Spelunking for Microbes

Hazel Barton, a geomicrobiologist at the University of Alabama, fell in love with caving at the age of 14 during an outdoor program. Caving and microbiology remained separate passions until Norman Pace, her postdoctoral advisor and fellow caver, urged her to leverage her unique skillset. More than 30 years later, Barton continues to explore caves to find answers to ecological and biological questions.

How has your caving experience influenced your research?

I’ve always taught my students that our decisions are driven by science, so our direction is dictated by the scientific question. Although many cave microbiologists usually work within half a mile of an entrance, my students and I can reach areas that are days away from an entrance. These deep caves are like a big, underground jungle gym. You’ll see some wild stuff there. Cavers tend to be super inquisitive people, exploring to see where the cave goes, so they make great scientists.

Where have your projects taken you, and what have you learned from these cave microbes?

My students and I studied antibiotic resistance in Lechuguilla Cave, one of the longest caves in the world.¹ Because of how the cave formed, microbes were isolated from the surface for millions of years. If the use of antibiotics led to antibiotic resistance, we wouldn’t expect to see any in the cave microbes. However, we saw every kind of natural antibiotic resistance in a cave bacterium, demonstrating antibiotics’ ancient origins.²

In Borneo, the caves are enormous—just black in every direction—and full of birds. Isotope data suggests that ammonia from bird droppings enlarges the cave as microbes convert it to nitric acid, contributing to the pitting and sculpting of cave passages. Not only that, but bird poop also degrades the nylon ropes we use to climb in the cave. We’re now harnessing this mechanism to compost and recycle nylon.

This interview has been edited for length and clarity.