There are thousands of different taxa, and their valves have different shapes and ornamentations. Because of their narrow ecological preferences, they can be used as ecological indicators for measuring pH and nutrient status in old sediments. They are studied in archaeology to trace ceramic and clothing fragments. In forensic research they are used to determine the cause of death in drowning cases.
Diatoms are very good indicators of water quality.
The identification of diatoms is a very tedious work, because microscope slides must be prepared, scanned, photographed, and the diatoms found must be linked to described taxa. The latter is normally done by comparing their images with those in atlasses, which is quite difficult even for experts because of the very subtle variations of the shapes and ornamentations. For this purpose the consortium, existing of diatomists, taxonomists, ecologists and pattern recognition experts, will create image databases and software for feature extraction, identification, as well as automatic microscope slide scanning including autofocusing. Much if not all information, image databases and software, will be made freely available by means of these webpages. After 3 years the public database contains approx 3400 images, whereas the non-public database contains approx 2500 more images.