TR135 • . ' . REPUBLIC OF SOUTH AFRICA DEPARTMENT OF WATER AFFAIRS An aid to the identification of the dominant and commonly occurring genera of algae observed in some South African impoundments. E. TRUTER Pediastrum spp. · CLASSIFICATION (Komarek and Fott, 1983 Phylum Chlorophyta (Green Class Chlorophyceae Order Chlorgcoccales Family Hydrodictyaceae Genus Pediastrum Morphology The cells form circular plates with odifferent in shape from those within nucleated with serrated edges. The f .. .O ccurrence Pediastrum is widely distributed in :tychoplankton of all types of waters DEPARTMENT OF WATER AFFAIRS HYDROLOGICAL RESEARCH INSTITUTE I An Aid to the Identification of the Dominant and Commonly occurring Genera of Algae observed in some South African Impoundments by E. Truter December 1987 Department of Water Affairs Private Bag X313 ( Pretoria 0001 ISBN 0 621 11510 X ··- SYNOPSIS The principal objective of this report is to serve as a guide for the identification and classification of microscopic algae commonly occurring in South African impoundments. A brief desc ri pti on of the morpho 1o gy and occurrence of each genus is given and illustrated by means of both drawings and photographs. In addition, data on the presence and dominance of different genera observed in 29 South African impoundments, sampled during 1986, are included. SINOPSIS Die hoofdoel van hierdie verslag is om te dien as •n hulpmiddel vir die identifikasie en klassifikasie van mikroskopiese alge wat algemeen voorkom in Suid-Afrikaanse damme. Die morfologie en voorkoms van elke genus word kortliks beskryf en ge'illustreer deur middel van sketse en foto•s. Data oor die dominansie en teenwoordigheid van die verskillende genera waargeneem in 29 Suid-Afrikaanse damme gedurende 1986 is ook ingesluit. ACKNOWLEDGEMENTS I would like to thank the following people for their help and support: Hrs. C.E. van Ginkel, Dr. H.R. van Vliet, Hr. C.A. Bruwer, Dr. P.L. Kempster, Hiss. A.M. Howman, Hr. H.R. Howard, Mr. G.E. Quibell, Hiss . J. Kilian, Mr. H.H. Bosman, Hrs, A. Hanekom (drawing of the figures), Mrs . C.A. Edwards and Mrs. B.H. Sutton (typing of the report) of the Hydrological Research Institute. Hr. W.E. Scott (National Institute for Water Research, CSIR, Pretoria), Hrs. H.J.F. Kruger (Western Transvaal Regional Water Company, Stilfontein) and Hr. C.G.H. Archibald (National Institute for Water Research, CSIR, Natal Region) for their valuable comments. The Water Bailiffs of the different dams for taking many of the algal samples. I am very grateful to Dr. G.W. Prescott, the author and copyright holder of "Algae of the Western Great Lakes Area" (1962) for kindly giving permission to use figures from the book. All the figures that appear in this report are redrawn from Dr. Prescott•s book. AUTHOR'S NOTE All the algae in this report are of microscopic dimensions and therefore require the use of a microscope for identification. Diatoms, except for Melosira and Cyclotella, were left out as their identification require specialized techniques and a good knowledge of their taxonomy. All the photographs were taken with a 35 mm camera fitted to a Zei ss Axi omat compound microscope and because the samples were stained with Lugol's solution, the colour of the cells is not natural. For the purpose of this study only genera were defined, with a few of the species names mentioned, if they occurred in abundance. Twenty-three dams were sampled over a period of 1 year (1986) and 6 dams in Natal over a period of 4 months. Samples from most of the dams were taken twice a month. (Part 4). UNITS AND SYMBOLS USED Metre m Millimetre mm Millilitre mt Micrometre Gram g Revolutions per minute rpm lll IV CONTENTS SYNOPSIS/SINOPSIS 1 ACKNOWLEDGEMENTS AUTHOR s NOTE 111 I INTRODUCTION 1 PART 1: MATERIALS AND METHODS 2 1.1 Sample collect1on and preservat1on 2 1.2 Equipment 2 1.3 Inverted m1croscope method 3 1.4 Ord1nary 11ght m1croscope method 3 1.5 Preparat1on of sl1des 4 PART 2: TAXONOMIC DESCRIPTIONS 5 2.1 Pr1mary class1f1cation of the algae 5 2.2 Phyla (d1visions) of algae 5 PART 3: CLASSIFICATION, MORPHOLOGICAL DESCRIPTIONS AND OCCURRENCE OF ALGAL GENERA 8 3.1 Dominant algal genera 8 3.2 Common algal genera 34 PART 4: RESULTS 62 4.1 D1scuss1on 62 4.2 Map of South Africa showing the dams from which samples were taken. 63 4.3 Tables of the dams sampled, 1nd1cating genera observed 64 GLOSSARY: TERMS RELATING TO ALGAE 93 REFERENCES 96 INDEX OF THE ALGAE DESCRIBED 97 V VI