Evolution over time of mackinawite generated on carbon steel by the SRB metabolic activity: an in-operando Raman study.

Mackinawite was biologically synthetized by immersing carbon steel coupons in artificial seawater containing Sulphate-Reducing Bacteria (SRB) for 6months. These coupons were removed from the culture medium solution and some were stored in air while others were placed in SRB-free culture medium solution. In operando Raman spectroscopy was used to analyse all these coupons immediately after extraction from the incubation medium and nanocrystalline, well-crystallized and partially oxidized mackinawite was detected.