Researchers believe oxygen may have existed in Earth's atmosphere about 700 million years earlier than we previously believed.
This finding could change the way scientists think about the development of the earliest life, a University of British Columbia press release reported.
Researchers analyzed the chemical composition of three-billion-year-old soil and found traces of oxygen. Scientists had previously believed that oxygen didn't show up until 2.3 million years ago, which has been commonly referred to as the Great Oxygenation Event.
"We've always known that oxygen production by photosynthesis led to the eventual oxygenation of the atmosphere and the evolution of aerobic life," Sean Crowe, co-lead author of the study and an assistant professor in the Departments of Microbiology and Immunology, and Earth, Ocean and Atmospheric Sciences at UBC, said.
"This study now suggests that the process began very early in Earth's history, supporting a much greater antiquity for oxygen producing photosynthesis and aerobic life," he said.
After Earth was born it lacked oxygen for a period of time that is believed to have spanned millions of years. Now, Earth's atmosphere is composed of 20 percent oxygen. The essential substance comes from the presence of environmental plant life that consumes carbon dioxide.
"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," Lasse Døssing, the other lead scientist on the study, from the University of Copenhagen, said.
"It's exciting that it took a relatively short time for oxygenic photosynthesis to evolve on Earth," Crowe told LiveScience. "It means that it could happen on other planets on Earth, expanding the number of worlds that could've developed oxygenated atmospheres and complex oxygen-breathing life."
Researchers hope to continue searching for signs of ancient oxygen from other sources.
"Research could also look at earlier rocks," Crowe told LiveScience. "Chances are, if there was oxygen 3 billion years ago, there was likely oxygen production some time before as well. How far back does it go?"
