Microbes can make rocks
In Sweden's Tjuv-Antes cave, researchers discovered that bacteria help build clusters of calcite rock that resemble popcorn and coral.
Entering the cave
Researchers enter Tjuv-Ante’s Cave.
Dripstones called coralloids coat the cave's ceiling. Dripstones are created by mineral-laden water seeping inside a cave.
Researchers collected rocks and microbes for testing.
The popcorn ceiling in Tjuv-Ante’s Cave.
Fingers of coral-like calcite dangle from the cave ceiling.
Water dripping into the cave in spring and summer spurs intense bacterial growth. The bacteria excrete calcium, which helps form the cave's calcite dripstones.
Sampling the microbes inside Tjuv-Ante’s Cave.
Cave popcorn, a type of dripstone.