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S C HW E R P U N K T 39 03 | LICHT GEDANKEN Contact Prof. Dr Kirsten Küsel Institute of Biodiversity Dornburger Straße 159, D-07743 Jena Phone: +49 36 41 9-49 461 Email: kirsten.kuesel@uni-jena.de www.geomicrobiology.de Prof. Dr Kai Uwe Totsche Institute for Geosciences Burgweg 11, 07743 Jena, Germany Phone: +49 36 41 9-48 651 Email: kai.totsche@uni-jena.de www.hydro.uni-jena.de In a further study, the scientists investi- gated the drill cores obtained from the CZE to look specifically at the microor- ganisms living in them. Microbiologists and geoscientists from the teams of Prof. Küsel and Prof. Totsche took small rock samples from the cores, which were examined for traces of microbial DNA contained within them (see also box on p. 38). Signs of life from ancient rocks It was discovered that signs of life were also present in the rocks itself: in the fi- nely crushed rock samples, researchers indeed found the genetic fingerprints of various microorganisms. »What we have discovered is that the microbial communities are linked to the permea- bility of the rock and therefore appear to depend on the rock’s cavity struc- ture,« says Prof. Küsel. »This controls the length of contact between water and the rock matrix, and thus determines the living conditions in the ecological niches,« explains Prof. Totsche. Areas of high permeability, where the water flows relatively quickly, are home to or- ganisms that are different from those in areas of limited permeability. Further- more, the organisms found in the rock samples differed from those in compa- rative samples from groundwater or soil. However, there were similarities to organisms discovered during the IN- FLUINS research drilling project in the Thuringian Basin. »These were samples from the same geological layer that we sampled in the Hainich,« says Totsche. For this reason, it is conceivable that the organisms have the same origin – but this theory will have to be supported by future research. What is certain is that the calcareous limestone rocks are over 230 million years old and were formed from sediments from the seabed. »This soil, too, once teemed with life,« says Kirsten Küsel. »It is possible that the microbes from the rock are descendants of these ancient organisms of 230 milli- on years ago.« Original Publications Archaeal diversity and CO 2 fixers [...]. Archaea 2017 DOI: 10.1155/2017/2136287 Aquifer configuration and geostructural links control the groundwater quality [...]. Hydrology and Earth System Science 2017 D OI: 10.5194/hess-2016-374