Locating cryptotephra in lake sediments using fluid imaging technology
Locating cryptotephra in lake sediments using fluid imaging technology
复制标题
使用流体成像技术定位湖泊沉积物中的隐叶藻
DOI：
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发表时间：
2014
影响因子：
2.1
通讯作者：
R. Bradley
中科院分区：
文献类型：
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作者：
Robert M. D’Anjou;N. Balascio;R. Bradley
我们报告了一种使用连续成像流式细胞仪和显微镜 (FlowCAM®) 定位和量化沉积档案中的隐孢子的新方法。 FlowCAM 快速拍摄悬浮液中流过显微镜镜头的颗粒，并对颗粒图像进行半自动分析。尽管潜在的沉积学应用有很多，但它主要具有生物学应用。在这里，我们测试了该仪器对不规则形状的多孔玻璃碎片进行成像以及筛选沉积物样本中是否存在隐毛藻的能力。首先，使用 FlowCAM 分析玄武岩和流纹岩火山灰的参考样品（筛分 <63 μm），证明该仪器能够拍摄单个火山灰碎片。使用最高质量的图像来创建火山灰颗粒的参考库，可以自动比较其他颗粒的形态。然后对含有已知火山灰浓度的湖泊沉积物样本进行了分析。火山灰图像库用于执行模式识别计算，自动将类似火山灰的图像与沉积物样品中的其他颗粒区分开来。将 FlowCAM 技术识别的火山灰碎片数量与使用偏光显微镜进行的手动计数进行比较，表明这种快速方法能够确定给定沉积物样品中火山灰的相对浓度。然而，FlowCAM 相对于手动计数系统性地低估了火山灰浓度。我们得出的结论是，凭借完善的图像库，FlowCAM 可以成为隐孢子虫和沉积学应用的有效工具，但它可能不适合大体积样品或颗粒形态超出图像库范围的情况。
We report a new approach to locate and quantify cryptotephra in sedimentary archives using a continuously-imaging Flow Cytometer and Microscope (FlowCAM®). The FlowCAM rapidly photographs particles flowing in suspension past a microscope lens and performs semi-automated analysis of particle images. It has had primarily biological applications, although the potential sedimentological applications are numerous. Here we test the ability of this instrument to image irregularly shaped, vesicular glass shards and to screen sediment samples for the presence of cryptotephra. First, reference samples of basalt and rhyolite tephra (sieved <63 μm) were analyzed with the FlowCAM, demonstrating the ability of the instrument to photograph individual tephra shards. The highest-quality images were used to create a reference library of tephra particles, against which other particle morphologies could be automatically compared. Lake sediment samples with known concentrations of tephra were then analyzed. The tephra image library was used to perform pattern recognition calculations, automatically distinguishing tephra-like images from other particles in the sediment samples. The number of tephra shards identified by the FlowCAM technique was compared to manual counting using a polarizing light microscope, demonstrating that this rapid approach is capable of determining the relative concentrations of tephra in a given sediment sample. However, the FlowCAM systematically underestimates tephra concentrations relative to manual counts. We conclude that with a well-developed image library, the FlowCAM can be an effective tool for cryptotephra and sedimentological applications, but it may be inappropriate for large volume samples or if particle morphologies are outside the range of the image library.