| dc.description.abstract | The core focus of my research is harmful algal blooms and the associated freshwater quality of South African freshwater resources. My research program is built on 4 united pillars: basic water quality and phytoplankton biodiversity, phytoplankton eco-physiology, molecular ecology, and bioinformatics.
Two important aims of my research were to investigate harmful algal bloom formation and to develop an early warning system, based on environmental modelling by means of hybrid evolutionary algorithms, for the prediction of algal-related impacts on drinking water purification. This has enabled managers and scientists to evaluate the processes in relation to potential impact risk scenarios. Based on these scenarios preventative measures can be derived and implemented, if necessary, thus reducing the algal-related impacts on the drinking water purification process. This may result in cost savings and facilitate the production of drinking water through-out the year. I have succeeded in doing this with the article published on the dynamics of toxic Microcystis blooms, my most cited paper to date. Furthermore, a rule-based agent for Microcystis and Ceratium, has already been developed and validated conceptually by a PhD student under my supervision and was then tested successfully in Rietvlei Dam as part of a WRC project. Two other rule-based agents developed for Microcystis and Microcystin have been tested for Rand Water and adopted into their Water Safety plan, by another PhD student under my supervision. During this research I had the opportunity to collaborate with Prof Friedrich Recknagel School for Earth and Environmental Sciences, University of Adelaide, Adelaide, Australia, as well as with Prof H du Preez and his co-workers from Rand Water.
To do this research, it was necessary to first obtain a more complete understanding of the physiological rationale for the occurrences of harmful algal blooms. In my research this was done with laboratory studies employing measuring techniques for chlorophyll fluorescence and enzyme activities. This research provided us with the basic knowledge to investigate the toxicity of harmful algal blooms as well as the environmental conditions triggering the toxic response through molecular ecology. The research also made it possible for me to collaborate with with Prof Kaarina Sivonen from the Helsinki University, Helsinki, Finland and Dr Downing from the Department of Biochemistry and Microbiology, NMMU Port Elizabeth.
The quality of our freshwater resources is a main driver of phytoplankton diversity and development of nuisance assemblages. The deterioration of water quality therefor needs to be constantly monitored together with phytoplankton diversity and biomass. My research programme at first focused on the middle Vaal River and its tributaries in the area. Water quality and the dynamics of phytoplankton assemblages have huge impacts on the
processes of drinking water treatment plants. Therefor a key aspect of my research programme involved the investigation into the problems caused by phytoplankton in drinking water treatment plants to aid in the development of conventional of water treatment techniques and the removal of phytoplankton cells or secondary products formed. My research in the aspect has been done in collaboration with Rand Water and MidVaal Water Company. One of the studies funded by the WRC in collaboration with Rand Water and IUCMA, investigated the water quality and algal assemblages in the Sabie River and its tributaries the Sand and Marite Rivers and included the Inyaka Dam. The area experienced a very dry season followed by a high rainfall season. The results emphasized the effect of climate change on the impact of land use on water quality. It furthermore documented the phytoplankton assemblages in these river systems. | en_US |
