Featured Research

from universities, journals, and other organizations

Tracking Ancient Earth's Oxygen Levels Provides Backdrop For Evolution

Date:
October 25, 2004
Source:
University Of Missouri-Columbia
Summary:
On the ancient Earth, acquiring enough ocean sulfate measurements to accurately define the ecological conditions during evolution has been a serious challenge. Now, a novel method for extracting sulfate from ancient rocks has enabled a research team including University of Missouri-Columbia geological science professor Tim Lyons to uncover new evidence for sulfate levels in prehistoric oceans.

Geologists have long considered sulfate, a common salt dissolved in seawater, as the key to determining how and when life evolved. On the ancient Earth, acquiring enough ocean sulfate measurements to accurately define the ecological conditions during evolution has been a serious challenge. Now, a novel method for extracting sulfate from ancient rocks has enabled a research team including University of Missouri-Columbia geological science professor Tim Lyons to uncover new evidence for sulfate levels in prehistoric oceans.

Lyons and his collaborators, whose findings are published in the scientific journal Nature, say their results are important because the amount of sulfate in seawater tracks the amount of oxygen present at that same time. Scientists want to know when and how fast oxygen accumulated in the prehistoric oceans and atmosphere because many forms of life on Earth, particularly multicellular organisms, could not flourish without it.

In their report, Lyons and his colleagues say they were able to confirm a prior suspicion that the rise in ocean sulfate levels, and therefore the oxygenation of the atmosphere, was a protracted process that extended 1 billion to 2 billion years after the first accumulation of oxygen in the atmosphere 2.3 billion years ago. The new estimates suggest that during the time period from roughly 2.3 billion to 1.2 billion years ago, the amount of sulfate grew from less than 1 percent to no more than 15 percent of today's value.

"If the increase in oceanic sulfate and atmospheric oxygen indeed extended over more than a billion years, that undoubtedly affected how and when many forms of life evolved," Lyons said.

The researchers conducted their research by analyzing 1.7 billion-year-old and 1.2 billion-year-old ocean sediments. Some of the measurements came from gypsum, a sulfate-containing mineral, from the arctic region of Canada. They also extracted sulfate from ancient limestone, which is more abundant than gypsum, using a method they helped pioneer.

To estimate levels of sulfate in ancient seawater, the team first measured the ratio of sulfur isotopes within the sulfate. Isotopes are atoms of the same element with different numbers of neutrons in their nucleus. In recent times, the isotopic composition of sulfate has varied little, which is consistent with the high concentrations of sulfate in modern seawater.

“We saw something really different,” Lyons said. “We saw very rapid isotopic variability, which suggests there wasn't much sulfate in the early ocean and that oxygen in the atmosphere remained comparatively low for more than 80 percent of Earth's history."

Joining Lyons in the research were Linda Kah from the University of Tennessee-Knoxville and Tracy Frank of the University of Nebraska.


Story Source:

The above story is based on materials provided by University Of Missouri-Columbia. Note: Materials may be edited for content and length.


Cite This Page:

University Of Missouri-Columbia. "Tracking Ancient Earth's Oxygen Levels Provides Backdrop For Evolution." ScienceDaily. ScienceDaily, 25 October 2004. <www.sciencedaily.com/releases/2004/10/041025115640.htm>.
University Of Missouri-Columbia. (2004, October 25). Tracking Ancient Earth's Oxygen Levels Provides Backdrop For Evolution. ScienceDaily. Retrieved August 22, 2014 from www.sciencedaily.com/releases/2004/10/041025115640.htm
University Of Missouri-Columbia. "Tracking Ancient Earth's Oxygen Levels Provides Backdrop For Evolution." ScienceDaily. www.sciencedaily.com/releases/2004/10/041025115640.htm (accessed August 22, 2014).

Share This




More Fossils & Ruins News

Friday, August 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Neanderthals Probably Died Out Earlier Than We Thought

Neanderthals Probably Died Out Earlier Than We Thought

Newsy (Aug. 21, 2014) — A new study is packed with interesting Neanderthal-related findings, including a "definitive answer" to when they went extinct. Video provided by Newsy
Powered by NewsLook.com
Disquieting Times for Malaysia's 'fish Listeners'

Disquieting Times for Malaysia's 'fish Listeners'

AFP (Aug. 19, 2014) — Malaysia's last "fish listeners" -- practitioners of a dying local art of listening underwater to locate their quarry -- try to keep the ancient technique alive in the face of industrial trawling and the depletion of stocks. Duration: 02:29 Video provided by AFP
Powered by NewsLook.com
Mother And Son Find Woolly Mammoth Tusks 22 Years Apart

Mother And Son Find Woolly Mammoth Tusks 22 Years Apart

Newsy (Aug. 15, 2014) — A mother and son in Alaska uncovered woolly mammoth tusks in the same river more than two decades apart. Video provided by Newsy
Powered by NewsLook.com
Fossils Reveal Ancient Flying Reptile With 'Butterfly Head'

Fossils Reveal Ancient Flying Reptile With 'Butterfly Head'

Newsy (Aug. 14, 2014) — Newly found fossils reveal a previously unknown species of flying reptile with a really weird head, which some say looks like a butterfly. Video provided by Newsy
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:
from the past week

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