Part of your research involves looking at how these microbes form or operate under very extreme conditions. What have you learned so far about how life forms in those environments?

Welander: These microbes have really learned how to modify their external structure, their membranes, using these lipids to help them withstand extreme conditions. They can use these molecules to make their membranes more rigid if an environment is too hot or more flexible if the environment is too cold. It shows that these molecules serve a purpose in helping them withstand these environmental stressors that they may encounter in their everyday environments.

Why did you start studying microbial lipid biomarkers? And what do you like about it?

Mayer: I took a class my second year of college that was called Biodiversity. We learned about every different branch of life and how it interacts with the Earth that we live on and that totally took my breath away. That was the first time I heard about microbes driving everything about the planet, from today to back when life first evolved, and I really wanted to find a way to study their fossils.

What is the most surprising thing that you’ve encountered in your time studying microbial lipid biomarkers?

Welander: You can have something that’s made by a bacterium and something that’s made by an alga, which are two different types of microbes from a geological and biological perspective. But then these two organisms make the same molecule using completely different genes and completely different proteins. That’s really an exciting concept and shows that this must be an important molecule for these organisms if they evolved independent mechanisms to make it.

Mayer: I think for me the most surprising aspect is how totally ubiquitous they are across all life. Every form of life has some kind of lipid in its membrane that is functionally or structurally similar to the lipid biomarkers that I’ve been studying in the lab during my PhD.

Let’s talk a little bit about astrobiology. How do you see your research relating to the search for life on other planets?

Welander: The core of astrobiology is that we are trying to understand whether there is life out there in the universe besides our own. One of the ways that our work is relevant is it’s showing us what is life capable of making that can be preserved – could we find these molecules on different planets?

Mayer: If there was life on Mars, you can perhaps use the same lessons we’ve learned about the early Earth to study Mars. That’s where I hopefully see my research going one day.

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