IRON BACTERIA – What is It?
Iron bacteria are naturally occurring microorganisms that have existed in waterways for millions of years and feed on iron present in soils or waterways. They thrive in low oxygen environments.
Fluffy orange brown coloured iron bacteria flocculate growth in a slow flowing creek.
No, it is not pollution and they are not dangerous, posing no health risk to the community or the environment, however contact with it should be avoided.
It is, however, very slippery so take care when walking in and around bodies of water that contain iron bacteria.
Iron bacteria can look different depending on how they grow in specific environments and the stage of growth they are in.
Commonly, iron bacteria will:
- Appear as slimy pieces of fluff that stains the ground an orange-brown colour resembling rust.
- Can create a rainbow, orange, or white coloured film that is often mistaken for oil or other pollutants in still or stagnant water.
Fluffy rust coloured iron bacteria flocculate growth in stagnant water stemming from saturated soils
Rusty brown shiny iron bacteria flocculate growth in a low flowing creek
Slimy rainbow white and orange coloured sheen of iron bacteria leaching from saturated soils upgradient of the footpath
Using a stick to break the surface sheen is a simple way to test whether it is iron bacteria or an oil spill. Iron bacteria will fracture and separate while oil will reform, clump, and stick.
There may also be a decaying swamp smell if iron bacteria are present. If you can smell petrol, oil, sewerage or chemicals, report it.
Iron bacteria can be found in many places, including:
- In slow moving streams, lakes, canals, and rivers with high amounts of iron.
- Creeks that are fed by water flowing under the surface (groundwater).
- On steep slopes where water seeps out of the ground.
- On rocks near waterfalls.
- Where sandstone has been crushed and used as fill.
- In or around sandstone outcrops.
- Piping, gutters, and other water infrastructure that have ground water sources.
Can we stop iron bacteria from growing?
Iron bacteria are naturally occurring and in most cases are difficult to prevent and remediate.
When flows are low it accumulates but clears itself up when sufficient flows can flush the bacteria away. However, improving drainage may help reduce re-occurrence.
The best thing to do is ensure that it is not an oil spill or other pollutant and leave it alone.