B. Papp szerk.: Studia Botanica Hungarica 32. 2001 (Budapest, 2001)

Buczkó, Krisztina, Reskóné Nagy, Mária , Vinogradova, Oxana N.; Kiss, Gábor: The occurence of Aphanothece stagnina (Spreng.) A. Br. in Lake Velence, Western Hungary

Near the areas of the "black waters", the water is clear and well illuminated. The bottom of "shallow waters" and canals is covered with peculiar algal mats which later arise as a result of the bacterial decay following the ageing of these mats, combined with the changes in the atmospheric pressure, and detach from the sediment from time to time. In a similar way, Aphanothece stagnina starts to develop (near the bottom) yet it takes some time until it lifts up and reaches the water surface. During the whole year of 1997, in the plankton of the "Német-tisztás" the dominance of Cryptophyta and Bacillariophyceae was observed. However, it was interesting, and even surprising, to detect Aphanothece stagnina in the sediment of "Lángi-tisztás". This location represents the transitional water body between the reserve and the recreation area. In the year 1997, "Lángi-tisztás" was the area of the whole lake with the highest degree of algae presence, that is, the area where they recorded the highest amount of biomass of the phytoplankton. Surviving the winter in the sediment, the dominant species of the summer plankton, Microcystis aeruginosa, causes occasional water bloom in the lake (RESKÓNÉ and TÖRÖKNÉ 2000). Aphanothece stagnina is known as a species quite common in the temperate zones (KOMÁREK and ANAGNOSTIDIS 1999). In Hungary, according to the computerised data base of the Flora et Iconographia Algarum Hungáriáé, Aphanothece stagnina can be found in the Danube (SZEMES 1967), in Lake Balaton (TAMÁS 1964) in Lake Fehér near Szeged (V. VARGA 1959, 1966) and recently in Kis-Balaton (VÍZKELETY 1996) and in Lake Baláta (BORICS et al. 1998). Besides water bodies, Aphanothece stagnina was also recorded in soils (FEHÉR 1936). For example, FEHÉR ( 1948) studied 122 soil samples from different Fig. 2. The occurrence of Aphanothece stagnina in Lake Velence.