Combining Molecular and Ecological Data of Terrestrial and Limnic Diatoms for Phylogenetic Analysis (BMBF Project AlgaTerra)

The Friedrich Hustedt Diatom Collection, curated at the Alfred Wegener Institute, contains type slides of diatom species described by F.Hustedt. These serve as reference material for the taxonomy of these species. According to the common practice of diatom study, the type material comprises the cleaned silica walls of the diatoms as these parts of the cell are easy to prepare and preserve and are used for the identification as well as the taxonomy of these algae. Recently, however, taxonomy of diatoms has begun to place more emphasis on other characters of the diatom cells, including morphological characters of live cells and DNA sequences.

 
In this project we wish to combine different morphological and molecular data in order to contribute to the taxonomy of freshwater diatoms of Germany. We aim to concentrate on the species described by F.Hustedt, but also to work with common or important species in Germany.

 
The aims of this project are:

1. To establish the localities of the type species described by F. Hustedt from terrestrial and limnic habitats from Germany.
2. To return to these localities at the same time of the year to re-establish living cultures of these earlier described species for deposition in modern culture collections, such as the SAG (Sammlung von Algenkulturen Göttingen). These new cultures will be designated as epitypes and epitype permanent preparations will be prepared and deposited in the Hustedt Herbarium at the AWI.
3. To perform phylogenetic analysis of these epitype cultures using an analysis of their rRNA genes or ITS regions if they are varieties of the same species.
4. To create a database from which an image-based key will be made to facilitate the identification of these diatoms from both living and cleaned material, using the epitype culture and the original material. These will be supplemented with database entries for other important terrestrial diatoms, so that a meaningful assemblage of terrestrial diatoms will be compiled for identification purposes.

This project belongs to the BMBF-Project AlgaTerra. Aim of the AlgaTerra project is to build a comprehensive, internet-available information system on terrestrial microalgae, integrating taxon, type, name and collection data as well as ecological and molecular information.