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| Diatoms are the most diverse protists in the world, representing 250 genera with about 10,000 species. They can be found in almost all the waters on Earth. Their cell walls vary greatly in shape and are exquisitely beautiful, so they are not only the favorites of taxonomists but also highly appreciated by many private collectors. |
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Diatoms are microscopic unicellular organisms, living solitarily or in colonies. Those diatoms that do form colonies have diverse shapes and often form linear or fan-shaped colonies. Some are enclosed in agar.
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| Diatoms have a very unique structure. Each diatom has a cell wall made up of two valves fitted together like a Petri dish and its lid. The upper valve, called the epitheca, and the lower valve, the hypotheca, are attached with a connective band called a girdle. Between the valves and girdle are intercalary bands. |
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Diatoms are divided into three groups based primarily on the morphological characteristics of the cells:
- Coscinodiscophyceae
radially symmetrical striae.
- Fragilariophyceae
bilaterally symmetrical striae without a raphe.
- Bacillariophyceae
bilaterally symmetrical striae with a raphe.
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