Subscribe free to our newsletters via your
. 24/7 Space News .

Lifting The Ceiling On Terran Lifeforms
by Michael Schirber for Astrobiology Magazine
Moffett Field CA (SPX) Nov 20, 2012

illustration only

The parachuting thrill-seeker Felix Baumgartner is not the only living thing to plunge through the jet stream.

Recent studies have confirmed that microbes exist in the stratosphere, the atmospheric region between about 18 and 50 kilometers in altitude. (Baumgartner leaped into history from 39 kilometers up.)

Biologists had once thought this zone was uninhabitable due to its low pressure, high radiation and absence of water and nutrients.

"Life surviving at high altitudes challenges our notion of the biosphere boundary," says David Smith of the University of Washington in Seattle.

Smith is trying to take a more complete census of life in the stratosphere using mountain-top observatories and high-altitude balloons (although he admits being jealous of the lift capacity of Baumgartner's balloon).

With funding from the NASA Astrobiology Institute, he and his colleagues hope to say where these high-flyers come from, where they are going and what their evolutionary trajectory has been.

The research should provide insights into a class of hardy microorganisms that can survive at the fringes of what we Earthlings consider habitable, both here and elsewhere.

"The stratosphere is very similar to the surface of Mars," Smith says. "There is no better place on our planet to match martian conditions, except inside environmental chambers."

The life forms adapted to sailing the high winds of Earth may give scientists clues on what to look for in the soils of Mars.

A hint of life in the air
Reports of life in the upper atmosphere go back as far as the 1930s. Studies conducted on samples collected in high-altitude balloon and rocket flights claimed to find microbes as high as 77 kilometers, but it's uncertain whether the bugs really came from high up, or were the result of surface contamination.

"I am skeptical of the pioneering flights," Smith says. "Almost no controls for sterilization are reported in the papers."

Getting reliable samples from the upper atmosphere is difficult and expensive. Researchers must process huge volumes of air to catch a single microbe, since the estimated concentrations are only a few microbes per cubic meter.

Smith believes the first solid evidence of life in the stratosphere was a 2002 balloon study, which collected viable cells at altitudes between 20 and 41 kilometers above tropical India.

How microbes reach high altitudes is not entirely clear. A small group of researchers contend that the microbes could be coming down from space.

But the organisms are more plausibly swept up in dust storms, hurricanes or other weather patterns, Smith says. Some microbes may even make the trip onboard commercial air planes flying in the lower stratosphere.

Born to spore
The observed microbes do not appear to be actively growing at high altitude.

"Our best picture is that microbes are simply enduring the upper atmosphere," Smith says. "They are hitching a ride on prevailing winds until landing in a distant environment, sometime later."

Many of these globetrotters are spore-forming bacteria. When placed under stress, these bacteria shut down their metabolism and shrink down in size. They form a hard shell-like shield around their exterior, while turning on internal defense mechanisms against UV damage to DNA.

"One could argue that the spore is an adaptation that evolved, in part, because of airborne transport," Smith says.

If a spore can land in a hospitable environment (and if it hasn't been damaged during its high-altitude voyage), it can reanimate itself. Researchers have typically relied on this reanimation to identify the organisms that use air travel. They place atmospheric samples in a nutrient-filled petri dish and then see what grows.

Smith thinks these "search and revive" missions have only scratched the surface of what is up there. "Only about 1% of microorganisms can actually be cultured in the laboratory," he says.

To see the beyond these one-percenters, Smith and his colleagues have begun using molecular-based techniques to identify biological material (both living and dead).

Their atmospheric samples come from a "laboratory in the sky" at Mt. Bachelor Observatory in central Oregon, which rises 2.7 kilometers above sea level.

Smith says this altitude gives them reliable access to the upper troposphere, which is just below the stratosphere.

Instead of trying to grow organisms in a petri dish, Smith and his colleagues extract DNA that they can match to a genomic library containing 60,000 microbial taxa. Preliminary results have shown microbes from every major domain of life can be found in the upper troposphere.

Jet stream feeds gene pool?
The data from Mt. Bachelor will improve estimates of the concentration of microbes in the upper atmosphere. It should also give the first long-term observations on how microbial counts vary with season and other weather patterns.

In order to sample higher altitudes, Smith is also working on a balloon mission with engineers from NASA Kennedy Space Center, called MIST (Microorganisms in the Stratosphere).

"We still have no idea where to draw the altitude boundary of the biosphere," Smith says. Experiments like MIST will "address how long life can potentially remain in the stratosphere and what sorts of mutations it may inherit while aloft."

Those mutations could potentially act like tiny "seeds" that fall down randomly over the face of Earth and potentially take root in a favorable environment.

"It is conceivable (though difficult to prove) that the evolution of complex life on our planet is owed, in part, due to airborne transport," Smith says.


Related Links
Astrobiology Magazine
Life Beyond Earth
Lands Beyond Beyond - extra solar planets - news and science

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

NASA Innovator of Year Hunts for Extraterrestrial Amino Acids
Greenbelt, MD (SPX) Nov 20, 2012
The hunt for the organic molecules that create proteins and enzymes critical for life here on Earth has largely happened in sophisticated terrestrial laboratories equipped with high-tech gadgetry needed to tease out their presence in space rocks and other extraterrestrial samples. A technologist at NASA's Goddard Space Flight Center in Greenbelt, Md., now wants to take that search to the s ... read more

China's Chang'e-3 to land on moon next year

Moon crater yields impact clues

Study: Moon basin formed by giant impact

NASA's LADEE Spacecraft Gets Final Science Instrument Installed

Martian And Terran History Finding a common denominator

Meteorites reveal warm water existed on Mars

NASA Rover Providing New Weather and Radiation Data About Mars

CU LASP package ready for MAVEN integration bound for Mars

NASA Selects Information Technology Flight Operations Support Contract

SciTechTalk: All work and no play?

Get some bed rest - all 21 days of it

Latest China military hardware displayed at airshow

Mr Xi in Space

China plans manned space launch in 2013: state media

China to launch manned spacecraft

Tiangong 1 Parked And Waiting As Shenzhou 10 Mission Prep Continues

Three ISS crew return to Earth in Russian capsule

Station Crew Off Duty After Undocking

Space station command changes

Russia restores space contact after cable rupture

France, Germany seek Ariane compromise at ESA space meet

ILS Launches the EchoStar XVI Satellite

Arianespace's fourth Spaceport mission with Soyuz ready for fueling

Ariane 5's sixth launch of 2012

Rare image of Super-Jupiter sheds light on planet formation

Astronomers Directly Image Massive Star's 'Super-Jupiter'

NASA's Kepler Wraps Prime Mission, Begins Extension

Lowell astronomer, collaborators point the way for exoplanet search

Bug repellent for supercomputers proves effective

Keeneland Project Deploys New GPU Supercomputing System for the National Science Foundation

Lockheed Martin Expands Range Of Cloud Computing Services for UK Government

Invisibility cloaking to shield floating objects from waves

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement