Struktura gatunkowa fitoplanktonu w cyklu rocznym w stawach Duzym i Malym [Park Solacki, Poznan]

Seasonal variations of the phytoplankton community followed, from December 1999 to November 2000, in two small ponds located within the Sołacki Park (Poznan, western Poland). In the collected material 208 (among them green algae constituted nearly half) species were identified and phytoplankton communities in both ponds are characterized by similar composition (similarity coefficient = 78.73%). The phytoplankton was dominated by diatoms, which were more abundant than blue-greens and green algae. Major dominants in the quantities were algae of the genera Cryptomonas, Cyclotella, Fragilaria, Gloeocapsa, Jaaginema, Limnothrix, Monoraphidium and Sphaerocystis. With greater stability of the water column and higher temperatures of water in the end of summer period the domination of blue-green algae was noted. During 1999- 2000 the phytoplankton biomass ranges were 0.073-75.641 mg/l in the DuGy Pond and 0.707- 39.005 mg/l in the Mały Pond.