Researchers investigate 'bright green' wall discovered deep in caves of New Mexico: 'Untouched for 49 million years'
Leslie Sattler
Sun, February 15, 2026 at 12:00 AM UTC
2 min read
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- Microbes in a New Mexico cave system are photosynthesizing using invisible light, specifically near-infrared light, which human eyes can't detect.
- The limestone surfaces inside the cave bounce near-infrared light around like mirrors, creating concentrations 695 times greater than those recorded at the cave entrance, where cyanobacteria colonies thrive.
- This discovery could revolutionize the search for life beyond Earth, as it suggests that organisms can survive and thrive in environments with extremely low light levels, potentially expanding the range of habitable planets.
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Microbes surviving without any light in a New Mexico cave system are photosynthesizing using invisible light, the BBC reported.
Hazel Barton, a professor of geological sciences at the University of Alabama, and Lars Behrendt, a microbial biologist at Uppsala University, explored the Carlsbad Caverns together in 2018. Deep inside an alcove far from the public walkway, they spotted bright green cyanobacteria blanketing the cave walls, thriving without a trace of visible light.
These organisms rely on chlorophyll d and f, rare types that absorb near-infrared light, which human eyes can't detect. The limestone surfaces inside the cave bounce this light around like mirrors, pushing it deep underground.
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In fact, where the cave was most devoid of visible light, the team measured near-infrared concentrations 695 times greater than those recorded at the mouth. The biggest cyanobacteria colonies clustered in those same remote stretches.
The team sampled additional caves throughout Carlsbad Caverns National Park and discovered light-harvesting cyanobacteria in every single one.
This finding could reshape how scientists hunt for life beyond Earth. Red dwarf stars, which account for most stars in the Milky Way, emit mostly near-infrared light. Barton and Behrendt have proposed a NASA project to determine the lowest light levels these organisms need to stay alive — data that could help focus the search for life-supporting planets using the James Webb Space Telescope.
For anyone who's looked up at the stars and wondered whether we're alone out there, this is pretty thrilling. Life might be able to exist in far more places than anyone assumed, and it took a pitch-black cave in the New Mexico desert to show us.
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"We showed that not only do they live down there, but that they photosynthesize in a completely sheltered environment where they've probably been untouched for 49 million years," Behrendt told the BBC.
"There are very, very few ways that oxygen can be made in an atmosphere without life," said Barton. "So, if you can find the oxygen in the atmosphere of one of those exoplanets, it's a very, very strong marker for potential life."
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