Lac Pavin

This lake is very peculiar. It is a meromictic lake. A meromictic lake is a lake which has layers of water that do not intermix. In ordinary, holomictic lakes, at least once each year, there is a physical mixing of the surface and the deep waters. But not here. That has the effect that at the lower part of the lake, the water has no oxygen. But it's full of life. Life that resembles earth 3 billion years ago. That Era was called archeicum, a period where earth and oceans were lacking oxygen. That's why biologists study these organisms here because they assume it will give them insight in early life development. 

Pascal Brackman