Phosphate biomineralization in mid-Neoproterozoic protists
Phosphate biomineralization in mid-Neoproterozoic protists
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DOI：
10.1130/g31833.1
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发表时间：
2011-06-01
期刊：
影响因子：
5.8
通讯作者：
Macdonald, Francis A.
中科院分区：
文献类型：
--
作者：
Cohen, Phoebe A.;Schopf, J. William;Macdonald, Francis A.
真核生物中生物矿化作用的起源和扩展在地球历史上发挥了关键作用，将生物过程和地球化学过程联系在一起。然而，由于生物矿化的早期化石记录有限，这种现象的出现受到很少的限制。尽管生物矿化的宏观证据直到埃迪卡拉纪晚期才为人所知，但我们在这里报告了加拿大西北部中新元古代(前Sturtian)地层中的鳞片微化石的生物控制的磷酸盐生物矿化作用。硅质岩和石灰石样品中磷灰石的鉴定，鳞片微化石相对于共生的有机壁蓝藻和尖晶石的明显坚硬的原始形态，以及磷酸盐组分的微观结构，支持了对成矿的初步生物控制。包裹细胞的矿化鳞片出现在广泛的现存原生生物中，但磷酸盐鳞片对一个现代绿藻分类群的明显限制表明，这些化石可能是从属的。记录十五英里组(加拿大育空地区)微化石中的原生磷酸盐生物矿化极大地扩展了生物控制矿化的已知记录，并为了解早期真核生物的多样性提供了一个独特的窗口。
The origin and expansion of biomineralization in eukaryotes played a critical role in Earth history, linking biological and geochemical processes. However, the onset of this phenomenon is poorly constrained due to a limited early fossil record of biomineralization. Although macroscopic evidence for biomineralization is not known until the late Ediacaran, we here report biologically controlled phosphatic biomineralization of scale microfossils from mid-Neoproterozoic (pre-Sturtian) strata of northwest Canada. Primary biological control on mineralization is supported by the identification of apatite in both chert-hosted and lime-stone-hosted specimens, the conspicuously rigid original morphology of the scale microfossils relative to co-occurring organic-walled cyanobacteria and acritarchs, and the microstructure of the constituent phosphate. Cell-enveloping mineralized scales occur in a wide range of extant protists, but the apparent restriction of phosphate scales to one modern taxon of green algae suggests a possible affiliation for these fossils. Documentation of primary phosphate biomineralization in Fifteenmile Group (Yukon Territory, Canada) microfossils greatly extends the known record of biologically controlled mineralization and provides a unique window into the diversity of early eukaryotes.