Tiny Organisms Create Dripstones in Caves: Possible Location for Life on Other Planets

It turns out that microscopic organisms may just be able to create dripstones in caves. The new findings reveal how biological life can influence the formation of Earth's geology, and may mean that the same could happen on other planets.

In the past, scientists believed that dripstones were created with geological or geochemical processes with no influence from living organisms. Now, though, it seems as if dripstones may be far more complex than that and that microbes may be responsible.

The researchers first stumbled upon these findings after examining dripstones in the Tjuv-Antes cave in Northern Sweden. This cave is home to a variety of dripstones which possessed distinct layers, mirroring how they had grown over time. The scientists found that the dark layers consisted of fossilized microbes while the light layers were made up of calcites.

"Microbes actively contributed to the formation of dripstones," said Magnus Ivarsson, one of the researchers, in a news release. "They didn't just live on the surface of them. These drops of water brought nutrients with them, which was consumed by the microbes. As the microbes metabolized they excreted calcium which precipitated and in time helped form the dripstones."

The layers reveal that the microbes were most active in the spring and summer when the rain dripped down through the soil and into the cave. This could mean that microbes on other planets could similarly live within caves. Studying these microbes is important not only for understanding the role these creatures play in creating dripstones, though, but also have implications for human health.

"Everyday millions of people go into underground caves: metros, train stations, etc." said Magnus Ivarsson. "These artificially constructed caves offer some of the same living conditions for microbes as naturally created caves. Health authorities are therefore interested in monitoring and understanding what kind of pathogenic microorganisms can live and grow on the walls of for example metro-stations."