discovered_02_2015

WWW.HZDR.DE discovered 02.15 TITLE But such results are only the beginning of research on microorganisms in the repository. In any case, the HZDR scientists have also been working on another project together with colleagues from other countries in Europe for quite some time now: Which other microorganisms are important in the repository? What will happen to the Gallionella ferruginea bacteria once all the highly radioactive waste is underground, the repository is closed, and the oxygen these organisms need to survive is eventually used up? As long as there are these and a number of other such questions for researchers to answer, these miniature life forms underground will continue to be a hot topic. PUBLICATIONS: E. Krawczyk-Bärsch, L. Lütke, H. Moll, F. Bok, R. Steudtner, A. Rossberg: "A spectroscopic study on U(VI) biomineralization in cultivated Pseudomonas fluorescens biofilms isolated from granitic aquifers", in Environmental Science and Pollution Research 2015 (DOI: 10.1007/s11356-014-3671-4) H. Moll, L. Lütke, V. Bachvarova, A. Cherkouk, S. Selenska- Pobell, G. Bernhard: "Interactions of the Mont Terri Opalinus clay isolate Sporomusa sp. MT-2.99 with Curium(III) and Europium(III)", in Geomicrobiology Journal 2014 (DOI: 10.1080/01490451.2014.889975) E. Krawczyk-Bärsch et al.: "Immobilization of uranium in biofilm microorganisms exposed to groundwater seeps over granitic rock tunnel walls in Olkiluoto, Finland", in Geochimica et Cosmochimica Acta 2012 (DOI: 10.1016/j.gca.2012.08.012) EU Takes a Closer Look at Until now, microorganisms haven't been given much consideration in the research conducted by natural scientists on possible repositories for high- and intermediate-level radioactive waste. That all changed when scientists - HZDR researchers among them - discovered underground microcosmoses existing in uranium mines as well as in the different rock formations under consideration as possible repositories. Since such microorganisms could affect the mobility of the radioactive waste deposited in underground environments, 15 research groups from eight European countries will be researching the possible ramifications that this life in miniature could have for the next four years. The EU is providing over four million euros of financing for activities encompassed in the project "Development of a Safety-related Knowledge Base for the Influence of Microbial Processes on the Geological Storage of Radioactive Waste" or "MIND" for short. "There are a number of processes in which microorganisms could play a role," geochemist Thuro Arnold of the HZDR Institute of Resource Ecology explains. As part of the MIND project, HZDR researchers are therefore working together with Spanish, British, and Czech colleagues to study how such microorganisms interact with the organic components of radioactive waste. This could, for example, include paper tissues used in a clinical institute or research lab to wipe up radioactive substances. Additionally, Thuro Arnold and his colleagues will also be taking a more in-depth look at the influence of microorganisms on highly radioactive waste such as used up fuel rods from nuclear power plants. If these were, for example, stored in granite rock, then a geotechnical barrier would be used to prevent the radioactive substances from entering other layers. Bentonite, which usually forms from weathering of volcanic ash, is a material that could possibly be used as a barrier preventing the penetration of ground water. The clay mineral montmorillonite contained in this rock swells as soon as it comes in contact with water, thus sealing possible cracks and fissures in the barrier. The presence of microorganisms, however, could cause the montmorillonite to transform into another clay material, such as illite. Since this material does not swell at all, the bentonite barrier would lose its swelling capacity. HZDR researchers are also planning to look into this during the course of MIND. CONTACT _Institute of Resource Ecology at HZDR Dr. Evelyn Krawczyk-Bärsch e.krawczyk-baersch@hzdr.de Dr. Henry Moll h.moll@hzdr.de _Junior research group "MicroSalt" at HZDR Dr. Andrea Cherkouk a.cherkouk@hzdr.de RESEARCH UNDERGROUND: Andrea Cherkouk, Evelyn Krawczyk-Bärsch, and Henry Moll track down life in the rock and thus in the repository (left to right). Microorganisms in Repositories

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