Jonathan C. Taylor

Can diatom-based pollution indices be used for biomonitoring in South Africa? A case study of the Crocodile West and Marico water management area

The inclusion of diatoms into the current suite of biomonitoring tools in use in South Africa, as well as the use of European and other diatom indices in South Africa, and in particular the Crocodile and West Marico water management area, is discussed. The indices, when compared to chemical analyses, proved useful in providing an indication of the quality of the investigated waters. Several widely distributed diatom species were shown to have similar ecological tolerances in South Africa when compared to Europe. Although most of the diatoms encountered in the study were cosmopolitan, several possibly endemic species were recorded. The occurrence of endemic species, not included in existing diatom indices may lead to miscalculations of diatom indices. It is concluded that although diatom indices developed in Europe and elsewhere are useful at the present to indicate water quality, a diatom index unique to South Africa including endemic species will have to be formulated.

Recommendations for the collection, preparation and enumeration of diatoms from riverine habitats for water quality monitoring in South Africa

Diatoms have become important organisms for monitoring freshwaters and their value has been recognised for cross-border water quality monitoring in the European Union. If South Africa is to include diatoms in the current suite of bioindicators, then thorough testing of diatom-based techniques is required. This paper provides guidance on methods through all stages of diatom collection, preparation and examination for the purposes of water quality assessment.

Zooplankton and diatoms of temporary and permanent freshwater pans in the Mpumalanga Highveld region, South Africa

This paper provides a description of the zooplankton and epiphytic diatom communities of permanent and temporary freshwater pans in the Mpumalanga Highveld region of South Africa. Few studies have investigated the biota of pans in this area, which is seriously threatened by mining and agricultural development. Nineteen pan sites within a 20 kmradius covering a wide range of water chemistries were sampled once for zooplankton, epiphytic diatoms and water physico-chemical data in 2009. Collected zooplankton and diatom samples were identified to species or genus level. Many of the zooplankton taxa reported in this study were not recorded in similar pan studies in South Africa and southern Africa. The study revealed a difference among the compositions of zooplankton and diatom communities between temporary pans and permanent pans. Zooplankton found exclusively in freshwater temporary pans included cladocerans (Megafenestra aurita and Scapholeberis kingi), calanoids (Mesocyclops major and Thermodiaptomus mixtus), a cyclopoid (Acanthocyclops vernalis) and a rotifer (Platyias quadricornis). Permanent pans were characterized by taxa such as cladocerans (Ceriodaphnia rigaudi and Dunhevedia crassa), a calanoid (Metadiaptomus transvaalensis), cyclopoids (Paracyclops fimbriatus and Eucyclops gibsoni) and rotifers (Brachionus dimidiatus and Brachionus plicatilis). The most commonly occurring diatom taxa in temporary pans included taxa indicative of slightly acidic to circumneutral, dystrophic and nutrient-poor waters such as Nitzschia acidoclinata, Gomphonema gracile and Eunotia bilunaris. Permanent pan assemblages were characterized by taxa typical of saline waters, including Nitzschia frustulum, Amphora veneta and Planothidium engelbrechtii. Species of the genera Pinnularia and Eunotia were almost totally absent from permanent pans.

Eolimna archibaldii spec. nov. and Navigiolum adamantiforme comb. nov. (Bacillariophyceae): two possibly endemic elements of the South African diatom flora tolerant to surface water pollution

Two little-known diatom taxa have been encountered in the saprobic and anthropogenically impacted waters of the Vaal River, South Africa. Eolimna archibaldii, an extremely small-celled species, is described as new to science. Navicula adamantiformis Archibald is transferred to the taxonomically-appropriate genus Navigiolum Lange-Bertalot, Cavacini, Tagliaventi and Alfinto, as no specific characters of N. adamantiformis coincide with Navicula sensu stricto.

Diatoms as water quality indicators in the upper reaches of the Great Fish River, Eastern Cape, South Africa

This study focused on the spring-fed upper reaches of the economically important Great Fish River with the aim of determining if diatoms could be used for biomonitoring in semi-arid conditions in southern Africa. Five sites were monitored monthly from 2010 to 2012. Of the 269 diatom taxa belonging to 51 genera identified, the dominant taxa were mostly those considered to be pollution-tolerant: Amphora pediculus, Craticula buderi, Fragilaria biceps, Nitzschia frustulum, Nitzschia paleacea, Planothidium lanceolatum and Rhopalodia gibba. A number of diatom-based numerical indices were used to infer water quality, including the generic diatom index, the specific pollution sensitivity index, the biological diatom index, and percentage pollution-tolerant valves, which forms part of the UK trophic diatom index. All index scores showed the Great Fish River to be impacted, and showed significant correlations of diatom species abundance with pH, NO3-N, electrical conductivity, NH4-N and CaCO3. Analysis revealed EC and NO3-N as the main environmental drivers affecting diatom community composition, followed by pH and PO4-P. The percentage of diatom deformities at all sites was high, at 3.5%. Diatom indices showed the river to be impacted by decades of agricultural activity, which was confirmed by chemical water analysis. Thus diatom indices can be used for biomonitoring in semi-arid areas.

Microcostatus schoemanii sp. nov., M. cholnokyi sp. nov. and M. angloensis sp. nov. three new terrestrial diatoms (Bacillariophyceae) from South Africa

The terrestrial diatom Microcostatus schoemanii sp. nov. is described from dry soils of the Faan Meintjies Nature Reserve (North‐West Province, South Africa). Microcostatus cholnokyi sp. nov. and Microcostatus angloensis sp. nov. are described from sandy soils at a colliery near the town of Kriel (Mpumalanga Province, South Africa). The morphology of these taxa is examined using both light and scanning electron microscopy and new taxa are compared with similar species. In M. schoemanii the density of the striae combined with the valve outline and the distance between the central raphe endings are the main distinguishing morphological features. M. cholnokyi is differentiated by the presence of a conopeum and the distinct structure of the microcostae. M. angloensis is similar to M. schoemanii but differentiated by the shape of the cell and the apices, the angle of striation and the distance in between the proximal raphe endings.

Two new species ofNitzschia(Bacillariophyceae) from freshwater environs of Lonar Crater Lake, India: Two newNitzschiafrom India

Diatom taxa in India were first documented by Ehrenberg and subsequently many studies have focused on the Western Ghats and Himalayan mountains while other regional environments were rarely explored. In the current study, the freshwater environs of the saline Lonar Crater Lake were investigated and two new Nitzschia species have been described. Nitzschia kociolekii sp. nov. and Nitzschia tripudio sp. nov. were sampled from bird feeding ponds associated with Lonar Lake. The morphological characters of the new species are similar to N. amphibia and N. frustulum but differ in terms of striae pattern, polymorphic areolae development, fibula and stria density. In addition, larger specimens of N. williamsii, a recently described taxon from Bangalore wetlands of Peninsular India, were found in a waterfalls flowing into Lonar Lake. All three taxa are freshwater diatoms and are possibly endemic to Peninsular India.

Two new species of Nitzschia (Bacillariophyceae) from freshwater environs of Lonar Crater Lake, India

Diatom taxa in India were first documented by Ehrenberg and subsequently many studies have focused on the Western Ghats and Himalayan mountains while other regional environments were rarely explored. In the current study, the freshwater environs of the saline Lonar Crater Lake were investigated and two new Nitzschia species have been described. Nitzschia kociolekii sp. nov. and Nitzschia tripudio sp. nov. were sampled from bird feeding ponds associated with Lonar Lake. The morphological characters of the new species are similar to N. amphibia and N. frustulum but differ in terms of striae pattern, polymorphic areolae development, fibula and stria density. In addition, larger specimens of N. williamsii, a recently described taxon from Bangalore wetlands of Peninsular India, were found in a waterfalls flowing into Lonar Lake. All three taxa are freshwater diatoms and are possibly endemic to Peninsular India.

Changes in the algal composition and water quality of the Sundays River, Karoo, South Africa, from source to estuary

A first survey was done on algae present in the Sundays River from its source to its confluence with the sea. Species found in the upstream sections of the river included indicators of good water quality, but the quality deteriorated downstream with peaks in algal abundance being ascribed to peaks in nutrient concentrations. Cyanobacteria and euglenoids were present in the upper and middle reaches of the river, but were absent downstream. Dinoflagellates became more important downstream, especially in the estuary. Dominant species, reaching high concentrations along the river, included Nitzschia frustulum, Nitzschia capitellata, Carteria klebsii, Chlorella vulgaris and Anabaena species. The presence of the diatom Eolimna comperei is a first record of its occurrence in South Africa. The Sundays River can be described as a brackish, hard water system with high nutrient concentrations in certain sections. The most important contributors to high nutrient concentrations were point sources in the vicinity of towns along the river banks, as well as diffuse sources contributing to high nitrogen concentrations in the fertile Sundays River valley. Increasing salinities were due to pollution, evaporation and agricultural activities in the valley.

Community participation in river monitoring using diatoms: a case study from the Buffelspoort Valley Conservancy

This study was undertaken to determine the present ecological state of rivers and streams in the Buffelspoort Valley Conservancy (BVC), against which later potential changes in, and impacts on, water quality could be measured. After very brief training, all field work, including site selection and sample collection, was carried out by the members of the Conservancy. All samples collected by the members of the Conservancy were of an adequate quality for analysis and yielded meaningful results. This study demonstrates that there is great potential for the use of diatoms in community monitoring programmes, mainly due to the ease and rapidity with which samples can be collected. The participation of communities is also vital in gaining a more complete overview of the diatom species occurring in South Africa.