Water quality assessment in the Poznan Solackie Ponds based on phycological studies conducted in 2012

Detailed phycological analysis aimed at the assessment of water quality in the Sołacki Park ponds in Poznań was performed during the vegetative season of 2012. Qualitative analysis revealed the presence of a total of 294 phytoplankton taxa (244 in the Mały Pond and 246 in the Duży Pond), most of which were green algae (total 32%) and diatoms (33%). However, quantitative evaluation showed that in the summer both ponds were dominated by green algae and in the fall by fi lamentous cyanobacteria. The highest phytoplankton abundance occurred in the fall (13 291 ind./ml in the Mały Pond and 20 288 ind./ml in the Duży Pond), when the proportion of blue-green algae was the greatest. The dominant species were: Ulnaria acus, Crucigenia tetrapedia, Tetraedron minimum, Planktothrix agardhii and Pseudanabaena limnetica. Signifi cant share of green algae of the order Chlorococcales, cyanobacteria and diatoms, indicator algae for eutrophy and meso- or polysaproby, suggested high fertility and signifi cant pollution of the investigated ponds. This study confi rms the need for continuous monitoring of the Sołackie Ponds, as well as periodic reclamation treatments in order to reduce eutrophication and improve water quality.