By Isabelle Charmantier

Bicosoeca growing on Asterionella
Ah, the snowflake: symbol of short winter days, crisp frosty mornings, Carol singing under the stars and the Christmas season.

However, this is not a snowflake. It is a photograph of the mass development of the flagellate protozoan Bicosoeca on Asterionella. Asterionella is a genus of pennate freshwater diatoms, which are frequently found in star-shaped colonies of individuals, and therefore look remarkably like snowflakes. Diatoms are a major group of algae, and when we think of algae, we often think of seaweeds, algal blooms, and the slimy, slippery plants that render walking in a stream in our bare feet treacherous.

And are algae plants anyway? There are some algal species that can act both as plants and as animals at the same time.

Algae can be quite beautiful, especially seen up close through a microscope. The Victorians certainly thought so and collected algae, pressed on herbarium sheets, and under slides. Victorian microscopists created artful arrangements of diatoms that were sold as miniature curiosities, beautiful patterns invisible to the naked eye that would come to life under a microscope. Today, Klaus Kemp is the only living practitioner of that singular art form, which displays nature in a structured and ordered way.

Another snowflake? Klaus Kemp, Diatoms, 1995, Freshwater Biological Association
By contrast, Hilda Canter-Lund captured the quintessential beauty of algae in its natural state. Canter-Lund (1922-2007) worked at the Freshwater Biological Association on the shores of Windermere, and studied fungal parasites, especially Chytrids. In 1949, she married fellow scientist and algologist John Lund who also worked at the FBA. Algae were the hosts for Hilda’s organisms, and the Lunds therefore worked together on Asterionella formosa and other diatoms which dominated the spring phytoplankton of Windermere.

Hilda Canter-Lund, Asterionella, 1995, Freshwater Biological Association,
Hilda Canter-Lund is best known for her remarkable photographs of freshwater algae, which bring out the underappreciated but astonishing diversity and beauty of form to be found in these organisms. In 1995, a collection of these photographs was published in a book entitled Freshwater Algae. Their microscopic world explored, with a text written by her husband. (Editor’s note – this book got a rave review when published but the only new copies I can find for sale are priced at £999.10 plus 2.80 P&P but second hand it’s a mere £150! – 2018 update – ebay now has copies for £99.99)

Hilda Canter-Lund, Micrasterias, 1995, Freshwater Biological Association,
Her photographs continue to inspire scientists and artists: The Hilda Canter-Lund Annual Photography Award is awarded every year by the British Phycological Society in recognition of the technical ability and aesthetic quality she brought to the study of algae. Most recently, artist Christine Hurford exhibited her art inspired from drawings and photographs of algae from the Freshwater Biological Association at Wray Castle, on Windermere (see

Key facts on algae:

  • Algae are at the base of the food chain;
  • They are found in marine and freshwaters, anywhere that has moisture;
  • There are hundreds of thousands of species, new ones are continually being identified;
  • They are many different groups, such as the Bacillariophyta (diatoms) and Cyanophyta (blue greens);
  • Some forms are toxic but some are edible; some have commercial uses;
  • They range in size from single cells to massive kelps.



Canter-Lund, H. and Lund J., Freshwater Algae. Their microscopic world explored, Bristol, 1995.


Webpage links and embedded video links:

You can see a short film about Klaus Kemp and his diatom arrangements here:

Many of Hilda Canter-Lund’s photographs are available on the Freshwater Biological Association’s digital archive:

More on algae:

Isabelle Charmantier is the Information Scientist at the Freshwater Biological Association @freshwaterbio

Editor’s note: while all these organisms fall within the traditional remit of botany only some are still considered to be green plants, the others fall into the Stramenopiles (Heterokonts) and are a lineage closely related to green plants.

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