Looking for microbial life in the planetary lava tubes on Mars
Volcanic eruptions are spectacles like no other, with the power to literally reshape the face of the Earth. They also offer unique opportunities for scientific exploration. In recent years, multiple expeditions have studied volcanic caves to advance our understanding of how the structures could form—and potentially support microbial life on Mars and other planets.
The Hraunrásir research team has already completed three such expeditions. Their fourth expedition took place in the spring of 2023 to the Fagradalsfjall volcano in Iceland, located about an hour away from Reykjavik, and unlike the previous expeditions, it took place recently after the volcano erupted. Led by Francesco Sauro, a geologist and speleologist at the University of Bologna, the team included five scientists, five explorers, and two special guests: Thermo Fisher Scientific application and product specialist Rogier Miltenburg and the Thermo Scientific Phenom XL G2 Desktop SEM.
A novel investigation of microbial life
In 2021, Miltenburg and the Phenom XL G2 Desktop SEM first traveled to where he worked with the group of scientific researchers in a first-of-its-kind exploration of volcanic caves. With the instrument on site, the team was able to collect and image bacteria samples, giving them a deeper understanding of the morphology of cave minerals without having to transport the samples to a lab first.
The Iceland expedition was the first of its kind to study lava tube formation while the tubes were still hot—around 100°C. The tubes are sterile when they are first developed, but as they cool, they transform into distinctive habitats that support flourishing microbial populations. Microorganisms quickly inhabit these spaces. By performing the bulk of their research and analysis on site during the cooling phase, the team hoped to uncover new details of how lava tubes are created, how they evolve while cooling, what metastable minerals form during this time, and how microbial life colonizes these originally pristine environments. All these topics have implications in the understanding of planetary lava tubes on Mars and other planetary bodies and their potential for astrobiology.
“With the last mission to the Salvages Island, those caves were worn and had seen millions of years of development and rock layer. It was like a time capsule,” Miltenburg said. “These new caves that were formed by the Fagradalsfjall volcano were the complete opposite. In the grand scheme of the geological time scale, it was as if these lava tubes were a millisecond old. It is fascinating to see that process, from the first colonizers of microbial life to form, what minerals develop, and how temperature impacts it all.”
An image that shows the wide variety of minerals collected from the lava tubes, taken from the Thermo Scientific Phenom XL G2 Desktop SEM.
Using a portable SEM at a volcano
Because of the success of the Selvagens expedition, the team knew they needed a portable electron microscope to take full advantage of the opportunity presented to them. They specifically requested the Phenom XL G2 Desktop SEM in order to image samples taken from the lava tubes just minutes after they were collected. The Phenom XL G2 Desktop SEM on site allowed the team to collect data without vigorous sample preparation.
“Time is of the essence with these samples,” said Miltenburg. “With the Phenom Desktop SEM, we did not need to worry that metastable minerals would break down during the time it would take to transport them to a full lab.”
Ultimately, the cutting-edge technology made it possible for the team to advance their microbiology research and mineralogy research in ways that would have been impossible anywhere else.
“With the Phenom’s energy dispersive X-ray spectroscopy (EDS), we could look at the mineral samples and see the shapes of minerals,” Miltenburg said. “Using other techniques would not give you all of the minerals present in the sample. For example, the Phenom XL G2 Desktop SEM allowed us to see five different minerals in a sample, some expected by the team, some completely new and unexpected. And we were able to clearly see the composition breakdown of each mineral.”
Phenom XL G2 SEM enables scientific breakthroughs
The Phenom XL G2 SEM proved critical for microbiology and minerology research conducted on the island.
“The team broke scientific boundaries,” said Miltenburg. “They were the first to ever enter these hot lava tubes, explore them, and collect samples.”
The mineralogists had expectations on what minerals they would find in these lava tubes, but with this research, that list of minerals will likely double. The microbiologists were able to gain insight into when life colonizes and pinpoint at what temperature microbial life first forms. The team was able to not only gather previously unharvested samples but also discuss their analytical results and formulate a theory in real time.
“The expedition brought together experts from varying disciplines and having the results there on site to discuss and collaborate together is invaluable,” said Miltenburg. “We could all see the results with our own eyes and discuss and work together to formulate our theories right on site.”
While they have yet to release their official findings, the work itself represents an important step in creating new scientific possibilities that will further our knowledge of life itself, both here and on Mars.
To learn more about the Thermo Scientific Phenom XL G2 Desktop SEM visit here.
Rogier Miltenburg is an applications and product specialist at Thermo Fisher Scientific
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