The chlorophyll photosynthesis implemented by plants began on Earth, according to various tests, already 3 billion years ago. However, oxygenation of the atmosphere seems to have occurred much later than the beginning of photosynthesis by plants, a process that in itself releases oxygen.
This is an enigma that geologists have not been able to solve, as recalled by Christopher Reinhard, a researcher at the Georgia Institute of Technology who, through a new study, conducted together with researcher Kazumi Ozaki and other colleagues, has tried to clarify the question a bit.
The researchers say they have discovered “that photosynthetic bacteria that use iron instead of water are fierce competitors for light and nutrients,” says Ozaki himself, now a researcher at the University of Toho, Japan.
This means that in the oceans of the primordial Earth the photosynthesizers that release oxygen could not effectively compete with their more primitive counterparts, ie those that consumed dissolved iron ions, very abundant elements on the primordial Earth.
These counterparts produced rust as a by-product instead of oxygen. For a long time, therefore, these photosynthesizers were able to overcome the photosynthesizers that produced oxygen.
The study was published in Nature Communications where it is available in complete form.