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WWW.HZDR.DE 08 09 TITLE // THE HZDR RESEARCH MAGAZINE "Here we collaborate with Karsten Pederson of Chalmers University in Swedish Göteborg, who has been studying the microorganisms in Scandinavian granite rock since the 1980s," explains Evelyn Krawczyk-Bärsch. A diverse array of microbiological matter resides up to 500 meters beneath the Earth's surface. As part of a new project, the Swedish researcher is currently studying the organisms in future Finnish repository ONKALO. Just like his colleagues at the HZDR, Karsten Pederson first isolates the organisms' genetic material, DNA, which is made of the same building blocks in all organisms on Earth. Researchers then determine the sequences of these building blocks for the genetic trait for a component of the ribosomes called 16S-RNA and thus the tiny protein "factories" inside bacteria and archaea. They then compare these sequences with the 16S-RNA genetic material of other microorganisms stored in the databank in order to identify the life form present in the sample taken or determine which species it is most closely related to. Microcosmos in the repository Using this method, Karsten Pederson uncovered an entire microcosmos of organisms underground long ago. He has been discovering the great diversity of life in Äspö since the 1990s. It doesn't look much different in the ONKALO tunnel 300 kilometers northwest of the Finnish capital Helsinki, which is set to act as a repository for used up uranium fuel rods from Finnish nuclear power plants starting in 2022. His colleagues at the HZDR have seen similar success. Together with his Swiss colleagues, Henry Moll is searching for microorganisms in the Opalinus clay formation in the canton of Jura - and has also found a wide variety of different bacteria groups using DNA analysis. Andrea Cherkouk examines the microorganisms which are present in the salt deposits the "Waste Isolation Pilot Plant" repository (WIPP) in New Mexico. And her doctoral candidate Miriam Bader has recently teamed up with Julie Swanson of the Los Alamos National Laboratory to examine how the archaea that live in salt interact with radioactive substances. Dead or alive? The DNA analysis gives researchers an overall idea of what organisms are in each rock formation. Since under certain conditions the genetic material of an organism can be preserved after its death, the discovery of this material only tells scientists that the bacteria or archaea identified in this manner lived there once. Whether or not they are still active or at least can be brought to life again only becomes apparent when - like on the stone walls of Äspö - biofilms grow. Or if the scientists succeed in growing this bacteria in the lab. Even doing that isn't at all that simple. "First of all, we usually don't know under which conditions the microorganisms grow," Andrea Cherkouk explains. What temperatures do the bacteria or archaea like, which degree Celsius will they just barely survive? How acidic can the water be, how much salt can be in it? What nutrients do the microorganisms need? Do these tiny life forms perhaps work together with other life forms, passing the torch back and forth in the form of lifegiving substances whose formation is distributed among multiple organisms? Since researchers have only examined samples of life underground at best, they don't know most of the answers to this multitude of questions. It is therefore necessary initially to produce the nutrient solution for growing microorganisms based on guesswork and using previous RESEARCH TRIP: Doctoral candidate Miriam Bader researched the interactions of microorganisms with radionuclides at the Carlsbad Environmental Monitoring and Research Center, a branch office of the Los Alamos National Laboratory. Photo: Julie Swanson PROCLIVITY: Halobacterium noricense DSM 15987, a close relative of a microorganism found in the American repository WIPP, grows mainly in environments where high salt concentrations are to be found.