PLANET EARTH Caves

There is, in fact, more life here than anyone would think possible, but the biggest surprise is something altogether more bizarre. These strange stalactite-like formations are known, rather appropriately, as snotites, the drops dripping from the ends are sulphuric acid, strong enough to burn skin. The snotites are, in fact, vast colonies of bacteria, capable of going a centimeter a day.



In this world without sunlight these bacteria extract energy from the hydrogen sulphide gas. Bacteria like these are known as extremophile（嗜极生物，或称作嗜极菌，生活在各种极端恶劣环境下的微生物） because of their ability to survive in such extreme conditions. And these extremophiles play another important role in this cave. Surprisingly, they are the basis of a food chain which supports, amongst other creatures, the larvae of these midges.



Villa Luz's ecosystem was certainly very remarkable, but cave explorers were soon to make an even more astonishing discovery. Beneath this arid landscape lies a subterranean wonderland. Without water one might not expect to find any caves, but beneath these rolling desert slopes in the United States lies one of the longest, deepest and most surprising caves in the world. Its secrets remained unknown until 1986, when cavers dug through several meters of loose rock to the bottom of this pit.