What is an Iron Film?
Iron films are a distinctive feature common to wetlands, seeps, and still areas of rivers and lakes. Though commonly mistaken for gasoline or oil pollution due to their coloration, iron films are naturally occurring, and are largely thought to be a consequence of iron-oxidizing microbes such as Leptothrix discophora. Also known as floating iron, iron-bearing films, Schwimmeisen (German), or Járnbrák (Icelandic), these films are all at once ubiquitous (found all over the world), visually striking, and potentially valuable as metal indicators or as a method of mining wastewater remediation. Despite this, these films and the bacteria associated with their formation are underrepresented in the literature, and often overlooked and misunderstood by the public.
I hope to, in some small way, remedy this situation. As an academic, I hope to help fill in this research gap in the future by studying iron films if time and resources permit me. As a hobbyist, I made this website so that I may share my photos and writings about these films and other natural science topics that intrigue me.
Have you encountered an iron film near you? I invite you to photograph the occurance and upload an entry to a site like iNaturalist! You will notice that other users commonly record iron-film observations as instances of Leptothrix discophora or just Leptothrix. This bacteria is definitely the poster-child for iron films.