Sulphur Cave spawns study

Researchers continue to find unique bacteria near Howelsen Hill

Melinda Dudley

— Though Sulphur Cave is rich in unique bacterial flora that make it a fascination to scientists, the small cave near Howelsen Hill poses its share of challenges to researchers.

“It’s very small and nasty, and it’s a pain in the butt to go in there,” said Norm Pace, a microbiologist at the University of Colorado in Boulder. Pace was a member of a crew that descended into Sulphur Cave on Saturday. He took samples to aid in studying some of the rare microorganisms that reside there.

Sulphur Cave is full of its namesake noxious, rotten egg-smelling gas – hydrogen sulfide to scientists – as well as potentially lethal levels of carbon monoxide and carbon dioixide.

To even descend in the limestone-walled space, the team had to use a specialized manhole blower to pump fresh air in, and constantly monitor the levels of the potentially lethal gases, said speleologist Fred Luiszer, also from the University of Colorado.

“It’s quite a dangerous cave,” Luiszer said. “One or two breaths down in that cave, and you’d pass out.”

“And I can taste the carbon dioxide,” he said. “You start getting a carbonated water taste in your mouth.”

Saturday’s expedition at Sulphur Cave was a follow-up to exploration by a team in August 2007. A team of five, including Luiszer, returned to collect further bacteria samples, as well as study insects dwelling the cave.

“Almost any time you take bug samples out of a cave, you find new species,” Luiszer said. “If (the cave) has been there for any length of time, it evolves new insects that are unique to that cave.”

In addition to conducting basic tests – pH, temperature, gas concentrations – the researchers also studied features that make Sulphur Cave stand out.

“There’s not too many places around the world that are like Sulphur Cave,” Luiszer said. “It’s just spectacular. The ceiling is covered with unusual gypsum crystals, which you see in very few caves.”

The gypsum crystals form when bacteria metabolizes the hydrogen sulfide gas and interacts with the limestone cave walls, Luiszer said.

Researchers have also long been interested in Sulphur Cave’s snottites – bacterial colonies that resemble stalactites, but have a snot-like consistency.

“The snottites this year weren’t nearly as well developed as last year,” Pace said, speculating that comparatively cold nights in recent weeks have hindered their growth.

“We’ll take a look and see whether we’ll find the same organisms as we found last year,” Pace said.

Curiously, many of the bacteria actually feed off the hydrogen sulfide, Luiszer said.

“It’s a little hard for us to believe that a living organism can actually utilize something that is so toxic to us,” Luiszer said.

The researchers are looking into securing long-term funding to facilitate continued study and preservation of Sulphur Cave, Luiszer said.

“It’s a unique cave that needs to be preserved,” he said. “It’s a scientific treasure.”

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