Accelerated low water corrosion: the microbial sulfur cycle in microcosm

• Published in: Npj Materials degradation Vol. 3; no. 1
• Main Authors: Smith, Martin, Bardiau, Marjorie, Brennan, Richard, Burgess, Heidi, Caplin, Jonathan, Ray, Santanu, Urios, Thomas
• Format: Journal Article Web Resource
• Language: English
• Published: London Nature Publishing Group UK 25.10.2019; Nature Publishing Group
• Subjects: 631/326/2522; 639/301/1023/1026; 704/172/169/209; Bacteria; Bacterial corrosion; Chemistry and Materials Science; Corrosion; Corrosion and Coatings; Corrosion products; Electrochemistry; Hydrogen reduction; Hydrogen sulfide; Iron oxides; Iron sulfides; Life sciences; Materials Science; Microbiologie; Microbiology; Oxidation; Sciences du vivant; Structural Materials; Sulfate reduction; Sulfides; Sulfur; Tribology
• ISSN: 2397-2106; 2397-2106
• DOI: 10.1038/s41529-019-0099-9

Accelerated low water corrosion is a form of marine steel corrosion caused by bacterial activity. It has a global spread and is potentially responsible for billions of pounds of damage. We have determined in detail both the chemistry of corrosion products and the associated microbiology at a UK site. The corrosion products form a layered structure with iron sulfides at the steel surface and iron oxides and sulfates in contact with water. The iron sulfides are formed by reaction of steel with hydrogen sulfide formed by sulfate-reducing bacteria and are oxidised through a series of sulfur oxidation states by sulfide-oxidising bacteria, forming acid at all stages and encompassing the whole of the bacterial sulfur cycle. The bacteria involved are endemic in anoxic bed sediment, and the process is a response to the presence of steel as an electron donor, and the generation of anoxic microenvironments within corrosion products.