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Here's a riddle. What does vaporizing minerals in Algeria have to do with the search for ancient life on Mars? Well, it all has to do with gypsum. Here's science reporter Ari Daniel.
ARI DANIEL, BYLINE: In a way, it all started with a road trip about a decade ago.
YOUCEF SELLAM: My father, he had the car, so I had to borrow the car from him. Yeah. He said, yeah, let's go together.
DANIEL: Youcef Sellam and his father were headed north to a gypsum quarry near the Mediterranean coast of their country, Algeria. Sellam says his dad had ignited in him a curiosity about the world since he was little.
SELLAM: The first science magazine I got, it was from my father. The first biology book, it was from my father.
DANIEL: Sellam went on to study microbiology and paleontology. He became interested in ancient microbes and the tiny fossils they leave behind in minerals like gypsum. And then, during an internship in Italy, he was chatting with his supervisor when the stars aligned.
SELLAM: He said, yeah, we know almost everything about the Mediterranean, but there is a place that we couldn't go, and we would like to get some gypsum.
DANIEL: That place was Algeria, which is how Sellam wound up driving his dad's green Toyota Echo to that quarry. Over a couple days, Sellam collected more than 60 pounds of gypsum.
SELLAM: I was the one making the sampling while my dad was just watching (laughter).
DANIEL: Back at the lab, Sellam saw sinuous filaments preserved in the mineral - ancient, fossilized microbes.
SELLAM: We cannot be 100% sure about the species.
DANIEL: They might have been a kind of algae or bacteria. Sellam ultimately got into a Ph.D. program in physics at the University of Bern in Switzerland.
SELLAM: He was like, OK, now we're talking (laughter).
DANIEL: And here's what Sellam decided to tackle. You can only look back at microbial life on Earth so far. That's because plate tectonics on our planet, when it was just a baby, erased the clues of its early existence.
SELLAM: So basically, we lost the first billion years regarding the history of the Earth, and we don't know what happened, so we have a gap.
DANIEL: A gap that includes any really ancient microbes. Luckily, though, there's Mars.
SELLAM: Mars is a screenshot of the early Earth, of course not exactly, but quite similar.
DANIEL: By studying Mars, scientists might learn about the ancient Earth. And if - and it's a big if - Mars has microbes fossilized in its gypsum, researchers will need the right tools to load onto rovers to look for that life. And that's where Sellam's Ph.D. came in, which focused on testing whether a powerful instrument about the size of a water bottle could detect the chemical signatures of life.
SELLAM: It's basically a laser beam hitting the sample, and this laser will vaporize part of the material, creating some atoms. You will have a spectra of the different elements that are existing in the rock.
DANIEL: Which reveals whether there's fossilized life in the rock. But before that laser could be sent to Mars, it had to be tested on Earth, and Sellam had the perfect sample - his Algerian gypsum.
SELLAM: We proved that our instrument is capable to detect signatures of life in the gypsum.
DANIEL: Suggesting that one day, it might help do the same on Mars. The results were published in the journal Frontiers in Astronomy and Space Sciences. Bonnie Baxter directs the Great Salt Lake Institute at Westminster University and wasn't involved in the research.
BONNIE BAXTER: What this study in Algeria really does is it sort of highlights that you can use chemical methods to infer that biology is in the mineral. And chemical methods are just a little more transferable to Mars.
DANIEL: Still, she says, the laser approach on the red planet might be tricky because it would have to detect fossils that are billions instead of millions of years old. Youcef Sellam is proud that his first ever scientific publication highlights Algeria, but just before he finished it up in September, his father passed away.
SELLAM: I wish I had my dad live in this moment, in reality, always standing with me and - yeah. Maybe he will say, don't stop here (laughter). Keep going.
DANIEL: Advice that Sellam is sure to follow.
For NPR News, I'm Ari Daniel.
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