A shared core microbiome in soda lakes separated by large distances

Area of Science:

• Microbial Ecology
• Biogeochemistry
• Astrobiology

Background:

• Alkaline soda lakes harbor productive phototrophic microbial mats due to high carbonate concentrations.
• Understanding the microbial drivers of productivity in these extreme environments is crucial for ecological insights and biotechnological applications.

Purpose of the Study:

• To elucidate the microbial community structure and functional roles in Canadian alkaline soda lake phototrophic mats.
• To identify the key microorganisms and metabolic pathways responsible for high primary productivity and carbon fixation.

Main Methods:

• Analysis of amplicon and shotgun DNA sequencing data from microbial mats in four Canadian soda lakes.
• Recovery of metagenome-assembled genomes (MAGs) for core microbiome bacteria.
• Proteomic analysis to understand resource allocation and niche partitioning.

Main Results:

• Identification of over 2,000 bacterial and eukaryotic species, with a core microbiome of under 100 abundant bacteria common to all lakes.
• Discovery that carbon fixation primarily occurs via the Calvin-Benson-Bassham cycle in Cyanobacteria, Gammaproteobacteria, and Gemmatimonadetes.
• Evidence for common selection principles driving community assembly from a global reservoir of alkaliphile biodiversity.

Conclusions:

• Soda lake microbial communities exhibit remarkable biodiversity and functional specialization, contributing to high ecosystem productivity.
• The findings provide a foundation for understanding life in extreme environments and developing biotechnologies for carbon dioxide conversion.