Featured Research

from universities, journals, and other organizations

Study Of Sulfides In Bacteria Casts Doubt On Evidence Of Life In Martian Meteorite ALH84001

Date:
May 12, 1998
Source:
Arizona State University
Summary:
The Martian meteorite ALH84001 gave people hope that it was evidence for extraterrestrial life because minerals found in it resembled minerals created by some unusual earthly bacteria. Now it appears that the bacteria themselves contradict that claim.

The Martian meteorite ALH84001 gave people hope that it was evidence for extraterrestrial life because minerals found in it resembled minerals created by some unusual earthly bacteria. Now it appears that the bacteria themselves contradict that claim.

In an article appearing in the May 8, 1998 issue of Science, a team led by two scientists from Arizona State University reports finding evidence for as many as three different iron sulfide minerals in two different bacteria known for generating magnetic compounds but not other iron sulfides normally found with them.

Using transmission electron microscope observations, the team, which includes ASU Geology and Chemistry/Biochemistry faculty members Mihaly Posfai and Peter R. Buseck, Iowa State University microbiologist Dennis A. Bazylinski, and California Polytechnic physicist Richard B. Frankel, found clear evidence of mackinawite and greigite and, possibly, cubic iron sulfide.

One of the iron sulfides they did not detect is pyrrhotite , a mineral that has been found in the now-famous Martian meteorite ALH84001 and that frequently occurs as a breakdown product of the other sulfides. Though pyrrhotite's presence in the meteorite has been cited as possible evidence of past Martian bacterial life, the study's evidence suggests that the bacteria may actually prevent its formation.

The study found evidence that the bacteria first produce mackinawite, a nonmagnetic iron sulfide, which then naturally converts to the magnetic greigite. It also suggests that this process may actually begin with cubic iron sulfide, which is unstable and rapidly becomes mackinawite. In the geological environment the bacteria are found in, the reaction sequence would also eventually lead to greigite breaking down into pyrite and pyrrhotite, but that reaction does not occur when the bacteria are present.

The team's research finding contradicts an earlier study that found pyrite and pyrrhotite present in the bacteria. As no subsequent study has been able to duplicate this result, the current team posits that earlier researchers may have confused cubic iron sulfide with these minerals, which give similar selected area electron diffraction patterns.


Story Source:

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


Cite This Page:

Arizona State University. "Study Of Sulfides In Bacteria Casts Doubt On Evidence Of Life In Martian Meteorite ALH84001." ScienceDaily. ScienceDaily, 12 May 1998. <www.sciencedaily.com/releases/1998/05/980512080935.htm>.
Arizona State University. (1998, May 12). Study Of Sulfides In Bacteria Casts Doubt On Evidence Of Life In Martian Meteorite ALH84001. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/1998/05/980512080935.htm
Arizona State University. "Study Of Sulfides In Bacteria Casts Doubt On Evidence Of Life In Martian Meteorite ALH84001." ScienceDaily. www.sciencedaily.com/releases/1998/05/980512080935.htm (accessed August 30, 2014).

Share This




More Health & Medicine News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3 Things To Know About The Ebola Outbreak's Progression

3 Things To Know About The Ebola Outbreak's Progression

Newsy (Aug. 29, 2014) Here are three things you need to know about the deadly Ebola outbreak's progression this week. Video provided by Newsy
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Who Could Be Burnt by WHO's E-Cigs Move?

Who Could Be Burnt by WHO's E-Cigs Move?

Reuters - Business Video Online (Aug. 28, 2014) The World Health Organisation has called for the regulation of electronic cigarettes as both tobacco and medical products. Ciara Lee looks at the impact of the move on the tobacco industry. Video provided by Reuters
Powered by NewsLook.com
CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

Newsy (Aug. 28, 2014) CDC director Tom Frieden says the Ebola outbreak is even worse than he feared. But he also said there's still hope to contain 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