The three life domains microbial communities of a tropical soda lake

Extreme environments, as soda lakes, represent excellent models to study how drastic environmental conditions shapes microbial diversity. In these ecosystems, microorganisms significantly contribute to biogeochemical cycles, but their community structure and both spatial and temporal dynamics remain largely unexplored. In this study, we monitored the microbial-3-domain-of-life composition in Lake Dziani Dzaha (Mayotte), a tropical saline alkaline lake. The exploration of the multiple facets of eukaryotic and prokaryotic diversity showed a higher value across local microbial communities rather than between communities. Diversity of the whole system was clearly impacted by the presence of chemoclines inducing a stratification of the water column into different ecological niches allowing communities differentiation. A detailed analysis of Bacteria, Archaea and Eukaryota showed that depth, season, and sampling year impacted differentially the establishment of each domain of life. Indeed, photosynthetic microorganisms were abundant in surface layers while chemotrophic microorganisms dominated in deeper layers, as Firmicutes and Bacteroidetes and putative methanogenic lineages, as Woesearchaeota. Our findings highlighted the importance of considering multi-domain microbial processes and interactions in time and space to better understand their impact on ecosystem functioning.