Diatoms

Diatoms are a type of microscopic algae (microalgae) that live mostly in water and make their own food by photosynthesis.

• They are easy to recognise because each diatom is covered by a hard, glass-like shell made of silica (the same material found in sand). This shell has beautiful patterns, like a tiny decorated box.
• Diatoms are a major part of phytoplankton (tiny floating plant-like organisms) and form an important first step in aquatic food chains—many small water animals feed on them.
• When diatoms photosynthesise, they release oxygen, so large numbers of diatoms help keep water bodies healthy and also support Earth’s oxygen supply.
• Over long periods, dead diatoms can collect on the sea or lake floor and form a powdery material called diatomaceous earth.
• Uses of diatoms (often through diatomaceous earth) include filters for water and liquids, mild polishing in some products, and certain industrial and medical applications.

Thinking of a diatom as a “tiny solar-powered cell inside a glass house” helps: it makes food using sunlight, releases oxygen, and supports many other living things in water.