Characterization of microbial communities associated with cyanoalgal bloom in a dam from Leon, Gto, Mexico by sequencing of variable regions of the rRNA genes 16S and 18S

Background: Algal blooms have become more frequent due to human activity, including climate change. Analyzing of microbial diversity during the events provides information of how disturbances are shaping ecosystem. Metagenome-based analysis provides a molecular approach that gives an overview of the dynamic of the cultivable and uncultivable microbial communities during the bloom. Goals: Our goal was to determine the microbial diversity: the species richness, and their abundance in the dam "El Palote" Leon, Gto. that presented algal bloom. Methods: Prokaryotic and eukaryotic microbial community composition was analyzed by 16S and 18S rRNA amplification and sequencing. Results: Biodiversity taxonomic analysis was measured by Shannon index showed similar distribution patterns between samples taken at surface and two-meter depth, while Simpson index presented differences. The prokaryotic dominant phyla were cyanobacteria of Planktothrix genera (67%, 0 m and 69%, 2 m), Proteobacteria (13.7 and 13%) and Bacte- riodetes (6 and 8.2%). Regarding eukaryotes the dominant groups were Opisthokonta as well as Stramenopila, Alveolata and Rhizaria (SAR). Quantile based analysis showed relative abundance differences Flayobacterium spp. Aeromonas spp., Rheinheitnera spp., Cetobacterium somerae and Cryptornonas curvata were majority at two meters depth, while Methylocaldurn szegediense, Pseudospirillum and Aeromonas sobria presented high abundance at the surface. Conclusions: The results showed an overview of microbial communities asociated with a cianoalgal bloom dominated by Planktothrix agardhii-rubescens.