Exploration of microbial biodiversity in polar glacial ice cores

• Applicant: Dr. Kerstin Töbe
• Subject Area: Oceanography
• Term: from 2008 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 75445610

The polar ice caps play a key part in providing an understanding of climate variability over the last eight glacial cycles and may give information about paleoenvironmental features and changes of microbial diversity in the past. Microbiological studies on polar ice cores are rare and focused so far on silty ice or accreted ice, which does not contain a climatic record anymore. Aim of this project is to detect, characterize, and compare the prokaryotic diversity in ice of different depths and different drilling projects in Arctic and Antarctic, in order to learn more about relations of past and recent communities and about potential alterations of ancient communities in relation to climatic changes. From this data set new proxies for climatic/ecological changes may be derived. Further, viability and metabolic activity of the bacterial cells within the ice will be evaluated to gain from the biological perspective a better understanding about survival/metabolism at subfreezing temperatures and from the geochemical perspective about persistence of gas records in the ice. Qualitative and quantitative information about bacterial communities of the past will be obtained by cultural techniques and a broad spectrum of molecular biological methods and microscopical techniques. To minimize the consumption of the valuable ice core material and enable work on common initial samples with our project partners, we optimized particularly the preparation and analytical methods for the specific requirements of ice core samples during the first year of support. This included also the establishment of separate laboratory facilities for ice core analytics and the development and generation of special equipment for ice core analytics. Furthermore, we developed specific primer and probes for qualitative and quantitative PCR and also for CARD-FISH applications. These primer and probes targeting a specific region of the 16S rDNA from bacterial DNA, which was isolated from a glacial ice core, from Dronning Maud Land, Antarctica. The horizon containing the DNA is dated to approximately 2154 years before present. The presence of the bacteria recognized by these oligonucleotide primer and probes could jointly be responsible for N2O abnormalities in glacial ice cores.

• DFG Programme: Infrastructure Priority Programmes
• Subproject of: SPP 1158: Infrastructure area - Antarctic Research with Comparative Investigations in Arctic Sea Ice Areas
• Participating Persons: Dr. Elisabeth Helmke; Professor Dr. Frank Wilhelms