A Review of Diversification Trends in Diatom Research with Special Reference to Taxonomy and Environmental Applications Using Examples from Lake Baikal and Elsewhere

The study of diatoms has diversified strongly since its beginnings in the 18th century. Early work focused upon collecting material for taxonomic analysis but by the mid 19th century a strong global perspective had already developed. In the 20th century, use of diatoms in biostratigraphy, environmental change and ecology and in biogeography proliferated as did work on diatom ultra structures, life cycles, and systematics. Most recently, systematics and molecular genetics have sought to reveal diatom genealogy and to refine taxonomy. Similarly, diatoms are used increasingly as time-space indicators of water quality and there is renewed interest in global diversity patterns. Taxonomy underpins these applications but changing concepts can either diminish or enhance the value of diatoms to the environmental sciences. Some ways in which taxonomic analysis of diatom assemblages can benefit environmental research are discussed with reference to material from Lake Baikal and elsewhere.