Final answer:
Sulfate-reducing bacteria are key to the process of metal corrosion, which is a complex REDOX and galvanic process that is expensive to manage due to its destructive nature on metals like iron. The exact mechanisms are not fully understood, but research is ongoing due to the significant economic impact, particularly in industries relying on iron.
Step-by-step explanation:
The sulfate-reducing bacteria play a pivotal role in the corrosion of metal structures, yet the intricacies of their mechanisms are not fully understood. Corrosion itself is a galvanic and REDOX process, which involves the oxidative deterioration of metals, often leading to the formation of oxides. Given the economic implications, particularly with iron, which sees annual costs of up to $100 billion in the U.S. for replacements due to corrosion, there's a significant incentive for research in corrosion protection and treatment methods.
While some metals like aluminum, chromium, and nickel develop protective oxide films that act as barriers against further corrosion, iron does not exhibit this property and hence is more susceptible to corrosion. Sulfate-reducing bacteria contribute to metal corrosion by using sulfate as a final electron acceptor in anaerobic respiration, which potentially influences the corrosion processes. These microbes, along with other sulfur-oxidizing and iron-oxidizing bacteria, play roles in the biogeochemical cycling of elements, impacting the environment and material integrity.