There is life very deep in the Earth upper crust and not only bacteria 

Reproduced from bbc-Earth, by Jasmin Fox-Skelly, November 24, 2015
"The strange beasts that  live in solid rock deep underground

Just how far down in the Earth's crust can animals survive? In the dark, hot depths of several South African gold mines, there live some tiny worms that may hold the key to answering that question.These creatures are the deepest living animals that have ever been discovered.Nematodes can transform into a special form called the dauerstage. In this form, they can survive harsh conditions for long periods before reawakening when the going gets good again.  Surely if any animal could live deep inside the Earth it would be this hardy worm?  This makes them similar to tardigrades: tiny creatures that can survive being boiled, frozen, crushed, dried out or blasted into space by going into a kind of stasis.  In the dauer stage, the nematode goes into stasis and its metabolism slows. The stage is triggered by a pheromone and occurs when there is a lack of food, high temperature, or overcrowding.  Nematodes in the dauer state are spectacularly resilient. When the space shuttle Columbia broke up after re-entering Earth's atmosphere in 2003, there were nematodes on board:they survived both the disintegration and the fall back to Earth.  Nematodes have populated almost all areas of the world. They can be found in hot springs, deserts, high up mountains and in the deepest oceans. They live in Antarctica, inside the bellies of other animals including humans, and even inside the placentas of sperm whales. Surely if any animal could live deep inside the Earth it would be this hardy worm.   No one knows how they got down there, but they could have been living in the mines for thousands of years. Their very existence suggests that complex life can survive far deeper in the Earth than was ever thought possible. most scientists believed that the bowels of the Earth could only house single-celled organisms like bacteria. In the deep Earth it is hot and dark, and there is very little oxygen. There is also not much food down there, so any animal making its home in the belly of the Earth would struggle to get a decent meal. One scientist thought differently. Gaetan Borgonie was previously at the University of Ghent in Belgium and is now at Extreme Life Isyensya in Gentbrugge, Belgium. He was convinced that one animal could survive deep down in the Earth's crust: a nematode worm. That is because nematodes are extremely hardy, able to cope with extreme heat, cold and dehydration. They have an ingenious trick that allows them to survive.  Borgonie decided to look for himself, but sceptical grant holders denied him funding. So he teamed up with Tullis Onstott of Princeton University in New Jersey, who also believed that nematodes could exist deep underground. The pair used money from their own savings to travel to South Africa.  Before this, nematodes were only known to live a few dozen feet underground They chose South African mines because they are the deepest accessible places on Earth.

Ore miners have drilled to depths of more than 2 miles (3.2km), so researchers can access Earth's hidden subterranean world.  Borgonie began searching the hot and humid mines for life. He took samples of water pouring from boreholes, which had previously been drilled into the rock by mine geologists to check for gas and water pockets ahead of mining operations. He then filtered the water, searching it for life. When he looked under a microscope he found lots of little worms, the first animals discovered this deep underground. Before this, nematodes were only known to live a few dozen feet (tens of metres) underground.The next step was to show that the worms originated in the mine, and had not been accidentally brought in on miners' shoes or through other contamination. To do this, Borgonie spent a year testing 8,343 gallons (31,582 litres) of water used in mining operations. He also searched the soil near the boreholes.  He found no worms in the mining water, demonstrating that the nematodes were not coming into the mine from above. The nematodes in the soil belonged to different species. He also demonstrated that the worms preferred to munch on the bacteria that live in the mine, rather than bacteria from outside, which suggested that the worms were well-established in the mine.  The team finally published their findings in 2011. "When you go underground the pressure increases, the temperature increases, oxygen diminishes and food becomes scarcer," says Borgonie. "Therefore one assumed that looking for multicellular life was akin to bonkers."Yet Borgonie did not just find one species of worm: he found four, living in three separate mines."

http://www.bbc.com/earth/story/20151124-meet-the-strange-creatures-that-live-in-solid-rock-deep-underground