A readily available SEM substrate for a random orientation of diatom frustules

The surface of a vinyl phonograph record was used for SEM imaging of the valves of the centric diatom Paralia Heiberg. This simple method allowed the imaging of various orientations and views of diatom valves without tilting or rotating the SEM stage. This mounting method proved to be more efficient than using traditional flat substrates such as cover slips or polycarbonate filters. Additionally, playing the phonograph record with mounted diatoms prior to SEM imaging fractured some Paralia valves and allowed the viewing of internal morphology. The use of this SEM substrate would be beneficial for other diatom species where it is difficult to match valve and face view morphology, and for species where producing different orientations of the valve is laborious.