Subsurface biota extends over a wide variety of habitats that can be spatially interconnected. The largest communities of this subsurface biota inhabit cavities and are well known mainly in caves where biologists are able to have access. Data about deep subterranean communities and arthropods living under one thousand meters was unknown.

An expedition to world’s deepest cave, Krubera-Voronja in Western Caucasus, revealed an interesting subterranean community, living below 2000 meters and represented by more than 12 species of arthropods, including several new species for science. This deep cave biota is composed of troglobionts and also epigean species, that can penetrate until -2140 m. Deep subterranean ecosystems should not be seen only as an evolutionary dead end towards the troglomorphic syndrome, but also as a shelter for epigean species populations, especially during long periods of time when surface conditions are severe for their survival. Most of the subsurface biota depends on allochthonous sources of organic carbon coming from: water percolating from the surface, sinking streams that enter caves, and activities of animals moving in and out of caves.

The biocoenosis and the vertical distribution of invertebrate fauna of Krubera-Voronja are provided, from its entrance to the remarkable depth of 2140 meters, including the discovery of world’s deepest dwelling arthropod.