Bacteria iron-depositing

Harder EC (1919) Iron-depositing bacteria and their geologic relations. US Geol Surv Prof Pap 113 Hartman H (1984) The evolution of photosynthesis and microbial mats a speculation on banded iron formations. In Microbial Mats Stromatolites. Cohen Y, Castenholz RW, Halvorson HO (eds) Alan Liss Pub, New York, p 451-453... 

Harder EC. 1919. Iron-depositing bacteria and their geologic relations [US Geological Survey Professional Paper 113]. Washington, DC US. Government Printing Office. 

Here oxidizing iron and manganese plays the role not of a source of energy but of detoxifier of a harmful released product. Thereby iron-depositing bacteria prevent the accumulation of iron and manganese in water. 

Metal depositors. Metal-depositing bacteria oxidize ferrous iron (Fe ) to ferric iron (Fe ). Ferric hydroxide is the result. Some bacteria oxidize manganese and other metals. Gallionella bacteria, in particular, have been associated with the accumulation of iron oxides in tubercles. In fact, up to 90% of the dry weight of the cell mass can be iron hydroxide. These bacteria appear filamentous. The oxide accumulates along very fine tails or excretion stalks generated by these organisms. 

In some reports Gallionella have been associated with manganese and iron deposits that also contain chloride. It has been postulated that deep undercut pits on stainless steels (especially at welds) containing such deposits are indirectly caused by these bacteria, since the iron-manganese deposition can be accelerated by Gallionella. In spite of numerous literature citings, however, evidence for stainless steel... 

The carbon dioxide produced can contribute to the corrosion of metal. The deposits of ferric hydroxide that precipitate on the metal surface may produce oxygen concentration cells, causing corrosion under the deposits. Gallionalla and Crenothrix are two examples of iron-oxidizing bacteria. 

Manganese and iron oxidation are coupled to cell growth and metabolism of organic carbon. Microbially deposited manganese oxide on stainless and mild steel alters electrochemical properties related to the potential for corrosion. Iron-oxidizing bacteria produce tubercles of iron oxides and hydroxides, creating oxygen-concentration cells that initiate a series of events that individually or collectively are very corrosive. 

Figure 17. Predicted Fe isotope variations produced by redox cycling of Fe due to APIO and DIR by bacteria, as envisioned from Fig. 16. The initial 6 Fe of the pool, as well as that of the influx of Fe(II), [JF n).Exi] is assumed to be zero. Solid lines show the 6 Fe values for ferric oxide/oxyhydroxide deposits as a function of solidification of the pool as an iron deposit is formed, and dashed lines show the 6 Fe values for Fe(II),. Depending upon the relative fluxes of external Fe(II), [Tpem-Ext], return of Fe(II) to the pool by DIR [Tpean Bio]. and precipitation of ferric oxide/oxyhydroxides by APIO [JF nnppd, a wide range of 6 Fe values can be produced.

Trolldenier G. 1988. Visualization of oxidizing power of rice roots and of possible participation of bacteria in iron deposition. Zeitschrift fur Pflanzenernahrung und Bodenkunde 151 117-121. 

Bacteria which oxidize ferrous iron (Fe2+) to ferric iron (Fe3+) such as Gallionella and Leptothrix species are termed metal-depositing bacteria. The result of this metabolic process is the formation of ferric hydroxide. 

UVi reduced to U,v by iron-reducing bacteria. May be important in the bio-geochemical deposit of U ... 

Ghiorse, W.C., Biology of iron- and manganese-depositing bacteria, Ann. Rev. Microbiol., 38, 515, 1984. 

Sobolev D. and Roden E. E. (2001) Suboxic deposition of ferric iron by bacteria in oppposing gradients of Fe(II) and oxygen at circumneutral pH. Appl. Environ. Microbiol. 67, 1328-1334. 

Edwards, K. J., Bach, W., McCollom, T. M., and Rogers, D. R. (2004). Neutrophilic iron-oxidizing bacteria in the ocean their habitats, diversity, and roles in mineral deposition, rock alteration, and biomass production in the deep-sea. Geomicrobiol. J. 21, 393-404. 

III) ion to metal gold with hydrogen gas (Kashefi et al., 2001). The compounds, metals, or ores thus formed are deposited around the hydrothermal vents. If the vents are heaved up to create a mountain after 10-100 million years, a mine seam is produced in which the ores mentioned above are involved. Usually, gold is found in the elemental or metal state. This will be explainable in some cases if gold has been formed by the action of the iron-reducing bacteria as mentioned above. 

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