Isolated ecosystem of Movile Cave, Romania

http://www.bbc.co.uk/earth/story/20150904-the-bizarre-beasts-living-in-romanias-poison-cave

https://en.wikipedia.org/wiki/Movile_Cave

Movile Cave has been cut off for millions of years. Its air is thick with harmful gases, yet it is home to an array of strange animals

An older article on BBC web about a cave in Romania, with an isolated ecosystem of animals living off of sulphuric chemosynthesis, methane and carbon dioxide. The bacteria in the case are “trapped” there since 5+ millions of years, various animals for several millions (2+) years.

I did not know there are isolated ecosystems on Earth. Very interesting.