Featured Research

from universities, journals, and other organizations

Scientists Find Evolution Of Life Helped Keep Earth Habitable

Date:
October 31, 2003
Source:
Lawrence Livermore National Laboratory
Summary:
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.

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.

Related Articles


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.

###

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy's National Nuclear Security Administration.


Story Source:

The above story is based on materials provided by Lawrence Livermore National Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Lawrence Livermore National Laboratory. "Scientists Find Evolution Of Life Helped Keep Earth Habitable." ScienceDaily. ScienceDaily, 31 October 2003. <www.sciencedaily.com/releases/2003/10/031031063656.htm>.
Lawrence Livermore National Laboratory. (2003, October 31). Scientists Find Evolution Of Life Helped Keep Earth Habitable. ScienceDaily. Retrieved January 27, 2015 from www.sciencedaily.com/releases/2003/10/031031063656.htm
Lawrence Livermore National Laboratory. "Scientists Find Evolution Of Life Helped Keep Earth Habitable." ScienceDaily. www.sciencedaily.com/releases/2003/10/031031063656.htm (accessed January 27, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Tuesday, January 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Aquaponics Turn Suburban Industrial Park Into Farmland: Hume

Aquaponics Turn Suburban Industrial Park Into Farmland: Hume

The Toronto Star (Jan. 27, 2015) — Ancient techniques of growing greens with fish and water are well ahead of Toronto bylaws. Video provided by The Toronto Star
Powered by NewsLook.com
Mexico's Volcano of Fire Erupts Again

Mexico's Volcano of Fire Erupts Again

Reuters - News Video Online (Jan. 26, 2015) — A huge plume of smoke shoots into the air as activity in Mexico&apos;s Volcano of Fire picks up again. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Time Lapse: Snow, Frost Piling Up in New York's Times Square

Time Lapse: Snow, Frost Piling Up in New York's Times Square

Reuters - US Online Video (Jan. 26, 2015) — Video shows the accumulation of snow and frost in New York City&apos;s Times Square over five hours on Monday. Time Lapse (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Researchers Put Tiny Helmets on a Hawk to Figure Out How It Targets Prey

Researchers Put Tiny Helmets on a Hawk to Figure Out How It Targets Prey

Buzz60 (Jan. 26, 2015) — A hawk wears a teeny tiny helmet to give scientists an insight into its hunting strategy. Jen Markham (@jenmarkham) explains. Video provided by Buzz60
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins