3: Control of Mineralisation Processes by Heterotrophic and Autotrophic Prokaryotes in High-pCO2-Biofilms of Tufa Systems

Principal investigator and Co-PIs

Project summary

The project investigates the effect of non-phototrophic bacteria on calcification and early-diagenetic modifications in high-pCO2-biofilms of calcite precipitating creeks.

As a basis, biodiversity analysis of non-phototrophic prokaryotes will be carried out using cultivation and cultivation-independent methods. Special attention will be paid to exopolymer-degrading prokaryotes. Based on rDNA sequences obtained fluorescence in situ hybridization (FISH) on hart part microtome section should reveal the distribution pattern of the bacteria and their relation to CaCO3 precipitates. CO2- and acetate-assimilating bacteria will be detected by incubation with 14C-labeled substrates and microautoradiography combined with FISH. These results will be used in conjunction with hydrochemical analysis of the macro- and microenvironment as a basis for model calculations assessing the quantitative effect on carbonate equilibrium, primary precipitates and diagenetic alterations in this high-pCO2-setting.
One aim of the study is to provide new arguments for the paleoenvironmental interpretation of tufa-like Proterozoic stromatolites, especially with regard to seawater chemistry and atmospheric pCO2.
The quantification of exopolymer-degradation and other aerobic and anaerobic processes in the biofilms will contribute to the understanding of microbial calcification in general.

Contact

Prof. Dr. Erko Stackebrandt, Microbiology TU Braunschweig & DSMZ