Morphology and Crystallo-Chemical Characteristics of the Fe-, Mn-, Mg-, Ca- Carbonates from Zagradje near Busovaca (Bosnia and Herzegovina)

Siderite, ankerite, calcite and aragonite are determined in well known hyalophane contained alpine veins from Zagradje near Busovaca. Siderite (45.3 % FeO) is the early carbonate in paragenesis. Arrangement of {0001}, {113}, {101} and {332} resulted in two types of habit: isometric with characteristic elements of trigonal symmetry and isometric with elements of pseudomonoclinic symmetry. Two ankerite phases are mainly determined through their Mn content (AI-4.30% MnO, AII-1.94% MnO) and their positions in paragenesis. The unit rhombohedron and twin on basal pinacoid are their representative habits. Saddle-shaped rhombohedrons of calcite and aragonite very rich in crystal faces ({110}, {010}, {011}, {021}, {111}, {121}, {031}, {051}, {012}, {032}, {122} and {362}) have been separated among late carbonates. The crystals of aragonite are strongly elongated in the direction of [001] and flattened on (110) and this face is the common twin plane. At the beginning initial solution was very rich in iron which rapidly decreased during crystallization. The solution contained more Fe, Mn and Mg at the beginning of crystallization and more Ca during the final stage. Such a complex solution generated the described carbonates according to their variable solubility. Determined elements confirm the existence of members including manganoan ankerites which are more common than generally thought. According to partial substitutions of Mn for Fe in octahedral sites ankerites would be formulated as; (Ca0.94Mn0.06)(Fe0.48 Mg0.45Mn0.16Sr0.02) (CO3)2 and (Ca0.94Mn0.06) (Fe0.46Mg0.53)(CO3)2

Exploring the microbial biotransformation of extraterrestrial material on nanometer scale

Exploration of microbial-meteorite redox interactions highlights the possibility of bioprocessing of extraterrestrial metal resources and reveals specific microbial fingerprints left on extraterrestrial material. In the present study, we provide our observations on a microbial-meteorite nanoscale interface of the metal respiring thermoacidophile Metallosphaera sedula. M. sedula colonizes the stony meteorite Northwest Africa 1172 (NWA 1172; an H5 ordinary chondrite) and releases free soluble metals, with Ni ions as the most solubilized. We show the redox route of Ni ions, originating from the metallic Ni2+ of the meteorite grains and leading to released soluble Ni2+. Nanoscale resolution ultrastructural studies of meteorite grown M. sedula coupled to electron energy loss spectroscopy (EELS) points to the redox processing of Fe-bearing meteorite material. Our investigations validate the ability of M. sedula to perform the biotransformation of meteorite minerals, unravel microbial fingerprints left on meteorite material, and provide the next step towards an understanding of meteorite biogeochemistry. Our findings will serve in defining mineralogical and morphological criteria for the identification of metal-containing microfossils

52nd CROATIAN AND 12th INTERNATIONAL SYMPOSIUM ON AGRICULTURE: proceedings

Sadržaj: Plenarna izlaganja / Plenary lectures, Agroekonomika i ruralna sociologija / Agricultural Economics and Rural Sociology, Genetika, oplemenjivanje bilja i sjemenarstvo / Genetics, Plant Breeding and Seed Production, Povrćarstvo, ukrasno, aromatično i ljekovito bilje / Vegetable growing, Ornamental, Aromatic and Medicinal Plants, Ratarstvo / Field Crop Production, Ribarstvo, lovstvo i pčelarstvo / Fisheries, Game Management and Beekeeping, Stočarstvo / Animal Husbandry, Voćarstvo / Vinogradarstvo i vinarstvo / Pomology / Viticulture and Enology, Poljoprivredna tehnika / Agricultural Engineerin