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Calcium adsorption and changes of the surface microtopography of cyanobacteria studied by AFM, CFM, and TEM with respect to biogenic calcite nucleation

Title data

Obst, Martin ; Dittrich, Maria ; Kuehn, Harald:
Calcium adsorption and changes of the surface microtopography of cyanobacteria studied by AFM, CFM, and TEM with respect to biogenic calcite nucleation.
In: Geochemistry, Geophysics, Geosystems. Vol. 7 (2006) Issue 6 .
ISSN 1525-2027
DOI: https://doi.org/10.1029/2005GC001172

Abstract in another language

We investigated calcium interactions with the surface of individual living cells of the freshwater cyanobacterium Synechococcus leopoliensis PCC 7942 under illumination and calcite supersaturation, with respect to calcium carbonate nucleation on the cell surface. Immobilized living cells were scanned by Atomic Force Microscopy (AFM) with conventional and chemically modified tips which were coated with carboxylic groups, so-called Chemical Force Microscopy (CFM). Calcium adsorption was heterogeneous and altered the surface charge of the cells. This was confirmed by bulk measurements of the zeta-potential at different Ca2+ concentrations and compared to measurements made with other bivalent cations (Mg2+, Sr2+, Ba2+). Zeta-potential increased rapidly (2 solution, using a 1.5 mmol L−1 NaHCO3 solution as background electrolyte in both cases. This was followed by the slow (several hours) formation of nonmineralized protuberances at the cell surface. These changes in the microtopography did not show obvious spatial relationship to surface charge or Ca2+ adsorption. The formation of the protuberances was reversible when Ca2+ was removed from the circumfluent solution. Ca2+ adsorption to the cell surface was faster than calcium-induced changes in the surface microtopography and much faster than calcite nucleation on the cell surface which was observed on a fraction of the cells in previous bulk experiments under similar supersaturation.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: BAYCEER135614
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 13:48
Last Modified: 15 Sep 2020 08:53
URI: https://eref.uni-bayreuth.de/id/eprint/56499