The existence of undiscovered strains of microbial lithoautotrophs is theorized based on some of these cycles, as they are needed to explain phenomena like the conversion of ammonium in iron-reducing environments. Lithoautotrophs may be present in the deep terrestrial subsurface (they have been found well over 3 km below the surface of the planet), in soils, and in endolith communities.
The existence of uncharted strains of lithoautotrophic microorganisms is proposed based on some cycles; these are necessary to explain occurrences like ammonium conversion in iron-reducing environments. Lithoautotrophs might be present in the deep terrestrial subsurface (they have been found over 3 kilometers below the planet's surface), in soils, and within endolithic communities.