Ecologists and planetary scientists from the University of Arizona led a study of microbial colonization on new lava flows at Fagradalsfjall on Iceland's southwest tip. The volcano erupted three times between 2021 and 2023, giving the team a rare natural triplicate of fresh flows to sample. The paper appears in Nature Communications Biology with Nathan Hadland as first author.
Researchers sampled freshly cooled lava within hours of solidifying and also collected rainwater, aerosols, soil and nearby rock. They extracted DNA and applied statistical and machine learning methods to identify organisms and infer their likely sources. Hadland noted that lava above more than 2,000 degrees Fahrenheit starts out essentially sterile.
Fresh lava held little water and almost no organic nutrients, making it a very low-biomass environment comparable to Antarctica or the Atacama Desert, according to Solange Duhamel. Single-celled organisms colonized quickly; diversity rose in the first year but then "tanked" after the first winter. Early colonizers mainly came from soil and aerosols, while after the winter most microbes arrived with rainwater, which can carry microbes and act as cloud condensation nuclei. The study helps frame questions about transient habitable conditions and biosignatures on worlds such as Mars.
Difficult words
- colonization — Process of organisms starting to live in a place
- microbial — Relating to very small living organisms
- aerosol — Tiny particles or droplets in the airaerosols
- biomass — Amount of living material in an environmentlow-biomass
- biosignature — Evidence that life existed or exists nowbiosignatures
- infer — To form an idea from available information
- triplicate — A set of three similar or identical items
- transient — Short lived lasting only a brief time
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could rainwater change which microbes arrive on new lava?
- Why might fresh lava be similar to Antarctica or the Atacama Desert?
- Do you think studies of new lava flows can help find life on other planets? Why or why not?
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