A collaboration of coast and countryside organisations on The Lizard Peninsula

Leptothrix discophora (photo by Amanda Scott)No, it’s not a miniature oil slick. That oily film on the surface of puddles on The Lizard is an iron-oxidizing bacterium.
Photo: Amanda Scott




Scientific name: Leptothrix discophora

What to look for:

· Colouring and appearance: Oily-looking film on surface of puddles on heathland. Breaks up into small plates when touched, rather than swirling like oil.

· Where: Globally, in habitats rich in iron

Leptothrix discophora While wandering across The Lizard’s heathlands, have you ever puzzled over the oily film you can see in puddles on the trackways or on still water between clumps of vegetation. It is not a case of someone being careless with an oil can: this is acutally a bacterium – Leptothrix discophora – one of a group of different species of bacteria that survive by oxidizing iron and other metals. The film you see on the water is created by the bacteria (which are themselves microscopic and therefore not visible to the naked eye). If you want to tell it apart from oil, gently push a twig through the surface (it will not hurt the bacteria). Oil will swirl, whereas a L. discophora film breaks up into tiny separate plates. You can see this clearly in the lower image on this page.

You can find out more about this rather beautiful bacterium with its iridescent film using the links below.

Did you know...?

...Linda Grashoff is an artist in the USA who features L. discophora in her work – as well as knowing much about its life history and habitats (check out the FAQs in the link below), it is worth a browse of her images and artwork.

Leptothrix discophora


Linda Grashoff's website


Published: April 2016
Author: Amanda Scott
Photos: Amanda Scott