The laboratory assays disclosed genetic material of microorganisms in the material and evidence that it was exposed to chemical degradation processes associated with the so-called chemosynthesis of bacteria. But this was not yet a direct demonstration of the living beings themselves. These were the first results of the scientists' laboratory experiments in the laboratory: They stimulated the microorganisms of the rock to grow by imitating their living conditions as well as possible. 65 degrees Celsius and a substrate that corresponds to basalt, through which the special deep water seeps, brought the success, Lever and his colleagues report: they were able to demonstrate the microbial production of methane.
The largest ecosystem on earth
"This provides the first direct evidence of life in the oceanic crust, and our findings suggest that this vast ecosystem is largely based on chemosynthesis, " Lever summarizes. According to the researchers, there are fine cracks in the basaltic oceanic crust through which water moves. Its chemical composition is fundamentally different from seawater, for example, it is free of oxygen produced by photosynthesis. Presumably, this deep water reacts with reduced iron compounds in the rock, releasing hydrogen, the scientists explain. "He can use the microorganisms as an energy source to convert carbon dioxide into organic material, " explains Lever. This in turn forms the basis for the nutrition of other microorganisms, because the basalt is the home of many different microorganisms, the scientists report. display
The deep ecosystem is thus completely independent of the sun's energy, which enables life on the earth's surface through photosynthesis. Plants, algae and a few other photosynthetic organisms use sunlight to convert carbon dioxide into organic matter. It forms the basis of the food chains on Earth and in the oceans. Life in the porous rocks of the oceanic crust, on the other hand, is fundamentally different: the driving force of life comes from geochemical processes, the researchers emphasize. The oceanic crust covers 60 percent of the earth's surface. This is the largest ecosystem on earth. All of these findings allow researchers to even look into the universe from the depths of the Earth: "It is possible that other planets also have life based on chemosynthesis, " says Lever.Mark Lever (Aarhus University) et al .: Science, doi: 10.1038 / nature12017 © science.de - Martin Vieweg