New research changes our understanding of early life on Earth

A new international study has revealed that perhaps the most important evolutionary change in Earth's history — the development of photosynthesis — happened roughly 300 million years before we previously thought.

Roughly 2.3 billion years ago, the Earth's atmosphere underwent a radical change known as the Great Oxygenation Event. This was when the combination of mainly nitrogen and carbon dioxide shifted to mostly nitrogen and oxygen, due to the evolution of photosynthesis by blue-green algae.

"This evolutionary event forever changed the composition of the atmosphere, supported the expansion of aerobic life, and charted a course for the ultimate evolution of animals including humans," Sean Crowe, the co-author of the study, told the Canadian Press.

Scientists have seen evidence that this evolutionary development happened long before the Great Oxygenation Event, even as far back as 2.7 billion years ago. However, since the oxygen these organisms produced was quickly removed from the air as it went into processes like rusting iron deposits, it was hard to find any solid evidence to show exactly how long ago the first photosynthesizing organisms appeared.

In this new study, Sean Crowe, an associate professor at the University of British Columbia, and Lasse Døssing, from the University of Copenhagen's Nordic Center for Earth Evolution, found that a 3-billion-year-old soil sample discovered in South Africa actually contained enough oxygen to not only prove that these organisms existed long before the Great Oxygenation Event, but around 300 million years earlier than any previously estimates.

"These findings imply that it took a very long time for geological and biological processes to conspire and produce the oxygen rich atmosphere we now enjoy,” Døssing said, according to a UBC news statement.

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This new discovery came about due to advances in technology that allowed the researchers to measure oxygen levels down to over 3,000 times lower than current levels in our atmosphere. These advances have now provided incredible new information about our own planet and the evolution of life here, and they may find their way into other important works as well.

According to Døssing, who spoke to the Canadian Press: "Technology similar to that used in our study could provide a powerful tool to search for oxygen and signs of life on planets such as Mars."

(Image courtesy: NASA)

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