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CaCO3 nucleation by cyanobacteria : laboratory evidence for a passive, surface-induced mechanism

Title data

Obst, Martin ; Wehrli, Bernhard ; Dittrich, Maria:
CaCO3 nucleation by cyanobacteria : laboratory evidence for a passive, surface-induced mechanism.
In: Geobiology. Vol. 7 (2009) Issue 3 . - pp. 324-347.
ISSN 1472-4669
DOI: https://doi.org/10.1111/j.1472-4669.2009.00200.x

Abstract in another language

Calcite nucleation on the surface of cyanobacteria of the Synechococcus leopoliensis strain PCC 7942 was investigated to assess the influence of photosynthetic uptake of inorganic carbon and active ion exchange processes across the cell membrane on the nucleation and precipitation mechanisms. We performed long-term precipitation experiments at a constant CO2 level in ambient air by adding suspensions of previously washed cyanobacteria to solutions of NaHCO3/CaCl2 which were supersaturated with respect to calcite. Induction times between 4 and 110 h were measured over a range of saturation states, Ω, between 8 and 4. The kinetics of CaCO3 nucleation was compared between experiments: (i) with ongoing photosynthesis, (ii) with cells metabolizing but not undergoing photosynthetic uptake of inorganic carbon and (iii) in darkness without photosynthesis. No significant differences were observed between the three treatments. The results reveal that under low nutrient concentrations and permanent CO2 supply, photosynthetic uptake of inorganic carbon predominantly uses CO2 and consequently does not directly influence the nucleation process of CaCO3 at the surface of S. leopoliensis. Furthermore, ion exchange processes did not affect the kinetics, indicating a passive nucleation process wherein the cell surface or extracellular polymers provided preferential sites for mineral nucleation. The catalyzing effect of the cyanobacteria on calcite nucleation was equivalent to a ∼18% reduction in the specific interfacial free energy of the calcite nuclei. This result and the ubiquitous abundance of cyanobacteria suggest that this process may have an impact on local and global carbon cycling.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: BAYCEER135540
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Heisenberg Professorship - Experimental Biogeochemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Heisenberg Professorship - Experimental Biogeochemistry > Heisenberg Professorship - Experimental Biogeochemistry - Univ.-Prof. Dr. Martin Obst
Research Institutions
Research Institutions > Research Centres
Research Institutions > Research Centres > Bayreuth Center of Ecology and Environmental Research- BayCEER
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences
Result of work at the UBT: No
DDC Subjects: 500 Science
500 Science > 550 Earth sciences, geology
Date Deposited: 13 Aug 2020 13:05
Last Modified: 15 Sep 2020 08:53
URI: https://eref.uni-bayreuth.de/id/eprint/56493