Featured Research

from universities, journals, and other organizations

NASA Scientists Confirm Toxic Seas During Earth's Evolution

Date:
October 10, 2005
Source:
National Aeronautics And Space Administration
Summary:
NASA exobiology researchers confirmed Earth's oceans were once rich in sulfides that would prevent advanced life forms, such as fish and mammals, from thriving. A team of scientists from the Massachusetts Institute of Technology and Harvard University, working with colleagues from Australia and the United Kingdom, analyzed the fossilized remains of photosynthetic pigments preserved in 1.6 billion-year-old rocks from the McArthur Basin in Northern Australia. They found evidence of photosynthetic bacteria that require sulfides and sunlight to live.

1.65 GaKombolgie Formation deposited by a braided river system that was probably syndepositional with the Barney Creek Formation and possibly feeding into the sea of the McArthur Basin (Photo: Jochen J. Brocks, 12 August 2003, Bardedjilidjiin Kakadu National Park, northern Australia).

NASA exobiology researchers confirmed Earth's oceans were once richin sulfides that would prevent advanced life forms, such as fish andmammals, from thriving. The research was funded in part by NASA'sexobiology program.

A team of scientists from the Massachusetts Institute of Technologyand Harvard University, working with colleagues from Australia and theUnited Kingdom, analyzed the fossilized remains of photosyntheticpigments preserved in 1.6 billion-year-old rocks from the McArthurBasin in Northern Australia.

They found evidence of photosynthetic bacteria that require sulfidesand sunlight to live. Known as purple and green sulfur bacteria becauseof their respective pigment colorations, these single-celled microbescan only live in environments where they simultaneously have access tosulfides and sunlight.

The researchers also found very low amounts of the fossilizedremains of algae and oxygen-producing cyanobacteria. The relativescarcity of these organisms is due to poisoning by large amounts ofsulfide.

"This work suggests Earth's oceans may have been hostile to animaland plant life until relatively recently," said Dr. Carl Pilcher,NASA's senior scientist for astrobiology. "If so, this would haveprofound implications for the evolution of modern life."

"The discovery of the fossilized pigments of purple sulfur bacteriais totally new and unexpected. Because they need fairly high intensitysunlight, it means the pink bacteria, along with their essential sourceof sulfide, close to the surface, perhaps as close as 20 to 40 meters,"said Roger Summons, Massachusetts Institute of Technology professor ofgeobiology. "The sulfide would have come from bacteria that reducessulfate carried into the oceans by the weathering of rocks."

"The McArthur Basin rocks were deposited over a very large area andover many millions of years, so it's likely they formed under waterthat was intermittently connected to or actually part of an ocean. Inturn, this implies the ocean had an abundant and continuous supply ofhydrogen sulfide and must have been quite toxic to any oxygen-breathingorganisms," said team member Jochen Brocks. "In fact, for seven-eighthsof Earth's 4.5 billion-year history, there was probably little oxygenin the oceans and certainly not enough to support oxygen-breathingmarine animals."

This research continued the efforts of NASA and partner institutionsto understand the early history of the Earth. Research results werepublished in the Oct. 6, 2005, edition of Nature magazine.

The research was conducted by a team working in Summons' laboratory.Team members include Jochen Brocks, formerly of Harvard and now atAustralian National University; Gordon Love, Massachusetts Institute ofTechnology; Stephen Bowden, University of Aberdeen, Scotland; GrahamLogan, Geoscience Australia; and Andrew Knoll, Harvard.

For electronic images and more information about this research on the Web, visit:

http://eaps.mit.edu/geobiology/research/Ancient_bacteria.htmlFor more information about NASA's astrobiology program on the Web, visit:

http://www.astrobiology.arc.nasa.govFor more information about NASA and agency programs on the Web visit:

http://www.nasa.gov/home


Story Source:

The above story is based on materials provided by National Aeronautics And Space Administration. Note: Materials may be edited for content and length.


Cite This Page:

National Aeronautics And Space Administration. "NASA Scientists Confirm Toxic Seas During Earth's Evolution." ScienceDaily. ScienceDaily, 10 October 2005. <www.sciencedaily.com/releases/2005/10/051010095336.htm>.
National Aeronautics And Space Administration. (2005, October 10). NASA Scientists Confirm Toxic Seas During Earth's Evolution. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2005/10/051010095336.htm
National Aeronautics And Space Administration. "NASA Scientists Confirm Toxic Seas During Earth's Evolution." ScienceDaily. www.sciencedaily.com/releases/2005/10/051010095336.htm (accessed September 16, 2014).

Share This



More Earth & Climate News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Researchers Explore Shipwrecks Off Calif. Coast

Researchers Explore Shipwrecks Off Calif. Coast

AP (Sep. 16, 2014) Federal researchers are exploring more than a dozen underwater sites where they believe ships sank in the treacherous waters west of San Francisco in the decades following the Gold Rush. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Isolated N. Korea Asks For International Help With Volcano

Isolated N. Korea Asks For International Help With Volcano

Newsy (Sep. 16, 2014) Mount Paektu volcano in North Korea is showing signs of life and there's not much known about it. 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