UNB Research

It’s life, but not as we know it? UNB researcher part of NASA-funded project exploring how to detect life on other planets

Author: UNB Research

Posted on Aug 30, 2022

Category: Research

Dr. Allison Enright is an assistant professor of earth sciences at UNB, but her current research has her staring at the stars.

This summer, Dr. Enright is a visiting scholar at Harvard University working on a research question that sounds straight out of science fiction: what might an alien form of life look like, and how would we know if we found it?

We spoke with her about the project, her role and what it means to be chosen for a visiting scholarship.

Can you tell us about the project that you're working on?

This project is part of an Interdisciplinary Consortium for Astrobiology Research (ICAR). These are massive, five-year projects funded by NASA and carried out by teams of up to 50 or 100 scientists.

In these ICARs, you’ll find researchers of all experience levels – from graduate students all the way to full professors – working with diverse skill sets to try to contribute to a particular question. This ICAR is called the Laboratory for Agnostic Biosignatures. This project is about signs of life we would see on other planets that have nothing to do with traditional biochemistry, like amino acids, lipids, or cell membranes.

The idea is to look for physical, chemical or other signs of life that would constitute a detection. The motivation for this approach is that we have no idea what kind of biochemistry we might expect on an extraterrestrial planet. So, if we arrive only with instruments and research to look for carbon-based life, there's a good chance we could miss a detection simply because our methods would be limited to life as we know it. Since, to the best of our knowledge, life on Earth has been evolving on its own for four billion years, we expect to see some diversity in another planetary body.

How do you detect life if you don’t know what you’re looking for, then?

Well, we have some ideas. I’m part of the electrochemistry theme, looking for evidence of metabolic chemical reactions using electrodes. Every organism alive, whether a microbe, a person or a tree, obtains energy from its environment by transferring electrons and putting them through a very precise set of biochemical machines to harvest energy. Removing those electrons from the environment is how cells power every kind of activity they do.

While we as people are most familiar with aerobic metabolism, where reduced carbon is oxidized by molecular oxygen, several other electron donor-acceptor pairs are used, especially by microbes, which can target elements like iron, sulphur and nitrogen.

So, the need for energy is a common trait for all life?

Exactly. When we’re looking at all the different life on Earth, this is what unites them. The universal commonality is the electron transfer. In using electrochemical techniques, what we're looking at, or what we're trying to find, would be evidence of biological energy transfer as carried out through those electron and ion interactions. What makes that appealing and robust, a biosignature we can have confidence in is that we know the electron transfer is the important part, not the actual bits of matter.

So, it doesn’t matter what the backbone molecule is for life or what specific process lifeforms use to acquire energy. We're not relying on what we know about specific lifeforms, but we also know that every single cell we've ever known to exist must transfer electrons.

How do you tackle the science of something as broad as detecting electron transfer?

Well, we need to simplify things a bit. In science, when you're doing weird and innovative stuff, you try to control everything you can. In this case, we’re using what we call iron bugs – microbes that exchange electrons with iron for sustenance. We're not only looking for iron, but we're using iron as kind of a guiding example for experiments because we know a lot about these microbes. They're easy to work with as experimenters.

You mention controlling everything possible in your experiments; what do you mean by that?

When we do research, we read many peer-reviewed manuscripts from other scientists describing their experiments. Their work helps us understand what happens in our experiments. When we’re doing experiments where we haven’t tried several parts before and where other people haven’t tried those parts before, we have many unknowns.
This can make it hard to identify the source of different effects or influences on the results. If you don't know why it's going wrong, you can't tell if your experiment worked. Should nothing have happened? Am I just bad at science? It can go either way.

What do you find exciting about this research?

Electrochemistry has been an undervalued tool in many astrobiology research because it can be very hard to do well. It's a bit sensitive, it's cranky, and you have to be patient with it.

It's less well developed than other areas of the field because there’s only a small community of experimentalists who work with these tools. What's exciting about this is that there's so much we can do because there are just so many questions that we have no information about.

That's exciting as an experimenter because you're less likely not to learn something. You might not get what you expected, but no matter what you do get, your understanding will grow. So, it's kind of. It is a nice opportunity to be looking at all this stuff in a way that no matter what we do, we’re learning something new and important.

Because of that, and because of NASA’s long sightlines and willingness to fund this discovery-based research, you get to see people be more creative and innovative because we have a fairly good idea that no matter what the result, the result is meaningful and worth doing.

What does it mean to you to work on this project?

It's exciting to be included in a project like this because it is so close to my research and an exciting opportunity to contribute. I'm happy to be working on this team. It's the kind of contribution you don't get brought into, especially after you've finished your PhD. You are not sure if your specialized knowledge is valuable enough to be brought into a project like this.

It's also not often that you get to work with a large group of people who share your goals and care about the same small, specific aspects of nature that you care about. What a wonderful group of people to be working with.

More information

Dr. Allison Enright (orcid) | Department of Earth Sciences | Faculty of Science

Research at UNB | Graduate Studies at UNB | Postdoctoral fellowships

NASA: ICAR program | Laboratory for Agnostic Biosignatures (LAB)