Life’s First Footsteps: How Icelandic Lava Reveals the Secrets of Colonization
Even after seemingly total devastation, life finds a way. Fresh lava flows, initially barren and inhospitable, are surprisingly quick to show signs of life. A recent study reveals that microscopic organisms initiate reclaiming these new lands almost immediately, long before plants or animals can establish themselves.
Iceland’s Volcanic Laboratory
Researchers from the University of Arizona, combining expertise in ecology and planetary science, turned to Iceland’s Fagradalsfjall volcano as a unique natural laboratory. The volcano erupted three times between 2021 and 2023, repeatedly blanketing the surrounding tundra with lava. This provided a rare opportunity to study primary succession – the colonization of entirely new, previously lifeless land.
“The lava coming out of the ground is over 2,000 degrees Fahrenheit, so obviously it is completely sterile,” explained Nathan Hadland, a doctoral student at the University of Arizona Lunar and Planetary Laboratory. “It’s a clean slate that essentially provides a natural laboratory to understand how microbes are colonizing it.”
The ‘Badass’ Microbes: Who Survives the Initial Assault?
The study focused on identifying the first organisms to take hold in this extreme environment. Fresh lava presents significant challenges: it retains little water and offers minimal nutrients. Despite these harsh conditions, microbial life colonizes the lava surprisingly rapidly.
“These lava flows are among the lowest biomass environments on Earth,” said Solange Duhamel, associate professor in molecular and cellular biology at the University of Arizona. “They are comparable to Antarctica or the Atacama Desert in Chile… But our samples revealed that single-celled organisms are colonizing them pretty quickly.”
Initial microbial diversity increases in the first year, but a sharp decline follows the first winter. This suggests that only the most resilient microbes – those capable of withstanding the cold and fluctuating conditions – survive the initial period. “the first colonizers are these ‘badass’ microbes, for lack of a better term, the ones that can survive these initial conditions, because there’s not a lot of water and there’s incredibly little nutrients,” Hadland noted.
The Unexpected Role of Rainwater
The research revealed a surprising shift in colonization patterns. Early on, microbes primarily arrived via wind-blown soil and aerosols. However, after the first winter, rainwater became the dominant source of new microbial life.
“Early on, it appears colonizers are mostly coming from soil that is blown onto the lava surface, as well as aerosols being deposited,” Hadland said. “But later, after that winter shift in diversity we observed, we see most of the microbes are coming from rainwater, and that’s a pretty interesting result.”
This finding highlights the role of atmospheric processes in seeding new environments. Rainwater, far from sterile, carries microbes from the air, demonstrating a link between weather patterns and biological colonization.
Implications for Life Beyond Earth
This detailed study of microbial primary succession, repeated across three separate eruptions, offers valuable insights with implications far beyond Earth. The volcanic landscapes of Mars share similarities with those found in Iceland.
“For the first time, we are beginning to gain a mechanistic understanding of how a biological community established over time, from the very beginning,” Duhamel said.
Understanding how life establishes itself on fresh lava on Earth can inform the search for life on other planets, particularly those with volcanic histories. The study suggests that even in seemingly inhospitable environments, the potential for life may exist.
Did you recognize?
Microbes can influence weather patterns! They can act as “cloud condensation nuclei,” helping to form rain droplets and potentially seeding new environments with life.
FAQ
Q: What is primary succession?
A: It’s the colonization of a completely new habitat, one that has never supported life before.
Q: Why is Iceland a good place to study this?
A: The frequent volcanic eruptions create new, sterile lava flows, providing a natural laboratory for observing colonization.
Q: What kind of microbes were found on the lava?
A: The study identified a range of microbes, with the most resilient species dominating the initial colonization phase.
Q: How does this research relate to the search for life on Mars?
A: Mars has extensive volcanic rock formations, and understanding how life colonizes lava on Earth can help scientists identify potential habitats on Mars.
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