Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Down That Long Dusty Trail

11.12.2003


While Mars can claim some unique features - the largest volcano and the deepest canyon in the solar system - its rocky, dusty, cold landscape has yet to yield signs of the ultimate prize: life.



Three simple words - follow the water - have become the mantra of astrobiologists studying the Red Planet because the presence of water is believed to be a prerequisite for life, either past or present.

But as scientists look for evidence of water on Mars, they are faced with an underlying dilemma: Will they know life when they see it?


“Scientists’ approach to finding life is very earth-centric,” said Kenneth Nealson, holder of the USC Wrigley Chair in Environmental Sciences. “Based on what we know about life on Earth, we set the limits for where we might look on other planets.”

In a paper published in the current edition of the journal Astrobiology, Nealson - and Bruce Jakosky of the University of Colorado - speculated that a microbe that exists in the coldest temperatures on Earth might provide clues about how a similar organism could survive beneath the Martian polar ice caps.

The microbe in question was discovered by Corien Bakersman, a postdoctoral student in Nealson’s lab, and remains the only one of its kind. It was isolated from a cryopeg - a small, salty, liquid lake found under the Siberian permafrost.

The bacteria, named Psychrobacter cryopegella, can grow at -10 Celsius and can stay alive and even keep metabolizing at an astonishing -20 Celsius While it isn’t able to replicate itself at that extreme temperature, it maintains the minimal metabolism needed to repair and maintain its cell structures.

“This organism can exist at colder temperatures than any previously discovered,” said Nealson, a professor of earth sciences and biological sciences in the USC College of Letters, Arts and Sciences.

“We know it’s possible here, so certainly it’s possible somewhere else. This bacteria expands the limits of life, so if you can find places on Mars that are minus 20 degrees centigrade, you should take a look.”

Nealson and Jakosky looked to the Martian polar regions for a habitat similar to the one in which cryopegella survives.

While temperatures at Mars’ equatorial and mid-latitudes regularly rise above -20 Celsius, it is unlikely that there is liquid water there because of its potential to be absorbed into the atmosphere, Nealson said.

But, liquid water could be found under the frozen polar caps, he added.

Climate changes on Mars, as with all of the nine planets that orbit the sun, are tied to its obliquity, or tilt of its axis with respect to its orbital plane.

Nealson and his colleagues proposed that as the Red Planet tilted - exposing more of itself to the sun at various times in its history - temperatures at the polar ice caps were warmed to minus -20 Celsius or higher.

“If the ice at the polar caps warmed to liquid water, organisms like cryopegella could have awakened and repaired any damage that might have occurred to their various cellular components,” Nealson said.

“Then, as the obliquity changed a few million years later and the planet got colder and colder, these organisms would have been the last survivors.”

But, he added, “I would never say, ‘Go and look for this bacteria.’ I would say, ‘This is a habitat that we should look at on Mars because on Earth, similar habitats have life.’”

The paper’s other contributors were USC’s Corien Bakerman and the University of Colorado’s Ruth Ley and Michael Mellon.

Usha Sutliff | USC News Service
Further information:
http://www.usc.edu/uscnews/story.php?id=9590

More articles from Life Sciences:

nachricht Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System

nachricht Biochemical 'fingerprints' reveal diabetes progression
22.08.2017 | Umea University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

Cholesterol-lowering drugs may fight infectious disease

22.08.2017 | Health and Medicine

Meter-sized single-crystal graphene growth becomes possible

22.08.2017 | Materials Sciences

Repairing damaged hearts with self-healing heart cells

22.08.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>