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Sulfur isotope fractionation was demonstrated in corrosion products resulting from the activities of sulfate-reducing bacteria within biofilms on copper surfaces. 32S accumulated in corrosion products, while 34S was concentrated in the culture medium due to fractionation. The accumulation of the lighter isotope was related to surface derivatization or corrosion as measured by weight loss.

Fungi were isolated and identified in ten aircraft that had been operating in marine tropical environments. Distribution and growth of fungi depended on availability of water and nutrients. Laboratory experiments demonstrated that surface washes, including the approved military maintenance procedure, were ineffective in removing fungal hyphae embedded in polyurethane coatings. Surface cleaning removed spores and discoloration associated with fungi, but fragments of the hyphae remained and grew as soon as conditions were favorable. Aged coatings fouled more rapidly than new coatings. Fungicides incorporated into the topcoats produced mixed results. Bare aluminum suffered localized corrosion when colonized by fungi.

Microbial colonization of metals (zirconium, chromium, niobium, tantalum, molybdenum, tungsten, and type 4340 steel [UNS G43400]) and susceptibility of these metals to microbiologically influenced corrosion by sulfate-reducing bacteria was investigated. Environmental scanning electron microscopy characterization after 12 months and 21 months showed patchy biofilms on all metals except tungsten. Weight loss after 24 months for zirconium and niobium were either nonexistent or negligible, indicating that these metals did not experience MIC under the test conditions.