Skip to comments.Scientists find evolution of life
Posted on 10/30/2003 5:04:39 PM PST by Dales
LIVERMORE, Calif. -- A trio of scientists including a researcher from the Lawrence Livermore National Laboratory has found that humans may owe the relatively mild climate in which their ancestors evolved to tiny marine organisms with shells and skeletons made out of calcium carbonate.
In a paper titled "Carbonate Deposition, Climate Stability and Neoproterozoic Ice Ages" in the Oct. 31 edition of Science, UC Riverside researchers Andy Ridgwell and Martin Kennedy along with LLNL climate scientist Ken Caldeira, discovered that the increased stability in modern climate may be due in part to the evolution of marine plankton living in the open ocean with shells and skeletal material made out of calcium carbonate. They conclude that these marine organisms helped prevent the ice ages of the past few hundred thousand years from turning into a severe global deep freeze.
"The most recent ice ages were mild enough to allow and possibly even promote the evolution of modern humans," Caldeira said. "Without these tiny marine organisms, the ice sheets may have grown to cover the earth, like in the snowball glaciations of the ancient past, and our ancestors might not have survived."
The researchers used a computer model describing the ocean, atmosphere and land surface to look at how atmospheric carbon dioxide would change as a result of glacier growth. They found that, in the distant past, as glaciers started to grow, the oceans would suck the greenhouse gas -- carbon dioxide out of the atmosphere -- making the Earth colder, promoting an even deeper ice age. When marine plankton with carbonate shells and skeletons are added to the model, ocean chemistry is buffered and glacial growth does not cause the ocean to absorb large amounts of carbon dioxide from the atmosphere.
But in Precambrian times (which lasted up until 544 million years ago), marine organisms in the open ocean did not produce carbonate skeletons -- and ancient rocks from the end of the Precambrian geological age indicate that huge glaciers deposited layers of crushed rock debris thousands of meters thick near the equator. If the land was frozen near the equator, then most of the surface of the planet was likely covered in ice, making Earth look like a giant snowball, the researchers said.
Around 200 million years ago, calcium carbonate organisms became critical to helping prevent the earth from freezing over. When the organisms die, their carbonate shells and skeletons settle to the ocean floor, where some dissolve and some are buried in sediments. These deposits help regulate the chemistry of the ocean and the amount of carbon dioxide in the atmosphere. However, in a related study published in Nature on Sept. 25, 2003, Caldeira and LLNL physicist Michael Wickett found that unrestrained release of fossil-fuel carbon dioxide to the atmosphere could threaten extinction for these climate-stabilizing marine organisms.
1) This would be a very poor thread to choose to engage in flamewarring or flamebaiting.
2) It would be wrong to try to guess my position based on me posting this thread.
I like your style!
Does not compute. Global warming sky is falling stupid computer model bump.
They just HAVE to add the propanda about "excess atmospheric CO2". Exactly "why" should a few more ppm of CO2 "threaten extinction" for critters who make their shells out of calcium carbonate?? Seems to me that it would be more likely to make them flourish in greater abundance.
100,000 years hence...
"The most recent ice ages were mild enough to allow and possibly even promote the evolution of modern gogatons," Xizirina said. "Without these hairless primates, the ice sheets may have grown to cover the earth, like in the snowball glaciations of the ancient past, and our ancestors might not have survived."
Remember, Philbert, environmentalism has become a religion and when you do not adhere to doctrine illogical bad things are promised.
If the FR has a secret NWO agenda ... master race - PLAN ---- I certainly would like to know about it !
But it is Halloween, almost. Might as well let your imagination run wild.
Just as long as the thread doesn't turn into another flame barrage or nasti fight (with moose bites and lutefisk smitings), then I don't have a dog in this hunt.
That's as may be, but science is about discovering how to explain the explainable.
Unless you believe in God that is, then it is easy to explain.
Saying "God did it" isn't an explanation. The question becomes: how did God do it?
There still would have been liquid water below the ice, because of the geothermal heat coming from the ocean floor. As is the case today, life could have been supported during these severe ice ages around the hydrothermal vents.