ASGP (2012), vol. 82: 361–369

FORMATION OF CALCITE BY CHEMOLITHOAUTOTROPHIC BACTERIA – A NEW HYPOTHESIS, BASED ON MICROCRYSTALLINE CAVE PISOIDS

Michał GRADZIŃSKI(1), Maria Jolanta CHMIEL(2) & Jacek MOTYKA(3)

1) Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 31-063 Kraków, Poland; e-mail: michal.gradzinski at uj.edu.pl
2) Department of Microbiology, Agricultural University of Cracow, Al. Mickiewicza 24/28, 31-120 Kraków, Poland; e-mail: mjchmiel at poczta.onet.pl
3) Faculty of Geology, Geophysics and Environment Protection, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland; e-mail: motyka at agh.edu.pl

Gradziński, M., Chmiel, M. J. & Motyka, J., 2012. Formation of calcite by chemolithoautotrophic bacteria – a new hypothesis, based on microcrystalline cave pisoids. Annales Societatis Geologorum Poloniae, 82: 361–369.

Abstract: A new mechanism, stimulating the precipitation of calcite, is postulated. The supersaturation with respect to carbonate minerals is changed, as a result of CO2 consumption by chemolithoautotrophic, hydrogen-oxidizing bacteria. This mechanism controls the growth of atypical, microcrystalline cave pisoids in Perlová Cave, in Slovakia. The pisoids grow under calm conditions in rimstone pools, where they are bathed continuously in stagnant water. The water is supersaturated, with respect to calcite and aragonite. The bacteria inhabit the outer parts of the pisoids, covered by biofilms. The biofilm influences the supply of the Ca2+ ion, slows down the precipitation rate, and favors calcite precipitation over that of aragonite. The calcite initially precipitates as bacterial replicas, which further act as seeds for the growing calcite crystals. This process leads to the obliteration of the primary, bacterial fabrics. Since hydrogen-oxidizing bacteria occur in a wide spectrum of natural habitats, the mechanism of calcification, postulated above, also may operate in other environments.

Manuscript received 20 November 2012, accepted 20 December 2012