Elucidating the ecological networks in stone-dwelling microbiomes

Area of Science:

• Environmental microbiology
• Geomicrobiology
• Archaeological science

Background:

• Stone surfaces present extreme environments with limited resources and harsh conditions (e.g., desiccation, high pH, irradiation).
• Microbial life persists on stones, exhibiting resistance to extreme environmental factors.
• Understanding the factors influencing these stone-dwelling microbial communities is crucial for conservation and scientific insight.

Purpose of the Study:

• To investigate the effects of climate and stone geochemistry on the microbiomes of Roman stone ruins in North Africa.
• To identify key microbial taxa and functional genes essential for survival in these extreme environments.
• To elucidate the interplay between environmental variables and microbial community structure and diversity.

Main Methods:

• Analysis of microbial communities from Roman stone ruins.
• Assessment of climate variables (e.g., water availability) and stone geochemistry (e.g., nutrient content).
• Metagenomic analysis to determine microbial community structure, diversity, and functional capacity.

Main Results:

• Stone microbiomes were dominated by Actinobacteria, Cyanobacteria, and Proteobacteria.
• Climate, particularly water availability, and stone geochemistry (biologically available P, Mn, Zn) significantly impacted microbial diversity.
• Metagenomes revealed enrichment of functions related to photosynthesis and UV protection, crucial for survival.

Conclusions:

• Climate and stone geochemistry are major drivers of microbial community structure and diversity on stone ruins.
• Specific microbial taxa (e.g., Geodermatophilaceae, Rubrobacter, Sphingomonas) are core members of these communities.
• The study expands understanding of microbial adaptation and survival strategies in extreme built environments.