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.

Related Articles


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 April 1, 2015 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 April 1, 2015).

Share This


More From ScienceDaily



More Health & Medicine News

Wednesday, April 1, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

7-Year-Old Girl Gets 3-D Printed 'robohand'

7-Year-Old Girl Gets 3-D Printed 'robohand'

AP (Mar. 31, 2015) — Although she never had much interest in prosthetic limbs before, Faith Lennox couldn&apos;t wait to slip on her new robohand. The 7-year-old, who lost part of her left arm when she was a baby, grabbed it as soon as it came off a 3-D printer. (March 31) Video provided by AP
Powered by NewsLook.com
Solitair Device Aims to Takes Guesswork out of Sun Safety

Solitair Device Aims to Takes Guesswork out of Sun Safety

Reuters - Innovations Video Online (Mar. 31, 2015) — The Solitair device aims to take the confusion out of how much sunlight we should expose our skin to. Small enough to be worn as a tie or hair clip, it monitors the user&apos;s sun exposure by taking into account their skin pigment, location and schedule. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Soda, Salt and Sugar: The Next Generation of Taxes

Soda, Salt and Sugar: The Next Generation of Taxes

Washington Post (Mar. 30, 2015) — Denisa Livingston, a health advocate for the Dinι Community Advocacy Alliance, and the Post&apos;s Abby Phillip discuss efforts around the country to make unhealthy food choices hurt your wallet as much as your waistline. Video provided by Washington Post
Powered by NewsLook.com
UnitedHealth Buys Catamaran

UnitedHealth Buys Catamaran

Reuters - Business Video Online (Mar. 30, 2015) — The $12.8 billion merger will combine the U.S.&apos; third and fourth largest pharmacy benefit managers. Analysts say smaller PBMs could also merge. Fred Katayama reports. Video provided by Reuters
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

 

Health & Medicine

Mind & Brain

Living & Well

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