J Taylor. School of Environmental Sciences and Development, North West University (Potchefstroom campus), Private Bag X6001,. Potchefstroom 2520.
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African Journal of Aquatic Science 2005, 30(2): 221 Printed in South Africa — All rights reserved
AFRICAN JOURNAL OF AQUATIC SCIENCE ISSN 1727–9364
Letter to the Editor
Diatomology in South African biomonitoring: the South African Diatom Collection In pursuance of J Taylor's paper on diatom collecting, published in Volume 30(1) of this journal, it seems opportune to update readers on current activity regarding the use of diatoms in biomonitoring and to highlight the status of the South African diatom collection.
The value of including diatoms in water quality and biomonitoring assessments has been recognised for many decades. Recently, there has been a sustained resurgence of interest in this application — bolstered by taxonomic and water quality/ecological inference software. Various diatom collections span many decades and thus provide a hitherto largely untapped source of historical water quality and other information that can inform the so-called ‘reference’ or predevelopment condition of many aquatic systems. The South African Diatom Collection, informally known as the Cholnoky Collection after its principal founder and curator, Bela Cholnoky, is considered to be one of the five most substantial and valuable collections available worldwide. Through his intensive and extensive taxonomic and ecological studies from 1952–1970, Cholnoky built up the diatom collection of the then National Institute for Water Research, Council for Scientific and Industrial Research (CSIR) in Pretoria, making it the centre for diatom research in this country. Cholnoky placed little faith in performing only chemical analyses of water quality, arguing forcefully that the chemical and physical characteristics of a water body could be determined more reliably and easily through a study of the diatom associations found living in it. The Cholnoky Collection, currently stored at the Durban laboratories of the CSIR, has remained almost completely disused since the late 1980s. North-West University (Potchefstroom campus) has now offered to house, curate and further develop the collection as a component of their environmental monitoring focus, and has made a substantial building available for this purpose.
With financial support from the Water Research Commission (WRC) and the kind co-operation of the CSIR, a small group of South African diatomologists has begun to resurrect the collection, thereby establishing the groundwork for a renewed thrust in which diatoms will provide useful and critical interpretations of water quality and ecological condition. The first phase of this work, completed and published as WRC Report No. TT 242/04, evaluated the 60 years of pre-computer data and information. This report, available free from the WRC, includes full details of the material in the collection. This report, available free from the Commission, includes full details of the material in the collection. The second phase, concentrating on the use of diatoms in riverine environments, is currently producing a sampling and methods manual — supported by DVD-based instructional imagery and an interactive taxonomic identification key. Subsequent phases will include, inter alia, computerisation of the information contained within the collection, training workshops for diatom sampling, sample preparation and taxonomic training for young South African diatomologists, the extension of the work into other environments — notably wetlands, effluent assessment and groundwaters — and the refinement and calibration of water quality, trophic/ saprobic and ecological, condition indices. Details of the Cholnoky Collection and the publications and other documents generated during the first two phases of this project may be found on the website www.dhec. co.za/diatoms.
WR Harding DH Environmental Consulting, PO Box 5429, Helderberg 7135 e-mail: CGM Archibald KZN Aquatic Ecosystems, 150 Prospect Hall Rd, 18 Aschcombe Park, Durban North 4051 J Taylor School of Environmental Sciences and Development, North West University (Potchefstroom campus), Private Bag X6001, Potchefstroom 2520
