Conveners
Natural Materials and Environments
- Herbert Pöllmann (Martin Luther University Halle-Wittenberg)
We investigated the sub-micrometer to nanometer scale organization of calcite and aragonite biocrystals with EBSD, FE-SEM and STEM. We highlight the very specific microstructural nature of foraminiferal calcite and aragonite, in particular, the extensive {001} twinning of shell carbonate, describe a new microstructure for the twinned crystals and show that species that developed...
We determined the crystallographic and microstructure properties of the biocalcite of two species of regular sea urchins by electron backscatter microdiffraction (EBSD) and laboratory X-ray diffraction. The spines are essentially single crystals despite their segmented and/or stereom-like structure of hollow space between calcite walls. The body test plates consist up up to 1mm sized...
To understand the influence of bacterial metabolic activity at calcite crystallization, we synthesized hydrogel-calcite composite aggregates with B. subtilis. Our results show that living microorganisms strongly influence the mineral microstructure and texture. This characteristic indicates that bacterial EPS can be developed as a further tool (a biomarker) for the recognition and...
This work compares dental enamel of 18 different species from the taxa of rodents (Rodentia), lagomorphs (Lagomorpha) and insectivores (Eulipotyphla). The enamel structure was analysed by scanning electron microscopy (SEM). To analyse the chemical composition of the dental enamel, energy-dispersive X-ray spectroscopy (EDS) was used together with X-ray powder diffraction for a structural...
Ikaite (CaCO3 x 6H2O) is a widespread mineral in cold regions of Earth. Furthermore, it plays a key role as a precursor of more stable calcium carbonates. However, the formation and transformation conditions of ikaite, especially for the heterogeneous case, are not well constrained. Using Cryo-Mixed-Batch-Reactor experiments and in-situ flow-through Cryo-Atomic-Force-Microscopy (CAFM), we...
