PS 36-7 - Unique community structure of the Microcystis dominated, eutrophic Lake Taihu

Abstract: The Microcystis-dominated harmful cyanobacteria blooms (cyanoHABs) are a cosmopolitan phenomenon across eutrophic lakes around the world. Bloom-forming cyanobacteria species are reported to closely interact with other members of the microbial community such as heterotrophic bacteria. Microbial community members may provide functional components to bloom forming cyanobacteria. Previous work has identified that the Microcystis associated community across the world shows similarity both in composition and in functional potentials, which implies that there is a potential unifying pattern of interactions between cyanobacteria species and associate bacteria globally (Cook et al., 2020). We hypothesize that a foundational interaction exists between those bloom-forming cyanobacteria and the associated microbial community, which thrive within the bloom forming community or influence the bloom forming community.Our goal was to identify the Microcystis associated microbial community using 16s rDNA sequencing to identify community associations. Lake Taihu, Jiangsu province, China well known for consistent harmful algal blooms was the study site and has been previously shown to exhibit unique Microcystis interactome features. Water samples were collected from sites within Lake Taihu with historical differences in organic and inorganic contamination. We applied 16s rDNA sequencing to profile the bacterial community composition and metagenomic shotgun sequencing to characterize the functional profile. Analysis identified common bloom forming cyanobacteria including Microcystis, Planktothrix, Pseudanabaena, Limnothrix and Dolichospermum. Unlike in previous studies Microcoleus Community analysis shows that Microcystis is weakly associated with other species. Phenylobacteria, previously shown to be strongly correlated with Microcystis, is rather positively correlated with Synecococcus and Microcoleus.