High-altitude microbes

by Maddie Duhon

Noelle Bryan spends her days exploring the microbial life in the upper limits of the biosphere right from the Life Sciences Building at Louisiana State University. Through a maze of hallways on the second floor, “Modes of Adaptation, Resistance, and Survival for Life Inhabiting a Freeze-dried-radiation-bathed Environment,” otherwise known as the MARSLIFE project, is providing insight to a question our entire world wonders – is there life beyond Earth?

More than 80% of the Earth’s biosphere (by volume) is permanently below five Celsius (41 Fahrenheit) and most of the biomass is microbial. Very little is known about the biology of microorganisms inhabiting these permanently cold environments.

Bryan, a graduate student researcher working on her PhD in Biological Sciences, and her team’s research efforts are contributing to fill this knowledge gap through laboratory- and field-based projects aimed at understanding the nature and the biogeochemical contributions of microbial life in environments below polar ice sheets and in the high atmosphere.

MARSLIFE is investigating microorganisms with tolerances to cold, desiccation, and radiation as models for astrobiology by using laboratory simulators to assess responses to temperature, pressure, and radiation conditions that exist in a range of extraterrestrial environments. This data will improve technologies for the detection and sampling of microorganisms under conditions similar to the surface of Mars.

According to the project’s website, bacteria have been widely documented in the troposphere and bacteria and fungi at altitudes as high as 65,616 feet (20 km) and first recorded over 80 years ago. MARSLIFE’s sampling in the stratosphere will provide information on organism’s ability to survive in extreme environments.

Environmental conditions (pressure, temperature, and radiation levels) at an altitude of about 100,000 ft (30 km) are similar to the conditions on the surface of Mars. Finding viable organisms in the stratosphere will provide insight to the possibility of life beyond Earth.

“This project with high-altitude microbes is something no one else is really doing,” said Bryan. “This makes a tricky situation because no one has said this before. We are very careful with our results because you have to show people you did it the right way. Our audience of scientists is prone to question everything. It’s not hard to tell people there are bacteria 10 feet off the ground. It’s when you have to tell them you found it 100,000 feet up. It’s there! It’s alive! You better be sure you know what you’re talking about. It’s a tough sell.”

On Monday, September 22, Bryan began her day with a few mathematical equations before setting up a survival experiment. She wants to know how high can these captured microbes can get before perishing in the freezing cold temperatures of high-altitude regions, where there is no food, no water, low pressure, and they receive constant blasts of ultra-violet light. Another question Bryan ponders is are these microbes surviving for weeks at these altitudes, or did they happen to catch the microbes at the perfect moment?

Bryan, a University of Louisiana at Monroe alumna, spent six years teaching junior high and high school science classes. She loved anything microbe-related, describing the fact that how bacteria run every process from the carbon cycle to the precipitation cycles as “the coolest thing.”

Although she had a stable career in the teaching field, she was unhappy. When she began to think about graduate school, her first thought was “how do I do this?”

“I was scared because I didn’t have a biology degree and basically wanted to switch careers,” said Bryan. “At LSU, people were the most helpful. The doors were open here. I had a secure teaching job, which I quit to become a student again!”

“Once I found this project it was a no brainer,” said Bryan. “I am surrounded by my leaders in this field. An expert on tough bugs is upstairs doing survival experiments. If I have a question, I have the direct source.”

These “bugs,” as Bryan affectionately calls them, were previously collected from 500 feet off the ground to 125,000 feet into the atmosphere with helium-filled balloons.


Can’t imagine 125k ft into the atmosphere? This photo was taken at approximately 100k ft (30k m) above Oregon with a weather balloon. (Source: http://en.wikipedia.org/wiki/High-altitude_balloon)

The subjects were then separated into two groups, which determined their torture. One group was desiccated; the other desiccated AND blasted with UV.

When grown in cultures, smooth colonies range in color from red to pink.

When grown in cultures, smooth colonies range in color from red to pink. Photo by Maddie Duhon

Deinococcus radioduran has been deemed the “toughest bacterium in the world.” (source) Not only can this “bug” withstand extreme amounts of ultra-violet radiation (radiation blasts up to 1000 times greater than a human), it can survive drought conditions of up to six weeks without water and grow in nutrient poor environments. This berry-shaped bacterium is the perfect constant for Bryan’s experiment.

Bryan started this one experiment at 8 p.m. the night before, looking at cultures in the bath shaker.

E. Coli, one of the variables, grows quickly, and was already visible in the cloudy mixture.

E. Coli, one of the variables, grows quickly, and was already visible in the cloudy mixture. Photo by Maddie Duhon

After removing the test tubes from the shaker, the volumes were concentrated into small plastic vials to make them easier to work with.

These little containers were placed into a “shaker” for ten minutes to create a “pellet” at the tip. This shaker is formally known as the Hermle Z180M, a machine that allows the centrifugation of these micro-samples.


Close-up of the variables. Photo by Maddie Duhon

The media the bugs were growing in was dumped out so there no food was left for them. They were re-spun and washed again to make 100% of any food left was gone.

Hear more about their torture –

“You have to be really organized and thorough,” said Bryan. “There are potential mistakes in prep because it is a lot of intricate small steps.”

To prevent mistakes, Bryan has written out step-by-step instructions in her lab notebook, which took two to three years to perfect and is something Bryan “cannot live without.”

Steps 1-6 took more than 1.5 hours.

Steps 1-6 took more than 1.5 hours. Photo by Maddie Duhon

This experiment is still in trial period right now, which according to Bryan is “hard to get used to because I want the answer now, but I have to run the experiment over and over again. It’s fun because all of a sudden you get an answer.”

Another plus of this research is that it allows undergraduate students the opportunity to work in a laboratory. A freshman spends a semester with a graduate student, learning how to make plates and set up experiments. Once they have the skills to do so, they get their own project and do research.

Not only does Bryan manage this experiment, she acts as a mentor for future scientists.

This project has been going on for a few years, and Bryan’s thesis is nearing the end. However, her interest in high-altitude microbes isn’t.


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