| --> Phycology is the study of algae - a group of organisms which are primitive and that are able to inhabit a wide range of diverse habitats. They vary from marine to freshwater, thermal springs to snow, aquatic to terrestrial habitats, and from microscopic to large kelps of greater than 30 metres. In spite of our lack of proximity to the sea, much of our research efforts concentrate on marine algae! Microscopic algae: Surveys of inshore marine microscopic plankton species are being carried out to provide important baseline data for future reference. Developmental and cell biological studies are being carried out on selected microalgal groups as well as ultrastructural and phylogenetic studies on microalgae using techniques such as light and electron microscopy. Toxic marine algae and their economic importance are being investigated in close co-operation with the Sea Fisheries Research Institute. Macroalgae: Interests revolve around the diversity of seaweeds in southern Africa, with distinctly different west (cold water), east (warm water) and south (mixed temperature) coasts providing different seaweed flora and marine communities. Little is known about the possibilities of using southern African seaweeds as a source of commercially valuable raw material. Our recent research efforts have concentrated on the biogeography of seaweeds in the Kwazulu/Natal and Mozambique regions, where a number have potential for commercial utilization. We are examining ways in which the seaweeds could be sustainably harvested or conserved as seed-stocks for utilization in seaweed farms.
Seaweeds produce gels (agar, carrageenan and alginic acid), with very specific binding, stabilizing and gelling properties, that are used for microbiological test plates (to identify bacteria and fungi in hospitals) jellies, jam, ice cream and toothpaste, and can chelate (bind) metals and nutrients. We are investigating the use of South African seaweeds and gels to remediate damaged soils and to monitor levels of pollution in the ocean. Seaweeds are also sources of novel chemicals some of which have antimicrobial properties; these are being investigated for their potential in food preservation, treatment of soil pathogens and as sources of new pharmaceuticals. Staff involved in this area of research: - Professor Richard Pien r,
- Dr Stuart Sym.
- Professor Alan Critchley (now at the University of Namibia) is still supervising some research projects.
Postgraduate students: - SUSAN BRADLEY (BSc Honours) Supervisor: Professor Richard Pien r
The ultrastructure and growth of the green dinoflagellate Lepidodinium viride with special reference to its endosymbiont.
Lepidodinium viride is a green dinoflagellate which contains chloroplasts which are thought to be prasinophyte in origin. Detailed optical and electron microscopy studies will be done on an isolate of L. viride from False Bay, Cape Town. Growth studies will also be done to establish to test the stability of this endosymbiotic association.
- ANGELA FREEMAN (BSc Honours) Supervisor: Professor Richard Pien r
A study of Gymnodinium cf galatheanum: A Toxic marine dinoflagellate from Namibia
A toxic dinoflagellate responsible for the mass mortality of fish in Namibian waters, and tentatively identified as Gymnodinium cf galatheanum, will be compared with a culture of Gymnodinium galatheanum which was obtained from the Danish Culture Collection. This work will involve a comparison of growth in batch culture, optical and electron microscopy and toxicity of each taxon. - RUSSELL GILLESPIE(PhD) Supervisor: Professor Alan Critchley (Now at the University of Namibia)
An investigation of Sargassum stocks at Reunion Rocks KwaZulu Natal South Africa
The brown algal genus Sargassum is problematic in that it has many species described which are highly morphologically variable. This work sets out to examine the populations of Sargassum at Reunion Rocks as a renewable resource of material (either for alginic acid extraction or other higher value products from this brown seaweed, ie fertilisers). In order to make recommendations for sustainable utilization of the resource, it was necessary to identify the species composition and examine seasonal variability of the population and its constituents. This involved detailed site assessments, demographic and detailed morphological descriptions and a study of the chemical constituents (i.e. alginic acid). All data collected have been treated to rigorous statistical analyses. Aspects of the research have been presented at several international phycological congresses, and the thesis is being reported in the form of published papers. - CLAUDIO MARANGONI (MSc) Supervisors: Professor Richard Pien r and Dr Stuart Sym
The potential for the introduction of alien phytoplankton by shipping ballast water: Observations in Saldanha Bay
Saldanha Bay is an important site for both shipping and mariculture. This study investigated the seasonal phytoplankton composition of Saldanha Bay and compared this with those encountered in ship ballast waters. Results indicate that the ballast waters do not pose a threat in Saldanha Bay, but this should be tempered with an awareness that ballast sampling strategies were not ideal and that such monitoring should be on-going. A catalogue of all organisms encountered during this study (173 taxa, mainly diatoms and dinoflagellates) has been constructed for future reference. - LAURA PINO (MSc) Supervisor: Professor Alan Critchley (now at the University of Namibia)
Morphological variation of the green alga Caulerpa racemosa from KwaZulu Natal South Africa
The green algal genus Caulerpa contains a number of species, all of which show a remarkable plasticity in their morphological appearance, so much so that there is considerable confusion between species (particularly racemosa) and subspecies; even ecads and morphotypes have been used by various authors to circumscribe the variation. This work sets out to examine the ranges of morphological variability within C. racemosa and closely allied species. Materials were collected from a number of localities in KwaZulu Natal and the range of variation determined. This variability has been described using numerical taxonomy. In addition, the most common forms have been cultured in the laboratory and responses to temperature and light have been recorded. Here we have been able to get a tremendously wide range of morphological expression, so much so that the concepts of several of the species have to be challenged. This study will lead to a better understanding of morphological expression as a response to environmental variables in Caluerpa and a taxonomic revision of the forms attributed to C. racemosa.
- MELANIE SKEGGS (MSc) Supervisor: Dr Stuart Sym
Characterisation of a novel structure in the Prasinophyceae
A novel structure, that has been nicknamed the bottle-brush structure, has been observed in unicellular green algae of the class Prasinophyceae, namely Cymbomonas tetramitiformis, Pterosperma cristatum, Pyramimonas propulsa, and a new Pyramimonas species. The continuity and extent of the structure within the cell is being investigated by viewing serial sections of embedded material using a transmission electron microscope. The composition of the bottle-brush structure is being ascertained using postembedding immunogold labelling and indirect immunofluorescence. |
