• picture
  • picture
PRI's Environmental News Magazine

Emerging Science Note/Ocean Life Evolution

Air Date: Week of October 31, 2003

stream/download this segment as an MP3 file

Living on Earth’s Cynthia Graber reports on a study that shows how the last great ice age may have ended when multi-celled organisms evolved into being.

Transcript

[SCIENCE NOTE THEME]

GRABER: Hundreds of millions of years ago, there were times when the earth was covered in ice from the polar caps all the way to the tropics. But about 500 million years ago, these extreme ice ages ceased, and glaciers have yet to reach tropical regions again. Now some scientists in California believe they know why.

Climate scientist Andy Ridgwell and his colleagues at UC Riverside and Lawrence Livermore National Lab discovered that the extreme ice ages stopped just about the time life in the ocean began to develop from single-celled organisms to more complex, multi-celled creatures. One of these tiny creatures began to manufacture a shell from a substance calcium carbonate. Turns out that when calcium carbonate dissolves in ocean waters it makes the water less acidic. It also stabilizes the water, preventing wild swings in pH. And since the pH of ocean water regulates the amount of carbon dioxide in the atmosphere, a more stable ocean pH means a more stable supply of heat-trapping carbon dioxide.

No one knows exactly why these tiny creatures evolved shells. It might have been to support a larger body, or to protect themselves from predators. But by doing so, these sea animals changed the chemistry of the ocean, and stabilized the carbon dioxide enough in the atmosphere to help make earth habitable for life, as we know it.

That’s this week’s Note on Emerging Science, I’m Cynthia Graber.

[EMERGING SCIENCE THEME]

CURWOOD: And you're listening to Living on Earth.

[MUSIC: Sparta “Glasshouse Tarot” WIRETAP SCARS (Dreamworks – 2002)]

 

 

Living on Earth wants to hear from you!

P.O. Box 990007
Prudential Station
Boston, MA, USA 02199
Telephone: 1-617-287-4121
E-mail: comments@loe.org

Donate to Living on Earth!
Living on Earth is an independent media program and relies entirely on contributions from listeners and institutions supporting public service. Please donate now to preserve an independent environmental voice.

Newsletter
Living on Earth offers a weekly delivery of the show's rundown to your mailbox. Sign up for our newsletter today!

Major funding for Living on Earth is provided by the National Science Foundation.

Committed to healthy food, healthy people, a healthy planet, and healthy business.

Innovating to make the world a better, more sustainable place to live.

Kendeda Fund, furthering the values that contribute to a healthy planet.

The Grantham Foundation for the Protection of the Environment: Committed to protecting and improving the health of the global environment.

Contribute to Living on Earth and receive, as our gift to you, an archival print of one of Mark Seth Lender's extraordinary hummingbird photographs. Follow the link to see Mark's current collection of photographs.