MACROALGA Ulva intestinalis (L.) OCCURRENCE IN FRESHWATER ECOSYSTEMS OF POLAND: A NEW LOCALITY IN WIELKOPOLSKA

A new locality of Ulva intestinalis was found near Krąplewo in the River Samica Stęszewska located in the Wielkopolski National Park region (Wielkopolska). On the basis of Carlson's index ranges, waters of the Samica Stęszewska river were qualified as eutrophic. In the river single thalluses of U. intestinalis which appeared by its banks were observed. The presence of this Ulva species thalluses in the Samica Stęszewska river confirmed the results of trophy examinations of this river. U. intestinalis is a species attached to eutrophic waters – both salty, slightly salty and inland. This next found site of this Ulva species is the 35th site on the inland area of Poland and the third in the Wielkopolska region. Altogether 59 localities of Ulva genera representatives, including U. intestinalis and 4 other species (U. compressa, U. flexuosa, U. paradoxa, U. prolifera) and one subspecies (U. flexuosa subsp. pilifera), were noted in limnic waters of Poland. The new locality of U. intestinalis in freshwaters of Wielkopolska contributes new and essential information about the distribution of this originally marine species on the inland area of Poland. The authors indicated the lack of studies in the scope of the mass thalluses influence from the Ulva genera on inland ecosystems and on water organisms inhabiting them.