Science News
from research organizations

Ancient soils reveal clues to early life on Earth

Date:
September 25, 2013
Source:
University of British Columbia
Summary:
Oxygen appeared in the atmosphere up to 700 million years earlier than we previously thought, according to new research, raising new questions about the evolution of early life.
Share:
       
FULL STORY

Some of the rocks that Crowe and his colleagues studied.
Credit: Nic Beukes

Oxygen appeared in the atmosphere up to 700 million years earlier than we previously thought, according to research published today in the journal Nature, raising new questions about the evolution of early life.

Researchers from the University of Copenhagen and University of British Columbia examined the chemical composition of three-billion-year-old soils from South Africa -- the oldest soils on Earth -- and found evidence for low concentrations of atmospheric oxygen. Previous research indicated that oxygen began accumulating in the atmosphere only about 2.3 billion years ago during a dynamic period in Earth's history referred to as the Great Oxygenation Event.

"We've always known that oxygen production by photosynthesis led to the eventual oxygenation of the atmosphere and the evolution of aerobic life," says Sean Crowe, co-lead author of the study and an assistant professor in the Departments of Microbiology and Immunology, and Earth, Ocean and Atmospheric Sciences at UBC.

"This study now suggests that the process began very early in Earth's history, supporting a much greater antiquity for oxygen producing photosynthesis and aerobic life," says Crowe, who conducted the research while a post-doctoral fellow at Nordic Center for Earth Evolution at the University of Southern Denmark in partnership with the centre's director Donald Canfield.

There was no oxygen in the atmosphere for at least hundreds of millions of years after Earth formed. Today, Earth's atmosphere is 20 per cent oxygen thanks to photosynthetic bacteria that, like trees and other plants, consume carbon dioxide and release oxygen. The bacteria laid the foundation for oxygen breathing organisms to evolve and inhabit the planet.

"These findings imply that it took a very long time for geological and biological processes to conspire and produce the oxygen rich atmosphere we now enjoy," says Lasse Døssing, the other lead scientist on the study, from the University of Copenhagen.


Story Source:

The above post is reprinted from materials provided by University of British Columbia. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sean A. Crowe, Lasse N. Døssing, Nicolas J. Beukes, Michael Bau, Stephanus J. Kruger, Robert Frei, Donald E. Canfield. Atmospheric oxygenation three billion years ago. Nature, 2013; 501 (7468): 535 DOI: 10.1038/nature12426

Cite This Page:

University of British Columbia. "Ancient soils reveal clues to early life on Earth." ScienceDaily. ScienceDaily, 25 September 2013. <www.sciencedaily.com/releases/2013/09/130925132317.htm>.
University of British Columbia. (2013, September 25). Ancient soils reveal clues to early life on Earth. ScienceDaily. Retrieved July 1, 2015 from www.sciencedaily.com/releases/2013/09/130925132317.htm
University of British Columbia. "Ancient soils reveal clues to early life on Earth." ScienceDaily. www.sciencedaily.com/releases/2013/09/130925132317.htm (accessed July 1, 2015).

Share This Page: