SPRINGFIELD — A broken water main and the subsequent accumulation of chlorine gas could explain the sudden disappearance of endangered gray bats from a cave in southeast Springfield.
Researchers Matt Forir, Dave Gaunt and Lisa McCann smelled the gas while exploring Sequiota Cave in December, looking for the source of a flood of red silt that was killing aquatic life in one fork of the cave’s stream.
“Our noses, eyes and throats were burning,” said Forir, a naturalist and cave expert with the Springfield/Greene County Parks Department. “We actually put on our gas masks and were constantly checking on each other. We turned around pretty quickly because we didn’t know where the chlorine was coming from.”
The team successfully traced the path of the red silt that day, but it wasn’t until January that the mystery of the chlorine gas’ origin was solved.
It came from chlorinated water, which spilled into the cave system when a 125-foot-long sinkhole developed and broke the water main. The sinkhole, southeast of Sequiota Cave, was also the source of the silt.
Forir, executive director of the Natural History Museum of the Ozarks at Riverbluff Cave, said his group of researchers found gray bats near the entrance of Sequiota Cave in December.
But at that time of year, the bats should have been far deeper in the cave — and hibernating.
“They were wide awake when they should have been asleep. It was very cold outside, and we saw them near the entrance, where I hadn’t seen them before at this time of year,” Forir said. “In January and February, we saw even fewer of them.”
The chlorine gas could be to blame, he said.
“It probably just drove them out of the cave,” he said. “Could they survive in the cold? I don’t know. Maybe the bats could have had a Plan B place to go.”
Gary Pendergrass, environmental compliance manager at City Utilities, said the gas was released when the cold water from the broken main flowed into the warmer environment of the cave.
“It didn’t have anywhere to go,” Pendergrass said.
The gas eventually dissipated, but Forir documented the incident for a report to the city-county parks board.
“There has never been a study done on chlorine’s impact on bats in a cave environment,” he said. “It’s an enigma. It’s a data point that might be useful if it happens somewhere else.”
The silt will eventually flush from the cave naturally, Forir said, and animals surviving in the stream’s other fork could repopulate the one affected by the flow.