Prompt Cast
The Deep Biosphere: Life Below the Surface
TLDR Scientists have discovered that the majority of life on Earth exists in the deep biosphere, below the surface. This hidden biosphere, found in places like deep mines and the Mariana Trench, is home to a diverse range of microbial life that has adapted to extreme conditions and may have implications for the evolution of life.
Timestamped Summary
00:00
According to some scientists, most of the life on Earth may not be accounted for by the biomass on the surface, but rather exists in the deep biosphere.
01:33
The deep biosphere refers to everything below the surface, from 2 meters down to 5 kilometers on land and from the bottom of the sea floor to about 10 kilometers in the ocean, where life exists despite the lack of light, oxygen, and extreme heat and pressure.
02:47
In the early 20th century, researchers discovered bacteria in deep oil wells and coal, challenging the belief that life couldn't exist in such extreme conditions, and later, in the 1980s, more microbes were found in core samples taken from below the surface of the ocean.
03:53
In 1992, Thomas Gold's paper "The Deep Hot Biosphere" proposed the existence of a hidden biosphere deep inside the earth, which has since been supported by the discovery of microbial life in the earth's subsurface.
04:59
Microbial life, including nematodes and evidence of life in mud volcanoes, has been found deep below the surface of the earth in places like the deepest mine in South Africa and the Mariana Trench, suggesting that there may be more microbial life below the surface than on the surface due to the abundance of microbes and the porous nature of rocks.
06:07
Microbes deep below the surface of the earth have novel ways of obtaining energy, are mostly anaerobic, have slow metabolisms, can lie dormant for extremely long periods of time, and there is an incredible diversity of life that goes down that far, suggesting that if life can exist so far below the surface, it might be possible elsewhere.
07:15
Microbes deep below the surface of the earth and potentially on Mars may have a role in the evolution of life, suggesting that life may have started below and come up to the surface.
