Featured Research

from universities, journals, and other organizations

Oxygen Theory Of Mass Extinction Questioned By New Research Findings

Date:
September 10, 2008
Source:
Dublin, University College
Summary:
Several theories have been proposed by scientists to explain the two mass extinction events which took place on the earth 250 and 200 million years ago. The Permian-Triassic catastrophe (250 million years ago) was the worst of all five of the mass extinction events to ever have befallen the earth. It eradicated almost 95% of all species, 53% of marine families, 84% of marine genera and an approximated 70% of all land species including plants, insects and vertebrate animals.

Several theories have been proposed by scientists to explain the two mass extinction events which took place on the earth 250 and 200 million years ago.

The Permian-Triassic catastrophe (250 million years ago) was the worst of all five of the mass extinction events to ever have befallen the earth. It eradicated almost 95% of all species, 53% of marine families, 84% of marine genera and an approximated 70% of all land species including plants, insects and vertebrate animals.

Many scientists suspect that the event was the result of a comet or an asteroid colliding with the earth. Others believe that flood volcanism from the Siberian Traps and the associated oxygen loss in the seas was the cause. While others continue to investigate the possibility that thinning levels of atmospheric oxygen caused the eradication of so many species at the time.

But new research findings by University College Dublin scientists published in Science question the theory of falling oxygen levels as a mechanism for causing the mass extinction events.

To assess the likely atmospheric oxygen levels at the time of the mass extinction events, using purposefully designed walk-in-plant-growth rooms equipped with thermal imaging system and full atmospheric, temperature and humidity control, Dr Claire Belcher and her University College Dublin colleagues spent several months measuring the lower limits of oxygen at which combustion can occur.

When the measurements were recorded, they compared their results with the charcoal in the fossil record from ancient times because the charcoal that remains in the fossil record reveals the presence of ancient wildfires which require a sufficient level of oxygen in the air for plants to burn.

“By performing experimental burns using pine wood, moss, matches, paper and a candle at 20C in varying ranges of oxygen concentrations and comparing these results to the occurrences of fossil charcoal throughout the Mesozoic (250-65 million years ago), we were able to identify that prolonged periods of low oxygen are unlikely to have occurred,” says Dr Claire Belcher from the School of Biology and Environmental Science, University College Dublin, the lead author of the report.

“Low oxygen atmospheres, less than 12%, are considered to be the primary driver of at least two of the ‘big five’ mass-extinction events,” explains Dr Belcher. “But our research findings question that hypothesis and highlight the need for more detailed studies of fossil charcoal across these mass extinction events.”

This is the first time that research to identify the lower limit of atmospheric oxygen under which combustion can occur have been conducted within fully controlled and realistic environments. The six walk-in chambers at University College Dublin, funded by EU Marie Curie, enable the realistic reconstruction of environmental conditions from the past.


Story Source:

The above story is based on materials provided by Dublin, University College. Note: Materials may be edited for content and length.


Cite This Page:

Dublin, University College. "Oxygen Theory Of Mass Extinction Questioned By New Research Findings." ScienceDaily. ScienceDaily, 10 September 2008. <www.sciencedaily.com/releases/2008/09/080908073751.htm>.
Dublin, University College. (2008, September 10). Oxygen Theory Of Mass Extinction Questioned By New Research Findings. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2008/09/080908073751.htm
Dublin, University College. "Oxygen Theory Of Mass Extinction Questioned By New Research Findings." ScienceDaily. www.sciencedaily.com/releases/2008/09/080908073751.htm (accessed September 30, 2014).

Share This



More Plants & Animals News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

California University Designs Sustainable Winery

California University Designs Sustainable Winery

Reuters - US Online Video (Sep. 27, 2014) Amid California's worst drought in decades, scientists at UC Davis design a sustainable winery that includes a water recycling system. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com
Argentina Worries Over Decline of Soybean Prices

Argentina Worries Over Decline of Soybean Prices

AFP (Sep. 27, 2014) The drop in price of soy on the international market is a cause for concern in Argentina, as soybean exports are a major source of income for Latin America's third largest economy. Duration: 01:10 Video provided by AFP
Powered by NewsLook.com
Mama Bear, Cubs Hang out in California Backyard

Mama Bear, Cubs Hang out in California Backyard

Reuters - US Online Video (Sep. 27, 2014) A mama bear and her two cubs climb trees, wrestle and take naps in the backyard of a Monrovia, California home. Vanessa Johnston reports. Video provided by Reuters
Powered by NewsLook.com
'Crazy' Climate Forces Colombian Farmers to Adapt

'Crazy' Climate Forces Colombian Farmers to Adapt

AFP (Sep. 26, 2014) Once upon a time, farming was a blissfully low-tech business on Colombia's northern plains. Duration: 02:05 Video provided by AFP
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