Rock Traits Drive Complex Microbial Communities at the Edge of Life

Antarctic deserts are among the driest and coldest ecosystems of the planet; there, some microbes survive under these extreme conditions inside porous rocks, forming the so-called endolithic communities. Yet the contribution of distinct rock traits to support complex microbial assemblies remains poorly determined. Here, we combined an extensive Antarctic rock survey with rock microbiome sequencing and ecological networks and found that contrasting combinations of microclimatic and rock traits such as thermal inertia, porosity, iron concentration, and quartz cement can help explain the multiple complex microbial assemblies found in Antarctic rocks. Our work highlights the pivotal role of rocky substrate heterogeneity in sustaining contrasting groups of microorganisms, which is essential to understand life at the edge on Earth and for the search for life on other rocky planets such as Mars.

Automated summary

Antarctic deserts are extremely dry and cold ecosystems. In these conditions, microbes survive inside porous rocks, forming endolithic communities. This study investigates the role of different rock traits in supporting complex microbial assemblies in Antarctic rocks. The findings highlight the importance of rocky substrate heterogeneity in sustaining contrasting groups of microorganisms and have implications for understanding life in extreme environments and the search for life on other rocky planets.