Black ceramic spheres as marker grains for microfossil analyses, with improved chemical, physical, and optical properties
Black ceramic spheres as marker grains for microfossil analyses, with improved chemical, physical, and optical properties
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黑色陶瓷球作为微化石分析的标记颗粒，具有改进的化学、物理和光学特性
DOI：
10.1016/j.quaint.2017.08.052
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发表时间：
2017
影响因子：
2.2
通讯作者：
Nakagawa Takeshi
中科院分区：
文献类型：
--
作者：
Kitaba Ikuko;Nakagawa Takeshi
标记粒法是孢粉学家常用的测定沉积物中绝对花粉浓度的方法。杜邦NEM塑料微珠和石松片是两种最常用的标记颗粒。杜邦NEM系列与石蒜片相比具有明显的优势，因为在许多生态系统中（特别是在过去），石蒜片不能保证是“外来的”。此外，NEM还具有高可视性，易于识别的球形，以及不同尺寸范围的可用性。然而，十多年来，NEM的生产一直不连续，世界孢粉学家正在使用他们自己库存的宝贵剩余数量非常少（=次优）。在此，我们提出一个解决方案。黑色陶瓷微球可以作为标记颗粒用于广泛的微化石分析（但在本文中，由于作者的专业知识，我们主要讨论该材料在花粉分析中的应用）。陶瓷球对花粉提取过程中常用的所有化学物质都具有耐受性，并且对物理应力具有极强的抵抗力。这些颗粒呈哑光黑色，呈球形，大小不一，密度与化石花粉颗粒非常接近（1.424 g/cm3vs）。平均1.494 g/cm3)，在酸性液体中长期储存不会改变颜色和密度。无论沉积物中花粉的浓度和成分如何，陶瓷球的行为都比柱石孢子更接近花粉粒。结合这些特性，使得黑色陶瓷球比杜邦NEM微珠或番茄孢子片更适合孢粉学家。陶瓷球法和体积法测得的花粉绝对浓度在误差范围内难以区分。另一方面，当样品中化石花粉粒相对较少时，用lycopodiummethod计算的浓度往往被显著高估。这种陶瓷微珠既可以作为不同尺寸范围的干粉，也可以作为两种尺寸范围的混合物，按规定的比例混合，分散在浮力中性的液体中，随时可以添加到沉积物样品中。以已知的比例混合两种不同的大小范围有助于检测任何实验室失败，这些失败不同地有利于恢复较大或较小的花粉类型。
Marker grain method is commonly used by palynologists to quantify absolute pollen concentration in sediments. DuPont NEM plastic microbeads andLycopodiumspore tablets are two of the most commonly used marker grains. The DuPont NEM series has an obvious advantage overLycopodiumtablets becauseLycopodiumis not guaranteed ‘exotic’ in many ecosystems (especially in the past). Moreover, NEM also has high visibility, easily identifiable spherical shape, and availability in different size ranges. However, the production of NEM has been discontinuous since more than a decade, and palynologists of the world are using the precious remainders of their own stock in very small (=suboptimal) quantities. Here we propose a solution. Microspheres of black ceramic can be used as marker grains for a wide range of microfossil analyses (in this paper, however, we mainly discuss the use of the material for pollen analysis because of the expertise of the authors). The ceramic spheres are tolerant to all chemicals commonly used during pollen extraction processes and is extremely resistant to physical stresses. The particles are matt black, spherical, available in a wide range of size clusters, have a density very close to that of fossil pollen grains (1.424 g/cm3vs. 1.494 g/cm3in average), and don't change color and density over a long storage in acidic liquids. The behavior of ceramic spheres was closer to the pollen grains than theLycopodiumspores regardless of the pollen concentration and composition in sediments. In combination, these properties make the black ceramic spheres an even better solution for palynologists than DuPont NEM microbeads orLycopodiumspore tablets. The absolute pollen concentrations estimated from ceramic spheres and those estimated from volume method were indistinguishable within errors. On the other hand, when the samples were relatively poor in fossil pollen grains, the concentrations calculated byLycopodiummethod tended to be significantly overestimated. The ceramic microbeads are available either as a dry powder in different size ranges, or as a mixture of two size ranges blended in a defined ratio and dispersed in a buoyancy-neutral liquid, ready to be added to sediment samples. Mixing two different size ranges in a known ratio serves to detect any laboratory failures that differentially favor recovery of larger or smaller pollen types.