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Calcium carbonate precipitation in cyanobacterial mats from sandy tidal flats of the North Sea

Kremer, B. and Kazmierczak, J. and Stal, L.J. (2008) Calcium carbonate precipitation in cyanobacterial mats from sandy tidal flats of the North Sea. Geobiology, 6, 46-56. ISSN 1472-4677.

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Official URL: http://dx.doi.org/10.1111/j.1472-4669.2007.00128.x

Abstract

Precipitated calcium carbonate was found in annual cyanobacterial mats developing on the beaches of the North Sea barrier island Schiermonnikoog (the Netherlands). A variety of different calcium carbonate morphs were found in the cyanobacterial mucous secretions and identified by light- and scanning electron microscopy and X-ray diffraction. Most of the calcium carbonate seemed to be associated with degrading extracellular polymer. It is conceived that supersaturation of calcium carbonate resulted from the periodic evaporation of the mats and from the release of calcium from the cyanobacterial mucous as a result of its degradation. The analysis of the carbon stable isotopic composition of the calcium carbonate showed only a slight depletion of 13C, indicating that it did not in major part originated from the decomposition of organic matter. The δ18O values of the calcium carbonate confirmed the temperature differences between spring and summer but excluded the possibility that excessive evaporative events controlled precipitation. The precipitation of calcium carbonate could represent a potential factor enhancing the stabilization of intertidal siliciclastic sediments through cementing the sand. The discovery of massive calcium carbonate precipitation in these cyanobacterial mats was unexpected and hitherto unknown.

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:4705
Deposited On:29 Sep 2009 02:00
Last Modified:24 Apr 2012 16:47

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