Diatoms under a Scanning Electron Microscope

This is a colorized scanning electron microscope image of a sample of freshwater diatoms collected from a creek in Pennsylvania. Diatoms are a type of algae and are commonly found growing on the glass of fish tanks. In nature they are the brown coating on rocks in a stream, or any body of water on earth. There are thousands of types of living diatoms and probably millions of types in the fossil record. The diatoms are mainly constructed from silicon dioxide – commonly called quartz by geologists. This very rugged and stable material allows the skeletons of these microscopic animals to become fossils.

It is near impossible to sum up the topic of diatoms in a short space. As a group they have a very rich scientific history as they have shaped both geology and biology studies. Specimens mounted on microscope slides were viewed for entertainment in Victorian England. There is little doubt that their variation in form and shape makes them interesting to study.