<p>Very little protection has been afforded to wetlands1 and estuaries within the South African legislative framework.2 These ecosystems are extremely important and valuable to mankind, the flora and fauna.3 The continued destruction of wetlands and estuaries is the most heinous act of environmental vandalism on a worldwide scale today.4 Wetland and estuarine loss has been accelerated and extended by human activities such as mining,5 urbanisation,6 drainage, river diversion,7 groundwater abstraction as well as climate change.8 Time is running out for so many critically important sites and for the world at large.9 Without wetlands and estuaries the biosphere10 cannot continue to do its essential work.11 Despite, the importance of a range of resources and services12 which wetlands and estuaries provide, these have been taken for granted by humans.13 As a result hereof, the maintenance of wetlands and estuaries has received low priority in many countries.14 This is further precipitated by the lack of interest and ignorance which result in the conversion of wetlands and estuaries into man-made structures.15 Research has shown that the lack of information and the awareness of the importance of these ecosystems has the made the conservation legislation for these ecosystems a toothless dragon.16 People are becoming increasingly aware17 of the loss of wetlands and estuaries, once in abundance and now merely shadows of their former nature.18 To investigate this lack of protection, the starting point would be the global level.</p>

Phytoplankton serve as the bottom of the marine food web and therefore play an essential role in marine ecosystems. On the other hand, coastal phytoplankton communities can adversely affect the marine ecosystem and humans. A variety of techniques have been developed to measure and study phytoplankton, including in situ methods (e.g., flow cytometry) and laboratory methods (e.g., microscopic taxonomy). These provide accurate measurements of phytoplankton taxa and concentrations, yet they are limited in space and time, and synoptic information is difficult to obtain with these techniques. Optical remote sensing may provide complementary information for its synoptic nature, as demonstrated by satellite estimates of major phytoplankton taxa in major ocean basins. It has remained a challenge, however, for coastal and estuarine waters due to their optical complexity. One pioneering work relied on hyperspectral absorption spectra of phytoplankton pigments (Millie et al., 1995), from which Gymnodinium breve (i.e., Karenia brevis) blooms on the West Florida shelf could be detected and quantified in situ. However, whether a similar approach can be developed for estuarine waters where toxic blooms are often found is still unknown. Thus, the objective of this study is to test and develop an approach to classify major phytoplankton taxa found in two estuaries in Florida, U.S.A., based on optical analysis of the phytoplankton absorption spectra. In this study, over 250 surface water samples were collected on numerous cruise surveys from two Florida estuaries (Tampa Bay, ∼1000 km2 on the west coast; and the Indian River Lagoon, ∼900 km2 on the east coast). The samples were filtered and then processed using standard NASA protocols to determine 1) their spectral absorption coefficients due to phytoplankton pigments, aph (λ) (m-1), and 2) their chlorophyll a concentrations (mg m-3). aph (λ) was further normalized by Chl a, resulting in chlorophyll-specific absorption coefficient, a aph∗ (λ) (m2 mg-1). For each sample, phytoplankton cell counts were enumerated by the Florida Wildlife Conservation Commission (FWC) Fish and Wildlife Research Institute (FWRI) through microscopic taxonomy. The a aph∗ (λ) data were then categorized based on the dominant phytoplankton taxa, and were separated as either bloom or non-bloom using a 100,000 cell∕L threshold of the dominant taxa. Three techniques were tested for classifying phytoplankton taxa using absorption spectra; a first derivative summation, a relative height analysis, and an integration analysis. The integration technique proved to be the most successful of the three. This technique performed an integration of a aph∗ (572-600nm) against a linear baseline, and yielded an 81% success rate (13 of 16 samples) and 9% false positive rate (13 of 144 samples) in separating blooms of the dinoflagellate Pyrodinium bahamense from other bloom and non-bloom taxa found in the Tampa Bay estuary. The same integration technique, but with the wavelength range shifted to 471 nm - 490 nm, was also applied to the samples collected in the Indian River Lagoon estuary from summer 2011 to study the green flagellate of the class Pedinophyceae.. The results showed an 80% success rate (8 of 10 samples) and a 0.5% false positive rate (1 of 156 samples) in separating the Pedinophyceae bloom taxa from other bloom and non-bloom taxa found in both the Indian River Lagoon and Tampa Bay. The number of bloom samples was relatively low (16 from Tampa Bay and 10 from IRL). Thus, the results from this study are preliminary and will require more sampling in order to further develop this technique to a practical method for field use. However, the results obtained from this study are comparable to those from other techniques for classification of phytoplankton taxa, for example, BreveBuster, SIPPER, FlowCAM, and satellite ocean color remote sensing of the open ocean. Yet this technique extends to optically complex estuarine waters, and therefore may represent a step towards the ultimate goal of applying satellite remote sensing in characterizing phytoplankton taxa in estuaries. Once confirmed with more samples from the same two estuaries as well as from other estuaries, an immediate next step may be the implementation of in situoptical instruments on either buoys (e.g., MARVIN in Tampa Bay) or flow-through systems to provide continuous characterization of major phytoplankton taxa in the two estuaries.

<p>Very little protection has been afforded to wetlands1 and estuaries within the South African legislative framework.2 These ecosystems are extremely important and valuable to mankind, the flora and fauna.3 The continued destruction of wetlands and estuaries is the most heinous act of environmental vandalism on a worldwide scale today.4 Wetland and estuarine loss has been accelerated and extended by human activities such as mining,5 urbanisation,6 drainage, river diversion,7 groundwater abstraction as well as climate change.8 Time is running out for so many critically important sites and for the world at large.9 Without wetlands and estuaries the biosphere10 cannot continue to do its essential work.11 Despite, the importance of a range of resources and services12 which wetlands and estuaries provide, these have been taken for granted by humans.13 As a result hereof, the maintenance of wetlands and estuaries has received low priority in many countries.14 This is further precipitated by the lack of interest and ignorance which result in the conversion of wetlands and estuaries into man-made structures.15 Research has shown that the lack of information and the awareness of the importance of these ecosystems has the made the conservation legislation for these ecosystems a toothless dragon.16 People are becoming increasingly aware17 of the loss of wetlands and estuaries, once in abundance and now merely shadows of their former nature.18 To investigate this lack of protection, the starting point would be the global level.</p>

No description available.

This thesis documents eight estuaries that are situated on the northern coastline of KwaZulu-Natal viz.: St Lucia, Mfolozi, Zinkwazi, Mvoti, Mngeni and those of the South i.e. Isipingo, Manzimtoti and Mkomazi. The documentation is aimed at undertaking a holistic approach on estuaries of KwaZulu-Natal approximately 10% and determines the influence of anthropogenic and natural impacts upon their health status. The study has also analysed selected sample estuaries of KZN in terms of their general natural characteristics, looked at the morphological features, riparian vegetation and land use directly from site visits and from aerial photographys, and determined the influence of anthropogenic and natural impacts in the estuaries. It also assessed the health status of the estuaries, proposed appropriate management strategies and reviewed the current status of estuaries in KZN / southern Africa. The researcher employed quantitative approach as a viable and the most relevant method where a holistic approach has been used. This was achieved through the execution of various techniques. For instance, reconnaissance survey was conducted including the usage of aerial photographys and topographical maps. Data was also collected using the YSI 6920 model. The study was also undertaken in order to determine whether the KwaZulu-Natal estuaries were still having a nursery function, which appeared to be losing when considering both primary and secondary activities that took place in the catchment areas. All of these estuaries were under a severe stress and pressure through natural and anthropogenic phenomenon. They were all suffering and gradually getting contaminated and depleted through anthropogenic activities that took place uncontrolled in their catchmenmt areas. Findings also show humans as the main culprits for estuarine contamination and degradation. It was discovered that about 84.2% of the catchment areas within the study area was human occupied. Their suffering differed as it depended on the extent in which catchment areas were utilized. Where anthropogenic activities took place alarmingly, estuaries also suffered a great deal. This posed a challenge to ecologists, hydrologist and environmentalists generally, and to physical geographers specifically since they regard estuaries as very important for their nursery functions and ecological balances. Mfolozi and St Lucia estuaries were found to be little affected from direct anthropogenic effects. Pollutants accumulating in the systems may have come from farmlands in the north of the Mfolozi and from the town of St Lucia in the case of the St Lucia estuary. However, more negative effects were clearly due to excessive sedimentation. The study has revealed that the Mfolozi mouth position had been artificially relocated on several occasions since 1952 by human intervention in the system. In these situations, the Mfolozi mouth may be located between one and two kilometres south of the St-Lucia mouth. Two estuaries, Mvoti in the north and Isipingo in the south were found to be the most affected water bodies by human activities occurring in the catchment areas and this has led to them having unhealthy water status. It was found that through anthropogenic interference, there were changes in the nature of runoff and water quality that was attributed to industrial pollution, runoff from agricultural activities, sewage effluent and the runoff from urban areas. There is evidence of extremely poor catchment management practices as proved by the poor state of many estuaries along the KwaZulu-Natal coast. The study recommended that for the important future well being of these estuaries, various tiers of catchment management authority must be put in place by the Department of Water Affairs and Forestry. The local authorities must proactively manage land uses and anthropogenic activities on and around the estuaries in order to minimise potential impacts on the systems. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2008.

This mini-dissertation contains the results of research to establish a[1 economic value for the mangroves of the Mngazana Estuary in the Eastern Cape. The research is presented in two parts. Component A comprises the literature review and also describes the scope and context for the study, its purpose and the proposed methodology. Component B presents the results of the research in the format of an article to be submitted for publication to the African Journal of Marine Science. Estuaries and mangroves are among the most threatened habitats in South Africa, with the third largest mangrove forest in South Africa at the Mngazana Estuary on the Wild Coast of the Eastern Cape gradually reducing in size. A lack of appreciation of their value has resulted in policies and decisions that promoted the conversion of estuary and mangrove ecosystems to alternative uses, and caused a large-scale loss of mangroves throughout the world. Apart from their key ecological role, the Mngazana Estuary mangroves provide important benefits to the 645 households in three villages that utilise the resources and the sustainable use and management of the mangroves is essential. Economic valuation ascribes values to traded and untraded environmental resources and is a tool that supports policy formulation and decision-making on sustainable management of resources like mangroves. The theory of total economic value provides the conceptual framework for estimating the economic value, but constraints limited this study to estimating the socio-economically significant benefits the mangroves bestow on the communities around the Mngazana Estuary. Using information collected in a household survey and focus group discussions, market-price methods were used to estimate the value of mangroves harvested for building materials and the subsistence consumption of fish by the communities. Values were estimated for mangrove-dependent canoe trails and honey production operations, while a recreational use value was estimated on the basis of travel costs and expenses incurred by visitors to the holiday cottages adjacent to the estuary. The results were incorporated in 20-year valuation models with the net annual benefits then discounted to present value terms. Sensitivity analysis was performed to estimate lower-bound, upper-bound and most-likely values for the benefits. The minimum economic value of the mangroves was estimated to be between R1.1 and R13.6 million, with a most-likely value at a real 5% discount rate of R7.4 million. This study has shown that policies for managing environmental resources must be ecologically, socially and economically sound. This requires an integrated approach to address the socio-economic needs of local communities while safe-guarding environmental resources. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

Global shifts in environmental decision-making from technocratic, top-down models to democratic, open-ended forums to address environmental issues have highlighted the complexity of environmental issues. As a result, the definition of these environmental problems in the political arena is highly contested and thus the process of formalising environmental discourses through environmental policy-making has become very important. Hajer’s (1995; 2003) argumentative discourse analysis approach is used as a methodology to examine environmental policy-making regarding the St Lucia estuary mouth, in KwaZulu-Natal. This is also used to structure the presentation of the analysis particularly according to the terms of the policy discourses, such as the broad societal discourses, the local discourses and and the storylines. The environmental discourses are characterised using Dryzek’s (1997: 8) taxonomy of environmental discourses, based on his broad definition of discourse as “a shared way of apprehending the world”. This research aims to identify the environmental discourses that emerged in the 1940 to 2005 period regarding the management of the St Lucia estuary mouth and the shifts in discourses that have taken place during this time. An analysis of the shifts in environmental discourses in the Greater St Lucia Wetland Park over a 65 year period revealed two significant events that punctuated the management discourses of the protected area and effectively divided the analysis into three succinct periods. These two events were the Kriel Commission of Enquiry in 1966 and Cyclone Demoina in 1984. The promethean, ecological modernisation and survivalist discourses were dominant throughout the three periods analysed. The evidence also shows that there has been a shift from modernist engineering discourse to a more ecosystem discourse which advocates that ‘let nature take its own way’. Science remains a dominant force in shaping environmental policy-making in St Lucia; however environmental problems have become discursive in the post-apartheid period in a democratic South Africa and thus require a discourse that has wider stakeholder representation. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2009.

Estuaries are complex ecosystems, typified by remarkable fluctuations in environmental conditions. In addition to this natural variability, stochastic events and anthropogenic influences effect change at different spatial and temporal scales. Macrozoobenthic invertebrates are preferable biological indicators because of their sensitivity to variations in habitat quality. This thesis describes inherent changes in the macrozoobenthos of temporarily open/closed estuaries (TOCEs) in KwaZulu-Natal, ‘change’ as measured in spatial and temporal community differences using various community metrics, namely species composition, abundance and diversity. Standard and widely published quantitative sampling techniques were employed, with simultaneous measurements of ambient physico-chemical conditions, including sediment characteristics. The thesis is in three parts. Regional distributions and long-term decadal-type changes in macrozoobenthic community structure were determined for 31 TOCEs using historical data (1998/9) compared with more recently collected data (2009/10). Results showed that, although of the same estuary type, the macrozoobenthic communities of these estuaries differed significantly. Furthermore, community composition did not reflect a north to south progression of predominantly tropical species to predominantly warm-temperate species. In the last decade, the macrozoobenthos of these systems had indeed changed (in composition, abundance and/or diversity), the scale of change within each estuary being estuary-dependent. The recolonisation of two urban and non-urban estuaries by macrozoobenthos following a stochastic flood disturbance was investigated, describing the short-term community changes during the recovery process. Differential recolonisation patterns were attributed to inherent differences in community composition and not to the influence of urbanisation. Recolonisation was marked by distinct changes in community structure, with the recovery trajectory being interrupted by localised disturbances (e.g. change of mouth state). Species indicative of the observed spatial and temporal community changes were examined for similarities in habitat association and trophic characteristics. The species that were representative of these KwaZulu-Natal TOCEs were identified and included common and highly abundant generalists of varying trophic groups. In conclusion, the present findings illustrated the effectiveness of using macrozoobenthic communities to depict ‘change’ over multiple temporal and spatial scales. This also supports their usefulness as a study group in environmental monitoring and detecting the loss of ecological functioning and biodiversity in estuaries in the long- and short-term. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

Estuaries, the interface of interaction of fluvial discharge and marine action serve as temporary repositories of materials (solid and dissolved) before finally exporting them to sea. This interchange of material is dependent on a range of factors such as tidal range, prism, and symmetry; fluvial flows and estuarine morphodynamics. The efficacy of transfer of materials to the marine environment is important for estuarine health particularly in estuaries located in highly developed areas such as the major coastal metropolitan areas of many countries. This study assesses the efficacy of the export of nitrates from three estuaries of the eThekwini Municipality of the city of Durban, South Africa which maintain an open mouth status, ensuring tidal exchange throughout the year. The focus of this study was to determine and analyze the net flux of nitrates between the Isipingo, Mgeni, and Tongati estuaries of the eThekwini Municipality, and their adjacent nearshore environments. It questioned whether the Isipingo, Mgeni, and Tongati estuaries were efficient at exporting nitrates to their adjacent marine environments. The abovementioned estuaries are classified as temporarily open/closed estuaries, and were chosen for this study, as they maintain an open mouth status for most of the year. An open mouth condition was critical in order to conduct this study, as tidal exchange, and the resulting nitrate fluxes, could occur. The net flux of nitrates was measured for these estuaries on a seasonal basis for both spring and neap tides. Measurements were taken over the tidal cycle, ensuring that the peak high and low tides were sampled. To determine the values of net flux, the cross-sectional area of the estuary mouths were measured; average flow velocities of water were measured; and average concentrations of nitrates were obtained. Results indicate that although there is a net export of nitrates to the nearshore environment, there were instances, particularly on the spring tide, when a net import of nitrates into the estuary occurred. The origin of the latter is likely derived from nearshore upwelling; unusually high biotic decomposition at sea and/or the longshore drift transport of decomposing sewage outfall. This creates an added dimension for consideration in estuarine management plans. Taking all three estuaries studied into consideration, a net export of nitrates for all seasons for the eThekwini Municipality was measured with a clear seasonal influence detected where high rainfall seasons led to greater export as a consequence of greater fluvial flows, erosion and leaching of agricultural lands and longer ebb duration. / Thesis (M.Sc.)-University of KwaZulu-Natal, Westville, 2011.

The significance of this research is to see if South Africa needs wetland and estuarine specific legislation to conserve these ecosystems. Indeed, South Africa is in need of wetland and estuarine specific legislat ion, to conserve wetlands and estuaries for future generations to come. The current law and policies do not suffice to conserve these service systems. South Africa does have statutes which afford protection to these ecosystems, but this protection is limited with regard to wetlands and estuaries. / Magister Legum - LLM