The Relationship between Seasonal Variation in Phytoplankton and Zooplankton Densities in Hirfanli Dam Lake (Kirsehir, Turkey)

Phytoplankton and zooplankton densities in Hirfanli Dam Lake were studied between July 1999 and June 2000. Inaddition, phytoplankton biomass was measured using chlorophyll a concentration. The density of Cladocera at the surface and thatof Rotifera at the bottom were low in the summer months. For phytoplankton, Cyclostephanos dubius (Fricke) Round was dominant.The variation in the density of organisms did not follow a known pattern. Species composition, seasonal distribution and species density variations show that the lake was advanced mesotrophic. The lake was alkaline and, from time to time, there was an odorin the littoral regions where algal bloom occurred.