| الوصف: |
Particle-attached bacteria are key biotic factors influencing the development of bloom-forming cyanobacteria dominated with toxigenic Microcystis. Therefore, knowledge about their ecological interactions (synergistic or antagonistic), niche occupancy, and co-occurrence patterns during different bloom developmental stages, and the looking for of autochthonous strains for cyanobacterial regulation, are essential. The aim was to describe bacterioplankton dynamics and their functional potential, including their influences on cyanobacteria and water quality, at the Sulejów Reservoir, Poland (Central Europe). Subsequently, bacteria with algicidal properties against Microcystis were isolated and characterized. Nitrogen-transforming proteobacterial taxa performing nitrogen fixation, nitrification, and denitrification, dominated at the beginning of summer. Then, in mid-summer, during mixed cyanobacterial bloom of Snowella, Aphanizomenon, and Microcystis, bacterial diversity significantly decreased, with higher domination of parasites/predators that fed on cyanobacteria. The post-summer was significantly dominated by toxigenic microcystin-producing Microcystis, which drove the highest negative impact on particle-attached bacteria. Despite this, Microcystis was associated with taxa feeding on their cells - Vampirovibrionales, and decaying exudates, including microcystin - Sphingobacteriales_env.OPS17, Sutterellaceae, and Anhiella. Parallelly, strains belonging to Bacillales, Exiguobacterales, Pseudomonadales, Enterobacteriales, Rhizobiales, and Xanthomonadales were isolated from the monitored reservoir, capable to lyse toxigenic M. aeruginosa cells in laboratory studies. Research funded: National Science Centre 2019/33/B/NZ8/02093 "ALGICYDY" |