29. June 2005: 40 Years with Diatoms
Anniversary of the Friedrich Hustedt Study Centre for Diatoms at the Alfred-Wegener-Institute, the Helmholtz Centre for Polar and Marine Research
On July 1st, the Friedrich Hustedt Study Centre for Diatoms will have been established for 40 years. With approximately 80,000 microscope slides, the extended diatom collection of Friedrich Hustedt, born in Bremen in 1886, is one of the largest of its kind anywhere.
Worldwide, diatoms represent about 25% of the plant biomass. Found in marine and freshwater the microscopic unicells are important biomass and oxygen producers. Through their photosynthesis, greenhouse gasses are converted to organic material and they therefore play a decisive role in the global carbon dioxide circulation. The fine filigree of the structure that distinguishes the species is complex but aesthetically beautiful. Some species have been used since the end of the 18th century for testing the resolving capacity of light microscope objectives. When individual cells die they remain as siliceous (silica dioxide) cell walls and sink to the bottom of the lake or ocean. Research has shown that the walls of fossil diatoms can give valuable information about past environment and climate conditions and serve as indicators for historical dating of sediments.
Friedrich Hustedt (1886-1968), school headmaster from Bremen, studied diatoms for most of his life and described about 2,000 new species. With a contract with the former Office of Soil Research, where the significance of his work for fundamental geological research was recognised, Hustedt left his school work in 1939 to devote all of his time to his research. Many of Hustedt´s early work concerned the diversity of the diatoms of the River Weser from Bremen to Bremerhaven. In 1955 he published a work on the diversity of diatoms in sand samples from Beaufort, North Carolina, U.S.A. The worldwide significance of diatoms can be seen from the number of the species found both here in Germany and in the USA. In time his collection became ever richer and no single collector has archived so many diatoms as Hustedt.
“Dr Reimer Simonsen established the collection in 1965 and was its first curator. We have been able to continually expand it over the past 40 years with material from many research expeditions and thanks to hundreds of colleagues from all over the world. Today we have one of the most important diatom collections in the world” Explains Dr Richard Crawford, present curator of the collection. Alongside the microscope slides are samples of material and an extensive library of diatom literature. For three years information on species and localities have been entered into an electronic database and is now available instantly to specialists all over the world over the internet (www.awi-bremerhaven.de/Research/hustedt1.html).
Industry utilises the diatom walls in the form of diatomaceous earth or Kieselguhr for polishing material and for filtering wine and beer. But there is more to the diatoms: nanotechnology is interested in the motility of such tiny cells and the wall design has been used as a pattern for car wheels. Oomega-3 fatty acids of the diatoms have been found to benefit the nervous system and researchers at the Alfred-Wegener-Institute are looking for the gene controlling fatty acid production in diatoms.
Bremerhaven, 29 June 2005
The banks of the river Geeste in Bremerhaven at low tide. Diatoms produce the firm, brownish surface of the wadden layer.
Motile diatoms of the genera Gyrosigma (0,1 mm long) and Navicula are frequent in the Geeste wadden.