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February 25, 2011 | 7
About 600 million years ago, when Earth was a little lonely (the Cambrian explosion of diverse life forms hadn't happened yet), the village of Lantian in central China was covered by an oxygenless ocean. The anoxic Lantian Basin would have been especially lonely, mostly unable to support large, complex, multicellular organisms that require oxygen for respiration.
But for brief periods, the water in the basin did hold oxygen, a team of U.S. and Chinese scientists now proposes in a paper published on February 16 in Nature. (Scientific American is part of Nature Publishing Group.) In those oxygenated flashes of time seaweeds and what may be algae or worms took hold. They died again when the oxygen dissipated, leaving behind more than 3,000 well-preserved fossils, such as this one preserving a three-centimeter-long seaweed. These are the oldest fossils of large seaweeds ever found, according to a prepared statement from the National Science Foundation, which partially funded the study. The excavating team identified 15 species of life recorded in the fossils.
—Francie Diep
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7 Comments
Add CommentI understood that a simple form of algae had, billions of yers ago, over a period of billions of years, oxygenated not only the oceans but the atmosphere.
Reply | Report Abuse | Link to thisAs I understand, seaweed is nonspecific name for several types of algae, all of which employ photosynthesis, similarly to plants, to produce oxygen. Do algae for some reason also require oxygen?
I'm sure these researchers are not mistaken about the conditions they have inferred about this ancient environment, but there seems to be a great deal of critical information that has been omitted from this brief report.
Keep laughing, because there may be something that you don't know.
Reply | Report Abuse | Link to thisThe Wikipedia entry, "Atmosphere of Earth", section "Evolution of Earth's atmosphere" contains the following statement:
"In the late Archaean eon an oxygen-containing atmosphere began to develop, apparently from photosynthesizing algae which have been found as stromatolite fossils from 2.7 billion years ago."
As I understand, the early earth contained little oxygen. Photosynthesizing algae is credited with producing essentially all of the Earth's oxygen, over a period of perhaps a couple of billion years, both in the atmosphere and that which is bound through oxidation with other minerals within the Earth's surface. If this algae had reabsorbed all the oxygen it produced, as you erroneously asserted, there would have never been a net increase in oxygen levels.
In any case, you should refrain from making ignorant, insulting remarks.
BTW, the wikepedia reference can be found at:
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Atmosphere_of_Earth#Evolution_of_Earth.27s_atmosphere
Since you're gonna be a twat about it, plants absorb oxygen ALL the time, not just at night. They just happen to produce a lot more oxygen through photosynthesis, so their net impact on oxygen is positive during the day, negative at night.
Reply | Report Abuse | Link to thisWhen everybody around you is an asshole, chances are, you are.
Seems like there's plenty of opinions here, but if, prior to the "late Archaean eon" Earth was oxygen-free and some photosynthesizing algae oxygenated the Earth - it must not have required much if any oxygen, or it never could have gotten started.
Reply | Report Abuse | Link to thisSome unreferenced sources indicating that 'plants absorb oxygen' is not really useful information, since those statements may be generally true without necessarily applying to the algae that originally oxygenated the Earth.
The issue I tried to raise is that the article describes "an oxygenless ocean" that existed in central China 600 million years ago, about 2 billion years after after the Earth is supposed to have been generally oxygenated by algae.
There seems to be some conflicting information from purportedly, at least, somewhat reliable sources, not to mention all of us ignorant, inadequate and insulting readers!
Can the author and/or editors perhaps clarify?
The atmosphere oxygenation was done by blue green algae. Not actually algae, but bacteria. True algae are more efficient and much larger, but the bacteria do the job. I believe that the blue green algae are classed as Archea. I might be wrong on this. Ask a Biologist.
Reply | Report Abuse | Link to thisThese bacteria are also the major source of fixed nitrogen for plant life. There are thousands of them for each plant on the planet. And yes, they can live without oxygen.
YetAnotherBob, I understand that what we used to call 'blue green algae' in our youth is now reclassified and called 'cyanobacteria', so you are probably right.
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