Microbial life in the lava tubes
Understanding the origins of life on this and other planets requires a sophisticated understanding of microbe-mineral interactions. Studying subsurface environments where microorganisms dominate the ecosystem is a good way to improve our understanding in this field. The EU-funded DECAVE (Understanding the nature and origin of black deposits in caves: New insights on enigmatic microorganisms and secondary minerals valuable for astrobiology) initiative studied microbial ecosystems in lava tubes and caves around the world to understand how microorganisms interact with geology in these environments and to identify biological or geochemical signatures. Researchers investigated ecosystems in lava tubes on Easter Island, the Canary Islands and the Galapagos Islands. In particular, research focused on speleothems – structures like stalactites and stalagmites formed in caves by the action of water. DECAVE identified the types of bacteria and other organisms growing in or on mineral deposits in the Canary Islands. Actinobacteria and Proteobacteria were the most common genera, and most bacteria found there were chemoautotrophs – organisms that create their own food from chemical processes. Another finding showed that there were many unidentified species in these caves. DECAVE also identified features suitable for use as biosignatures – geological identifiers of life in hostile environments, or even on other planets like Mars. Overall, these results contribute to researchers' understanding of life in hostile environments. DECAVE results will help in the search for life on Earth and maybe even on Mars.
