A University of Alabama professor specializing in the esoteric field of biomineralization has discovered a way to prove the timing of the early origins of life on Earth and possibly, in the years to come when rock samples are returned from Mars, to determine if life was present on the red planet.

Professor Alberto Perez-Huerta, a Ph.D. holder from the University of Oregon and who completed post-doctoral work at the University of Glasgow in Scotland, discovered a way to use a very special instrument, a Local Electro Atom Probe, or LEAP for short, to analyze a specific mineral in ancient rock that could only have been generated by a living bacterial organism. His research lays a foundation upon which other scientists can build more accurate theories about early life on Earth.

Rock samples from about 3.5 billion years ago are known to bear a particular crystal that is only 60-80 nanometers in size, but no one could determine if the crystals were geologically formed or biologically formed. That is where Perez-Huerta's discovery comes into play.

"My idea was that if these crystals were formed by bacteria they needed to have some kind of traces, organic components that show they are biological in nature," Perez-Huerta said. "What I did was use the atom probe machine to look at the atoms inside these crystals at the nano scale. It's perfect for this scale."

Working with collaborators who collected some recent samples of the bacteria, Perez-Huerta analyzed the extracted crystals. They created identical crystals in the lab using chemical processes then analyzed both crystals to see if there were differences.

"We used the Atom probe to look at these crystals. What we found was that the ones from the bacteria have atoms of carbon and nitrogen inside, so atoms of carbon and nitrogen − the building blocks of life − were in the biological crystals, while the ones formed in the lab and by other non-biological processes didn't have those carbon and nitrogen atoms," Perez-Huerta said.

The groundbreaking discovery can help scientists probing the origins of life on Earth determine whether those ancient rock samples bearing the crystals are biological or geological in nature. The LEAP fires a laser at a sample that is extremely small. A nanometer is one-billionth of a meter. As an example, a human hair is between 80,000 and 100,000 nanometers wide. The samples used in the LEAP are 60-80 nanometers wide and completely invisible to the naked eye.

The laser heats the sample and draws off individual atoms, which can be analyzed to determine their composition. The difference between minerals produced by biological and geological processes can then be seen at this atomic level, giving researchers of life's origins a new tool to work with to establish exactly when and how life emerged on this planet.

Perez-Huerta's journey of discovery began in Spain. He is a native of Cangas de Onís, a small village in the northern province of Asturias. By his own admission, Perez-Huerta was not a good student. While a university education at that time was free in Spain, a prospective student had to make qualifying scores to gain entry into the best fields of study. Lacking the scores to qualify for his dream occupation, that of a marine biologist, Perez-Huerta said he opted for geology because they needed people and the discipline did not have a minimum score requirement.

"When I got into college, my main interests were parties, girls, and playing volleyball. During my third year in college, I took a course in paleontology and the professor changed my life. He was very interested in a group of common fossils that have living relatives now. It shocked me that he was not talking about dinosaurs or other iconic fossils. I thought he was crazy because he liked fossils nobody cared about and it made me ask why," Perez-Huerta said.

Professor Fernando Alvarez at Universidad de Oviedo set Perez-Huerta on a course of discovery that led him to work on biomineralization, the process that living organisms use to create minerals. Even the human body does this. At the University of Oregon where he was studying fossils and how they recorded ancient climate information, Perez-Huerta realized he needed to know more about how biological organisms formed things like shells. He began his post-doctoral work at the University of Glasgow in Scotland, one of the best places in the world to study biomineralization.

In Glasgow, he was able to use a number of sophisticated tools and instruments to conduct his studies. When he came to the University of Alabama to interview, it was the presence of an earlier LEAP machine that fascinated him and helped draw him to this school. He was impressed by the friendliness here and with the opportunity to do research in any area he wished. Perez-Huerta teaches courses in geological sciences and conducts his research during his non-teaching hours.

When Perez-Huerta came to UA in 2009, the LEAP was not being used for biological research. His idea to use it for that purpose sprang from his work in Glasgow and also from the idea that the LEAP could pull individual atoms from crystals for analysis. He already knew about the crystals formed by certain types of bacteria, and using atom probe tomography opened the door for his discovery.

"With the instrument we had here, we could not analyze organic samples or biominerals. Biominerals have an organic part and a mineral part. Like our bones, they are mainly organics and water and we have a small fraction of minerals. We realized we didn't have the right instrument. We now have quite a new instrument. We acquired a new generation of the instrument and it was actually the first one in North America that was purchased by an academic institution," Perez-Huerta said.

The idea of ancient life in the rocks from about 3.5 billion years ago has been around for a while, but the evidence was indirect and derived from chemical processes. Perez-Huerta's process can help nail down physical evidence of early life.

"That's a huge discovery because now we can go to those crystals found in the geological record 3.5 billion years ago, use the same approach and determine if those samples have the carbon and nitrogen. If they do, they were formed by bacteria. So will know if bacteria were there over 3 billion years ago," Perez-Huerta said.

The professor has not actually analyzed rocks that old. What he has done is create a process that did not exist before that will enable the analysis of ancient samples in ways that were previously impossible. By laying this foundation, Perez-Huerta hopes that others will see the work he has done and get in touch with him to apply the process to their samples to build upon his work.

"In a sense, we have now an approach and a technique that can give us the kind of, not indirect evidence, but the smoking gun. We can get any kind of crystals of any size and analyze them. We can tell whether these are made by organisms. That's how you tease apart minerals formed by geological processes, chemical processes, volcanic eruptions to something formed by an organism," Perez-Huerta said.

"Early life on planet is something people have a lot of interest in. There is a lot of factions. You would think there would be more collaboration, but people want to keep their samples to themselves. They want to do their things. Hopefully, once the study is out there and people see it, it will gain traction and colleagues will call me to collaborate."

The professor credits the University of Alabama with investing in the necessary research infrastructure to enable him and fellow researchers to make important discoveries.

"It is good to see the administration and the vice president of research are invested in the infrastructure that allows us to do this. Hopefully, this shows some kind of return on investment."