Was there life on Mars?
It’s a question researchers like University of Tennessee at Chattanooga Assistant Professor of Geology Ashley Manning-Berg continually seek to answer.
Early this semester, Manning-Berg was one of 32 early-career scientists selected to participate in a NASA workshop at Goddard Space Flight Center near Washington, D.C., for what she called “an intense week coming up with ideas of how to look for life on Mars.”
The first NASA Astrobiology Mission Ideation Factory brought together early-career scientists—including planetary geologists, geoscientists, chemists and biologists; people who have been on previous missions to Mars; and subject-matter experts from various fields to develop and refine ideas for an astrobiology-based future mission.
The week was an eye-opening experience, Manning-Berg said.
“It was probably one of the best weeks I’ve ever had,” she said. “We focused on extant life—living organisms—and we had no limitations. We just reached for the stars and took what we thought we could do without the consideration of funding and without the consideration of technological limitations—and we ended up designing our own mission to Mars as groups.
“We all had our own little niche, but we all overlapped, making for really good conversations. At the end of the week, we actually got to present our ideas to NASA headquarters—to people who make instruments for missions and people who look at missions.”
Manning-Berg joined the UTC faculty in 2019 after spending one year as a visiting assistant professor at Case Western Reserve University’s Earth, Environmental and Planetary Sciences department. She said she was selected to participate in the weeklong workshop based on research expertise that started during her undergraduate days.
As a University of West Georgia student, she grew organisms in the geology lab and watched them die. During that process, she got an idea of how shapes would change as an organism entered or was preserved into a rock.
“I am interested in everything from dying to the time that we collect that organism,” she explained. “I should say I’m not necessarily interested in what that organism is; I’m more interested in how it interacts with its chemical environment. How does the chemistry of the environment interact with the microbes? How do the microbes interact with the chemistry or change the chemistry of the environment?
“I have been working on this basically my entire career.”
After spending time as a research geologist in the Engineer Research and Development Center at the U.S. Army Corps of Engineers, Manning-Berg received master’s and doctoral degrees in geology from UT Knoxville—where she focused on geochemistry.
At first, Manning-Berg’s research centered on the calcification of evaporates from a billion years ago, but she shifted her focus after seeing silicified microbial mats in the Angmaat Formation on Baffin Island in Canada while pursuing a Ph.D.
“These are microbial mats that look like they were preserved yesterday. They’re absolutely beautiful,” she said.
Those mats contained silica, a compound composed of silicon and oxygen atoms and one of the most abundant minerals on Earth. Silica is a vital component in the Earth’s crust and has numerous scientific applications due to its unique properties.
Manning-Berg spent so much of her Ph.D. pursuit studying that mineral, she gained a nickname.
“I was known as the ‘Silica Girl,’” she said with a laugh, “because silicification was something that was covered early—from probably the late ’80s to early ’90s. We’ve known about this process for a while, then everything just stopped. For my Ph.D. dissertation, I started to really investigate the extent to which these organisms are preserved in this type of rock.
“I had so many questions at the end of my Ph.D. that I’ve just run with that since then. I’ve really started to investigate how the silica process is happening, how microbes interact together and how that chemistry might influence how they’re preserved.”
Now, she said, it’s a big question because of Mars. Her research in understanding both the changes in morphology or shape and the chemistry “has allowed me to be a part of the astrobiological community.”
“As we start to look at Mars for evidence of life—at this point extinct life more so than extant—we’re starting to think, ‘Hey, maybe silica could be a phase that’s really interesting on Mars,’” she said. “It exceptionally preserved microfossils on Earth from a billion years ago when Mars would have had water on the surface and would have behaved a lot like early Earth. Silica might be one of the minerals preserving organisms.
“So when we think about life on early Mars, having the ability to overlay the chemistry on top of the morphology gives us a sense of … hope? I don’t want to say ‘security.’ A sense of hope that could be signs of previous life on Mars.”
Whether the NASA workshop was a one-time-only fun exercise or the first step toward the next step isn’t known right now, she said, but being involved in Mars research is what she wants to be doing.
From Planet Earth, that is.
Manning-Berg laughed and shook her head when asked if she wanted to participate in a mission to Mars.
“I am scared to leave the planet,” she said, “and the idea of going through the atmosphere is terrifying—then landing on Mars would also be terrifying. So I’ll just stay here.
“I have plenty of friends who want to go to Mars. I will let them collect the rocks and send them to me or show them to me through a Zoom call from Mars.”