biostudies-literatureKrausfeldt LEDOD | USA | U.S. Army Corps of EngineersUSGS Environmental Health ProgramDOD | USA | U.S. Army Corps of Engineers (USACE)e0070923https://www.ebi.ac.uk/biostudies/studies/S-EPMC11265339biostudies-literatureUnknown9(7)The occurrence of cyanobacterial harmful algal blooms (cyanoHABs) is related to their physical and chemical environment. However, less is known about their associated microbial interactions and processes. In this study, cyanoHABs were analyzed as a microbial ecosystem, using 1 year of 16S rRNA sequencing and 70 metagenomes collected during the bloom season from Lake Okeechobee (Florida, USA). Biogeographical patterns observed in microbial community composition and function reflected ecological zones distinct in their physical and chemical parameters that resulted in bloom "hotspots" near major lake inflows. Changes in relative abundances of taxa within multiple phyla followed increasing bloom severity. Functional pathways that correlated with increasing bloom severity encoded organic nitromSystemsMicrobial diversity, genomics, and phage-host interactions of cyanobacterial harmful algal blooms.PMC11265339W912HZ-19-2-0014Dadlani MMazzei VFortman PEKarwacki EUrakawa HLee HWSmith RPRosen BHColwell RRKrausfeldt LELopez JVLoftin KAShmakova EfalseMicrobial diversity, genomics, and phage-host interactions of cyanobacterial harmful algal blooms.The occurrence of cyanobacterial harmful algal blooms (cyanoHABs) is related to their physical and chemical environment. However, less is known about their associated microbial interactions and processes. In this study, cyanoHABs were analyzed as a microbial ecosystem, using 1 year of 16S rRNA sequencing and 70 metagenomes collected during the bloom season from Lake Okeechobee (Florida, USA). Biogeographical patterns observed in microbial community composition and function reflected ecological zones distinct in their physical and chemical parameters that resulted in bloom "hotspots" near major lake inflows. Changes in relative abundances of taxa within multiple phyla followed increasing bloom severity. Functional pathways that correlated with increasing bloom severity encoded organic nitro2024-01-01T00:00:00Z2024 Jul2025-04-19T13:11:16.555Z2025-04-19T13:11:16.555ZS-EPMC112653393885620510.1128/msystems.00709-23