Diatoms and People
A frequently asked question is “what use are the diatoms?” Of course now we can point to new interests but for many years they have been utilised in a wide variety of industries in the form of their fossil remains
Vast deposits of diatoms (diatomite) have been found in the Urals, Russia, Eastern Europe, in Barbados, West Indies, in Oamaru, New Zealand, and in Lompoc California, USA. Some of these are being extensively mined for commercial use.
Diatoms may also accumulate in the sediments in a different form. All live cells contain oil reserves and if this becomes incorporated in the sediments before becoming dispersed in the water, large quantities of oil may become trapped beneath the sediment surface and eventually sealed in the rocks and compacted to form petroleum. Most of such deposits in the world today come from the rapid burial of massive blooms of diatoms and other microalgae. The largest bloom areas where the burial of diatoms occurs rapidly is in regions of the oceans where nutrient bottom water is brought to the surface where the algae can use the nutrients to multiply rapidly.
The raw material, Diatomite, Diatomaceous earth or Kieselgur (German), has a number of valuable properties: high porosity, hygroscopicity, low coefficent of heat conductivity, etc. It is extremely light and varies in quality according to purity and composition (small species or large, freshwater or marine, finely broken or intact).
Our tour on the immense world of the diatoms has finished. Those of you, who encountered them for the first time, could see that our knowledge of the “oat animals” discovered about three hundred years ago is huge. However, we would like to conclude our “dive” into the depth of microworld with the words of C. G. Ehrenberg: “I am ending this communication with the feeling that I was not able to fathom this profundity of organismic creation. To have opened it should be my excuse for time and energy spent. May fresh and soulful eyes delve into nature and collect which it conceals — not purposeless — in darkness and smallness.” (1830)
As building material diatomite was used in the ancient world, when constructing vaults and arches in Rome or erecting the Sophia cathedral in Constantinople. Today diatomite is used for producing light fire-proof heat- and sound-isolating bricks and slabs. Today it has many uses. Generally it serves as a very fine polish for diamonds or teeth and other abrasives. It also acts as an inert stabiliser for creams, pastes, rubber, asphalt, sulfur cement and paints and as accommodating base, in pills, powders, ointments, etc. Another important use is in the form of fine filters that are used throughout the wine and brewing industries. Perhaps most famously, Alfred Nobel used diatomaceous earth as a stabilizer in the manufacture of dynamite – nitro-glycerine is absorbed and stabilised by the glass walls of the diatoms.
Diatomite is used in surgery and balneology. It is an excellent substitute for cotton and disinfectant in bandaging wounds (practised during World War II), treating extensive burns, dermatitis, eczemas, and even surgical tuberculosis. Diatomaceous mud has a fine effect on skin nerve endings.
Increasingly, diatoms play an important role in the global economy. Cultures of living diatoms are now being used for the production of food or valuable biochemical compounds.
Diatoms also have a use as individuals or in their ecological associations — in forensic work. Any crime involving natural waters may well concern diatoms. Because of their finely-resolved habitat specificity, the diatoms found on a body can often point precisely to the scene of a drowning.
Even modern technoloogy is finding that it can learn from the microarchitecture of these organisms. On a grand scale there are examples of buildings erected according to the principle of the diatom frustule. For example, the proportions created by nature itself were used without additional calculations when building the pier of Berlin open-air Waldbuhne Theater. On a much smaller scale the exquisite precision of the formation of the cell wall is finding great interest in the new field of nanotechnology, though the surface has, as yet, been hardly scratched.