Researchers can now access one of the largest diatom databases on the Internet. With a current size of approximately 300,000 preserved samples and 80,000 microscope slide preparations, the collection is invaluable for science. Diatoms are unicellular photosynthetic organisms that occur both in marine and in freshwater environments. They are an important part of the food chain, and represent useful indicators for ecological and climatic change. Their unique feature is a cell wall constructed of silica organized in a characteristic structure. Diatoms are classified according to this structural pattern of the walls.
In 1965, Dr Reimer Simonsen founded a facility for diatom study at the "Institut für Meeresforschung", and named it after Friedrich Hustedt, a scientist from Bremen ("Friedrich-Hustedt-Arbeitsplatz"). The facility was integrated into the Alfred-Wegener-Institute of Polar and Marine Research (AWI) in 1986. It is one of the largest and best-equipped diatom collections in the world. It serves as a fundamental tool for marine and freshwater research. “Whoever investigates marine or freshwater organisms, needs a standard for species identification. This is provided through a precise set of nomenclatural rules and a system of voucher specimens. For diatoms, prepared slides for light microscopy serve this function”, says Dr Richard Crawford, the current manager of the Friedrich Hustedt Arbeitsplatz.
In recent years, a database has been configured. Information about species, the researchers who discovered and named them, sites of type collections, habitat types, illustrations, and much more may be found in this data base. Since its foundation, the Friedrich Hustedt facility has received numerous specimens of new species from across the world. The most recent example is a donation of about 2500 diatom preparations from Norwegian scientist Prof. Dr. Grethe Hasle. She recognised that the diatom Pseudo-nitzschia variety multiseries was responsible for producing a highly potent toxin that is accumulated in bivalves (mussels). When consumed by humans, this toxin can cause memory loss, and may even be fatal.
Dr Linda Medlin’s molecular biology group at the AWI is developing equipment containing a DNA microchip that is able to discover species of Pseudo-nitzschia. Using this method, it should be possible to detect potentially harmful planktonic algae in the German Bight. In 1999, Friedel Hinz, technical assistant at the Friedrich Hustedt facility, co-authored a publication on potentially toxic species of Pseudo-nitzschia in Argentinian waters.
The diatom database underpins much aqautic research but also allows international networking through the data, while the reference system facilitates species identification. In Europe, the database is the centre piece of an online identification system for freshwater diatoms being developed as part of the Algaterra project.
Bremerhaven, 26th January 2004
