[B-PT03] Biomineralization, Geochemistry, and Environmental Studies

[BPT03-P05] Improved 3D imaging accuracy of diatoms using synchrotron micro X-ray CT

*Kotaro Hirose¹, Kentaro Uesugi², Yukiko Nagai³, Takashi Toyofuku³, Seto Yusuke⁴, Masahiro Yasutake², Yuki Sada², Masayuki Uesugi², Akihisa Takeuchi², Yusuke Takeda² (1.Institute of Natural and Environmental Sciences, University of Hyogo, 2.JASRI, 3.JAMSTEC, 4.Osaka Metropolitan University)

Keywords:diatom valves, 3D imaging, X-ray micro-Computed Tomography, synchrotron-light

Measurement of structure by X-ray micro- Computed Tomography (CT) is effective in obtaining morphological information and 3D images of microfossils. Some microfossils, such as foraminifera, have been studied by X-ray micro-CT, and new paleoenvironmental proxies focusing on the shell volume and pore geometry have been proposed. On the other hand, since diatoms are one of the smaller microfossils, the resolution of a laboratory-type CT system is insufficient, and there are currently few reports of measurements.
In this study, diatom shells were measured using a micro/nano CT system at SPring-8. The samples were placed on a CNT sheet laid on a SUS pin for measurement. The exposure times for the micro-CT and nano-CT modes were set to 30 msec and 300 msec, respectively, with an energy of 20 keV in both cases.The pixel size of the acquired data is 0.496 µm/pixel and 0.0415 µm/pixel in both modes, respectively, and clear 3D images of Coscinodiscus perforatus., Surirella fastuosa, and Pleurosigma sp. were obtained. Notably in nano-CT mode, sub-micron scale pores and process were resolved.