{"id":40209,"date":"2016-07-20T11:50:04","date_gmt":"2016-07-20T15:50:04","guid":{"rendered":"https:\/\/brocku.ca\/brock-news\/?p=40209"},"modified":"2016-07-21T09:53:55","modified_gmt":"2016-07-21T13:53:55","slug":"brock-university-led-team-discovers-way-of-tapping-into-and-testing-earths-prehistoric-air","status":"publish","type":"post","link":"https:\/\/brocku.ca\/brock-news\/2016\/07\/brock-university-led-team-discovers-way-of-tapping-into-and-testing-earths-prehistoric-air\/","title":{"rendered":"Brock University-led team discovers way of tapping into and testing Earth\u2019s prehistoric air"},"content":{"rendered":"

A Brock University-led international research team has discovered a new way of measuring past oxygen levels on Earth: by tapping into the actual air that existed almost a billion years ago.<\/span><\/p>\n

\u201cThere was a lot of debate as to what the oxygen content was 800 million or more years ago,\u201d says Professor of Earth Sciences Nigel Blamey. \u201cWe\u2019ve come up with a direct method of analyzing the content of those trapped fossil gasses in the atmosphere and found that the oxygen level was approximately half of what it is today.\u201d<\/p>\n

This will give us a better understanding of how life evolved.<\/span><\/p>\n

Up until now, through indirect methods, scientists estimated that oxygen comprised a high of just two per cent of the Earth\u2019s atmosphere 800 million to one billion years ago.<\/p>\n

But the team found that the average oxygen content of the Earth\u2019s atmosphere was 10.9 per cent, more than five times greater than previously thought and about half of today\u2019s oxygen level.<\/p>\n

\u201cThis will give us a better understanding of how life evolved,\u201d says Professor of Earth Sciences Uwe Brand.<\/p>\n

The team, consisting of research partners from the United States, Scotland, France, Australia and China, collected samples from across the globe of a mineral called \u2018halite,\u2019 which is the natural form of table salt; its chemical name is \u2018sodium chloride.\u2019<\/p>\n

Within the halite are tiny microscopic bubbles called \u201cinclusions.\u201d Scientists discovered that some of these bubbles may contain atmospheric gasses, but the bubbles were too small to examine.<\/p>\n

But Blamey was able to do so, thanks to highly specialized equipment that his then-PhD advisor David Norman built in the 1970s. In the early 2000s, Blamey and Norman revamped the machine, which consists of a sophisticated vacuum system attached to an instrument called a quadrupole mass spectrometer.<\/p>\n

To measure what is inside the bubbles, Blamey places a halite sample in a vacuum chamber and crushes the sample into small pieces. As the samples are broken, the trapped fossil gas is\u00a0drawn into a the highly-sensitive quadrupole mass spectrometer, which is able to read and analyze the gas content and composition.<\/p>\n

\u201cIt\u2019s a direct measurement of the atmosphere of that time, not an interpretation,\u201d says Brand, adding the presence of Earth\u2019s other two major atmospheric gasses \u2013 nitrogen and argon \u2013 can also be determined.<\/p>\n

\"Oxygen-Infographic\"This new method, and the subsequent findings, have huge implications for how we understand the development of life on Earth.<\/p>\n

Earth\u2019s oldest fossil record dates back to around 3 billion years ago with the presence of stromatolites. These are rocks formed by layers and layers of cyanobacteria, a single-celled microbe that gets its energy from the sun and is known today as \u201cblue-green bacteria.\u201d<\/p>\n

The ancient cyanobacteria produced oxygen so that ‘abundant’ oxygen first started to appear around 2.3 billion years ago. Basic life forms that consumed oxygen began to emerge.<\/p>\n

Scientists estimated oxygen levels at various time periods through the presence of certain mineral deposits and redox sensitive proxies, and extrapolated the life forms that would have existed at those times.<\/p>\n

It is widely believed that a huge spike in oxygen occurred around 550 million years ago, for an unknown reason. But with Blamey and team\u2019s findings, it appears that this oxygen increase may have occurred much earlier than previously thought.<\/p>\n

\u201cOur finding answers one big question, did life come first or atmospheric oxygen; it is the latter,\u201d says Brand.<\/p>\n

\u201cNow the next thing is for paleobiologists to look for the organism that gave us this kick in oxygen,\u201d at that time, he says.<\/p>\n

The team\u2019s findings shed light on more than just the evolution of life forms on Earth.<\/p>\n

\u201cDeciphering the oxygenation history of the atmosphere and oceans is critical to understanding weathering processes, sedimentary environments, climate change, mass extinctions, tectonic events, and the evolution of Earth\u2019s biota,\u201d says the team\u2019s study.<\/p>\n

And, the findings can help determine the evolution of life on Mars and other planets, says Uwe.<\/p>\n

The study, titled \u201cParadigm shift in determining Neoproterozoic atmospheric oxygen,\u201d is scheduled to appear in the August edition of Geology<\/em>, the monthly journal of the Geological Society of America.\u00a0The paper can be found\u00a0<\/span>here.<\/a><\/p>\n

Brock University Professor of Earth Sciences Nigel Blamey talks about 800-million-year-old oxygen discovered in rocks:\u00a0<\/strong>
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