Until recently, most scientists believed that only single-celled creatures were capable of enduring life in the hot, high-pressure zone beneath Earth's crust. Now they've discovered tiny worms (pictured above) who live as many as 2.2 miles below ground. What else will we find living deep inside the Earth?
Here's a report from this week's Nature magazine:
The subsurface biosphere, which extends more than three kilometres into the Earth's crust, hosts a range of single-celled organisms, but it was thought that the constraints of temperature, energy, oxygen and space would mean that multicellular organisms could not survive at this depth. Tullis Onstott and colleagues report the detection of nematode worms, including one previously unknown species, in 0.9–3.6-km-deep fracture water beneath the mines of South Africa. The authors took various steps to ensure that the nematodes were indigenous to the water from the deep subsurface and were not recent surface of mining contaminants.
The worms, which measure up to half a millimetre, can tolerate high temperatures, reproduce asexually and preferentially feed on bacteria from the subsurface. These attributes all facilitate adaptation to life in the subsurface.
If these tiny worms live by feasting on bacteria beneath the surface, what's feeding on the worms? I hope the answer is dragons.
Find out more via Nature.