The Mystery of Earth’s Oxygen
2013 10 09
By Carl Zimmer | NYTimes
To Donald E. Canfield, there’s something astonishing in every breath we take. “People take oxygen for granted because it’s just there and we breathe it all the time,” said Dr. Canfield, a geochemist at the University of Southern Denmark. “But we have the only planet we know of anywhere that has oxygen on it.”
What’s even more astonishing is that the earth started out with an oxygen-free atmosphere. It took billions of years before there was enough of it to keep animals like us alive.
Although scientists have been struggling for decades to reconstruct the rise of oxygen, they’re still making fundamental discoveries. In just the past two weeks, for example, Dr. Canfield and his colleagues have published a pair of studies that provide significant clues about some of the most important chapters in oxygen’s history. They’re finding that our weirdly oxygen-rich atmosphere is the result of a complicated dance of geology and biology.
To study the ancient atmosphere, geochemists examine the chemical fingerprints left behind on rocks. Some rocks contain molecules that could have formed only in the presence of oxygen. The more of those molecules geochemists find in a rock, the more oxygen must have been in the atmosphere at the time.
When they look at the oldest rocks on earth, they find no trace of oxygen in the atmosphere. Instead, their research indicates that earth’s primordial air was made up mostly of carbon dioxide, methane and nitrogen. The sun’s rays created some free oxygen by splitting it off from carbon dioxide and other molecules. But the oxygen disappeared almost as soon as it was formed.
That’s because oxygen is an enormously friendly element, forming bonds with a wide range of molecules. It attached to the iron in rocks, for example, creating rust. It joined with hydrogen spewed out from volcanoes to form hydrogen peroxide and other compounds. Our planet, in other words, was a giant oxygen vacuum in its early years.
That changed about three billion years ago. In the Sept. 26 issue of Nature, Dr. Canfield and his colleagues reported the fingerprints of oxygen in rocks from that time period. They estimate that the atmosphere three billion years ago had only 0.03 percent of today’s oxygen levels. That may not sound like much, but it marked a huge shift in the earth’s chemistry.
Sunlight alone couldn’t have put that much oxygen in the atmosphere. Only life could.
By three billion years ago, some microbes had evolved the ability to carry out photosynthesis. Floating at the surface of the ocean, they used energy from sunlight to grow on carbon dioxide and water. They gave off oxygen as waste.
Much of the oxygen released by these photosynthetic microbes was sucked out of the atmosphere by the earth’s vacuum. When microbes died, oxygen reacted with their carbon.
But a tiny amount of oxygen remained behind because some of the organic matter from the dead microbes sank from the surface of the ocean to the sea floor, where oxygen couldn’t react with it. The oxygen remained in the air.
Read the full article at: nytimes.com
Discoveries of Oxygen
Mars had an oxygen-rich atmosphere four billion years ago
Cosmic Dust --"A Clue to Origin of Earth’s Oxygen and Water?"
World’s oldest fossils: Researchers claim bacteria existed on Earth before OXYGEN
Latest News from our Front Page
Nigel Farage (UKIP) Speech on the EU, UK & Mass Immigration
2014 03 08
UKIP Nigel Farage Spring Conference speech - 2014
Red Ice Radio:
Nigel Farage MEP - The State of the EU & The Undemocratic Treaty of Lisbon
Labour wins UK by-election as Ukip trumps Tories
The ruling coalition in the UK was dealt a blow in the latest by-election test, as the UK Independence party pushed the Conservatives and Liberal Democrats into third and fourth ...
Pentagon studying Putin’s body language to predict his behavior
2014 03 07
The Pentagon has spent hundreds of thousands of dollars in recent years so that researchers can study the body movements of foreign leaders, including Russian President Vladimir Putin, in hopes of predicting future behavior.
An article published by USA Today reporter Ray Locker on Thursday and corroborated by documents discovered by RT provides rare insight into a scarcely-discussed military effort that ...
Pentagon Claims That Climate Change ‘Enables Terrorism’
2014 03 07
In it’s latest Quadrennial Defense Review the Pentagon has said that climate change and ’erratic’ climate will cause increased terrorist activity.
The four yearly reports highlight threats that face civilization and this years homed in on climate change causing an increase in terrorism.
It also mentioned that rises in sea levels and other issues associated with a warming planet will lead ...
Scientists Control Tiny Mechanical Probes Inside Human Cells
2014 03 07
Nanotechnology doesn’t get as much attention these days as genetic and stem cell approaches to medicine, but all three aim to target the causes of illness with greater precision and less collateral damage in the rest of the body than conventional approaches.
Nanotech breakthroughs have come more slowly than many had hoped, but a recent success shows progress toward the goal ...
Fukushima: The Ticking Nuclear Bomb. Over 800 Tons of Radioactive Material Pouring into Pacific Ocean
2014 03 07
First published by GR in October 2013
In August this column ran a piece claiming that the Pacific Ocean was being poisoned by radioactive material escaping from Fukushima, two years after the devastating tsunami and meltdown at the Japanese nuclear facility. Three months later, shocking evidence points towards a calamity situation.
Silence from the corporate media.
There is growing evidence coming from ...
|More News » |