Microorganisms colonising La Palma lava tubes offer clues for life on Mars

A newborn world

After the Tajogaite volcano on La Palma erupted on 19 September 2021 and continued for 85 days, it left behind freshly formed lava tubes. These subterranean spaces, described by researchers as a "newborn world," contained no soil or vegetation, creating a sterile environment where life had to start from scratch. The research team accessed the tubes between one and two years after the eruption, when conditions were still extreme: air temperatures reached 60°C and rock surfaces exceeded 90°C.

The lava tubes constitute an authentic 'newborn world', without soil or vegetation, where the first living beings must open the way for the ecosystem to develop.

First colonisers

The study shows that the earliest microorganisms arrived mainly from the outside, carried by air as aerosols or spores, or associated with animals such as birds, rodents and insects. These inputs introduced organic matter into the initially sterile environment and encouraged the appearance of the first biological communities. By analysing how these pioneers gained a foothold in such harsh conditions, the scientists gained insight into the fundamental mechanisms of ecosystem recovery after a volcanic eruption.

A Martian analogue

The relevance extends beyond Earth. Because lava tubes on Mars share similarities with these newly formed subterranean environments, the La Palma tubes serve as a natural laboratory. The research opens new lines of investigation into habitability on other planets. As the Andalusian regional government noted, the results "help to define how some biological communities could emerge, evolve and be maintained in subterranean environments on Mars."

International collaboration

The project, supported by the Andalusian Council of Universities, Research and Innovation, involved the Institute of Natural Resources and Agrobiology of Seville (IRNAS-CSIC), the Geological and Mining Institute of Spain (IGME-CSIC), the University of Almería, the University of Huelva, and collaborators from the University of Évora and INESC TEC in Portugal, plus the Canarian Speleological Federation. Their work, now published in Environmental Microbiome, represents an early view of how life takes hold in a completely new and sterile setting.

These environments have become a natural laboratory for studying the limits of life in extreme conditions, which opens new lines of research related to habitability on other planets.