The Formation of Oxalate Patina on the Surface of Carbonate Rocks Under the Influence of Microorganisms

Abstract

With the use of modern mineralogical and biological methods in natural and experimental conditions the research of mechanisms of oxalate patina formation on the carbonate rock surface has been carried out. On the result basis the role of microorganisms in metasomatic crystallization processes on marble and limestone surfaces was specified. The interdependence between biological and environmental factors of crystallization was found. It is shown that the phase composition of fungal crystallization products depends on the variable content of organic acids in fungal culture and the calcium carbonate is stimulating the oxalic acid excretion rate. It was shown that biogenic calcium oxalate crystallization starts from bi-pyramidal weddellite crystals, goes through crystal splitting and ends with the formation of dumb-bell shaped and later spherical whewellite and weddellite joints formation.The present results give a scientific basis for creating new methods of cultural heritage stone monument preservation with the use of modern biotechnologies.