The ecology of some urban-impacted coastal vleis on the Cape Flats near Cape Town, with special reference to phytoplankton periodicity

Bibliography: leaves 191-196.This thesis stemmed initially from the author's desire to investigate the phytoplankton assemblages of the freshwater vleis of the Cape Peninsula. This aspect of the limnology of the Cape Flats vleis has received only scant attention by other researchers (over 40 years ago), and no comprehensive studies of their seasonal phytoplankton periodicities had been attempted. The paucity of information regarding the phytoplankton of the winter-rainfall, Mediterranean-climatic systems of the Cape Peninsula was found to not only be limited to South Africa. The literature survey undertaken for this study (Chapter 1) revealed•a general lack of information for shallow, nutrient-enriched, coastal systems, with virtually no data available for coastal systems in winter-rainfall regions. The thesis includes a description not only of the phytoplankton, but also of the limnology of each vlei as they are currently understood; this information is synthesized in Chapters 2 and 3 and collates all the available information accumulated by the Cape Town City Council (CCC) since it commenced monitoring of both vleis almost a decade ago. These chapters also contain details of the available bibliography for each system and form the first compilation of the available data for these waters. The inclusion of these chapters enabled comparisons to be made between the water chemistry regimes during the current study with those prevailing during earlier years. During the course of the study the author came across other pertinent aspects of each vlei which necessitated sub-investigations. The details of these are also included in the limnological chapters