Manganese nodules on the sea floor seem to be a source of oxygen and may have been formed by bacteriaScience History Images / AlamyMetallic nodules found deep in the sea seem to be producing significant amounts of oxygen by some unknown mechanism, researchers revealed last year. Now, we may have found out how it is happening and the same process could also produce oxygen to help terraform Mars.Chaomin Sun at the Chinese Academy of Sciences in Beijing and his colleagues have discovered that two species of deep-sea bacteria can produce large quantities of oxygen. Whats more,