Oxygen may have been present on ancient Earth
Washington: A new research from MIT has found evidence of early oxygen on our planet.
Today, oxygen takes up a hefty portion of Earth's atmosphere. However, very early in Earth's history, O2 was a rare player in the turbulent mix of primordial gases. It wasn't until the “Great Oxidation Event” (GOE), nearly 2.3 billion years ago, when oxygen made any measurable dent in the atmosphere, stimulating the evolution of air-breathing organisms and, ultimately, complex life as we know it today.
Now, a new research had suggested that O2 might have been made on Earth hundreds of millions of years before its debut in the atmosphere, keeping a low profile in “oxygen oases” in the oceans. The MIT researchers found evidence that tiny aerobic organisms may have evolved to survive on extremely low levels of the gas in these undersea oases.
In laboratory experiments the researchers found that yeast — an organism that can survive with or without oxygen — is able to produce key oxygen-dependent compounds, even with only miniscule puffs of the gas.
The findings suggested that early ancestors of yeast could have been similarly resourceful, working with whatever small amounts of O2 may have been circulating in the oceans before the gas was detectable in the atmosphere.
“The time at which oxygen became an integral factor in cellular metabolism was a pivotal point in Earth history,” said Professor of Geobiology Roger Summons.
“The fact that you could have oxygen-dependent biosynthesis very early on in the Earth's history has significant implications,” added Summons.
Former MIT graduate student Jacob Waldbauer and colleagues had suggested that perhaps O2 was in fact present on Earth 300 million years before it spiked in the atmosphere — just at extremely low concentrations that wouldn't have left much of a trace in the rock record. They reasoned that, even at such low levels, this O2 may have been sufficient to feed aerobic, sterol-producing organisms.
The study has been detailed in the Proceedings of the National Academy of Sciences.