Structural and functional characteristics of phytoplankton, algal mats, detritus and water quality under main abiotic factors in urban ponds (case study of urban settlement Hostomel, Bucha district, Kyiv Region, Ukraine). Report І. Species and taxonomic composition, ecological diversity of phytoplankton and filamentous algal mats characteristics under main abiotic factors

Abstract

The paper considers species and taxonomic composition of phytoplankton and algal mats in ponds of Hostomel urban settlement under effect of main abiotic factors. The research was carried out in May 2021. The ponds under study are shallow and the photic zone occupies the entire water column. The dissolved oxygen content was high. According to nutrient content the ponds are eutrophic. Planktonic algal communities were marked by high diversity. The identified algae referred to 8 phyla, 13 classes, 29 orders, 49 families, 87 genera and 134 species, represented by 136 infraspecific taxa. The floristic diversity at the phylum level was mainly formed by Chlorophyta, Bacillariophyta and Cyanobacteria, at the class level – Chlorophyceae, Bacillariophyceae and Cyanophyceae, at the order level – Sphaeropleales, Euglenida, Chloreallales and Bacillariales, at the family level – Scenedesmaceae, Euglenidae, Bacillariaceae, Selenastraceae and Chlorellaceae, at the genus level – Desmodesmus, Nitzchia, Monoraphidium, Trachelomonas and Euglena. According to biotopic preference planktonic and planktonic-benthic forms prevailed. In Pond ІІІ, floating algal mats were observed. They appeared when benthic communities composed of Charophyta, Bacillariophyta, Chlorophyta and Euglenozoa rose to the water surface. Their cell count reached 28168–368149 thousand cells∙m–2, biomass – 21–362 g ∙ m–2. Algal mats caused a local negative effect due to water column shadowing. High diversity of algal communities makes it possible for pond ecosystems to function even under human impact.