Diloreto, Zach A. and Garg, Sanchit and Bontognali, Tomaso R. R. and Dittrich, Maria. (2021) Modern dolomite formation caused by seasonal cycling of oxygenic phototrophs and anoxygenic phototrophs in a hypersaline sabkha. Scientific Reports, 11 (1). ARTN 4170.
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Official URL: https://edoc.unibas.ch/87741/
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Abstract
The "Dolomite Problem" has been a controversy for over a century, owing to massive assemblages of low-temperature dolomite in ancient rocks with little dolomite forming today despite favorable geochemical conditions. Experiments show that microbes and their exopolymeric substances (EPS) nucleate dolomite. However, factors controlling ancient abundances of dolomite can still not be explained. To decode the enigma of ancient dolomite, we examined a modern dolomite forming environment, and found that a cyclic shift in microbial community between cyanobacteria and anoxygenic phototrophs creates EPS suited to dolomite precipitation. Specifically, EPS show an increased concentration of carboxylic functional groups as microbial composition cycles from cyanobacterial to anoxygenic phototroph driven communities at low-and high- salinity, respectively. Comparing these results to other low-T forming environments suggests that large turnover of organic material under anoxic conditions is an important driver of the process. Consequently, the shift in atmospheric oxygen throughout Earth's history may explain important aspects of "The Dolomite Problem". Our results provide new context for the interpretation of dolomite throughout Earth's history.
Faculties and Departments: | 05 Faculty of Science > Departement Umweltwissenschaften > Geowissenschaften > Physiogeographie und Umweltwandel (Kuhn) |
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UniBasel Contributors: | Bontognali, Tomaso |
Item Type: | Article, refereed |
Article Subtype: | Research Article |
ISSN: | 0169-5487 |
Note: | Publication type according to Uni Basel Research Database: Journal article |
Identification Number: | |
Last Modified: | 10 Feb 2022 08:00 |
Deposited On: | 10 Feb 2022 08:00 |
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