PDF(Pubmed)
Abstract：
Calcium carbonate (CaCO3) is abundant on Earth, is a major component of marine biominerals and thus of sedimentary and metamorphic rocks and it plays a major role in the global carbon cycle by storing atmospheric CO2 into solid biominerals. Six crystalline polymorphs of CaCO3 are known-3 anhydrous: calcite, aragonite, vaterite, and 3 hydrated: ikaite (CaCO3·6H2O), monohydrocalcite (CaCO3·1H2O, MHC), and calcium carbonate hemihydrate (CaCO3·½H2O, CCHH). CCHH was recently discovered and characterized, but exclusively as a synthetic material, not as a naturally occurring mineral. Here, analyzing 200 million spectra with Myriad Mapping (MM) of nanoscale mineral phases, we find CCHH and MHC, along with amorphous precursors, on freshly deposited coral skeleton and nacre surfaces, but not on sea urchin spines. Thus, biomineralization pathways are more complex and diverse than previously understood, opening new questions on isotopes and climate. Crystalline precursors are more accessible than amorphous ones to other spectroscopies and diffraction, in natural and bio-inspired materials.
摘要：
碳酸钙（CaCO3）在地球上很丰富，是海洋生物矿物的主要组成部分，因此也是沉积和变质岩的主要组成部分，它通过将大气中的CO2存储到固体生物矿物中，在全球碳循环中起着重要作用。已知CaCO3的六种结晶多晶型物-3无水：方解石，文石,球铁石,和3水合：ikaite（CaCO3·6H2O），单水方解石(CaCO3·1H2O，MHC),和碳酸钙半水合物(CaCO3·½H2O，CCHH).CCHH是最近发现和表征的，但完全作为一种合成材料，不是天然存在的矿物。这里,用纳米尺度矿物相的MyriadMapping(MM)分析2亿个光谱，我们找到了CCHH和MHC,连同无定形前体，在新鲜沉积的珊瑚骨骼和珍珠层表面，但不是在海胆刺上。因此，生物矿化途径比以前理解的更加复杂和多样，打开同位素和气候的新问题。结晶前体比无定形前体更容易受到其他光谱和衍射的影响，在自然和生物启发的材料。
