21. okt 2005 00:00
Until a few years ago, scientists were unaware that life existed far inside in the planet Earth. In recent years, Norwegian researchers have surveyed life several hundred metres under the ocean floor.
The picture shows a submarine with tentacles used to explore ocean depths all the way down to 6000 metres. Photo: GV-Press/Science Photo Library In the mid-1990s, the Norwegian geologist Ingunn Thorseth discovered microorganisms that live in the remains of volcanoes. Microorganisms are minuscule life forms that are critical for all other life on Earth. The discovery made Ingunn believe that it was also possible to find similar life in the seabed. She had, in fact, found traces of microorganisms in samples from the Pacific.
3500 metres down
In the summer of 1998, one of Ingunn's colleagues, Rolf Birger Pedersen, set out to see if the theory was valid. Rolf Birger shipped out on one of the Russian MIR submarines, and then went down to a depth of 3500 metres with Russian and US researchers. The dive took place near Svalbard, and the goal was to take samples of the seabed along the volcanoes on the mid-Atlantic Ridge.
In the briny deep
No one had ever been at such a great depth in this area. It was an exciting voyage down into the briny deep; the descent took an hour and a half. It was pitch black from just 100 metres down.
Consequently, the crew turned on the submarine's powerful headlights. Even with them, it was only possible to see ten short metres ahead. Down on the sea floor, the scientists observed lava flows and clay, sponges and Northern pink shrimp. And marine 'snow' ? remnants of and waste from animals and plants that constantly rain down onto the seabed.
They took samples from the seabed. The submarine was equipped with grapplers, a kind of claws that they used to gather samples from the lava flows. The lava was placed in a basket that accompanied the submarine up to the surface.
The first life on Earth?
The samples were tested by researchers at the University of Bergen. As they are suspected, there were microorganisms in the volcanic remains. The researchers also managed to extract DNA and a particular type of bacteria. Some of the bacteria live on hydrogen, while others eat iron from the rock on which they live.
Here, the MIR submarine being lifted off the host vessel - ready to explore the ocean depths. The Norwegian researcher Rolf Birger Pedersen was on board a submarine like this one on a research voyage. PHOTO: KLOCKARGÅRDENS FILM AB
What makes these organisms unique is that they get their energy from the inside of the Earth. All other life on Earth gets its energy from the sun. This means that this research can tell us a great deal about the evolution of life on our planet. Perhaps life originated in precisely this kind of environment?
How did the microorganisms get into the seabed?
The volcanoes along the mid-Atlantic Ridge seethe and boil constantly. When volcanic eruptions take place, molten lava spews forth at a temperature of no less than 1200 degrees Celsius. When the lava cools, the microorganisms move in. They gradually penetrate the cracks and settle in the new ocean floor crust formed by the volcanoes. Over a long period of time, the layers of lava settle on top of each other, contributing to what is known as the deep biosphere. Over millions of years, the deep biosphere has grown to a depth of 400 metres of lava.
Translation: Linda Sivesind
*Published in 'Nysgjerrigper' No. 1 2004*
Last modified: 21.10.2005