The corrosion potential of 4 tropical D. desulfuricans isolates was determined using a semicontinuous batch culture technique in a 56 day test incubated at 37.degree. C. The corrosion potentials for mild and stainless steel of marine or brackish water isolates (0.55 and 0.0026 mg/cm-2 per day-1) were observed to be approximately twice those of freshwater isolates (0.23 and 0.0014 mg/cm-2 per day-1). Under comparable experimental conditions of severe anaerobic corrosion, stainless steel was > 200 times more resistant than mild steel.