Present-day characteristics of phytoplankton, microphytobenthos and phytoepiphyton of the Kaniv reservoir

Abstract

The paper considers the present-day taxonomic and ecological diversity, spatial patterns of phytoplankton and algae on the interface of two phases: water – substratum (microphytobenthos and phytoepiphyton) in the most typical biotopes of Kaniv Reservoir in summer seasons of 2017–2022. 301 species (311 intraspecific taxa) of algae have been identified from 142 genera, 75 families, 44 orders, 15 classes and 8 phyla. At the phyla level Bacillariophyta, Chlorophyta and Cyanobacteria dominated. The highest number of species and infraspecific taxa – 143 (146) have been found in microphytobenthos. The highest diversity at the level of genera (98), families (57), orders (37), classes (11) and phyla (7) was observed for the phytoplankton. The phytoplankton was dominated by Chlorophyta and Bacillariophyta, the microphytobenthos and phytoepiphyton – by Bacillariophyta. The highest level of species similarity has been recorded between the algal communities at the interface of two phases: water – substratum, the highest dissimilarity – between phytoplankton and phytoepiphyton. According to geographic distribution cosmopolite species prevail, according to saprobity – χ-ο- and β-mesosaprobic organisms, according to salinity preferences – indifferent species, according to pH preferences – alcalifilic species. According to biotopic preference typically planktonic and eurytopic forms dominate the phytoplankton, and benthic and eurytopic forms dominate the microphytobenthos and phytoepiphyton. Comparing the present-day findings with the retrospective data has not shown any significant changes in the phytoplankton and the microphytobenthos structures. As before, Chlorophyta, Bacillariophyta and, to a lesser extent, Cyanobacteria continue to dominate in phytoplankton, and Bacillariophyta and Chlorophyta – in microphytobenthos. It is explained by natural internal processes prevailing in Kaniv Reservoir, relatively stable level of human impact, and constant algal flow from Kyiv Reservoirs and tributaries. Nowadays phytoplankton, microphytobenthos and phytoepiphyton are distinguished by high taxonomic diversity and play an important role in Kaniv Reservoir biodiversity.