Marine diatom

Scanning electron micrograph showing the surface detail of a Marine diatom. Diatoms are single celled algae that live in most aquatic environments, both fresh and salt water. They are non-motile and are restricted to shallow waters as they require sunlight for photosythesis. Diatoms are usually between 2 and 200 microns in diameter, have a hard shell and often display a natural symmetry.