Succession, composition and structure of microphytobenthic communities of the large eutrophic Oka River in Russia, before its confluence with the Volga River

This study characterized the benthic algal communities at the mouth of a large eutrophic-hypertrophic river, specifically during the vegetation period of 2019 and the summer-autumn period of 2020. Emphasis was placed on the composition, taxonomic structure, and the seasonal and interannual variability of abundance and diversity indicators. Detailed analysis was conducted on communities from bottom sediments, rocky substrates, and higher aquatic and coastal-water plants. Results show significant variations in composition and taxonomic structure across different substrate types and time frames. The dominant species complexes exhibited both temporal and substrate heterogeneity. Key findings highlight the importance of considering various substrate types and time periods, and they underline the observed changes in taxonomic group abundance. Such insights are crucial for comprehensive assessments of benthic algae communities in large eutrophic-hypertrophic rivers.