The inhibition of calcite precipitation by natural organic material (NOM) in solutions seeded with calcite was investigated using a pH-stat system. Experiments were carried out using three NOMs with different physical/chemical properties. For each of the materials, inhibition was found to be more effective at lower carbonate/calcium ratios and lower pH values. The reduction in the precipitation...

The Mg/Ca ratios of biogenic calcite is commonly seen as a valuable palaeo-proxy for reconstructing past ocean temperatures. The temperature dependence of Mg/Ca ratios in bivalve calcite has been the subject of contradictory observations. The palaeoceanographic use of a geochemical proxy is dependent on initial, rigorous calibration and validation of relationships between the proxy and the ambi...

We investigated the roles of three proteins associated with the formation of otoconia including fetuin A, osteopontin (OPN), and otoconin 90 (OC90). In situ atomic force microscopy (AFM) studies of the effects of these proteins on the growth of atomic steps on calcite surfaces were performed to obtain insight into their effects on the growth kinetics. We also used scanning electron microscopy t...

The carbonate mineralogy of the calcified hydrozoan family Stylasteridae is controlled largely by phylogenetic rather than environmental factors. In a comprehensive study— the first of its kind—of the mineralogy of almost an entire family of calcareous organisms, this finding is well documented. X-ray diffraction analyses of 24 of 25 genera indicate that the skeletons of most species analyzed (...

The formation mechanism of the thermodynamically unstable calcite phase, very high Mg calcite, in biological organisms such as sea urchin or corallina algae has been an enigma for a very long time. In contrast to conventional methods such as KBr pellet Fourier Transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), FTIR microspectroscopy (FTIRM) provides additional information about...

Under extreme water deficit, endolithic (inside rock) microbial ecosystems are considered environmental refuges for life in cold and hot deserts, yet their diversity and functional adaptations remain vastly unexplored. The metagenomic analyses of the communities from two rock substrates, calcite and ignimbrite, revealed that they were dominated by Cyanobacteria, Actinobacteria, and Chloroflexi....

The formation mechanism of the thermodynamically unstable calcite phase, very high Mg calcite, in biological organisms such as sea urchin or corallina algae has been an enigma for a very long time. In contrast to conventional methods such as KBr pellet Fourier Transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD), FTIR microspectroscopy (FTIRM) provides additional information about...

A theoretical model for the plastic deformation of calcite, based on symmetry arguments and dislocation theory, is presented. Flow mechanisms suggested by the model conflict with those previously determined by Turner. Predictions from the model include translation gliding on e., ri, f and mI parallel to <110 ( i = 1,2,3; j = 1,2,3,4 ), and twin gliding on r (+) and (-) senses; s = 2.065, 0.630 ...

This final report summarizes the work completed on the two year pilot project, which concluded 31 July 2016. The first section summarizes the two previous reports to place the current work in context. Two new research results sections are included here. The first concerns the use of a synthetic peptide, mimicking natural eggshell protein believed to be influential in biomineralization, to exami...

Transition metal atoms are one of the key ingredients in the formation of functional 2D metal organic coordination networks. Additionally, the co-deposition of metal atoms can play an important role in anchoring the molecular structures to the surface at room temperature. To gain control of such processes requires the understanding of adsorption and diffusion properties of the different transit...