Diatoms (Bacillariophyceae) of the transitory zone of Wolnica Bay (Dobczyce dam reservoir) and Zakliczanka stream (Southern Poland)

摘要

Results from the study on the diatom flora of the transitory zone of Wolnica Bay and Zakliczanka stream are presented. The paper is focused on detailed floristic examination of diatoms, which constitute the highest number of species amongst algal flora of the material studied. 178 diatom taxa representing 49 genera were within the investigated material. The major group was represented by the family of Naviculaceae with the richest in species genus Navicuta (24 taxa), followed by Fragilaria sensu lato (19 taxa), Gomphonema (18 taxa), and Nitzschia (18 taxa). Only 14 out of 178 taxa recorded attained relative abundance exceeding 5 % in at least one of the samples studied. The main part of the diatom flora was composed of species, which are well known from mesotrophic, p-mesosaprobic, and alkaline waters. However, such halophilic species as Caloneis molaris, Fallacia pygmaea, Navicula capitatoradiata, N. phyllepta N. wiesneri, Nitzschia constricta, N. debilis, and Rhopalodia acuminata, characteristic for brackish or freshwater with high electrolyte content, were also observed there. Although numerous diatom species in the material studied are cosmopolitan forms, some taxa of poorly known distribution have also been found. The group of the most interesting taxa included: Cyclotella woltereckii, Fragilaria spinamm, Gomphonema clava, G. paral-lelistriatum, Luticola dismutica, Navicula associate!-, and N. trophicatrix. Photographic documentation for 176 recorded diatom taxa is presented.