Browsing by Author "Keats, Derek W."

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    The experimental cultivation and alginate properties of South African kelps
    (University of the Western Cape, 2003) Harper, Mellisa N; Keats, Derek W.; Anderson, Robert J.
    Alginates are used in various industries and the quality of alginates used must be controlled. Alginates used for medical purposes must be of a very high quality. The cost of obtaining high-quality alginate is high and very time-consuming. A simple procedure is described for the purification and extraction of alginate from the kelp Laminaria pallida. The kelp was divided into different sections, including the blades. The stipes were cleaned and some were peeled and extractions were made of all the different sections including the peels. Analysis of the purified alginate showed a protein content below detectable levels and a very low polyphenol content. The purified alginate was highly viscous, with24 - 29 centipoise for a0.l %o solution. Using this method a higher quality alginate can be obtained from any section of the kelp and this will help in more medical advances
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    First report of the melobesioid alga (Corallinales, Rhodophyta) Mesophyllum incisum (Foslie) Adey in South Africa
    (Elsevier, 1997) Keats, Derek W.; Maneveldt, Gavin W.
    Mesophyllum incisum is reported and studied for the first time in South Africa. It has a th all us surface (SEM) with Leptophyturn-type epithallial cells. TetraJbisporangial conceptacles are mound-like and lack a peripheral rim but have a flattened pore plate. The rosette cells surrounding the tetrasporan gial po res are distinct from su rrounding roof cells (SEM, surface view) in be ing narrower, and sunken below the level of the surrounding pore plate. The cells of filaments bordering the tetrasporangial conceptacle pore canal differ from the othe r roof cells within the pore plate in being more elongate, narrower, and often more densely staining. Pore canal filaments also generally contain fewer cells than the surrounding filaments of the pore plate and th e pore can al is more-Dr-less parallel sided. Our material agrees closely with the species as reported in Australia.
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    Site selection and community participation in the development of Gracilaria Gracilts (stackhouse) steentoft, irvine and farnham mariculture in the Western Cape province, South Africa.
    (University of the Western Cape, 1999) Brown, Bernadette; Keats, Derek W.; Anderson, Robert J.
    The seaweed Gracilaria gracilis has been shown in previous studies to have potential for mariculture along the West Coast of South Africa. However, the selection of suitable sites is crucial for the success of a farming enterprise. The variables important in the success or sustainability of suspended raft culture, and the environmental factors influencing these variables, were identified through a literature review. A suitable site was defined as a site with surface water temperature of between 10 and 17 "C, water depth of between 2 and 10 m below surface, and wave heights of less than 4 m. Data and information about these factors were obtained from sources such as the Sea Fisheries Research Institute, the SADCO database, the CSIR and from volunteers in St Helena Bay. The objectives of this study were to convert available data into formats that could be used in a Geographical Information System (GIS), and to predict suitable and available sites for suspended cultivation of Gracilaria gracilis in Saldanha Bay, Langebaan Lagoon and St. Helena Bay. Data were converted to digital format and data layers created. Each data layer represented suitable and unsuitable areas. Areas with existing mariculture, harbours, ship traffic zones and other uses were excluded to determine the real available areas. The Saldanha Bay-Langebaan lagoon system and St Helena Bay, have sites that show potential for suspended cultivation of G. eracilis. The total sizes of the areas selected as suitable are 975.4 ha in Saldanha Bay and 474.8 ha in St. Helena Bay. Some sites predicted as suitable are located in areas known to be subject to conditions not suitable for seaweed mariculture, and led to the conclusion that the accuracy of input data or method of analysis must be improved.