A Methods Manual for the Collection, Preparation and Analysis of ...

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Campus) where the application of numerical diatom indices to South African rivers was tested(Taylor, 2004). Other students are now engaged in both diatom ecological and taxonomicstudies at M.Sc. and Ph.D. level. This revival of interest in the diatoms together with theproduction of standard protocols and the rigorous testing of numerical diatom-based indices,should culminate in the realisation of Cholnoky’s prediction that diatom associations can beused to give a reliable and accurate indication of the chemical and physical characteristics of awater body.3
2. How do you recognise diatoms in natural environments?A common source of error in inferring ecological conditions using diatom communities arisesfrom sampling from un-colonised substrata. Diatom communities may be detected onsubstrata by feel (slimy or mucilaginous) or may be seen as a thin golden-brown filmcovering substrata. In some conditions or at certain times of the year this film may becomethicker and much more noticeable. The essential natural microhabitats are solid substrata,exposed damp sediments and the stems of rooted vegetation. Diatoms are also present in theseston or suspended component of the phytoplankton. Man-made and other objects (paper orplastic bags, pieces of wood) are also frequently colonised by diatoms.1 23 45 6Fig. 1 and Fig. 2 show a thick layer of diatom cells attached to boulders. Fig. 3 shows a layer ofdiatom cells growing both on sediment and on pebbles. Fig. 4 shows diatoms growing thickly aroundsubmerged tree branches. Fig. 5 shows the film of diatoms to be found on the submerged stems ofPhragmites australis. Fig. 6 shows diatoms inhabiting sediments.4
Page 1 and 2: A Methods Manual for theCollection,
Page 3 and 4: This report is part of a set on Dia
Page 5 and 6: FOREWORDThis method manual is inten
Page 7 and 8: TABLE OF CONTENTSNOTE TO THE USER .
Page 9 and 10: GLOSSARYAerophilic - Depending on f
Page 11 and 12: Phytoplankton - The phytoplankton c
Page 13: photomicrographs earned high praise
Page 17 and 18: 4. Diatoms - Colony formation and a
Page 19 and 20: 5.1 Pennate and Centric diatomsPenn
Page 22 and 23: SECTION 2: FIELD PROCEDURESTo facil
Page 24 and 25: depending on the period of exposure
Page 26 and 27: 2.3.2 Examination of fresh material
Page 28 and 29: 3. Toolkit for Fieldwork (field app
Page 30 and 31: 5. Site selection for water quality
Page 32 and 33: 6. Sampling locality details and fi
Page 34 and 35: 8. Choice of substrata (detail)Samp
Page 36 and 37: 10 Preservation of diatom material
Page 38 and 39: 1: Micro-pipette 1 ml with disposab
Page 40 and 41: 1.2 Pre-preparation examination of
Page 42 and 43: 1.3.2.3 Shake the sample well and p
Page 44 and 45: one is available the peroxide can b
Page 46 and 47: 2 Preparation of diatom slidesHealt
Page 48 and 49: 2.1.9 After the diatom-coated cover
Page 50 and 51: 4. ArchivingIt is important to reta
Page 52 and 53: affected at counts of 300 and above
Page 54 and 55: 6. Counting records (electronic and
Page 56 and 57: The main source of variability is,
Page 58 and 59: 11. Key reference worksThere are se
Page 60: HARDING WR, ARCHIBALD CGM, TAYLOR J

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