classiﬁcation of all rRNA sequences is urgently needed. Eﬀorts in collaboration with Bergey’s trust are ongoing and the information will be incorporated as soon as it becomes electronically available. CONCLUSIONS The new SILVA system provides comprehensive, quality controlled, richly annotated and aligned, reference rRNA databases to support the molecular assessment of bio- diversity, as well as investigations of the evolution of organisms. Applications of the databases range from basic research in microbiology and molecular ecology to the detection of contaminants and pathogens in biotechnol- ogy and medicine. Molecular taxonomy and diagnostics have already revolutionized our view on microbial diversity on Earth (17,30,31), and the added value of molecular techniques for the determination of eukaryotic diversity has recently been documented by Tautz et al. (32). The SILVA databases combined with the ARB software suite provide a stable and easy to use workbench for researchers worldwide to perform in depth sequence analysis and phylogenetic reconstructions. It is designed as a knowledge database to assist in the daily eﬀort to keep pace with the increasing amount of data ﬂooding our general-purpose primary databases. ACKNOWLEDGMENTS We would like to thank Ralf Westram for expert assistance with the ARB software suite, the company Pixelmotor for designing and implementing the webpage and all colleagues and students who helped with the manual curation of the databases. We would also thank James Cole, George Garrity and the RDP II team for help with Pintail and fruitful discussions. We are grateful for funding from the Max Planck Society. Funding to pay the Open Access publication charges for this article was provided by the Max Planck Society. Conﬂict of interest statement. None declared. REFERENCES 1. Fox,G.E., Pechman,K.R. and Woese,C.R. 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