Imagine looking at the sky, and being able to see nearly 20 miles up a balloon carrying a small device with tiny sticky rods inside and an LSU Tiger Eye adorning its outside. With this device, MARSLIFE researchers including LSU Biological Sciences PhD student Noelle Bryan and her advisor Brent Christner, currently an adjunct faculty member in the LSU Biological Sciences department and a research professor at University of Florida, hope to capture and map out the bacteria that live from the level of your feet up to the stratosphere.
“We wanted to find organisms that we could culture in the lab to use as our lab-rats for Mars simulation experiments,” Noelle said. “If you have the toolkit to be alive at 36 kilometers above the Earth, where you have the same temperatures, pressures, relative humidity and UV radiation levels that you would experience on the surface of Mars, then you have everything you would need to survive in that situation.”
Noelle is a researcher on the MARSLIFE project: Modes of Adaptation, Resistance, and Survival for Life Inhabiting a Freeze-dried-radiation-bathed Environment. Noelle and the MARSLIFE team, including LSU Physics & Astronomy Professor T. Gregory Guzik and researcher Michael Stewart, collect and characterize microorganisms from the troposphere and the stratosphere, or the almost-space regions at altitudes reaching 30 miles above Earth. The project was funded through the NASA Experimental Program to Stimulate Competitive Research (EPSCoR) and the Louisiana Board of Regents.
From an office made colorful with plush toys in the shape of bacteria, water bears and other microorganisms, Noelle walks into a laboratory busy with the sound of shaking glassware. She picks up two large cone-shaped flasks and inspects cloudy pink and orange liquids in their bottoms.
“I grow up volumes of these bacteria,” Noelle said. “These were recovered from about 30 kilometers over Texas and New Mexico. You can see that they are pigmented. This pink one is actually named Roseomonas,” she said, pointing to the flask with the pink liquid. “All of my bugs are pigmented. Yellows, oranges and pinks. These pigments can actually act as sunscreens. When you are above the ozone layer and you are getting blasted with UV radiation, the fact that you are highly pigmented might be an advantage. That’s one of the things that we are trying to determine.”
The MARSLIFE project uses a high-altitude balloon and automated mechanical device system to capture bacteria from the stratosphere using small sticky rods. The team has collected bacteria from Louisiana, Texas and New Mexico.
“Designing a lightweight and sealed container, from a microbiology standpoint, to fly on a small latex sounding balloon was quite an achievement,” said Stewart, a MARSLIFE project manager and researcher in the LSU Physics and Astronomy department. “The most challenging aspects of the experiment was to develop a system that worked exactly as the requirements specified in such an extreme environment and to know that it worked as designed.”
A group of undergraduate students in the LSU Physics and Astronomy department and in the LSU Biological Sciences department, under the direction of T. Gregory Guzik, Michael Stewart and Doug Granger, helped design and develop the high-altitude balloon system for microbe retrieval from the stratosphere. The group described the system in 2014 in the Journal of Microbiological Methods. The helium-filled balloon vehicle, while it can’t reach “outer space,” can rise 1,000 feet per minute up to a height of 100,000 feet.
Once the balloon system captures a sample of microorganisms in the stratosphere, the researchers signal for the balloon to be cut away and the payload returns to Earth on a parachute. Noelle then isolates and cultures any bacteria brought back down. She then puts them to the test, to see how long they can survive when frozen, dried and blasted with UV radiation, the kind that can give you a nasty sunburn and even damage your DNA.
So far in her project, Noelle has focused primarily on the freeze-drying conditions of the stratosphere when testing her “bugs.” The extreme low relative humidity is the first test she puts her bacteria to, because this is the first challenge the bacteria would have faced when they were first launched into the atmosphere from Earth. The next test for her bacteria will be high levels of UV radiation.
“We put the bacteria we have recovered in this desiccation chamber and we drop the relative humidity down to 18%, which is similar to what we have measured at our balloon altitudes,” Noelle said, pointing to a lab-bench see-through chamber full of a blue desiccant and petri-dishes with bright orange bacteria inside. “I’m trying to determine how long a bug I isolated from the stratosphere can remain viable under these conditions.”
Noelle has found that while some of her bacteria are wimps, others can survive extremely low relative humidity conditions, or with almost no water, for more than 14 days. What’s even stranger is that some of them survive these conditions without creating endospores, tough shells that some bacteria are able to retreat into when under stress. In fact, the bacteria Noelle has found in the upper atmosphere, which represent a surprisingly wide range of genera and are closely related to soil bacteria and other commonly known bacteria.
“These are microorganisms that we already knew about, but we didn’t know they could do this,” Noelle said. But if these common bacteria can survive the extreme conditions of the stratosphere, that’s potentially a problem for Mars expeditions.
“Things that go to Mars right now aren’t sterile,” Noelle said. “They are dirty. We are putting bacteria from Earth on Mars. The argument is that they won’t survive for long. But what if we have some of these Earth bugs that are exceptionally hardy, and they don’t die? Then you’ve got something to worry about, especially if you are sending up a life detection mission. The whole point is to determine if there is life on Mars. But if you are sending up something covered with Earth microorganisms, you need to be able to distinguish between them and potential Mars microbes.”
Prior research has mostly consisted of one-shot experiments that failed to quantify bacteria at altitudes above cloud-level.
“There is no previously published data [on concentrations of microorganisms] above 10 kilometers,” Noelle said. “We are really traversing into unknown territory. And nobody has done this quantitatively, or with repeated measures. That’s what we wanted to do, to set ourselves apart. We wanted to be able to definitively show that the microorganisms we recovered at these altitudes were legitimate stratospheric organisms. So we went forth, and we did that.”
The MARSLIFE project research is unique in quantifying or determining the concentrations of bacteria present at these high altitudes. One of the reasons for doing this is because environmental conditions including pressure, temperature and radiation levels at altitudes more than 100,000 feet above Earth are similar to the conditions on the surface of Mars. If bacteria from Earth can survive stratospheric conditions for long periods of time, not only could they journey to Mars on our spacecraft, but this could be a positive sign for the potential of bacterial life on Mars.
“In the search for life beyond Earth, we need to better understand the limits of life within those environments where life presently exists on Earth,” Christner said. “Studying microbial durability in Earth’s stratosphere is aiding efforts to define the boundaries that limit life as we know it.”
“Finding viable organisms in the stratosphere will provide insight to the possibility of life beyond Earth.” – Noelle Bryan, LSU, MARSLIFE project
“The combination of relative humidity, temperature, pressure and UV fluence conditions in the stratosphere is not available anywhere else on the surface of Earth,” Noelle said. “So this is a really unique place to find a very clear analogue to Mars.”
For more information on the MARSLIFE project, visit http://laspace.lsu.edu/marslife/.