PROFILE Alef dos Santos, who recently came to Umeå as a postdoctoral researcher, studies extremophiles – microbial life that thrives in extreme environments. His research brings together chemistry, microbiology, and space science at the Chemical-Biological Centre, KBC, to identify biosignatures – chemical traces of life – that could indicate extraterrestrial life.
I am confident there is microbial life elsewhere in the solar system
“Extremophiles survive in the harshest environments on Earth, so why wouldn’t they survive on Mars or the icy moons of Jupiter and Saturn?” Alef dos Santos says.
When I meet Alef in his lab at the Department of Chemistry in the KBC-building, he is in the process of growing microbes in petri dishes. “I just received these two weeks ago and now I’m cultivating them until I have enough to start my experiments in a simulated Mars environment,” he says. The microbes originate from Antarctica and are accustomed to extremely cold and nutrient-poor environments.
Interior view of Saturn's moon Enceladus. NASA's Cassini spacecraft discovered the moon has a global ocean, heated by hydrothermal activity. A plume of ice and water vapor sprays from fractures in the moon's south polar region.
Image NASA/JPL-CaltechAlef's research has taken him to some of the most extreme environments on Earth. As part of his PhD studies, investigating if microbes could live on Saturn’s icy moon Enceladus, he went to the volcanic Al Wahbah crater in Saudi Arabia. The similarities between a sandy desert and an icy moon might seem scarce, but looks can be deceiving.
“This crater hosts a salt lake, with high pH, and warm temperatures – conditions that are not too different from the hydrothermal vents found on Enceladus,” says Alef. He managed to isolate 48 strains of thermo-haloalkaliphilic bacteria from the crusty salt layers – findings that were featured on the cover of the journal Astrobiology. “Finding a place on Earth that mimics extraterrestrial environments make it easier for us to study the possibilities of life beyond Earth“.
Alef dos Santos are collecting samples of the crusty salt layer from the bottom of the volcanic Al Wahbah crater. From the samples he detected 48 strains of bacteria living in the extreme environment.
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Alef dos Santos studied the microbial life in the volcanic Al Wahbah crater. The salty, warm and alkaline environment serves as an Earth analogue for Saturn's ice moon Enceladus.
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The Al Wahbah crater is the remains of a volcano.
Image Alef dos Santos
The desert surrounding the Al Wahbah crater in Saudi Arabia, reminiscent of the fictional sand planet Arrakis, is a hostile place for most organisms.
Image Alef dos SantosHis journey into astrobiology began in a chemistry lab at the Federal University of São Carlos, Brazil. He discovered a strain of a black fungus, Rhinocladiella similis, growing inside a bottle of hydrochloric acid. He managed to isolate the strain, which set the course for his Bachelor’s and PhD studies of characterising biosignatures. “If, or when, microbes interact with their environment, they change it, leaving behind clues that we can categorise,” he explains.
To detect biosignatures, Alef used mass spectrometry, a technique that identifies the unique chemical fingerprints of molecules by measuring their masses. He hopes to continue with this technique in Umeå, where the Swedish Metabolomics Centre, supported by SciLifeLab, offers state-of-the-art facilities. “I think I’d be the first in Umeå to use the facilities for astrobiological research,” Alef says.
Alef dos Santos, postdoctor at the Department of Chemistry, studies biosignatures in preparation for future Mars missions.
ImageRebecca ForsbergHere in Umeå, Alef extends his search for biosignatures using spectroscopy. “Infrared spectroscopy helps me identify chemical bonds in organic compounds, while Raman spectroscopy will give complementary data on molecular structures,” he says. Together, the complementary techniques give a more complete picture of how life influences its surroundings.
For instance, one of the signatures of the black fungi is the molecule melanin, same as the one found in our skin. “Melanin helps protect the fungi from harsh radiation,” he explains. “On Mars, where radiation levels are extreme, finding traces of melanin could be a strong indicator of past or present life.”
While directly detecting microbes on Mars or a moon can be really tricky, Alef instead wants to look at the signals the microbes, or their surrounding environment, emit. By growing extremophiles in Mars-like conditions, Alef studies the samples using only techniques that will be available on future Mars missions, like ExoMars. As such, he hopes to determine which biosignatures the rover should look for.
“The more we understand how microbes alter their environment, the better equipped we are to recognise those changes elsewhere in the solar system,” he says. “This is crucial for the future search for life beyond Earth.”
Rhinocladiella similis, or black fungus, growing in a petri dish in Alef dos Santos' lab. The orange bacteria is the one from Antarctica that arrived two weeks ago.
ImageRebecca ForsbergMars used to have liquid water, and the question is whether life could have thrived there. With the loss of most of its atmosphere, the water on Mars evaporated, leaving the dry, red planet that we know today. But given how life exists even in the most extreme places on Earth, Alef has his hopes that if something used to thrive on Mars, there might still be traces of it.
This is part of his project at Umeå University, where he recently joined Merve Yeşilbaş’s lab, and shifted his focus from fungi to cyanobacteria. These are microorganisms that, just like plants, use photosynthesis and carbon dioxide to produce energy. “Luckily, Mars’s atmosphere – although very thin – consists almost entirely of carbon dioxide.”
Regolith mixture based in the geochemical composition of Mars, which Alef dos Santos uses for his simulated Mars experiments.
Image Rebecca ForsbergBy measuring the biosignatures that cyanobacteria have in a simulated Mars environment, Alef hopes to open a window to the red planet’s past. For instance, a byproduct of cyanobacteria's photosynthesis is oxygen, which can contribute to oxidation of minerals – acting as a possible biosignature. “Mars has a lot of oxygen-rich minerals, which could be indicative that it used to have a population of cyanobacteria,” Alef says.
On Earth, cyanobacteria have been found surviving within rocks, in lava tubes or below the upper ground layer. “Perhaps it’s the same on Mars, waiting to be discovered underneath the surface” he says.
As a kid, Alef dreamt of the universe and to study astronomy. But looking at the courses, math and physics did not appeal to him as much as chemistry and biology did. Now, he is very happy to contribute to space research through astrobiology. “We are quite a small field, but the research we do is essential for the search of life elsewhere.”
Alef dos Santos, postdoctor at the Department of Chemistry.
ImageRebecca ForsbergHowever, he never lost his love for stargazing. “I got my first telescope as a student, and that’s actually how I met my wife – she wanted telescope recommendations!” he laughs. She will soon join him in Umeå, along with their two cats. “And with the dark winters, I finally might have time to pick up the telescope again,” he adds.
His ultimate dream is to work for a space agency like ESA or NASA. “The biggest scientific questions revolve around how life emerged and whether we are alone. Now, I get to be part of finding the answer.”
Alef dos Santos research is part of an interdisciplinary project that brings together researchers from several departments within the Chemical-Biological Centre, KBC. His research is made possible through collaboration with scientists from the Department of Chemistry, the Department of Ecology and Environmental Sciences, and the Umeå Marine Sciences Centre, UMF.
The project is funded by Kempestiftelsen.