Population dynamics of the freshwater dinoflagellate <i>Ceratium hirundinella</i> in the largest shallow lake of Central Europe, Lake Balaton, Hungary

Abstract

SUMMARY. Horizontal distribution, long‐term (1933–82) and short‐term (day‐to‐day) changes in abundance, vertical stratification and circadian rhythm of the freshwater dinoflagellate Ceratium hirtmdinella were studied in Lake Balaton, the largest shallow lake of Central Europe. The lowest abundance was consistently found in those areas of the lake which had the strongest currents. The density of C. hirundinella seemed to be, at least in those parts of the lake above the level of fertility considered oligotrophic, insensitive to changes in trophic conditions; only its relative contribution to total biomass decreased with increased enrichment. During the day the bulk of the population stayed at a level in which the light intensity was between 126 and 440 μE m ‐2 s ‐1 PAR.