Currently, molecular oxygen constitutes 21 percent of the air we breathe, which represents a significant portion of the Earth’s atmosphere. However, in the turbulent primordial gas mixture that characterized the atmosphere of our world in its distant past, there was little molecular oxygen, or maybe even was virtually nonexistent.
It was not until the Great Oxidation, about 2,300 million years, when oxygen started to have an appreciable influence on the atmosphere, stimulating the evolution of air-breathing organisms that were more complex, until finally allow the emergence of life just as we know it today.
Now, new research of MIT suggests that molecular oxygen may have formed on Earth hundreds of millions of years before it passed into the atmosphere, keeping discreetly in a series of ‘oxygen oases’ located in the oceans.
In laboratory experiments focused on modern yeast as a model organism, and conducted at MIT, Jacob Waldbauer, Roger Summons and Dianne Newman have discovered that it (an organism that can survive with or without oxygen) is capable of key compounds dependent on the oxygen, but only has tiny amounts of gas. The result supports the theory that oxygen, as well as producers and consumers, could be present on Earth long before the gas appeared in the atmosphere.
The ancestors of the yeast might have a similar capacity, working with small amounts of molecular oxygen that may exist in the oceans before the accumulation of gas in the atmosphere began to be noticeable.
Waldbauer and his colleagues suggest that some 300 million years before the molecular oxygen concentration in the atmosphere being fired, maybe the gas was already present on Earth, even at extremely low concentrations that would not have left almost no trace in the log mineral.
They argue that even such meager amounts; this could be sufficient molecular oxygen to sustain some aerobic organisms.
The research team believes that, most likely, cyanobacteria, also known as blue-green algae that live in the sea surface, developed very early in the ability to produce molecular oxygen using sunlight. But instead of accumulating in the water and then into the atmosphere, much of the molecular oxygen was consumed perhaps very rapidly by aerobic organisms primitive. Other processes, geochemical, probably consumed the remaining molecular oxygen.
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