Download Iron Bacteria Fact Sheet

Iron Bacteria Fact Sheet
Description.
Iron Bacteria (Ferrobacillus, Gallionella, Thiobacillus, Leptothrix and Sphaerotilus) are a group of small
(0.5 to 1.5 um), unicellular, organisms which grow in chains and excrete a mucilaginous sheath. (Image 1)
This sheath becomes light brown from iron oxide (Fe (OH) 3) and appears as a fuzzy coating on any
available substrate (Image 2). Iron oxide is formed as the bacteria oxidizes ferrous iron (Fe 2) to ferric iron
(Fe3). The ferric iron becomes iron oxide when it is exposed to air (O2) and water (H2O). It is the
oxidation of ferrous to ferric that produces the energy needed for the bacteria to survive. This makes them
autotrophic, or self feeding, as opposed to heterotrophic. Heterotrophic organisms require a food source
produced by others, like animals do.
Ecological Implications:
Iron Bacteria can be found in streams, lakes, ponds and ditches throughout the North Carolina. They are
indicative of iron rich water, ground water seeps and low flow conditions. These waters are often acidic or
in contact with an anaerobic sediment layer because ferrous iron is favored in these conditions. Although
unsightly, Iron Bacteria are not known to pose any environmental or human health risk.
What I see.
Image 1. Iron Bacteria Sheaths.
What you see.
Image 2. Iron Bacteria on a twig.
Questions?
Mark Vander Borgh
Environmental Sciences Branch
North Carolina Division of Water Quality
Phone: (919) 733 9960
Email: [email protected]