L. Hably szerk.: Studia Botanica Hungarica 23. 1992 (Budapest, 1992)

Stollmayerné Boncz, Emilia: The alga species of the Csömör pool II.

CHARACTERIZATION AND SYMBOLS OF THE SAMPLING POINTS After snow thaws in early spring, the lake is filled with water, especially in wetter years, like 1987. In years like that we can often see open-water surfaces, and access to the island is a problem (Map 2). In warm-summer periods, especially following a dry winter (e.g. in 1988), by August we find water only at sampling point 2. After the fire, the island gets dry as well, with some water accumulating only in the footprints. After 1988 the water conditions became similar to those of 1984. Thus sampling was carried out with difficulties again in some periods and certain sampling points, due to high water level or evaporation. The sampling points used in 1984 were maintained, with exception of those located on the island. There, the morphology became more even after the extinction of the Sphagnums. Sampling points 5 and 7 'ceased'. The current sampling point 6 corresponds to the former point 7. Sampling points 1, 2, 3, 8 and 9 can be easily reached from the shore. Sampling point 1 is populated by reed-grass and mut-grass. Sampling point 3 seems to become similar to the sampling point 1 due to the spreading of Typha. At sampling point 2 we can find water throughout the year, sometimes populated by floating Lemna minor and Ricciocarpus natans. The 'island' can be reached best from the direction of sampling site 3. Opposite the "entrance" we find sampling point 4, generally covered with water. At sampling point 6, only two samples could be gathered during the study period. One of them was collected from hollows with peat moss (Sphagnum), while the other was collected from trodden footprint, moisture accumulated in the traces of human steps. Sampling points of the period 1987-90 are summarized in Table 1. SAMPLING PROCEDURE The samples were collected monthly, about 8 a.m. each time, into glass-jars which can be hermetically closed. The pH values were measured with Universal indicator paper. Most of the samples were immersed ones, not marked specifically in the Tables. It was experienced as early as 1984 that the leaves of the Typha were densely incrusted, and in the shallow parts, algal masses in the benthos could be observed by the naked eye. Therefore the recent investigations were extended to these spots of interest as well. The benthos was sampled laterally by opening the glass under water, taking special care not to stir up the mud. These samples are marked as 'B' (benthic). The incrustation on the Typha leaves was sampled in two ways: 1. over the water level, on dry parts formerly covered with water, 5 cm long leaf parts were cut off from Typha latifolia and put into dry glass. Under laboratory