Geology and elevation shape bacterial assembly in Antarctic endolithic communities

Area of Science:

• Microbiology
• Ecology
• Geology

Background:

• Antarctic ice-free areas harbor diverse, adapted microbial communities, with endolithic growth being a dominant life-form.
• Understanding the assembly mechanisms of these endolithic microbiomes in extreme environments is crucial but remains limited.

Purpose of the Study:

• To investigate the diversity and assembly of endolithic bacterial communities in Antarctica.
• To determine the influence of rock type and elevation on microbial community structure and heterogeneity.

Main Methods:

• Metagenomic analysis was employed to examine bacterial communities.
• Communities were studied across different rock types (granite, sandstone) and a wide elevation range.

Main Results:

• Granite supported richer and more heterogeneous endolithic communities than sandstone.
• Elevation did not affect taxonomic richness but significantly influenced community composition turnover.
• Community turnover along elevation gradients was modulated by geology, with greater turnover between different rock types.

Conclusions:

• Geology and elevation are primary drivers of endolithic bacterial heterogeneity in Antarctic cold-arid environments.
• Deterministic processes, particularly variable selection, shape microbial assembly along elevation gradients.
• Warming temperatures may pose a threat to the persistence of these specialized extremophilic organisms.