8. Hazel Barton on the hidden worlds beneath us

so humor me why should we care

yeah how do I distill down everything that I'm passionate about into why do we care do you care about the climate so we can solve that do you care about infectious disease and antimicrobial resistance it's like I hope so.

We can cure that.

Are you concerned about recycling and being able to convert plastics into innocuous chemicals in the environment? Do you concern about being able to obtain rare earth elements and other critical minerals that we can use to make...

you know, electronics and batteries for EV cars.

I mean, all of these things we can solve with microbes in caves.

It also helps us understand, for me, which gets me excited, is how those caves form.

And over time, what are the processes? When I started my lab, we used to think that caves formed in two ways.

One was with rainwater.

So as rainwater goes through the soil, it picks up dissolved CO2, and that makes a weak carbonic acid.

It's the same acid that's in like a soda, right? So sugar rots your teeth.

Also, the acid in the soda is bad for your teeth.

The other is that you have deep water that can pick up sulfuric acid.

And so where you have the right kind of chemistry, either near a volcano or petroleum reserves, you can actually get the sulfuric acid forming and that can carve caves.

They have carbon and sulfur, and those are the two ways that the caves can be made.

My lab has shown that you can do it with iron.

We believe that you can do it with manganese and we've recently shown that you can do it with nitrogen.

So you can extrapolate that to other environments where if you don't have exactly the same conditions you have here, you can have caves form in lots of different ways.

And of course that's relevant for astrobiology.

So looking for the potential of life elsewhere, what processes could create a subterranean environment that could support life elsewhere where those conditions have met.

And even the big thing we're into now is photosynthesis in the dark.

So we have a big project on photosynthesis in the dark, which is obviously relevant if you've got an M-type star, which is the most common star in the galaxy.

So trying to understand how life could form around a different sun.

All of that comes from caves.

So just a couple of insignificant little bits here and there.