BGD

Biogeosciences Discussions

BGD

Biogeosciences Discuss.

1810-6285

Göttingen, Germany

10.5194/bg-2021-146

Manifestations and environmental implications of microbially-induced calcium carbonate precipitation (MICP) by the cyanobacterium Dolichospermum flosaquae

Abdel-Basset

Refat

https://orcid.org/0000-0001-6212-3717

¹ Hasssan

Elhagag Ahmed

https://orcid.org/0000-0002-9051-3066

¹ Grossart

Hans-Peter

https://orcid.org/0000-0002-9141-0325

² ³

Botany and Microbiology Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt)

Dept. Experimental Limnology, Leibniz Institute for Freshwater Ecology and Inland Fisheries, D-16775 Stechlin, Germany

Dept. of Biochemistry and Biology, Potsdam University, 14469 Potsdam, Germany

08 07 2021

2021 1 22

2021

This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/

This article is available from https://bg.copernicus.org/preprints/bg-2021-146/

The full text article is available as a PDF file from https://bg.copernicus.org/preprints/bg-2021-146/bg-2021-146.pdf

The aim of this work is to explore the ability and magnitude of the temperate cyanobacterium Dolichospermum flosaquae in microbially-induced calcium carbonate precipitation (MICP). Environmentally, MICP controls the availability of calcium, carbon and phosphorus in freshwater lakes and simultaneously controls carbon exchange with the atmosphere. Cultures of flosaquae were grown in BG11 medium containing 0, 1, 1.5, 2 and 4 mg Ca2+ L−1, as cardinal concentrations previously reported in freshwater lakes, in addition to a control culture (BG11 containing 13 mg Ca2+ L−1). Growth (cell number, chlorophyll a, and protein content) of D. flosaquae was generally reduced by elevating calcium concentrations of the different salts used (chloride, acetate, or citrate). D. flosaquae exhibited its ability to perform MICP as carbonate alkalinity was sharply increased up to its highest level (six times that of the control) at a citrate concentration of 4 mg Ca2+ L−1. Calcium carbonate was formed at a pre-precipitation stage as the minimum pH necessary for precipitation (8.7) has been scarcely approached under such conditions. In this work, MICP took place mostly empowered by photosynthesis and respiration. Residual calcium exhibited its lowest value at 4 mg Ca2+ citrate L−1, coinciding with the highest alkalinity level. Precipitated calcium was increased with chlorophyll a content, but not with increasing cell numbers.