Various -omics Tools Reveal the Versatility of Cyanobacterial Bloom Formers in the Lake Okeechobee Watershed
Location
HCAS Guy Harvey Oceanographic Center, Nova Southeastern University
Start
2-14-2025 2:00 PM
End
2-14-2025 2:15 PM
Type of Presentation
Oral Presentation
Abstract
Our laboratory has studied cyanobacterial harmful algal blooms (cyanoHABs) in nearby Lake Okeechobee (LO) watershed. Because of multiple negative environmental and human health impacts, we have now characterized potential bloom drivers and successional stages. Our research has applied an integrative approach to: (a) assess biodiversity and phylogeny of cyanobacteria and associated microorganisms (i.e. cyanobacteria-microbiota) in various phases of bloom events, and (b) investigate the genetic basis and functional roles of cyanobacteria-heterotrophic microbial diversity along a spatiotemporal gradient. Using monthly Lake O sampling for 3 years and a variety of “-omics” methods such as 16S rRNA amplicon sequencing, metagenomics and metatranscriptomic methods, we have developed a better understanding of microbial community dynamics. During one bloom season (2019-2020), over 70 metagenomically assembled genomes (MAGs) helped corroborate Lake O biogeographical zones with distinct microbial community composition and functions. Identification of novel cyanoHABs and changes in relative abundances of taxa within multiple bacteria tracked bloom severities. Functional pathways that correlated with increasing bloom severity encoded organic nitrogen and phosphorus utilization, storage of nutrients, exchange of genetic material, phage defense, and protection against oxidative stress, suggesting that microbial interactions may promote cyanoHABs resilience. Cyanobacterial communities appeared highly diverse, with ubiquitous picocyanobacteria. Genomic comparisons indicated a functionally diverse cyanobacterial community with varying capabilities to store nitrogen via cyanophycin and phage defenses with CRISPR and restriction modification systems. In situ mesocosm experiments on the Caloosahatchee River (Southwest Florida, USA), tested the effects of artificial loading of nutrients (phosphorus, nitrate, ammonia and urea) on pelagic microbiomes. Metatranscriptomes characterized the community response associated with upon treatment with ammonium and urea for 72 hours, primarily inducing photosynthesis and both phosphate and carbon transport and metabolism. Urea addition also induced upregulation of carbon storage, amino acid metabolism, microcystin biosynthesis, and other processes associated with cell growth and appeared to intensify a concomitant Microcystis bloom in 2021.
Various -omics Tools Reveal the Versatility of Cyanobacterial Bloom Formers in the Lake Okeechobee Watershed
HCAS Guy Harvey Oceanographic Center, Nova Southeastern University
Our laboratory has studied cyanobacterial harmful algal blooms (cyanoHABs) in nearby Lake Okeechobee (LO) watershed. Because of multiple negative environmental and human health impacts, we have now characterized potential bloom drivers and successional stages. Our research has applied an integrative approach to: (a) assess biodiversity and phylogeny of cyanobacteria and associated microorganisms (i.e. cyanobacteria-microbiota) in various phases of bloom events, and (b) investigate the genetic basis and functional roles of cyanobacteria-heterotrophic microbial diversity along a spatiotemporal gradient. Using monthly Lake O sampling for 3 years and a variety of “-omics” methods such as 16S rRNA amplicon sequencing, metagenomics and metatranscriptomic methods, we have developed a better understanding of microbial community dynamics. During one bloom season (2019-2020), over 70 metagenomically assembled genomes (MAGs) helped corroborate Lake O biogeographical zones with distinct microbial community composition and functions. Identification of novel cyanoHABs and changes in relative abundances of taxa within multiple bacteria tracked bloom severities. Functional pathways that correlated with increasing bloom severity encoded organic nitrogen and phosphorus utilization, storage of nutrients, exchange of genetic material, phage defense, and protection against oxidative stress, suggesting that microbial interactions may promote cyanoHABs resilience. Cyanobacterial communities appeared highly diverse, with ubiquitous picocyanobacteria. Genomic comparisons indicated a functionally diverse cyanobacterial community with varying capabilities to store nitrogen via cyanophycin and phage defenses with CRISPR and restriction modification systems. In situ mesocosm experiments on the Caloosahatchee River (Southwest Florida, USA), tested the effects of artificial loading of nutrients (phosphorus, nitrate, ammonia and urea) on pelagic microbiomes. Metatranscriptomes characterized the community response associated with upon treatment with ammonium and urea for 72 hours, primarily inducing photosynthesis and both phosphate and carbon transport and metabolism. Urea addition also induced upregulation of carbon storage, amino acid metabolism, microcystin biosynthesis, and other processes associated with cell growth and appeared to intensify a concomitant Microcystis bloom in 2021.