reduced sulphur from the treated stream, in one of its oxidation states, and thus linearise the biological sulphur cycle. This remains a major bottleneck in the development of biological wastewater treatment technology. Floating sulphur biofilms are observed as surface layers in numerous aquatic sulphide-rich environments, and it has been suggested that they play a role in the biological cycling of sulphur. The use of sulphur biofilms for the removal of elemental sulphur was identified in this study as a possible means for addressing the technological bottleneck, especially in passive wastewater treatment systems. There is, however, little documented information in the literature on the structure of floating sulphur biofilms, the microbial species responsible for their occurrence or bio-process applications of the system. A linear flow channel reactor was developed to simulate natural conditions and enabled the study of floating sulphur biofilm under controlled laboratory conditions. It was observed that these biofilms developed through three distinct stages termed Thin, Sticky and Brittle films. A microprobe study showed the presence of a steep Redox gradient established across (260 to 380 μm) depth of the floating sulphur biofilm of ~ 0 to -200 mV (top to bottom), which correlated with pH and sulphide gradients across the system. Structural investigations embedded in an exopolymeric matrix containing clearly defined channels and pores. Sulphur crystals were found to develop within the biofilm and above a certain size these disengaged and then settled in the liquid phase below the biofilm. These features, together with the ability of the biofilm to remain suspended at the air/water interface thus provide the surface requirement, and indicate that these structures may be understood as “true” biofilms. In order to study an apparent functional differentiation within the floating sulphur biofilm system, a method was developed to expand its various components over a 13 cm length of agarose tube and across which an oxygen/sulphide gradient was established. This was done by inserting a sulphide plug in the bottom of the tube, overlaying this with the biofilm mixed and suspended in agarose and leaving the tube to open air. After allowing for growth, the different components of the microbial population occurring at various levels across the oxygen/sulphide gradient were sampled. The microbial population was found to resort in distinct functional layers. Aerobes including Acidithiobacillus and Azoarcus, Acidithiobacillus, Thiothrix, Thiovirga and Sulfurimonas were found in the upper oxidised layer. Aerobe and facultative anaerobes such as Chryseobacterium, Bacteroides and Planococcus were found in the middle and heterotrophic anaerobes such as Brevundimonas and uncultured anaerobes were found in the bottom anoxic layer. This enabled the development of a first descriptive structural/functional model accounting for the performance of floating sulphur biofilms. The potential of the floating sulphur biofilm for use as a bioprocess unit operation for sulphide removal in lignocellulose-based low-flow passive systems for acid mine drainage wastewater treatment was investigated. The linear flow channel reactor was scaled up and it was shown that the optimum sulphide removal of 74 % and sulphur recovery of 60 % could be achieved at 20 °C. In a further scale up of the linear channel reactor, the floating sulphur biofilm reactor was developed and operated. Sulphide removal and sulphur recovery of 65 and 56 % respectively was measured in the process. An understanding of the nature and function of floating sulphur biofilms and the further development of their potential application in sulphide removal in aquatic systems may provide a useful contribution to the treatment of acid mine drainage and other sulphidic wastewaters.
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Flock inspired area coverage using wireless boid-like sensor agents

- Chibaya, Colin, Bangay, Shaun D

Authors: Chibaya, Colin , Bangay, Shaun D
Date: 2008
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/433440 , vital:72970 , 10.1109/UKSIM.2008.102
Description: Simulated flocking is achievable using three boid rules [13]. We propose an area coverage model inspired by Reynolds’ flocking algorithm, investigating strategies for achieving quality coverage using flocking rules. Our agents are identical and autonomous, using only local sensory information for indirect communication. Upon deployment, agents are in the default separation mode. The cohesion rule would then guarantee that agents remain within the swarm, covering spaces with explored neighbour spaces. Four experiments are conducted to evaluate our model in terms of coverage quality achieved. We firstly investigate agents’ separation speed before the speed with which isolated agents re-organizes is investigated. The third experiment compares coverage quality achieved using our model with coverage quality achieved using random guessing. Finally, we investigate fault tolerance in the event of agents’ failures. Our model exhibits good separation and cohesion speed, achieving high quality coverage. Additionally, the model is fault tolerant and adaptive to agents’ failures.
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Forensic Entomology: An Introduction, D.E. Gennard book: review

- Villet, Martin H, Richards, Cameron S

Authors: Villet, Martin H , Richards, Cameron S
Date: 2008
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/451690 , vital:75070 , https://hdl.handle.net/10520/EJC32766
Description: Since the publication of Smith's (1986) "A manual of forensic entomology", there have been a series of useful texts in forensic entomology, some written as authoritative resources (Byrd and Castner 2001; Greenberg and Kunish 2002; Wyss and Cherix 2006) and others as training manuals (Catts and Haskell 1990). Dorothy Gennard's contribution is a bit of both, being the first text written primarily as a broad introduction to medico-criminal forensic entomology for specialised undergraduate classes.
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Fungal remediation of winery and distillery wastewaters using Trametes pubescens MB 89 and the enhanced production of a high-value enzyme therein

- Strong, Peter James

Authors: Strong, Peter James
Date: 2008
Subjects: Fungal remediation Distilleries -- Waste disposal Wine and wine making -- Waste disposal Bioremediation Laccase Enzymes -- Biotechnology
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:3932 , http://hdl.handle.net/10962/d1003991
Description: In this study white-rot fungi were investigated for their efficiency at distillery wastewater remediation and the production of laccase as a valuable by-product. Distillery wastewaters are high in organic load and low in pH. The presence of phenolic compounds can lead to extremely colour-rich wastewaters and can be toxic to microorganisms. The presence of the inorganic ions may also affect biological treatment. White-rot fungi are unique among eukaryotic or prokaryotic microbes in possessing powerful oxidative enzyme systems that can degrade lignin to carbon dioxide. These ligninolytic enzymes, such as lignin peroxidase, manganese peroxidase and laccase, are capable of degrading a vast range of toxic, recalcitrant environmental pollutants and this makes the white-rot fungi strong candidates for the bioremediation of polluted soils and waters. The laccase enzyme alone has shown remediation potential in wastewaters such as beer production effluent, olive mill wastewater, alcohol distillery wastes, dye-containing wastewaters from the textile industry as well as wastewaters from the paper and pulp industry. It has been shown to be capable of remediating soils and waters polluted with chlorinated phenolic compounds, polyaromatic hydrocarbons, nitrosubstituted compounds and fungicides, herbicides and insecticides.
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Global diversity of mayflies (Ephemeroptera, Insecta) in freshwater

- Barber-James, Helen M, Gattolliat, J-L, Sartori, Michel, Hubbard, Michael D

Authors: Barber-James, Helen M , Gattolliat, J-L , Sartori, Michel , Hubbard, Michael D
Date: 2008
Language: English
Type: text , Article
Identifier: vital:6895 , http://hdl.handle.net/10962/d1011655
Description: The extant global Ephemeroptera fauna is represented by over 3,000 described species in 42 families and more than 400 genera. The highest generic diversity occurs in the Neotropics, with a correspondingly high species diversity, while the Palaearctic has the lowest generic diversity, but a high species diversity. Such distribution patterns may relate to how long evolutionary processes have been carrying on in isolation in a bioregion. Over an extended period, there may be extinction of species, but evolution of more genera. Dramatic extinction events such as the K-T mass extinction have affected current mayfly diversity and distribution. Climatic history plays an important role in the rate of speciation in an area, with regions which have been climatically stable over long periods having fewer species per genus, when compared to regions subjected to climatic stresses, such as glaciation. A total of 13 families are endemic to specific bioregions, with eight among them being monospecific. Most of these have restricted distributions which may be the result of them being the relict of a previously more diverse, but presently almost completely extinct family, or may be the consequence of vicariance events, resulting from evolution due to long-term isolation.
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Guidelines for Constructing Robust Discrete-Time Computer Network Simulations

- Richter, John, Irwin, Barry V W

Authors: Richter, John , Irwin, Barry V W
Date: 2008
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/429896 , vital:72649 , https://doi.org/10.1007/978-1-4020-8737-0_69
Description: Developing network simulations is a complex task that is often per-formed in research and testing. The components required to build a network simulator are common to many solutions. In order to expedite further simulation development, these components have been outlined and detailed in this paper. The process for generating and using these components is then detailed, and an example of a simulator that has been implemented using this system, is detailed
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Harvesting strategies of fuelwood and kraalwood users at Machibi : identifying the driving factors and feedbacks

- Scheepers, Kelly

Authors: Scheepers, Kelly
Date: 2008
Subjects: Fuelwood -- South Africa -- Eastern Cape Forest ecology -- South Africa -- Eastern Cape Natural resources -- South Africa -- Eastern Cape Natural resources -- Management -- South Africa -- Eastern Cape Conservation of natural resources -- South Africa -- Eastern Cape Landscape protection -- Economic aspects -- South Africa -- Eastern Cape Fuelwood consumption -- South Africa -- Eastern Cape Fuelwood consumption -- Economic aspects -- South Africa -- Eastern Cape Forests and forestry -- South Africa -- Eastern Cape Fuelwood conservation -- South Africa -- Eastern Cape
Language: English
Type: Thesis , Doctoral , PhD
Identifier: vital:4765 , http://hdl.handle.net/10962/d1007167
Description: Forest and woodland ecosystems provide a variety of natural resources such as fuelwood, brushwood and kraal posts to local communities, as well as possess important cultural and spiritual value. However, many forests and woodlands worldwide have been unsustainably used and managed. Thus, under pressure from the international conservation community to recognise the importance of people's relationships with their surrounding natural environment, particularly for the natural resources it can provide, and given a move away from the management of forests and woodlands for sustained yields, and according to simple cause and effect models, in favour of systems approaches, South Africa has developed some of the most progressive natural resource management policies in the world. Nevertheless, for these policies to be sensitive to local contexts, there remains a need for a better understanding of how local people in different contexts, determine forest and woodland ecosystems to be of use to them, and what 'usefulness' means to different groups of resources users. This is a case study, which examines the role of fuelwood, brushwood and kraal posts in the rural livelihoods of the people of Machibi village, located in the Eastern Cape province of South Africa, through people's preferences for particular landscapes and species, accessed for these purposes, and the trade-offs people make between resource availability and resource accessibility. Key objectives of the study are to 1) determine the preferred landscapes and species for fuelwood, brushwood and kraal posts at Machibi, 2) determine the landscapes and species actually used for fuelwood, brushwood and kraal posts, and 3) with the help of a conceptual model, and using iterative modelling as a tool, determine the factors that influence people's harvesting strategies in terms of the costs and benefits associated with the different landscape and species options. On the basis of this knowledge, the study provides some guiding principles for the better use and management of these landscapes and species for fuelwood, brushwood and kraal posts. An innovative research approach and methodology that integrates social and ecological systems, works across disciplines, and draws on different types of knowledge is used to develop and test a conceptual model of the harvesting strategies of fuelwood and kraalwood users at Machibi. Participatory methods such as workshops, participatory resource mapping, ranking exercises and trend-lines were used to tap into local knowledge while plotless vegetation sampling and GIS maps were used to capture the scientific information. Results showed that people did not always use the landscapes and species they preferred. However, the local people did behave in a rational manner by weighing up the returns from harvesting and accessibility costs associated with the respective options available to them, before selecting the option(s) associated with the greatest net benefits. At the landscape level, people made trade-offs between the returns from harvesting and the accessibility costs of using particular landscapes in addition to costs associated with the physical work of harvesting fuelwood, brushwood or kraal posts from these landscapes. At the species level, people made trade-offs between the returns from harvesting and the accessibility costs of harvesting particular species for fuelwood, brushwood and kraal posts, or the costs of commercial alternatives. Costbenefit factors that influenced people's resource use patterns also differed across landscapes and species for fuelwood, brushwood and kraal posts, respectively. Consequently, a range of diverse and flexible management options and strategies is recommended for the wise use and management of these landscapes and species, focused on short, medium and long term goals. These strategies examine the use of cost - benefit incentives to influence people’s landscape and species use patterns.
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Herbivory-induced reduction in photosynthetic productivity of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae), is not directly related to reduction in photosynthetic leaf areas

- Ripley, Bradford S, deWet, L, Hill, Martin P

Authors: Ripley, Bradford S , deWet, L , Hill, Martin P
Date: 2008
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/451425 , vital:75048 , https://hdl.handle.net/10520/EJC32746
Description: The purpose of this investigation was to determine whether the reduced photosynthetic productivity of water hyacinth plants subject to N. eichhorniae adult feeding was simply the result of reduced leaf area, or if more complex mechanisms were involved.
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High level internet scale traffic visualization using hilbert curve mapping

- Irwin, Barry V W, Pilkington, Nick

Authors: Irwin, Barry V W , Pilkington, Nick
Date: 2008
Subjects: To be catalogued
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/429911 , vital:72650 , https://doi.org/10.1007/978-3-540-78243-8_10
Description: A high level analysis tool was developed for aiding in the analysis of large volumes of network telescope traffic, and in particular the comparisons of data col-lected from multiple telescope sources. Providing a visual means for the evaluation of worm propagation algorithms has also been achieved. By using a Hilbert curve as a means of ordering points within the visual-ization space, the concept of nearness between nu-merically sequential network blocks was preserved. The design premise and initial results obtained using the tool developed are discussed, and a number of fu-ture extensions proposed.
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Home range dynamics of spotted grunter, pomadasys commersonnii, in a South African intermittently open estuary

- O'Connell, Bronwyn Anne

Authors: O'Connell, Bronwyn Anne
Date: 2008
Subjects: Grunts (Fishes) -- South Africa -- Eastern Cape , Pomadasys -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Estuarine fishes -- South Africa -- Eastern Cape , Estuarine fishes -- Habitat -- South Africa -- Eastern Cape , Fishery management -- South Africa -- Eastern Cape , Fishes -- Home range , Fishes -- Home range -- South Africa -- Eastern Cape
Language: English
Type: Thesis , Masters , MSc
Identifier: vital:5286 , http://hdl.handle.net/10962/d1005130 , Grunts (Fishes) -- South Africa -- Eastern Cape , Pomadasys -- South Africa -- Eastern Cape , Estuaries -- South Africa -- Eastern Cape , Estuarine fishes -- South Africa -- Eastern Cape , Estuarine fishes -- Habitat -- South Africa -- Eastern Cape , Fishery management -- South Africa -- Eastern Cape , Fishes -- Home range , Fishes -- Home range -- South Africa -- Eastern Cape
Description: The spotted grunter (Pomadasys commersonnii) is an important, estuarine-dependent, fishery species in southern Africa. Since estuaries are essential habitats in the life history of this species, the quantification of area use patterns and movements is important for fisheries management. In this study, acoustic telemetry was used to investigate movements, use of habitat and home range dynamics of spotted grunter in the small intermittently open East Kleinemonde Estuary on the Eastern Cape coast of South Africa. Nine spotted grunter (range: 326-489mm TL) were surgically equipped with uniquely coded acoustic transmitters. Positional fixes were obtained by manual tracking tagged individuals on six days and six nights during five tracking sessions from March to November 2004. In addition, five stationary data-logging receivers, moored at specific locations from the mouth to the top of the estuary provided additional long-term monitoring. Kernel home ranges (95% UD) varied in size (26 296-165 321m²) but were all located in a common high use area situated between 300-1 300m from the estuary mouth, which coincided with the highest abundance of prey items. There was no significant variation in home range size [C² (N = 9, df = 4) = 4.18; p = 0.38] between the temporally segregated tracking sessions (over nine months). The persistence of these home range estimates were confirmed by the long-term data-logging receivers. There was no significant diel variation in home range size [F(4, 64) = 0.05, p = 0.99] or core area size [F(4, 64) = 1.40, p = 0.25]. Fish length showed negative, although not significant, relationships between home range size (p = 0.225); number of home range areas (p = 0.065); core area size (p = 0.512) and home range length (p = 0.320). Use of habitat and home range dynamics of spotted grunter in the East Kleinemonde Estuary were consistent over the nine month study period, and they appeared to be influenced more by biotic than abiotic factors. However, when the mouth opened at the end of the study, most tagged fish vacated their home ranges and emigrated to sea.
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Household attributes promote diversity of tree holdings in rural areas, South Africa:

- Shackleton, Charlie M, Paumgarten, Fiona, Cocks, Michelle L

Authors: Shackleton, Charlie M , Paumgarten, Fiona , Cocks, Michelle L
Date: 2008
Language: English
Type: text , article
Identifier: http://hdl.handle.net/10962/141301 , vital:37960 , DOI: 10.1007/s10457-007-9066-5
Description: Trees within the homestead area provide many functions to rural households. However, within the semi-arid regions of southern Africa, there has been only limited examination of the correlates between the socio-economic attributes of rural households and the density, species richness and types of trees they keep. This paper reports on a multivariate analysis of household attributes in relation to homestead tree holdings from six rural villages in South Africa. In terms of density of trees per household, gender of the household head was the only significant correlate, with female-headed households having significantly fewer trees than their male-headed counterparts. This was especially so for the density of indigenous trees.
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Hydrolytic enzymes in sewage sludge treatment: a mini-review

- Burgess, Jo E, Pletschke, Brett I

Authors: Burgess, Jo E , Pletschke, Brett I
Date: 2008
Language: English
Type: Article
Identifier: vital:6478 , http://hdl.handle.net/10962/d1006166 , http://hdl.handle.net/10520/EJC116535
Description: Biological wastewater treatment processes can be classified as either aerobic or anaerobic. These two biological treatment processes are each characterised by groups of micro-organisms and their associated enzymes. Hydrolytic enzymes secreted by these micro-organisms are vital for the rate-limiting step of hydrolysis in the treatment of highly polymeric substrates present in sewage sludge. In this mini-review, the effects of mass transfer limitation, metabolic intermediates, extracellular polymeric substances (EPS), electron acceptor conditions and pH and temperature on the activity of these enzymes are summarised. The most salient and current perspectives of the significance and the role that hydrolytic enzymes play in sewage sludge treatment are highlighted.
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