This database is the result of a collaboration between RBGE and Steve Juggins at the Department of Geography, University of Newcastle, with diatom specimens, images and taxonomic data being supplied by RBGE, while UNC contributes diatom specimens and ecological data (see Acknowledgements section below for list of contributors). Data displayed are actually supplied through simultaneous queries to two separate databases located at RBGE and UNC respectively.

TAXON SELECTION
For the purpose of this pilot study, we have initially covered selected taxa from both lotic and lacustrine freshwater environments as well as nearshore marine and brackish habitats. Most of the taxa to date are benthic and thus few centric diatoms are included. Wherever possible, we have catalogued several specimens per taxon, to avoid a biased view of the taxon. All specimens of a given taxon are returned as search results, rather than singling out one to represent the taxon as a whole.
Please bear in mind that whole genera may be missing or poorly represented due to the selective and progressive nature of the work.
 
TAXONOMY
Please note that using a synonym as a search term will result in the search failing; you are then automatically provided with an option for searching for the accepted name and this will provide a link to the relevant specimens. Alternatively, it is possible to browse lists of genera and species, which contain both synonyms and accepted names for each entry. Thus, you can exploit the full potential of this database regardless of which taxonomy you are using.

Names used here are largely as in the DIATCODE checklist of British Diatoms, with some additional recent taxonomic changes included. In some cases, like the genus Achnanthes, we are aware that classificatory changes are under way but until their completion the existing taxonomy will be used. A list of the literature used for identification is provided below.

Unfortunately it is almost inevitable that mistakes occur, due to the sheer volume of the data. We very much appreciate users' feedback both on imaging and taxonomic issues, so please feel free to get in touch with us (contact: s.droop@rbge.org.uk).
 
IMAGES
All images are acquired as 8-bit greyscales using brightfield light microscopy and a 1018x1008 pixel CCD camera.  For details of the image acquisition process see the detailed protocol on the ADIAC public data web page.

Each specimen is represented by a display image chosen to represent a general impression of the taxon, and, in the case of later images, additional focal plane images which show a variety of different morphological features of taxonomic interest. The display images carry a 10 µm scale bar as well as a 1x1 µm square designed to show up monitor-related display problems.

All display images are in JPEG format and vary with the size of the diatom, but all have been reduced to 75% of their original size to reduce download time (thumbnails are GIF format and 25% of the orginal image size). The display images are slightly compressed to speed up downloading, but the largest images may approach sizes of approx. 100 kb, and for users with slow connections download times may still be considerable. However, we have taken great care to accurately represent all taxonomically relevant detail in this database, and it was felt that taxonomic detail should not be sacrificed for speed in this instance.

At present there are approx. 2,300 images viewable in this database, representing approx. 750 names.

 
ACKNOWLEDGEMENTS
The following people have been involved in the making of this database:

Royal Botanic Garden Edinburgh:
Micha Bayer
Martin Pullan
Stephen Droop
David Mann

Department of Geography, University of Newcastle:
Steve Juggins
Mary Lewis
Annie Clarke
Ritchie Head
Kaarina Weckström
 
 

LITERATURE USED FOR IDENTIFICATION OF SPECIMENS:

Chang, T.-P. & Steinberg, C. (1988): Epiphytische Diatomeen auf Cymatopleura und Nitzschia. Diatom Research 3: 203-216.

Cox, E.J. (1987): Placoneis Mereschkowsky: The reevaluation of a diatom genus originally characterized by its chloroplast type. Diatom Research 2: 145-157.

Flower, R.J. , Jones, V.J. & Round, F.E. (1996): The distribution and classification of the problematic Fragilaria (virescens v.) exigua Grun./Fragilaria exiguiformis (Grun.) Lange-Bertalot: a new species or a new genus? Diatom Research 11: 41-57.

Hartley, B. (1996): An Atlas of British Diatoms. Biopress Limited, Bristol, UK. 601 pp.

Hasle, G.R. & Syvertsen, E.E. (1996): Marine Diatoms. Pp. 5-386 in "Identifying Marine Diatoms and Dinoflagellates", edited by Tomas, C.R. Academic Press, London, UK.

Hendey, N.I. (1964): An Introductory Account of the Smaller Algae of British Coastal Waters. Part V Bacillariophyceae (Diatoms). H.M. Stationery Office. 317 pp.

Hustedt, F. (1930): Die Kieselalgen. Part 1. Reprinted 1962, Verlag von J. Cramer, Weinheim, Germany. 920 pp.

Kociolek, J.P. & Stoermer, E.F. (1987): Ultrastructure of Cymbella sinuata and its allies (Bacillariophyceae), and their transfer to Reimeria, gen. nov. Syst. Bot. 12: 451-459.

Krammer, K. & Lange-Bertalot, H. 1986-1991. Bacillariophyceae, Parts 1-4. Volume 2 of "Süsswasserflora von Mitteleuropa", edited by Ettl, H. et al. Gustav Fischer Verlag, Stuttgart, Germany.

Krammer, K. (1992): Pinnularia - eine Monographie der europaeischen Taxa. Bibliotheca Diatomologica Vol. 26. Verlag J. Cramer, Berlin, Germany. 353 pp.

Krammer, K. (1997): Die cymbelloiden Diatomeen. Bibliotheca Diatomologica Vol. 37. Verlag J. Cramer, Berlin, Germany. 469 pp.

Lange-Bertalot, H. & Metzeltin, D. 1996. Indicators of Oligotrophy. Iconographia Diatomologica Vol. 2. Koeltz Scientific Books, Koenigstein, Germany. 390 pp.

Mann, D.G. & Droop, S.J.M. (1996): Biodiversity, biogeography and conservation of diatoms. Hydrobiologia 336: 19-32.

Mann, D.G. (1989a). The species concept in diatoms: evidence for morphologically distinct sympatric gamodemes in four epipelic species. Plant Systematics and Evolution, 164, 215-237.

Ricard, M. (1987): Diatomophycees. Atlas du phytoplancton marin, vol 2: 1-297, Paris.

Round, F.E., Crawford, R.M. & Mann, D.G. (1990): The diatoms. Biology & morphology of the genera. Cambridge Univ. Press. 1-747.

Simonsen, R. (1987): Atlas and Catalogue of the diatom types of Friedrich Hustedt. Vol. 1: Catalogue. pp. 1-525. Vol. 2: Atlas, Taf. 1-395. Vol. 3: Atlas, Taf. 396-772. J. Cramer Berlin/Stuttgart.

Snoeijs, P. et al. (1993-98): Intercalibration and distribution of diatom species in the Baltic Sea. Volumes 1-5. Opulus Press, Uppsala.

Snoeijs, P. (1992): Studies in the Tabularia fasciculata complex. Diatom Research 7: 313344.

Van der Werff, A. & Huls, H. 1976. Diatomeenflora van Nederland. Otto Koeltz Science Publishers, Koenigstein, Germany.

Williams, D.M. & Round, F.E. (1987): Revision of the genus Fragilaria. Diatom Research 2: 267-288.

Witkowski, A. (1994): Recent and fossil diatom flora of the Gulf of Gdansk, Southern Baltic Sea. Bibliotheca Diatomologica Vol. 28. Verlag J. Cramer, Berlin, Germany. 313 pp.

Witkowski, A., Lange-Bertalot, H. & Metzeltin, D. (2000): Diatom Flora of Marine Coasts I. Iconographia Diatomologica Vol. 7. A.R.G. Gantner Verlag K.G., Ruggell, Liechtenstein. 925 pp.