These environments include freshwater bodies characterized with neutral to slightly acidic pH, oxygen gradients and organic matter.

Examples of these sites include freshwater streams and wetlands, iron seeps, water pipes, surface of sediments [6][7] Their growth under suitable conditions is easily recognized with fluffy microbial mats, surface biofilms made up of oxidized Fe and Mn minerals with orange to dark brown color.

Leptothrix cholodnii  SP-6 is a member of this group with an isolate and sheath-former under laboratory conditions.

[8] Metabolism They grow as aerobic, chemoorganoheterotrophs under circumneutral pH conditions.

[6] They can utilize a range of organic carbon substrates as electron donors.