High complexity and diel dynamics of planktonic microbiome revealed by multi-omics in Taihu, China

Cyanobacterial blooms result from continued short-term succession of planktonic microbiomes, but these short-term variations are little known. Here we address this question with a field diel study in Lake Tai. By integrating untargeted metabolomics—verified by targeted metabolomics—and metagenomics, we reveal the diel cycle of planktonic microbiome in Lake Tai are highly dynamic and complex. First, metabolite abundance and their molecular mass display clear diel changes along with shift in the taxon abundance and biological functions, following the same environmental factors. Some taxa and biological functions (reactions) are highly correlated with the metabolite abundance, and large compounds appear to be more taxon specific. Second, phytoplanktonic and overall planktonic microbiome showed different temporal variation of abundance, opposite levels of abundance and different molecular sizes, and different inter- and intra-specific diversity dynamics. Last, planktonic microbiomes are highly dynamic and complex in inter- and intraspecific diversity in merely one diel cycle, which point to different temperature preference between species, Microcystis aeruginosa and Anabaena sp. This difference was experimentally confirmed in laboratory. Using a multi-omics approach, our study underscores the importance of diel interaction triad between population abundance, biological functions, and environmental factors in leading to microbiome structural change and blooms.