Microbial Ecology in Volcanic Soils

Volcanic soils represent dynamic substrates in which microbial life drives the earliest stages of ecosystem development. Fresh volcanic deposits are virtually sterile yet supply essential minerals and energy sources that select for specialised pioneer microorganisms. Through processes of chemolithotrophy, autotrophy and organic–inorganic cycling, these communities establish the foundations for subsequent plant colonisation, soil formation and nutrient turnover. Key environmental controls include pH, mineralogy, temperature gradients and gaseous emissions such as sulphur dioxide, each of which shapes community assembly and function. In the first years to decades after an eruption, microbial networks evolve from simple assemblages of iron- and sulphur-oxidisers to more diverse communities capable of nitrogen fixation, organic carbon utilisation and mutualistic interactions with nascent vegetation. Understanding these successional trajectories has broad implications for biogeochemical modelling, rehabilitation of degraded landscapes and even the search for life in extraterrestrial volcanic analogues.

Research from Nature Portfolio

Recent studies have illuminated colonisation patterns on brand-new lava flows and ash fields. Work on very young volcanic terrains demonstrates that initial community structure is determined more by the nature of the habitat (such as fumaroles or lava tubes) and the identity of pioneer taxa than by substrate age alone. Autotrophic iron- and hydrogen-oxidisers dominate in fresh deposits, fixing carbon and nitrogen to create bioavailable resources. These investigations reveal parallels with early Earth ecosystems and offer models for detecting biosignatures on Mars, where past volcanism and water activity may have supported similar processes.

Research into the influence of sulphur dioxide exposure on fresh basaltic ash has shown that long-term gas exposure imposes a strong selective pressure, favouring autotrophic iron-oxidisers and certain CO₂- and N₂-fixing bacteria. As gas emissions decline, community composition shifts towards heterotrophic consortia more akin to mature forest soils. Such findings underscore the role of volcanic gases in steering pioneer succession and highlight how changing chemical regimes modulate microbial diversity and function.

Microbial Ecology in Volcanic Soils publication trend

The graph below shows the total number of articles in microbial ecology in volcanic soils across all publications each year (not limited to Nature Index journals).

Technical terms

Pioneer species: Early microbial colonisers that initiate ecosystem development on sterile substrates.

Chemolithotrophy: Metabolic process by which organisms derive energy from the oxidation of inorganic compounds such as iron or sulphur.

Autotrophy: Capability of organisms to fix CO₂ into organic matter using chemical or light energy.

Rhizosphere: The narrow zone of soil surrounding plant roots, enriched in microbial activity and influenced by root exudates.

Succession: Sequential changes in community composition and function over time following disturbance or substrate formation.

References

1. Patterns and drivers of microbiome in different rock surface soil under the volcanic extreme environment. iMeta (2023).
2. Young volcanic terrains are windows into early microbial colonization. Communications Earth & Environment (2024).
3. Sample Collection and Return from Mars: Optimising Sample Collection Based on the Microbial Ecology of Terrestrial Volcanic Environments. Space Science Reviews (2019).
4. Characterization of the bacterial communities on recent Icelandic volcanic deposits of different ages. BMC Microbiology (2018).
5. Unique pioneer microbial communities exposed to volcanic sulfur dioxide. Scientific Reports (2016).
6. Bacterial Community with Plant Growth-Promoting Potential Associated to Pioneer Plants from an Active Mexican Volcanic Complex. Microorganisms (2022).