Nanometer-Scale Chemistry of a Calcite Biomineralization Template: Implications for Skeletal Composition and Nucleation
Nanometer-Scale Chemistry of a Calcite Biomineralization Template: Implications for Skeletal Composition and Nucleation
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DOI：
10.1073/pnas.1522864113
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发表时间：
2016-11-15
影响因子：
11.1
通讯作者：
Gagnon, Alexander C.
中科院分区：
文献类型：
--
作者：
Branson, Oscar;Bonnin, Elisa A.;Gagnon, Alexander C.
浮游生物、珊瑚和其他生物体产生碳酸钙骨骼，这些骨骼是它们生存不可或缺的一部分，是全球碳循环的关键组成部分，并在地球化学中记录了过去海洋条件的档案。这些生物矿物形成的一个关键方面是有机模板结构和矿物沉淀过程之间的相互作用。实验室研究表明，这些原子尺度的过程可以深刻影响矿物的结构和成分，但人们对它们在钙化生物体中的重要性知之甚少，因为很难在空间相关尺度上测量体内生物矿物界面的化学性质。了解模板在生物矿物成核中的作用及其在骨骼地球化学中的重要性需要一种综合的多尺度方法，该方法可以将有机矿物界面的原子尺度观察置于更广泛的结构和地球化学背景下。在这里，我们使用原子探针断层扫描 (APT)（一种具有 ngs 埃级空间分辨率的 3D 化学成像技术）和飞行时间二次电离质谱 (ToF-SIMS)（一种具有亚微米分辨率的 2D 化学成像技术）绘制了有孔虫 Orbulina universa 碳酸盐骨架内嵌入有机模板结构的化学图谱。我们定量地将这些观察结果联系起来，揭示了 O.universa 中的有机模板独特地富含 Na 和 Mg，并有助于骨骼内的化学异质性。我们的 APT 分析揭示了有机表面的阳离子组成，提供了证据表明除 Ca2+ 之外的阳离子（以前被认为是生物矿物模板中的被动旁观者离子）对于定义有机模板上碳酸盐成核的能量可能很重要。
Plankton, corals, and other organisms produce calcium carbonate skeletons that are integral to their survival, form a key component of the global carbon cycle, and record an archive of past oceanographic conditions in their geochemistry. A key aspect of the formation of these biominerals is the interaction between organic templating structures and mineral precipitation processes. Laboratory- based studies have shown that these atomic-scale processes can profoundly influence the architecture and composition of minerals, but their importance in calcifying organisms is poorly understood because it is difficult to measure the chemistry of in vivo biomineral interfaces at spatially relevant scales. Understanding the role of templates in biomineral nucleation, and their importance in skeletal geochemistry requires an integrated, multiscale approach, which can place atom-scale observations of organic-mineral interfaces within a broader structural and geochemical context. Here we map the chemistry of an embedded organic template structure within a carbonate skeleton of the foraminifera Orbulina universa using both atom probe tomography (APT), a 3D chemical imaging technique with ngs angstrom ngstrom-level spatial resolution, and time-of-flight secondary ionization mass spectrometry (ToF-SIMS), a 2D chemical imaging technique with submicron resolution. We quantitatively link these observations, revealing that the organic template in O. universa is uniquely enriched in both Na and Mg, and contributes to intraskeletal chemical heterogeneity. Our APT analyses reveal the cation composition of the organic surface, offering evidence to suggest that cations other than Ca2+, previously considered passive spectator ions in biomineral templating, may be important in defining the energetics of carbonate nucleation on organic templates.