Oxygen Vanishing From The Earth's Atmosphere Over The Last 800,000 Years, Study Reveals
The researchers from Princeton University examined the ice cores gathered in Greenland and Antarctica to identify the levels of the oxygen over the last 800,000 years. They discovered that the concentration of oxygen in the Earth's atmosphere have declined by nearly 0.7 percent.
The study was printed in the journal Science. It also indicates that in the past 100 years, the atmospheric oxygen has dropped by 0.1 percent due to the burning of fossil fuels, which expends oxygen and generate carbon dioxide.
On the other hand, the drop in the atmospheric oxygen over the past 800,000 years did not change the amount of carbon dioxide in the atmosphere. This becomes a paradox to the scientists and they tend to apply the theory for how the atmospheric carbon dioxide, global carbon cycle and earth's temperature are associated on geologic timescales, according to Science Daily.
John Higgins, the co-author of the study and an assistant professor of geosciences in Princeton explained that the oxygen record could tell a change in the amount of carbon dioxide entering the atmosphere and ocean. On the other hand, he said that the atmospheric carbon dioxide levels aren't changing because the earth has had time to respond via better silicate weathering rates. The researchers theorize that the reason for the lack of carbon dioxide is due to the series of slow chemical reactions between the atmosphere and rocks, which is called silicate weathering.
Daily Mail reported that the drop in oxygen level is due to an increase in erosion. This leads to freshly exposed sediment being oxidized by the atmosphere thus reducing the atmospheric oxygen levels. Another factor is the interaction with the oceans. With the global warming, the oceans cannot absorb oxygen. On the other hand, cooler waters could take in more gas.
"Understanding the history of oxygen in Earth's atmosphere is intimately connected to understanding the evolution of complex life. It's one of these big, fundamental ongoing questions in Earth science," said Prof. Higgins.