Diatoms – tiny but important

Biodiversity and oxygen production in a glass box

Abstract

Diatoms are mainly photoautotrophic, microscopic, unicellular eukaryotes and enormously important primary producers, producing at least 25 per cent of global oxygen. Diatoms live in plankton as well as in the benthos of all marine and limnic ecosystems, but also to some extent in terrestrial ecosystems. The outstanding feature of the species-specific very diverse diatom morphology is the cell wall made of silica. The endosymbiosis events and evolution of their plastids as well as the specific combination of metabolic pathways are unique. The species diversity of diatoms, which represent the most species-rich group of algae, can only be roughly estimated at this time. This species diversity is being explored using integrative taxonomy (analysis of cultures, morphology, genetics, etc.). Diatoms are ideal bioindicators for water quality assessments using microscopic and increasingly DNA-based methods due to their high species diversity, individual density and species-specific occurrence in all types of water bodies.