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DIATOMS

Diatoms are single-celled algae with a silicaceous covering composed of silicon dioxide. Diatoms use silicic acid to create their frustules. This soluble form of silica is taken up by silicon transporters into the silica deposition vesicle where it is precipitated. Several molecules have been implicated in the precipitation and structure on a nanoscale: silaffins, silacidins, cingulins and long-chain polyamines. Evidence suggests that structuring of assemblages and the final frustule shape is influenced by actin microfilaments and microtubules of the cytoskeleton. This outer shell has a symmetrical structure with the smallest components visible with a microscope known as punctae.

The spacing between each puncta varies with the species. Different diatoms have therefore been used as tests of different degrees of resolution. In addition to their use for this purpose they have sometimes been used to create complex images under the microscope, either alone or combined with the scales of butterfly wings. These images are referred to as arrangements or arranged diatoms. These arrangements were produced in the 19th century as an entertainment for microscopists, and in the 20th century by Klaus Kemp of England, now deceased, and others. Today there are still a few mounters who practice this art. Antique as well as modern examples were quite tedious to produce and quite expensive today. Examples of single diatoms are shown below, using various colors of DIC illumination. Examples of some arrangements are shown on the arrangement page elsewhere on this site.

diatom diatom diatom
 N. Iridis diatomdiatom
lyrellaspectabilis diatom diatom