Scientists Claim Oxygen Existed 300M Years Before Being Found in Atmosphere
Scientists have reported that their new studies suggest oxygen may have been present in Earth’s ancient oceans millions of years ago, long before it appeared in the atmosphere.
Analysts from Massachusetts Institute of Technology (MIT) believe oxygen may have existed in so-called “oxygen oases” found in the oceans, many years before what they call the “Great Oxidation Event” (GOE).
Scientists are saying that about 2.3 billion years ago, the Great Oxidation Event caused the release of oxygen into the Earth’s atmosphere. Oxygen molecules were rare before the GOE and the planet was covered in mix of poisonous gases, they say.
Get Our Latest News for FREE
MIT researchers found evidence that small aerobic organisms may have evolved to exist on exceedingly low levels of oxygen in underwater oases.
Roger Summons, Professor of Geobiology, Jacob Waldbauer, former MIT graduate student, and Dianne Newman, formerly with the MIT Department of Biology and now at the California Institute of Technology, executed laboratory experiments on yeast, which does not need oxygen to survive.
The results showed that yeast could produce important oxygen-dependent composites with just small bursts of gas. Based on these results, the analysts theorized that early predecessors of yeast could have similarly worked with the meager amounts of oxygen found in the oceans.
"We know all kinds of biology happens without any O2 at all. But it's quite possible there was a vigorous cycle of O2 happening in some places, and other places it might have been completely absent," said Waldbauer, the Study co-author, in an MIT press release.
The scientists used modern yeast to test their theory, setting up an experiment to pinpoint the exact moment yeast switches from anaerobic to aerobic activity. The analysis revealed that without the presence of oxygen yeast could take sterol from its surroundings without creating any on its own.
However, when tiny amounts of oxygen were pumped in, the yeast began using O2 combined with glucose to make its own sterols. According to the research even microscopic, nanomolar, quantities of oxygen were enough for yeast to produce steroids.
"The time at which oxygen became an integral factor in cellular metabolism was a pivotal point in Earth history. The fact that you could have oxygen-dependent biosynthesis very early on in the Earth's history has significant implications," said Summons in a press release.
According to Summons and his colleagues, oxygen could have been present on Earth 300 million years before it developed in the atmosphere. However, such low concentrations would not have imprinted much on the rock record.
Regardless the scientists said that these levels could have been enough for aerobic, sterol-producing organisms to feed on.
These studies were published in the Proceedings of the National Academy of Sciences.
