Diatoms are small, single-celled organisms that make up diatomaceous earth. They were first discovered in 1702 by Anton van Leeuwenhoek and for hundreds of years these microscopic creatures have been studied and analyzed. Richard B. Hoover contributed to this research by traveling the world, studying diatoms and collecting new species. In a June 1979 issue of National Geographic, he published his exciting findings on these extraordinary organisms.

Below are some of the most exciting and intriguing findings regarding diatoms:

• While studying a collection of diatoms in Belgium, which had been dried on paper in 1834, Richard B. Hoover was surprised to discover that after adding water to a slide, the diatoms revived and began to swim… after almost 150 years!
• More than twenty-five thousand species of diatoms have been discovered, none of which have the same shell.
• Diatoms exist in large numbers in most bodies of water around the world. In fact, just one liter of seawater can contain up to ten million diatoms!
• The greatest number of diatoms exists in the cold oceans.
• Diatoms can thrive wherever there is light, water, carbon dioxide, and nutrients. In some cases, diatoms can even live out of water: in humid conditions, they can live in the topsoil or attached to moss, tree trunks, and even brick walls.
• Diatoms are very hardy and can withstand long droughts.
• Diatoms vary greatly in size, with the largest measuring just a millimeter across.
• A species of diatom found on Cape Cod, known as Hantzschia virgata, burrows into the sand at high tide. Just after the tide goes out, the diatoms slide to the surface to bask. Their timing is impeccable as they know precisely when to burrow back into the sand, retreating moments before the tide returns. In fact, it was found that even after keeping these diatoms for weeks in a laboratory, their time remained constant. They continued to dig in and out of the sand with such amazing precision that their actions could be used to predict the tide!
• Diatoms are impressive shell builders. They transform dissolved silicon into a silica almost identical to the opal in the gemstone.
• Diatoms contribute enormous amounts of oxygen to our atmosphere.
• Large numbers of diatoms die and sink to the bottom of river beds, lakes and oceans. In some areas, the seabed can be covered in a layer of up to 984 feet (300 meters)! Over many years, these dead diatom layers fossilize and become rich deposits of diatomaceous earth or diatomite.