Almost 350,000 people visit Carlsbad cavern each year, yet most would be completely unaware that the cave is the setting to one of the most baffling scientific discoveries of the past decade. In the seemingly pitch dark, microbes were able to harness light for energy – the same kind of light given off by red dwarf stars, the most common kind of star in our galaxy. This, says Barton, means we can search for extraterrestrial life in more places than prevously thought.
In 2018, Behrendt had just finished his PhD. He had also won an academic prize, which awarded him some money. He contacted Barton and asked her if she would accompany him on an expedition. Luckily, she agreed.
“The first thing you do in the Carlsbad cave is you kind of go down on the tourist trail, and then you turn around a corner,” says Barton. “I don’t know how many times I’ve done that trail, probably 40 times. At that point, you go around the corner, and then behind you there’s an alcove, and it’s completely black.”
For more than 20 years, Barton has been studying microscopic life found deep underground. Yet what happened next was a surprise, even to her.
Behrendt shone a torch on the wall. Although the alcove was pitch black, the light revealed a blanket of green microbes clinging to the wall. Later tests revealed they were cyanobacteria; single celled organisms related to bacteria. Unlike most bacteria, though, cyanobacteria (also known as blue-green algae) use light from the Sun to make food.