Thursday, April 16, 2009

Ancient Antarctic Ecosystem: Isolated for Millions of Years

"Ancient Ecosystem Found in Ice Pocket"
Discovery (April 16, 2009)

"Beneath a glacier in Antarctica, scientists have discovered a community of microbes growing in frigid pools of salty water.

"It's a particularly tough environment, with no light, no oxygen, and extremely cold temperatures. But the microbes appear to live -- and thrive -- off a combination of iron and sulfur, according to a new study. The result of that strange metabolism is a brilliant red streak of cascading ice called Blood Falls...."

This patch of anaerobic things is interesting because it's in an environment that's a bit like subsurface Europa (one of Jupiter's moons). And, since it's been isolated for millions of years, studying it may help biologists understand how life handles Earth's glacial periods.

Earth's climate isn't exactly stable. There have been a half-dozen major glacial periods in the last 1,000,000,000 years. Here's a rough chronology:
  • 925,000,000 years ago
    • 125,000,000 years pass, then
  • 800,000,000 years ago
    • 120,000,000 years pass, then
  • 680,000,000 years ago
    • 230,000,000 years pass, then
  • 450,000,000 years ago
    • 120,000,000 years pass, then
  • 330,000,000 years ago
    • 328,000,000 years pass, then
  • 2,000,000 years ago
It's too early to tell, but we may be coming out of the one that started about two million years ago. Or, maybe we're just in an interglacial period, with another big freeze on the way: I've read it both ways.

That ice age that started 800,000,000 years back, by the way, was a bad one: glaciers got to within 15 degrees of the equator.

Another thing: Those dates are rather approximate. One thing that keeps scientists busy is working out more accurate (or less inaccurate) ways of telling how long ago something happened. I got those numbers from the Glacier article on Encyclopedia of Earth: which are pretty close to other best-estimate approximations.

Attention Earthlings: Change Happens

Earth's a big place, with a long history. Quite a bit has changed since microorganisms started metabolizing CO2, with O2 as a byproduct.

When I was growing up, civilization was going to end when the next ice age started. Now, there's another version of 'and we're all gonna die' making the rounds. I don't know what the Earth my great-great-great-great grandchildren live on will be like, but I'm pretty sure that it won't be exactly the way it is now.

Change happens.

Related posts More at
  • "Glacier"
    Encyclopedia of Earth
  • "Fossile Mysteries"
    San Diego Natural History Museum
    • Timeline of Earth's most recent 2,500,000,000,years

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