Microbes of certain species cause cave growth
Carlsbad Caves from New Mexico (Photo: jb10okie / Flickr CC by ND 2.0)
Microorganisms are everywhere, they can be found without problems in the stratosphere, and deep, very deep underground. Naturally, microorganisms also exist at the bottom of the oceans, they feel good in caves. At the same time, microorganisms of some species can cause the growth of caves, destroying rocks.
In a new study published in the reputable journal Chemical Geology, scientists pay attention to the cave system in Italy, which is still growing. These caves are located in limestone, which is quickly destroyed by acid.
In addition, hydrogen sulfide was discovered in the caves (yes, that same gas with the smell of rotten eggs). While hydrogen sulfide is toxic to humans and animals, some types of microorganisms feel great in the environment of this gas. Moreover, for these microorganisms, hydrogen sulfide is food. Cave dwellers of microscopic sizes simply do not have other sources of food, so they use hydrogen sulfide to ensure their vital functions, releasing sulfuric acid as waste. Accordingly, sulfuric acid dissolves limestone, which leads to a slow but steady growth of caves.
This phenomenon is not common and ubiquitous - in the world there are not many caves where there is hydrogen sulfide. Plus, microorganisms that can use it also live far from everywhere. But all this is also not a rarity. For example, a similar situation is observed in the Carlsbad Caves, in New Mexico.
Now scientists continue to study cave microorganisms, which often surprise specialists. For example, some time ago, microbes were found that live in caves that have never encountered antibiotics, but are nevertheless resistant to their effects.