Diatoms are a group of single-celled algae. Their structure is characterized by the glassy cell wall with silicon as the main component. The cell wall consists of two dishes that fit together like a box and a lid. The bowls are decorated with complicated or non-complicated structures that are species specific.

Factors such as temperature, salinity, nutrient richness and acidity influence the presence of diatom species. They respond quickly to changing environmental conditions. This makes them extremely suitable as indicators for the assessment of water quality within the Water Framework Directive (WFD). Diatoms are also relatively quick and easy to sample and can be easily identified to the species level.

In archeology, diatoms are used to reconstruct information on the living environment and its changes over time. Diatoms have great added value for reconstructing the landscape, climate change and the living environment.