ABSTRACT
Seasonal variations of plankton, expressed in terms of species composition and cell density in relation to selected physicochemical water parameters, were investigated in Malilangwe reservoir, Zimbabwe, between February and October 2011. In total, 98 phytoplankton species (2 Dinophyta, 4 Euglenophyta, 14 Bacillariophyta, 50 Chlorophyta, 13 Desmids and 15 Cyanophyta), 66 zooplankton species (13 Cladocerans, 7 Calanoids/Cyclopoids, 46 Rotifers) and two others (Chaoborus sp. and Hydracarina) were recorded. Chlorophyta, Dinophyta and Cyanophyceae comprised the bulk of the phytoplankton, while Rotifera and Cladocera dominated the zooplankton community. A typical seasonal succession of plankton species occurred from February to October. Algal blooms were observed during May to July, dominated by Anabeana sp., Nostoc sp., Anabeana circinalis, Zygenema sp., Anabeana sporiodes, Ceratium hirudinella and Perinidium sp. Redundancy Analysis (RDA) showed that water level, conductivity, pH, dissolved oxygen, temperature, reactive phosphorus and macrophyte cover accounted for most of the distribution of the plankton species.
ACKNOWLEDGEMENTS
This study was made possible through the financial support of the DAAD (A/10/02914) and a Malilangwe Trust Research Grant. Special thanks go to Lenin Dzibakwe Chari, Patrick Mutizamhepo and Clemence Chakuya of the University of Zimbabwe. Also to Philemon Chivambu, Pandeni Chitimela and Pamushana, guides from the Malilangwe Wildlife Reserve who assisted during the fieldwork. Our appreciation also goes to Elizabeth Munyoro and the technical staff of the Department of Biological Sciences, University of Zimbabwe, for all their technical support during the study.