WASHINGTON: Canadian and U.S. researchers found in a study that the abundance of oxygen in the earth’s atmosphere surfaced in “whiffs” from a blue-green algae, which was found in the oceans 2.5 billion years ago.
The researchers claimed that the “whiffs” of oxygen took place in the following 100 million years. This significantly changed the amount of oxygen in the earth’s atmosphere, therefore creating a fully oxygenated atmosphere 2.4 billion years ago. This was referred to as the Great Oxidation Event.
“Until now, we haven’t been able to tell whether oxygen concentrations 2.5 billion years ago were stable or not. These new data provide a much more conclusive answer to that question,” Brian Kendall, a coauthor of the study and earth and environmental sciences professor at the University of Waterloo, said in a news release.
The researchers’ new study revealed that a burst of oxygen production from photosynthetic cyanobacteria partially increased the levels of oxygen in the earth’s atmosphere.
In 2007, Professor Ariel Anbar, a coauthor of the study from Arizona State University found evidence of the early oxygen whiffs in black shales in Western Australia. These fossilized black shales were found on the seafloor of an ancient ocean.
The researchers found the black shales had high levels of molybdenum and rhenium, where these elements were present before the Great Oxidation Event. Molybdenum and rhenium are commonly found in land-based sulphide minerals, which are quite sensitive to oxygen. The researchers found that the black shales contained a high level of another element called osmium, which is found in earth-based sulfide minerals.
