Featured Research

from universities, journals, and other organizations

Martian Life? Small Percentage Of Martian Soil Samples Could Have Biological Origin

Date:
August 24, 2007
Source:
European Planetology Network
Summary:
A new interpretation of data from NASA's Viking landers indicates that 0.1% of the Martian soil tested could have a biological origin. The researchers suggest that a hydrogen peroxide-water based organism would be quite capable of surviving in the harsh Martian climate where temperatures rarely rise above freezing and can reach -150 degrees Celsius at the poles.

This image, taken by Viking 2 Lander camera 2 at Utopia Planitia, shows a thin layer of water ice frost on the martian surface. The image was taken on 18 May 1979, almost exactly one martian year (687 days) after frost first appeared at this spot and was imaged by Viking 2. The layer is thought to be only a couple thousandths of a centimeter thick. It is speculated that dust particles in the atmosphere pick up tiny bits of water. When it gets cold enough for carbon dioxide to solidify, some of it attaches to the dust and ice and it falls to the surface.
Credit: NASA

A new interpretation of data from NASA's Viking landers indicates that 0.1% of the Martian soil tested could have a biological origin.

Related Articles


Dr Joop Houtkooper of the University of Giessen, Germany, believes that the subfreezing, arid Martian surface could be home to organisms whose cells are filled with a mixture of hydrogen peroxide and water. In a presentation at the European Planetary Science Congress in Potsdam on Friday 24th August, Dr Houtkooper will describe how he has used data from the Gas Exchange (GEx) experiment, carried by NASA's Viking landers, to estimate the biomass in the Martian soil.

Dr Houtkooper said, "The GEx experiment measured unexplained rises in oxygen and carbon dioxide levels when incubating samples. If we assume these gases were produced during the breakdown of organic material together with hydrogen peroxide solution, we can calculate the masses needed to produce the volume of gas measured. From that, we can estimate the total biomass in the sample of Martian soil. It comes out at little more than one part per thousand by weight, comparable to what is found in some permafrost in Antarctica. This might be detectable by instruments on the Phoenix lander, which will arrive at Mars in May next year."

Dr Houtkooper and his colleague, Dr Schulze-Makuch from Washington State University, suggest that a hydrogen peroxide-water based organism would be quite capable of surviving in the harsh Martian climate where temperatures rarely rise above freezing and can reach -150 degrees Celsius at the poles.

A 60% solution of hydrogen peroxide has a freezing point of - 56.5 degrees Celsius, and the supercooling properties of such mixtures could mean that metabolic activity could survive at even lower temperatures. In addition, hydrogen peroxide-water solutions tend to attract water, which means that organisms could scavenge water molecules from the Martian atmosphere.

The downside of the water-scavenging biochemistry is that if the organisms were exposed to liquid water or warm atmospheres with high humidity, they could die through over hydration. In this case, the cell would break down, releasing oxygen. Any organic compounds could then react with the hydrogen peroxide, releasing carbon dioxide, water vapour and traces of nitrogen and minor constituents.

Dr Houtkooper said, "This hydrogen peroxide-water hypothesis could provide answers for several aspects of the Viking results that remain unexplained thirty years on. The concept of this type of life is also interesting for planners of future missions searching for life on Mars. With the long timescales involved in planning and launching Mars landers, there is a dire necessity to anticipate what kind of life we should expect to find and where we should be looking. Organisms with the hydrogen peroxide-water biochemistry would be more likely to be active in colder areas on Mars with high water vapour concentrations, as would be expected along the polar ice fringe. Looking further ahead, a sample return mission would mean that we could use all that present technology affords to analyse signs of life.

However, if the organisms were to have the chemistry we are proposing, they may well decompose completely into gases during the journey back to Earth, without leaving even a smudge behind."

The existence of organisms with the hydrogen peroxide-water chemistry would raise interesting questions about the origins of life on Earth. Dr Houtkooper does not think that it would necessarily imply independent origins for terrestrial and Martian life. "A detailed study of the biochemistry and genetics would be needed to determine whether the life forms were related. The transfer of terrestrial organisms to Mars or vice versa is a possibility given favorable conditions for the origin and persistence of life on both planets early in solar system history. The transfer of terrestrial organisms by early spacecrafts to Mars that either landed or crashed is a possibility, but it is not plausible that these organisms evolved in a few years."

Hydrogen peroxide is not unknown in the metabolic processes of terrestrial organisms. The Bombardier beetle, Brachinus Crepitans, uses a 25% solution of hydrogen peroxide to produce a steam explosion in the face of pursuing predators.

Dr Houtkooper said, "There does not appear to be any basic reason why hydrogen peroxide could not be used by living systems. While organisms on Earth have found it advantageous to include salt in their intracellular fluids, hydrogen peroxide may have been more suitable for organisms adapting to the cold, dry environment of Mars."

Background Information

NASA's Viking Mission to Mars was composed of two spacecraft, Viking 1 and Viking 2, each consisting of an orbiter and a lander. TheViking 1 Lander touched down on 20th July 1976, followed by the Viking 2 Lander 3rd September.

Each lander conducted four experiments intended to detect the presence of microbiological life on the Martian surface. Soil samples were retrieved by the landers' extendible arms.

The Gas Exchange Experiment (GEX) looked for changes in the makeup of gases in a test chamber, changes that would indicate biological activity.

The Labeled Release Experiment (LR) was set up to detect the uptake of a radioactively-tagged liquid nutrient by microbes and then analyse gases emitted by any microbes for signs of the tagging.

The Pyrolytic Release Experiment (PR) heated soil samples that had been exposed to radioactively-tagged carbon dioxide to see if the chemical had been used by organisms to make organic compounds.

The Gas Chromatograph -- Mass Spectrometer Experiment (GCMS) heated a soil sample and revealed an unexpected amount of water but failed to detect organic compounds.


Story Source:

The above story is based on materials provided by European Planetology Network. Note: Materials may be edited for content and length.


Cite This Page:

European Planetology Network. "Martian Life? Small Percentage Of Martian Soil Samples Could Have Biological Origin." ScienceDaily. ScienceDaily, 24 August 2007. <www.sciencedaily.com/releases/2007/08/070824122441.htm>.
European Planetology Network. (2007, August 24). Martian Life? Small Percentage Of Martian Soil Samples Could Have Biological Origin. ScienceDaily. Retrieved December 21, 2014 from www.sciencedaily.com/releases/2007/08/070824122441.htm
European Planetology Network. "Martian Life? Small Percentage Of Martian Soil Samples Could Have Biological Origin." ScienceDaily. www.sciencedaily.com/releases/2007/08/070824122441.htm (accessed December 21, 2014).

Share This


More From ScienceDaily



More Space & Time News

Sunday, December 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Spokesman: 'NORAD Ready to Track Santa'

Spokesman: 'NORAD Ready to Track Santa'

AP (Dec. 19, 2014) Pentagon spokesman Rear Adm. John Kirby said that NORAD is ready to track Santa Claus as he delivers gifts next week. Speaking tongue-in-cheek, he said if Santa drops anything off his sleigh, "we've got destroyers out there to pick them up." (Dec. 19) Video provided by AP
Powered by NewsLook.com
NASA's Planet-Finding Kepler Mission Isn't Over After All

NASA's Planet-Finding Kepler Mission Isn't Over After All

Newsy (Dec. 18, 2014) More than a year after NASA declared the Kepler spacecraft broken beyond repair, scientists have figured out how to continue getting useful data. Video provided by Newsy
Powered by NewsLook.com
Rover Finds More Clues About Possible Life On Mars

Rover Finds More Clues About Possible Life On Mars

Newsy (Dec. 17, 2014) NASA's Curiosity rover detected methane on Mars and organic compounds on the surface, but it doesn't quite prove there was life ... yet. Video provided by Newsy
Powered by NewsLook.com
Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Evidence of Life on Mars? NASA Rover Finds Methane, Organic Chemicals

Reuters - US Online Video (Dec. 16, 2014) NASA's Mars Curiosity rover finds methane in the Martian atmosphere and organic chemicals in the planet's soil, the latest hint that Mars was once suitable for microbial life. Linda So 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


Space & Time

Matter & Energy

Computers & Math

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