L. Hably szerk.: Studia Botanica Hungarica 23. 1992 (Budapest, 1992)
Buczkó, Krisztina; Ács, Éva: Preliminary studies on the periphytic algae in the branch-system of the Danube at Cikolasziget (Hungary)
In the laboratory the coats were washed off with a fine brush into known amounts of water. The surface of the substrate was measured. Afterwards the samples were handled as if they were planktonic samples. Algae were identified under light and scanning electron microscope, counted by UTERMÖHLs (1958) method taking the statistical results of LUND et al. (1958) into consideration. Diatoms were identified under light microscope after digestion with H2O2. For the necessary SEM identification we followed KISS' method (KISS 1986). Complexometric titration with Titriplex R III against mixed indicator tablets (Aquamerk R 8011, E. Merck, Darmstadt, Germany) was used for determination of total hardness. Determinations were made directly in the field immediately after taking the water samples. The values of water hardness in Table 1 are given in German degrees (°d). (1 d = 10 mg of CaO/1 = 0.18 mmol/1 of alkaline earth ions.) The constancy of a species was calculated as Q= 100Ni/S, where Ni was the number of the samples in which the species was present and S was the total number of samples. A species was given constancy value 5 if C = 80-100%, 4 if C = 60-80% etc. The dominance value of a species was calculated as Di= 100Ai/M, where Ai was the number of the individuals of the given species and M was the total number of individuals in the sample. For cluster analysis the SYN-TAX III program was used (PODANI 1988) with WPGMA fusion algorithm. RESULTS AND DISCUSSION Altogether 179 taxa were identified (Cyanophyta 12, Euglenophyta 6, Chromophyta 88 - incl. Bacillariophyceae 83, Cryptophyta 10, Chlorophyta 63 - Fig. 2). The detailed list of the taxa is presented in Table 2. Bacillariophyceae 83 46% Fig. 2. Percentile proportion and number of taxa in different phyla (Chromophyta divided into 3 groups Bacillariophyceae, Xanthophyceae and Chrysophyceae) 52
