Fungal biomineralization in a surficial vadose setting, Temara district (Saibles D’Or), northwest Morocco

Abstract

The mineralogy and ecology of the crystals that occur at the microbe-mineral interface, and the evolution of minerals around calcified filaments in a calcretized calcarenite from Temara (Rabat south, Morocco) are the focus of this study. From X-ray diffraction (XRD), high-resolution field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) studies, it is apparent that complexity of the interface between mineral-microbe can be investigated at the nanometre scale. Previous workers proposed a model for the evolution of the fungal filament biomineralization that describes the episodic modification of weddellite into whewellite, a phase absent from the present study. The common association of carbonate phases with microorganisms suggests that the organisms enhance conditions suitable for the growth of morphologically diverse crystal forms. A nanocrystalline calcium carbonate phase maybe a transient precursor phase of calcite mediated by the lichen Xanthoria parietina. Despite extensive studies on biomineralization, little is known about the causes of polymorph selection during fungal oxalate mineralization in nature.