Algae flora of the water reservoir of the object of cultural and historical heritage "Aksakovsky park" (Orenburg region, Russia)

An object of cultural and historical heritage "Aksakovsky Park" (Orenburg Region, Russia) was allocated in order to preserve the historical sites associated with the name of the famous writer S.T. Aksakov. The pond, located in the protected area, was founded in 1767-1769, has undergone several reconstructions, but has never been scientifically studied. To assess its ecological state, the algae flora of the reservoir was studied. 96 species and varieties of microalgae and cyanobacteria were identified, belonging to 7 phyla, 10 classes, 24 orders, 36 families, 63 genera. Three new species for the algae flora of the Orenburg Region were found: Asterococcus superbus (Cienkowski) Scherffel, Raphidocelis danubiana (Hindák) Marvan, Komárek & Comas, Cryptoglena skujae Marin & Melkonian. A. superbus is rare in Russia. Our data expands the understanding of this species distribution. Structural and functional indicators of the development of algae flora indicate both the violation of the stability of the ecosystem and the process of accelerated eutrophication. In addition, the significant development of Cyanobacteria poses a potential threat to the health of animals and humans using this reservoir as a source for watering (animals, birds) or a recreation area (humans).