Distribution Dynamics of Vegetative Cells and Cyst of Ceratium hirundinella in Two Reservoirs, Turkey

The seasonal variation and vertical and horizontal distributions ofceratium hirundinella (o.f.müller) dujardin and occurrence of its cyst form inerfelek and dodurga reservoirs (sinop, turkey) were studied between august2010 and july 2011. our results showed that cyst form was observed withvegetative cells in phytoplankton. ceratium hirundinella was recorded in highnumbers in autumn/winter periods in these reservoirs. winter conditions did notaffect presence/absence of the species, but influenced the cell densities. vegetativecells were observed mostly in lacustrine and transition zones, horizontally in tworeservoirs and also cyst form was recorded in erfelek reservoir but not found indodurga reservoir vertically. dissolved oxygen had positive correlation withvegetative cells and also ph, conductivity and redox potential were importantfactors for vegetative cells and cyst occurrence.