In underground caves?

Question

In the underground caves, where there is permanent darkness, a variety of organism exist. In terms of energy flow, how can this be possible?

Answer 1

There is still energy in the form of nutrients that reaches these regions as water travels through sediments from surface areas that do receive energy from the sun. There is also stored energy in the compounds that make up the rock substrate in the caves. There are microbes present that can break down these compounds to produce chemotrophic energy. It is this energy that may form the source for the food chain in question. At one time, the sun provided much of the initial energy that drives these systems, it is simply delayed in its arrival (sometimes millions of years) and transported via compounds that at some time had some direct or indirect solar influence.

Answer 2

They live on detritus that works it way deep into the cave.

Answer 3

well, there still warmth, and light in the forms which are not visible, such as infrared light.