Young volcanic terrains are windows into early microbial colonization

Volcanic eruptions generate initially sterile materials where biological processes are absent, allowing for the fresh colonization by new organisms. This review summarizes the characteristics of volcanic habitats that are available for pioneer microbial colonization, including hot springs, fumaroles, lava tubes, and recently cooled rock surfaces and interiors. Eruptions provide unique insight into microbial community development in extreme environments. The trajectories that these ecosystems follow are largely dictated by the initial environmental conditions and identities of the colonizers, rather than the age of the system. The review also discusses how studies of microbial communities in young lava flow fields can provide insights into the possibility of life on Mars, which was volcanically and hydrologically active in the past. Understanding biosignature preservation as well as the metabolisms and survival mechanisms of microorganisms in volcanic systems has implications for how an ecosystem might have developed on early Earth and possibly Mars.