discovered_02_2015

WWW.HZDR.DE discovered 02.15 TITLE experience. Under such conditions, the cultivation of unknown bacteria isn't always met with any measure of success: "Only a portion of the microorganisms found in the rock can then be cultivated in the lab," as Henry Moll sums up the situation. The unhurried life Researchers also need a bit of patience when cultivating bacteria. Since resources are often scarce underground, the organisms there are used to working with very few resources and tend to grow very slowly. On the other end of the spectrum, Escherichia coli, the bacterium that lives in the human intestine, can reproduce in just 20 minutes under optimal conditions on the Earth's surface. Even if most other bacteria tend to be considerably slower, they would still be considered sprinters in comparison to life underground: Microorganisms in this underground environment often take days and weeks to reproduce. Geomicrobiologist Hans Røy of the university in the Danish Aarhus has estimated that in certain regions the bacteria 20 meters beneath the surface of the Pacific may take a good thousand years to reproduce. Dresden researchers don't have that much time. Andrea Cherkouk has to wait several weeks until the microorganisms from the salt of a planned repository have grown in her lab. And the number of organisms from the clay of the planned Swiss repository will have doubled after just a few days. At least when Henry Moll cultivates it in a medium that meets its needs perfectly. In fact, he has found this perfect mix for a whole series of microorganisms from the clay belonging to a variety of different bacteria groups such as Paenibacilli, Sporomusa, and Clostridium. Nitrate eaters Henry Moll feeds these microorganisms a carbon "pyruvate" compound, which plays an important role in the metabolic processes of many life forms. The bacteria don't just live in the lab, after all, but also in clay rock made up of carbon compounds. Since water and space are scarce here, the microorganisms tend to be more inactive. Not only that, ROCK LAB: Workers scrape off rock formations in the Mont Terri rock lab (Switzerland); scientists research the characteristics of Opalinus clay in order to find out if highly radioactive waste can be safely stored here. Photo: swisstopo I Comet Photoshopping GmbH I Béatrice Devènes TINY LIFE FORM: The isolate Paenibacillus sp. MT-2.2 from the rock lab Mont Terri is capable of surviving in the Opalinus clay (picture taken with a phase contrast microscope).

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